Preventing HIV with PrEP

21 February 2017
Presented by Chris Smith, Kat Arney.

This week, we investigate the HIV preventative measure PrEP, which could be turning the tide on new infection rates - but is it safe to buy online? Plus, the toughest ever spider's web, a journey back through the history of language and the plant that could help clean up our oceans.

In this episode


00:55 - Seagrasses clean up polluted waters

Could seagrass hold the key to cleaning up our oceans?

Seagrasses clean up polluted waters
with Drew Harvell, Cornell University

For years we’ve abused the oceans and used them as dumping grounds for everything from plastics and chemicals to industrial waste and even raw sewage. This is having a devastating effect in some areas by causing bacteria to thrive, which is killing off fish and corals and also increasing the odds of humans becoming unwell. Now scientists have discovered that the sea may have its own solution in the shape of seagrasses, which come with their own inbuilt water cleansing system. Drew Harvell, from Cornell University spoke to Chris Smith about these mysterious plants...

Drew - Seagrasses are flowering plants so just like our grasses on land they have little flowers and they produce seeds which are then sexually produced and start new plants. They also can clonally produce so vast meadows can spread really quite quickly. Seagrass beds are the base of the food chain in the ocean. They provide critical nursery areas for baby fishes, and forage fishes which are big fishes like salmon and even killer whales eat. They also do a lot of filtering of coastal pollution and even absorb carbon dioxide. So seagrass meadows are considered a source of what we call blue carbon in a sense they can absorb a lot of carbon dioxide and potentially mitigate ocean warming impacts.

Chris - What have you been asking in this present study about seagrasses?

Drew - In this study we wanted to focus on the filtration services of seagrass and their capability to reduce bacteria in the water in areas where there was very high sewage pollution. We worked on these four islands in Indonesia that were very large sources of sewage pollution and we examined how the levels of bacteria changed as the water passed over the seagrass beds. This was done by my post-doc, Joleah Lamb, in collaboration with Indonesian scientists that we’d been working with and they both studied particular species of bacteria which is the one that we in the United States use for testing the quality of our waters (the enterococcus). And then when they found a large impact of the Enterococcus, they went and completely sequenced all of the bacteria in the water and showed large reductions in multiple pathogens that could affect humans as well as fishes and invertebrates.

Chris - So, in a nutshell, where you see seagrass you see fewer nasty bacteria?

Drew - Exactly. There’s a big difference in the levels of bacteria that have passed over the seagrasses. So we think of them as a possible mitigation for sewage pollution or a way to make the water cleaner and healthier.

Chris - How much of a difference was there in terms of the bacterial burden in the water when you compare areas that have got a lot of seagrass with those that haven’t?

Drew - At some of these sites there were levels of potentially pathogenic marine bacteria that impact human, fishes, and invertebrates that were reduced by 50 percent when the seagrass meadows were present compared to sites without seagrass meadows.

Chris - How do you think the seagrass is doing that then?

Drew - that’s really one of the exciting frontiers for our future work. We’re very excited to work out what are called the mechanisms by which seagrass are removing bacteria. One possibility is that a lot of the animals that live in the seagrass, such as the clams, the bivalves, the sponges are filter feeders and they’re directly sucking up bacteria for themselves. But we also think that the seagrasses can detoxify or remove the bacteria. For example, seagrasses produce oxygen and a lot of these bacteria can’t live with oxygen and so that’s an important mechanism of detoxification. And then finally, there are the microbiome of the seagrass, the bacteria that live on the surface of the seagrass, can also kill the bacteria. So there are a range of these different mechanisms that we’re investigating.

Chris - Do you think then, that it might be worth probing seagrass to see how they’re doing this and whether there might be some potential untapped resources in there that we could use for making human’s healthier? We know that we’re facing an antibiotic apocalypse where there are just not drugs for some of these infections any more. Do you think seagrass might have lurking in it a solution?

Drew - Oh that’s such a great question. There’s so much potential for innovation in the way that we deal with our pathogen bacteria in our society and, of course, we should be looking to natural sources like the oceans and seagrasses. So yes, for example, there’s a bacterium that lives on seagrasses that kills harmful algal blooms so likely there are some bacteria that live on seagrasses that could also kill other bacteria. So that’s a very exciting frontier for discovery.

Passenger drone

06:03 - Would you ride a drone to work?

A trial for a passenger drone was announced in Dubai this week, but how would it work?

Would you ride a drone to work?
with Peter Cowley

Dubai announced trials this week of a drone with a difference - it’s designed to carry a person around! It’s scheduled to begin operating in July. But how will it work, and is this the future of travel? Techspert Peter Cowley spoke to Kat Arney about how this drone would work.

Peter - Well it is, obviously, bigger than the ones you’ve seen. You can actually get vertical takeoff drones effectively using propellers that will carry over 200 kilos now so all it’s to do with is the amount of power. Effectively this drone is a helicopter, isn’t it? And helicopters can carry very much more than that. This drone will, apparently carry 100 kilos for 23 minutes at about 60/70 miles an hour and then, after a 2 hour charge, can do it again. So certainly, there is the engineering capability to build these.

Kat - So the next big question, obviously, is this sounds like the commuter solution of choice. Who would actually pilot this thing and how does it not crash presumably if there’s other drones around?

Peter - Exactly, yes. In fact, other people are working on ones with pilots but, of course, the whole point of this one is that there isn’t a pilot so you don’t need to know how to fly. The idea is it’s autonomous so that it takes off from a certain point programmed into a map and it lands somewhere else. Apparently you can press a button to cause an emergency hover but, of course, that would be frightening just sitting there.

Kat - Getting stuck on a ferris wheel’s bad enough.

Peter - Apparently there’s a sensor so if something goes wrong they’ll take it over but, otherwise, it’s automatic. Like any device, whether it’s autonomous car which is coming up, there’ll be loads and loads of sensors avoiding buildings. It’s actually easier in many ways to be safe in three dimension than it is two dimensions because it’s a lot less cluttered.

Kat - So you can go up and over any problems that you see in your way?

Peter - Correct. That’s the idea exactly.

Kat - I guess this is building on the robotic transport we have now. There are tube lines in London that are, effectively, drive themselves. Not that many people know that.

Peter - Yes, that’s right. The operator there is just opening the doors say on the Dockland Light Railway. You still need a human on there. The Gatwick and Stansted expresses are driverless completely but, of course, that’s a very short line. There was actually, a few years ago, a twenty seater jet flew 500 miles in the UK with the pilot on the ground. But, in this case, it’s autonomous.

Kat - The really big question is: is this safe and also, is it legal, but is it safe?

Peter - Well the legal bit - who knows. I had a quick check of the Dubai rules and they’re pretty similar to the UK and US rules which means you do need a pilot. Is it safe? Apparently they’ve got eight propellers and they say that four’s enough - who knows. And, in fact, I’ve looked on various websites and I can’t find one where they’re demonstrating it with a human inside it. Would I fly in it? Probably not from this Chinese company but if one of the big - say BMW or something - produced one two or three years after people have been using it, I’m sure I would.

Kat - The thing is that we see these incredible ideas. Amazon are going to start delivering things that you’ve ordered online. There are now food delivery drones that will go round at street level. Is any of this really practical or this just a marketing stunt?

Peter - No. In this case this is just probably marketing this first one, but it’s definitely the future. There’s no doubt we will end up with flying vehicles doing things, whether it’s delivering parcels, pizzas, or people really. So yes, there’s a whole load of legislative changes, a whole load of societal changes that people will accept it but, give it a few years and they will gradually come in. If you move forward a decade or two, I’m sure we’ll have the future science fiction films that we’ve seen for many years starting to appear - those sort of vehicles.

Kat - This is the sort of thing that we’ve talked before on the programme about when we've talked about cyber security, the internet of things, that there is a problem with the legislation not keeping up with the technology. Are people in transport departments in government really starting to think seriously about this?

Peter - They are, all over the place. Some of the states are more advanced than other ones and I suspect Dubai because it’s very, very advanced. They’ve got off the reliance on oil over the last 30 years or so. Everybody’s working on this. Of course there's some push back and there's only going to be the early adopters who’ll use it but there is a lot of discussion. The big one, of course, is artificial intelligence and robots. How is that going to affect our roles in life? How are we going to occupy our time in 30 years time if it’s all being done by a soft or a hardware robot?

11:08 - Deadly spider's web could make safer space travel

One of America's most hated spiders isn't all bad: its web could teach us to make much tougher materials.

Deadly spider's web could make safer space travel
with Hannes Schniepp, The College of William and Mary in Virginia

Spiders: feared by some, their silk is nevertheless about 5 times stronger than steel, making them very interesting in our quest to engineer cheap, strong materials. This week, scientists have put one of America’s most dangerous spiders under the microscope to discover the secret of how it makes its particularly strong web. They discovered that, by adding little loops, it can make a strong and stretchy material that’s much less likely to break under under stress. Using the same technique, we could engineer super tough, flexible materials in the future. Georgia Mills spoke to Hannes Schniepp from The College of William and Mary in Virginia...

Hannes - The specific spider we’re working with is the brown recluse spider, which is actually quite infamous in the United States because it has a very bad bite and it has a quite dangerous venom. So a lot of people in the United States know about the brown recluse spider but we’d actually like to feature some of it’s really interesting properties. The silk of most spiders they’re really cylindrical just like a hair, but the silk of the brown recluse spider, if you look at it under the microscope,it just looks like a piece of sticky tape. This flat ribbon shape allows the spider to take this silk and form it into loops and these loops make the material extraordinarily tough, and that makes it a better material for the spider in order to capture prey.

Georgia - Why would loops make it tougher?

Hannes - Yeah. That’s really the very interesting thing and very puzzling. What actually happens is that first of all because the silk is so sticky these loops that the spider makes, they’re closed loops and they have relatively strong loop junctions or joints. And if you start pulling on the material, at some point these loops can actually open and release some additional links of the material. So that means you start stretching the material, and as soon as you reach the critical force that’s required to open one of the loops, the link that’s stored in this loop is released and then the silk fibre is relaxed a little bit. Then you stretch it again until the next loop opens and so on and so on, and in the process you stretch and release the material many, many times and that is something that takes a lot of energy, and that’s what we material scientists call ‘toughness.’

Georgia - Oh wow! So then the poor fly, or whatever it is they eat, it’s got so many loops to break as it were. It’s just going to take too much energy to actually cut through one of these fibres.

Hannes - That is correct. Isn't that absolutely fascinating? We sometimes think of it as the ultimate barbed wire. So you have an incredibly sticky material which is, at the same time, also one of the strongest materials that we have. So if a poor little creature gets stuck in there there’s no way out.

Georgia - Oh dear! Can we take this? What kind of applications could this tough material have?

Hannes - For instance, if you think like if you're jumping down and you wear a parachute, and you want to open the parachute and, at the moment, when you open there’s an enormous amount force that goes into the cord that holds the parachute. So there we could use a material that has such loops built in to make it a little bit more stretchier and better at absorbing the energy without breaking.

We’ve also thought about to protect structures from impact - let’s say weapons - that might be useful, or you could think about if you have a structure in space where you have space debris or micro meteorites flying around at very high velocities. You could think about making a web of such material around these structures to protect them from such high energy objects.

Georgia - I love that image of a spider’s web in space hoovering up all the meteors and things. Spider’s silk is incredible but it is, as you mentioned, tiny. Do you think it’s going to be feasible to scale this up to such an extent that it’s actually useful to us?

Hannes - Well, in a way, we actually scaled this up and because we were so fascinated by this we thought wow, is this real because it’s so surprising that this works. We also developed mathematical models to simulate the kind of energy gains that we would get from a material like this. And the first thing we did was we just went to the drawer in our lab and took a piece of sticky tape and then we just manually put a loop into the sticky tape, and then we tested this tape as you test any material. We put it in a mechanical tester and we measured the energy that it takes to break this material and we indeed found out that, even with one single loop, we increased the energy that this can absorb by about 30 percent, which is totally in line with our predictions. So that means if we find out a way to have many loops in there we could actually increase the toughness, or the ability of the material to absorb energy tremendously. And with this simple example, you can see it does not necessarily have to be at the micro or nano scale to make this work.

Creepy hand

Can we trust Hollywood when it comes to psychopaths?

Graihagh Jackson has been enjoying some fava beans and nice chianti while looking into this week's myth-conception.

Graihagh- There’s a particularly chilling scene in a film which has always stuck with me: Hannibal Lector sauteing the pre-frontal lobe of Paul Krendler’s brain in white wine and shallots. In my eyes, Hannibal the cannibal is the ultimate villain because:

He’s exceptionally skilled at killing people and feels no remorse or empathy. Ergo, you can’t barter your way out of this one.
He always has this creepy, calm demeanour - he’s never unnerved or unhinged despite the enormity of what’s he’s doing.
He has this distinguished career, further veiling his ability to eat people.
Oh, not to mention, he’s highly intelligent and can outsmart everyone in the FBI.

A plus b plus c plus d = once Hannibal’s got his eye on you, you’re toast, possibly served with a side of quince jelly. The idea that psychopaths like Hannibal exist is terrifying and even more so given the fact that some some scientists think they make up 1% of the population. Think about how many people you’ve met over your life - statistically, you’re likely to have met a few - that guy you met at some networking event, your highly manipulative ex-girlfriend and - depending on how much you like your job - your boss.

The thing is - a meta analysis that looked at 187 papers charting psychopathy and intelligence found no evidence that psychopaths are smarter than the average person. The study looked at those with esteemed careers as well as those in prison and do you know what they found?

Psychopaths, in fact, scored ‘significantly’ below average on intelligence tests. And a similar study published in 2011 in Journal of Psychopathology and Behavioral Assessment found the same.

I know what you’re wondering, given you can’t trust Hollywood’s depictions of psychopaths, it would be good to know what psychopathy is…

It’s a personality disorder and because of that, it falls on a spectrum - like age and height - and is commonly diagnosed using a 20-part checklist called the Hare Psychopathy Checklist-Revised. In the States, if you score 30 out of 40, you’re deemed a psychopath, in the UK, the cut off is 25.

It measures a number of traits, which includes things like callousness, insincerity, selfishness, an inability to accept responsibility for one’s actions or plan for the future, overconfidence, impulsivity and violence.

Turn all those traits up to maximum - like sliding up all the inputs on our mixing desk in the studio - and you’re a psychopath. However, turn up a few and you may have psychopathic traits, but it doesn’t make you a psychopath and what’s more is that some researchers from Oxford University have found you actually may be more successful if you have some of these traits.
The Wisdom of Psychopaths: What Saints, Spies and Serial Killers Can Teach Us About Success by Kevin Dutton

Those diagnosed as a psychopath rather than simply having some of the traits, commonly have a different brain structure with deficiencies in the amygdala and the orbitofrontal cortex - these two areas are associated with emotions and decision making. Interestingly, scientists aren’t sure whether psychopaths don’t experience emotions at all or whether they can but then cannot use that information later on when making a decision.

Which makes sense if you think back to the long list of traits before - the callousness, the selfishness, the inability to plan for the future, overconfident, manipulative, cunning etc. And whilst some of these may appear to make psychopaths seem clever, statistically speaking, they’re not. It’s a facade, which means if Hannibal the cannibal does break through our tv screens into reality, you can rest assured it’s unlikely he’ll be able to outsmart the FBI forever.

20:24 - How does language change through time?

How does language change throughout time, and how did it begin in the first place?

How does language change through time?
with Claire Dembry, Cambridge University Press; Mirjana Bosik

The British National Corpus is a collection of over 100 million words from samples of written and spoken English. However, 90% of it is written down, which limits what we can do with it. So, two years ago, a collaboration between Cambridge University Press and Lancaster University set about bringing the corpus into the 21st century. Emma Sackville heard how from Cambridge University Press’ Senior Language Research Manager, Dr. Claire Dembry…

Claire - Typically, when we recorded people’s conversations in the past you would have a massive tape recorder, and you’d put it on the table, and press the button, and they’d usually be somebody else there, kind of like this so that the conversation was, typically a bit self conscious. So what we did was ask people to make recordings on their smartphones or their tablet or whatever. The kind of became part of the conversation; people didn’t really realise that they were being recorded. So that’s meant that the recordings that we’ve gathered are really natural so we’ve got all kinds of really interesting topics.

Emma - So what have been some of the applications? What are you collecting this data for?

Claire - Here at Cambridge University Press we’re really interested in language teaching so we want to know that we’re teaching learners the best stuff. The things that are the most useful. More widely though, the whole of the data set will be publically available to any researcher and there’s so many, I think, fascinating questions we can ask. Also, one thing I think is really nice is that someone had prompted you with a question - how do you feel about the environment? You’ll say oh I’m very concerned about the environment. But because this is a free, unprompted collection of language, what we can also see is the topics that people are interested in. So there’s a wider social implications as well.

Emma - What have been the main or most surprising trends or differences in words?

Claire - Initially we had quite a lighthearted look at stuff. So we were interested in which words have gone up in frequency, which words had gone down. So we talk about tea almost exactly the same amount as we used to before - obviously it’s a massive concern. We looked at the word “love.” In the 90s we find that people loved their family, and their brothers, and their mum. And in our recent collection people love handbags, and cheese…

Emma - That’s kinda sad!

Claire - But language changes. And really what we’re saying there is that the word love is used differently. So that’s a nice example that reflects how language has changed.

Emma - So even in 25 years there’s been a pretty big difference in how we use language which got me thinking would we be able to recognise language from the 90s even if we might cringe at the hair in fashion.

And for suth my dear friends we can work out the words in a merry eve of Shakespeare.

But if we went really far back would we be able to understand english? And, if it comes to it, where did language even come from in the first place?

Mirjana - My name is Mirjana Boskik. I’m a university lecturer and I do research in the field of aspects of language comprehension.

Emma - How do we process language in the brain?

Mirjana - The current view is that there are two joint but functionally instinct networks. So one being bi-hemispheric networks, both left and right hemispheres that is the network for essentially basic comprehension so mapping sound to meaning. And then on top of that we have the left hemisphere network that seems to be dealing with specifically grammatical aspects of that sentence.

Emma - Is it that grammar side of things that makes humans distinct from animals because, obviously all animals do sort of communicate?

Mirjana - Yes, that is one of the current ways of thinking about it. Human language allows us to express pretty much anything. We can express past, and future, and possibility and that has not been observed in any other animal species.

Emma - Do we know when that ability evolved?

Mirjana - In short.... No. There was lots of speculation on this and one of the ideas is that something probably to do with tool usage. That the use of complex tools would be something that would require complex thinking allowing or triggering language. We know that in humans there is a white matter tract that links from tool to temporal regions in the left hemisphere that is really necessary for language comprehension. Comparing the consistency of those white matter tracts in humans versus chimps or macaques shows that this is much more prominent in humans.

Emma - If we were to go back in time, would we be able to understand the language that our ancestors were speaking?

Mirjana - I suppose it’s a question of how far back you go. I was looking up for English for instance, you would probably be able to understand language from 1500 or so but not language from the 5th century. So languages are going to evolve and develop over time. There are going to be different influences that are feeding in and then shaping how a particular language ends up looking. It’s a continuous process of development, obviously. But I think in the case of the english language, you would not be able to understand Old English, so what’s being spoken in the 7th century.

Emma - So some words might come and go and we might never find out exactly how language started. But there’s one thing we know for certain - the British will always be talking about tea!

26:31 - Getting diagnosed with HIV

The story of one man's experience of being diagnosed with HIV.

Getting diagnosed with HIV
with Greg Owen

According to the WHO, 36.7 million people around the world were living with HIV - human immunodeficiency virus - the agent that causes AIDS - at the end of 2015. And while rates of HIV are greatest in Sub-Saharan Africa, it is still a global problem. In fact, the UK has had one of the highest rates of new HIV diagnosis in western Europe, particularly in London, and rates of new diagnosis had been steadily rising… until last year. Preliminary data from several clinics across London show, on average, a 40% drop in new diagnoses over the last year. And HIV specialists think this could be down to a procedure called PrEP, short for “pre-exposure prophylaxis”. This is where uninfected individuals take anti-HIV medication - which many people are currently obtaining online - to reduce the chances of them becoming infected if they do come into contact with the virus. Greg Owen was diagnosed with HIV 18 months ago. He told Graihagh Jackson his story...

Greg - I was in a 7 year relationship and engaged to be married to my ex-fiance and came out of that relationship at the start of 2013, and I was flung into a scene that I wasn’t familiar with when I went into that relationship. There were no hookups, there were no chemsex parties, it was a very different set-up in London as to the world I find myself in.

Graihagh - Sorry, what’s chemsex?

Greg - Oh yeah. Chemsex is the use of party drugs closely associated with sexual behaviour where they pretty much go hand in hand. It’s three specific drugs, it would be mephedrone, crystal meth, and GHB and can be an extensive period of maybe one night into two or three days long of partying and sex.

Graihagh - Blimey. So you came out of a 7 year relationship into this. How was that?

Greg - It was not nice. My ex-fiance - our relationship actually disintegrated because he was diagnosed as HIV positive. For him it was pretty much the end of his life as he knew it and our relationship as it existed and he fell apart. So for me, I was experiencing quite a lot of emotional trauma and significant life changes because of that and a lot of distress. That, coupled with the fact that I was flung onto a scene that I was very, very unaware and unprepared to deal with. For the first year I was very much, because of me ex’s experience, I was very much adherent to condoms.

But then the second year I think what happened was I hit what I would call a double dip depression. So I kind of got clear of the initial trauma but then the reality of what my life was then and how drastically different it was and it was a complete upheaval. I didn’t just lose my fiance, I lost my flat, my cat, I couldn’t go to work, I wasn’t functioning properly and, as a result of that, my sexual risk taking and my behaviour changed. It started to come out of that dip of depression and started to assess where I was with my life and my sexual behaviour, and just kind of socially where I was, and what I was doing, and emotionally too.

I thought I’m probably not going to be able to address behaviours at the moment but what I can do is maybe think about PrEP. Then I go to Dean Street the next day to have a HIV test just to confirm that I’m definitely negative because I tested negative about 12 months before, so I could definitely start PrEP safely. And 20 minutes after arriving at the clinic I was in the consultation room, and I have a fingerprint test and two dots came up so it was a HIV positive diagnosis. So the irony of eventually managing to get a hold of PreP, and to start that having finally decided that this was the right option for me and I was going to start being proactive and responsible, to then have just missed the boat was a little bit mind blowing to be honest.

Graihagh - What went through your mind when you saw those two dots?

Greg - Since my ex’s diagnosis I’d been actively campaigning, as a HIV negative person, trying to dispel some of the myths and deconstruct some of the stigma around HIV. And I just sort of had a really bizarre, strange moment of pure clarity and I thought you know what, now is the time to put my money where my mouth is. Now I’m going to tell 8,000 people on social media that I got a HIV positive diagnosis.

Graihagh - What was the reception you got from people?

Greg - I think I had, within two or three hours, 350 likes and 175 comments, and then when I opened my messaging inbox I had about 50 disclosures from people in my immediate network, in my extended network, and people who I’d never met. And I couldn’t beleive. I know this sounds really weird but even someone like me who was HIV aware and had worked very loosely on the periphery of HIV awareness and campaigning I was like oh, I never would have thought that person was HIV positive. It just goes to show we have a very strange perception of who gets HIV and who doesn’t and, in actual fact, HIV does not discriminate. Anyone who has sex can become HIV positive. So, for me, it was a very big learning curve but also, I think, I felt incredibly supported. Not one stigmatising, judgemental, moralising comment… nothing. And from that moment on I think that was all that I needed to just pull me into getting on with things.

Graihagh - Such a contrast to your ex’s experience isn’t it?

Greg - In my diagnosis that is because I detailed every emotion and every feeling and he swung into my mind that that this point we would have been split up about two and a half years. And he was very much in my thoughts and in my feelings I think. I had a failed suicide attempt at the end of 2013 because of the distress and the trauma that I was under. I had an experience from my ex and I was so confused by that. I was thinking I’d been a good gay, I was committed to this relationship, and I was invested in our future and he was my priority and our relationship took precedent over everything else. I’d done all the things I’m supposed to do and I’m meant to do. Why is this horrible thing happening to me? I couldn’t make sense of it.

But I’m incredibly grateful that I got through that experience and this suicide attempt failed because, in actual fact, when it came round and landed firmly on my doorstep, I was able to take learnings from that. And I have to say, if you experience something as painful as that at some point in your future, if you’re able to take something positive and are learning from it, it really does soften the sting that that leaves behind. So I am grateful for that experience.

If you have had thoughts of suicide, or need someone to talk to, please contact a regional helpline such as the Samaritans (UK) or LifeLine (Australia).


33:29 - What is the difference between HIV and AIDS?

What is HIV, how do you catch the infection, and what could be behind the recent reduction in cases?

What is the difference between HIV and AIDS?
with Laura Waters, Mortimer Market Centre, London

What is the distinction between HIV and AIDS, and what might be behind the recent reduction in new infections? Chris Smith was joined by Laura Waters from Mortimer Market Centre, a sexual health clinic in London.

Laura - HIV is a virus. It’s an infectious particle. It stands for Human Immunodeficiency Virus and it’s an infection that’s spread primarily through sex and it enters the body and it targets a type of white blood cell. White blood cells are cells in the body that are responsible for fighting infection. It enters a particular type of white blood cell called a CD4 cell and the best way to describe these cells really is that they’re like the conductors of an orchestra. If you whole immune system, which is lots of types of cells and proteins and chemicals is an orchestra, the CD4 cell’s a conductor.

Now HIV enters these cells and it uses the cells to replicate itself but destroys them in that process and, over time, it greatly damages the immune system leaving somebody susceptible to serious infections. Symptoms like diarrhoea, weight loss and particular types of cancers, and it’s that constellation of conditions that is AIDS (Acquired Immune Deficiency Syndrome). Many people with HIV never develop AIDS because we diagnose it, and treat it before the immune system can be damaged enough to allow AIDS conditions to take hold.

Chris - How long generally elapses between a person acquiring the infection and then developing those symptoms of AIDS assuming that they don’t get diagnosed and treated?

Laura - How long it takes someone to develop AIDS will vary, and it depends mainly on that individual's immune system which is governed mainly by their own genetics. So it can be anything from two or three years through to ten, fifteen, or even years. There’s a small proportion of people who actually keep the virus under control and remain quite healthy for decades but, on average, it will typically be between five and ten years after getting the infection that people start to get sick.

Chris - If HIV is an infection of the blood stream and it’s harboured by immune cells in the blood stream, how does it come to be transmitted through sexual activity?

Laura - The virus itself, although it replicates inside immune cells, it basically travels around every body fluid. It gets into every single part of the body. You can find it spinal fluid, you find it in blood, you find it in the gut, and you find it in sexual fluids as well. So you find it in semen, you find it in viginal fluids, and you find it in rectal fluids as well. So, although it’s replicating in the immune cells, it’s floating around the body everywhere.

Chris - When a person becomes infected, how would they know?

Laura - When people first get infected, it’s a viral illness like any other viral illness so many people develop non-specific viral symptoms: fevers, rash, high temperatures, enlarged lymph glands. But this may be dismissed as just a viral illness which, in many ways, is correct, it’s just that no-one’s thought to test for HIV. At least half of people will have something that, when they look back, was a significant more severe than usual viral flu-like illness. Then, typically, there’ll be no symptoms at all until the manifestations of a damaged immune system start to become apparent.

Chris - If a person does suspect they might have contracted it and they come to a clinic like yours, how do you diagnose it?

Laura - It depends on timing. Most clinics now use point of care tests - that’s a finger prick or saliva test where you get an immediate result. But most of those tests use slightly older technology so it can take up to 12 weeks for a test to show up as positive. So if someone was infected today, with some of those point of care tests, it could be three months later before that shows up on those tests.

If somebody has suspected early HIV, so they have symptoms consistent with early HIV, they’ve had a risk exposure to HIV, then we do a standard blood test where you take blood from a vein in the arm. That’s sent to the lab where we do more detailed tests and more sensitive tests and those will show up positive for most people within four weeks.

Chris - Your clinic is one of the centres that seen a very dramatic reduction in the numbers of cases being diagnosed. Put some numbers on it for us and also tell us why you think that is?

Laura - Our clinic, the Mortimer Market Centre, has collected data along with three other big central London clinics, and that’s 56 Dean Street, Homerton, and Barts Health and we all saw a 40 per cent reduction in new HIV cases in 2016 compared to 2015. Why we think that is is a number of reasons. Now the reason that’s being most discussed is the advent of Pre-exposure Prophylaxis or PreP, so taking HIV drugs before an exposure to reduce the risk of getting HIV and it’s thought that that’s led to this sudden, dramatic downturn in new diagnoses.

Other important factors are the fact that we have fewer and fewer undiagnosed people. We know in gay men who are the biggest risk group for new HIV in the UK, most infections come from people who don’t know they have the virus, so these are undiagnosed people who are responsible for transmitting most of the new virus onwards. And, actually, the undiagnosed proportion has come down so now only 13 percent of people with HIV in the UK are estimated to not know their status. Now that’s still too high but it’s the lowest it's been in some time. So by testing and knowing your status you are less likely to pass the virus on to somebody else.

The other important factor is treatment. People with HIV who are on treatment have a zero, or close to zero chance of passing the virus on to sexual partners. About 94 per cent of people with HIV are on treatment and undetectable. So it’s a combination of PrEP, better diagnosis, and the fact that people with HIV are on treatment that keeps the virus suppressed and means the risk of passing it on is very, very, very, low...


39:58 - How does PrEP stop new HIV infections?

How does PrEP work, and is it really behind the reduction in HIV cases?

How does PrEP stop new HIV infections?
with Sheena McCormack from University College London

There's an HIV prevention measure called PrEP that looks like it could be responsible for a huge decline new infections, but how does it work? Sheena McCormack from the University College London conducted the PROUD study investigating the effects this drug could have, and she spoke to Kat Arney...

Sheena - PrEP stand for Preexposure prophylaxis, and prophylaxis is prevention, and preexposure is self-explanatory. So it’s a prevention you take in advance of being exposed to HIV and we are, as Chris mentioned, using antiretroviral drugs and anti-HIV drugs as PrEP. There is only one drug at the moment that’s licensed for use as PrEP and that’s a drug called Truvada and it does exactly what Laura explained, it stops HIV multiplying and that gives the body a chance to get rid of the infected cells when they’re caught in sexual fluids. So that’s how it works.

Kat - What are the side effects?

Sheena - We’ve used the drug for treatment for a long, long time so we are already quite familiar with the side effects and it actually very, very well tolerated. Only about 5 or 10 percent of people will ask to change that drug and they tend to be indigestion side effects very early on. The only side effects, I guess, we worry about in people who are taking the drug who have HIV are the longer term side effects in kidneys and potentially reducing bone density. But PrEP is something that we anticipate will take for a much shorter period of time. A sort of period of time like Greg explained when behaviours just change in that period before somebody can get things together again. It’s very unlikely that there are going to be side effects that really matter with shorter term exposure.

Kat - What did you find in your study when you were looking at the effects of this drug and what were you doing there?

Sheena - Our study was a bid different to the ones that had gone before. There’d been a study in gay men before that finished in 2010. They compared the PrEP drug Truvada to a dummy pill (placebo), and they showed a 44 percent reduction in HIV which is very exciting, but that is only partial protection. Something we were worried about in the broad community in the UK was if you gave people a pill that partially protected them, might it mean they then would abandon all other methods to reduce HIV infection, including condoms. If you threw away the condoms, maybe 44 percent would drop to 20 percent.

So we had to do a study a different way where we had a control group that knew they weren’t on PrEP, and a group who were on Prep who knew they were. So we randomised people to get PrEP straight away in the first year or to get it for the second year after a year of no PrEP, and that gave us the chance to compare PrEP to no PrEP. What we found, to our surprise, two things. First of all the rate of HIV was much, much higher than we expected in those not on PrEP. It was 9 percent per year and that is like 18 times higher than the general gay population, and PrEP reduced HIV by 86 percent. So much better than the dummy pill trial.

Kat - So, as you say, it’s not complete protection, so this isn’t a chemical condom, is it? People can’t just take it and go “I’m fine for everything now - let’s party”?

Sheena - Well Kat, it’s funny, in our study we only saw three infections in PreP users and in all of those individuals the story sounded like the weren’t taking the drug at the time of exposure.

Kat - Although, obviously, HIV is not the only sexually transmitted infection that you can pick up.

Sheena - Exactly. It only protects you against HIV and it’s not absolutely perfect. I think it would be unreasonable to expect anything biological to give you absolutely perfect protection. But the number of breakthrough infections that we’ve seen with PrEP have only been a handful so far so it is extremely good biologically. But it still is going to depend on people taking it in a period of risk.

Kat - And as we heard from Greg he went to get tested so he could get it and then discovered he had HIV. Quite briefly, is there a risk that people won’t be able to get it because they are carrying the infection and then also giving it to people with the infection might get HIV strains that are resistant?

Sheena - The biggest risk of that if the virus is multiplying like mad. If you’ve got that acute infection that Laura was describing and you give a little bit of drug, then you do increase the chance of resistance developing. So we want to test people, obviously, and make sure we know their status before starting PrEP. But the chance of somebody coming on the day they are acutely infected is, actually, pretty low. And, I have to say, in the study we didn’t do that we gave PreP straight away and we didn’t really see problems with following that particular path.

PrEP t shirt

45:11 - Be PrEP-ared: buying anti-HIV drugs online

With PrEP drugs unavailable from National health services for many, some are taking matters into their own hands.

Be PrEP-ared: buying anti-HIV drugs online
with Will Nutland, London School of Hygiene and Tropical Medicine

The NHS will soon start trialling Truvada - the drug used in PrEP - on 10,000 people to see how might be best to roll out the PrEP programme. But, in the meantime, there are more than 655,000 gay and bisexual men in the UK - way more than the 10,000 places allotted. So, in the absence of a vaccine, men are taking matters into their own hands, as Graihagh Jackson found out...

Will - I’m Will Nutland and I’m the co-founder of and I’m also a social researcher at the London School of Hygiene and Tropical Medicine.

For people like me who want to start using PrEP right now, I have a couple of options. One of those options is to try and get a private prescription, so get a doctor to write a prescription for me but that would cost me in the region of about £400 a month so about £5,000 per year. The other option is that I could buy a generic formulation of PreP online that’s nine times cheaper than it would be for me to buy a private prescription.

Graihagh - And when you say generic, what do you mean?

Will - By generic PrEP, I mean exactly the same formulation of PrEP that is provided and manufactured by the drug company Gilead. Gilead have an international patent on the drug Truvada but, under international laws, countries are allowed to produce a generic formulation of drugs if that country has a particular health emergency or a health crisis and can’t afford to buy the patented form of that drug. So places like India, there are drug companies there that are producing exactly the same formulation of drug but on a generic formulation. And it’s perfectly legal in the UK for someone like me to buy that generic formulation of PrEP so long as it’s for personal use.

Graihagh - So it may be legal but it does sound kind of shady the fact that it has to go through a different countries to get through customs. Why is that?

Will -  Yes. Whenever we talk about people buying generic pills online of course it raises red flags for people. So that’s why are working in coalition with our sibling website “I want PrEP now” have worked together to put some safeguards in place and, broadly, we’re looking at three sets of safeguards. The first is that we’ve done test purchases to make sure that my debit card or my credit card isn’t getting ripped off when I go onto those websites. The second safeguard is to make sure that the drugs actually arrive at the address that we’ve been given. The third safeguard, and probably the most important safeguard, is to make sure that the drug I’m putting in my body is actually what it says on the bottle. I want to make sure that I am taking PrEP and it’s going to protect me against HIV rather than taking something that is a fake drug.

So colleagues at 56 Dean Street have now done more than 250 tests on different people who have been taking generic PreP and there’s absolutely no evidence that from this half a dozen websites that we’ve looked at that there’s any fake drug. So we are fairly confident, as confident as we can that people who are buying drugs from these featured websites are buying the real thing.

Graihagh - That’s really promising and really reassuring to know. But I wonder why you would prefer to use something like PrEP over other methods, say condoms?

Will - I think the question is: why would somebody want to take PrEP is a very interesting question. I’m a public health doctor, I’ve worked in  HIV prevention for more than twenty years. I’ve worked in some of the UK's leading HIV organisations and despite huge amounts of money and some fantastic work that’s been done to drive down HIV incidents in the UK, HIV incidence has been increasing for the last ten years or more. We know that condoms have been incredibly effective at reducing tens of thousands of HIV infections in the UK, but the strategies that have been used for the last five or ten or more years aren’t pushing HIV infections down across the whole of the population. I think what’s exciting about PrEP is that all the evidence is showing that if PrEP is highly targetted at those people who are most likely to be involved in HIV exposure, then not only will HIV be prevented in those individuals but if enough people start using PrEP, as a nation we can finally start to see HIV diagnosis going down. So, from my public health perspective, I think PrEP is hugely exciting in building up of the health of our nation.

Graihagh - But why do you personally prefer it?

Will - I’ve always lived with a sense of fear that I could become infected with HIV even when I am consistently using condoms. So for me, it allows me to have sex without fear, without anxiety and without stress and for lots of us we haven’t been able to do that for a very long time.

Graihagh - Do you think this is the ticket out?

Will - I don’t think PrEP on it’s own will be what leads to the eradication of HIV. I think PrEP, if it’s used in combination with continued condom use, with treatment as prevention. And by that I mean that people who are already infected with HIV are offered treatments to suppress their viral loads and, therefore, are unable to pass on HIV as soon as possible after diagnosis. If we make sure that there is good sexual health education across our nations, including good sex education in schools. If all of these things are combined together, then I think we have a really good chance of massively preventing new HIV infections.

But let us not forget that we already have about 100,000 people living with HIV across the Uk and it’s really important to make sure that their health is maintained and that those people are supported as people living with HIV.

Could PrEP turn the tide on HIV?
with Sheena McCormack and Laura Waters, Mortimer Market Centre

Chris Smith spoke to Sheena MacCormack and Laura Waters about how the NHS was justifying the cost of the drug, and whether PrEP might turn the tide on HIV.

Sheena - That, of course, is something the NHS looks at very closely with any new drugs that are being introduced and, actually, the cost effectiveness of PrEP is really clear in the long term - the usual economic time line of 80 years. But, inevitably, the NHS is pretty concerned about their budget in the short and medium term and what might have to be sacrificed to pay for anything new.

So the models that the NHS reviewed, the cost effectiveness models of PrEP, suggested the only way that the NHS could be really confident of PrEP being cost effective in the short term was if the price was reduced from its current list price, which is pretty high, because Truvada at the moment, of course, remains branded. But that branding will end shortly, we believe, and then there will be several versions of Truvada made by generic manufacturers. There will be competition and the price should be coming down.

Chris - Why is the NHS funding this at all? When we were researching this programme a number of people put it to us they were unwilling to come and talk about it for reasons known best to them. But they were saying why is the NHS funding this at all - what’s the justification? One person said “well, if I had a drinking hobby I wouldn’t expect the NHS to pay for me to have a taxi home to prevent me from drink-driving and potentially placing myself and others at risk. So why do we pay for this form of personal recreation and not another?”

Sheena - The NHS makes decisions very carefully on two characteristics: clinical effectiveness and cost-effectiveness. We’ve shown this drug is incredibly effective at preventing HIV, which is an extremely expensive infection to manage because it’s a tablet a day, or more, for a lifetime and potential complications through ageing with HIV that we perhaps haven’t fully anticipated yet. But HIV is very costly for the NHS so, obviously, if you can save HIV infection it makes sense.

And, as I mentioned before, PrEP is something that people would take for a short period to support them through behaviour change, just in the same way that that we support people that have alcohol dependency or drug dependency. We support them with talking therapy or other means through their behaviour change. That seems entirely appropriate. But the decisions are made on clinical effectiveness and cost effectiveness. It’s actually just as simple as that.

Chris - Looking beyond the shores of our own country for a minute. This is a global problem and the bulk of the problem sits in Africa. Therefore, situations like we have here and solutions like we’re looking at here probably are beyond the reach of those people?

Sheena - Well, you’d think so but, actually, PrEP is being rolled out in Kenya and South Africa, so there are PrEP programmes. In some cases they’re targeted at particular populations where the rates of HIV are extremely high and in others it’s a little bit more generalised, and you’re trying to take advantage of people’s motivation to help to help themselves. Whether that’s to come and get tested for HIV and to go onto treatment or to prevent themselves, as I say, during a risky period of their life.

Chris - Indeed. And Laura our last thoughts from you…

Laura - I think that PrEP, combined with other strategies, we really do have the opportunity now and I really do think that the figures that we’ve described in London, we’ve got the opportunity to really turn this around and eradicate new HIV in places like the UK. And I think the people who criticise PrEP who are concerned that why should we support people’s bad behaviour, there are many, many conditions that the NHS spends millions of pounds on that are driven by behavioural choices that others may not think the best, and Sheena has mentioned them: smoking, and drug use, and alcohol etc. And I think the days we start rationing or limiting people’s access to really effective prevention and effective treatment based on the behaviour they’ve taken part in is a really dangerous and slippery slope. So it works, HIV infections were going up and they seem to be coming down, and we should have access to PrEP on the NHS, without a doubt.

55:50 - QotW - Would a mirror in space show us our past?

Would a mirror lightyears away in space show us our planet's ancient history?

QotW - Would a mirror in space show us our past?

Graihagh Jackson answered David's cosmic question...

Graihagh - A million years ago, only very early species of humans had begun to evolve and much debates around what they were doing - like could they control fire, and did they have language?

By putting a mirror in space, could we find out? I put this to Cambridge’s Hannah
Harahan. First though, let’s just unpack this astronomical question. What is a light year?

Hannah - When we look up at the night sky, we’re actually seeing the stars as they were sometime in the past because the light that's reaching us from these stars today has left the stars possibly hundreds of thousands of years ago.

Graihagh - Does that mean then, if there are some aliens a million light years away and they happen to glance in Earth’s direction, they wouldn’t actually see us here talking, they’d see Earth a million years ago?

Hannah - Exactly.

Graihagh - That’s because the light took a million years to get there. That’s assuming they have light sensitive eyes and use them as we do.

Hannah - If we could magically put a mirror a million light years away in space then, in theory, if we were able to reflect an image of the Earth that we could see back on Earth, the light would have left the Earth two million years ago.

Graihagh - Okay David. It’s theoretically possible but there’s one big hitch here. We can barely image planets a hundred light years away, let alone if you times that distance by ten thousand. But the other thing to contend with is the mirror itself.

Hannah - The size of the mirror that we would need would be absolutely huge. I haven’t actually done the calculation but it is possible that the size of the mirror would be so big and it would be so massive that it could actually collapse to form a black hole. So it’s definitely not technically feasible at the moment but, in theory, we could look back into the past.

Graihagh - There you have it David. I hope that answers your question. Next week we’ll be getting our knickers in a twist over this…

Stephen - I always seem to go for a pee within thirty minutes of drinking a cup of tea. And when I’m using the toilet I often say to myself is that the same cup of tea I’m getting rid of? How much of that drink was absorbed into my body so if I go for a pee within an hour of drinking a cup is this the same liquid I’m getting rid of?

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