New bivalent Covid vaccine

We are no strangers to new vaccines - over the past couple of years, several have been manufactured and millions of doses administered to help us build immunity to SARS-CoV-2, the virus that causes COVID-19. But while our vaccines have remained the same since the start of the pandemic, the coronavirus causing it has not. We have seen variants sweep through populations causing spikes in infection before another one inevitably seems to take hold. The most recent variant - omicron - has been responsible for the uptick in cases we have seen over the past month or so in the UK. But now, a new vaccine, made by Moderna, has just been approved for use in the UK, and this one has had an update. Here to tell us more is Mary Ramsay from the UK Health Security Agency…

Mary - So the vaccine is very similar to the previous one. And the way these vaccines work is by triggering your body to make a protein. That protein is what's acting as the vaccine, the original vaccine by Moderna made you make a spike protein, which is the protein that's thought to be important for protection against COVID. And that protein was from the original strain that was identified in Wuhan. But this new vaccine has two components. Half of it is the old vaccine, and it makes your body make that original spike protein, and the other half helps you to make the protein that is the one from Omicron, which is a slightly different form of the same spike protein. So the vaccine really is very, very similar apart from the fact that you get two boosts to your immunity, one against the Wuhan strain and one against the Omicron strain.

James - Is there anything to suggest that by engineering this new bivalent vaccine, one which is effective against both the original variant and the omicron variant of the virus, you're compensating on the effectiveness against one of the variants in order to have better protection across the board?

Mary - No, not really. They compared the immune responses against a range of variants, but against the original one, you've got a really good boost. Obviously, most people who will be having this vaccine have already had several doses of the original vaccine. So they boosted very well to that. So that gave them high levels against that, but actually slightly higher than you saw with a normal vaccine. And then on a top of that, they got this additional boost against the Omicron BA. 1 strain, which was the first omicron strain to emerge. So actually, we're getting better and broader immunity with each element of the vaccine.

James - You mentioned some of the success that you've had in some trials. So when will this be available? And for who?

Mary - I think the UK has bought a lot of this vaccine, and we're also working with Pfizer who are doing a similar process. So we're expecting to have both of those vaccines available if the Pfizer one gets approved, or the Moderna one is the first one to be approved. We hope that the Moderna and probably the Pfizer are going to be available this winter. So we're hoping that a good proportion of the winter programme will be with these variant vaccines. However, it's possible, certainly in the early stages, if we only have one vaccine, there will be perhaps not be enough to do everyone. And I think the basic message we need to get over is that even the old form of the vaccine does give you a very good boost. It gives you a very good boost against Wuhan strain, the original strain, but also against the Omicron strain and against other strains. And actually, as you know, we are not going to know which strain is circulating this winter until we get there. So the real important message is to have the vaccine on time, because either booster is better than no booster. I'm hoping that most people will be able to get the offer of the bivalent vaccine, but the other vaccine is still very, very good. And boosting your immunity will give you protection against the more severe forms of disease, whatever strain comes in.

James - And Mary, are there other vaccines being adapted to combat variants of concern.

Mary - Both of those manufacturers are able to twist the technology to introduce other variants. And I know they are looking at other potential variants to include in the vaccine. And then some other manufacturers are using different approaches. Some, companies have used what we call adjuvants. So these are additional elements in the vaccine that help to boost the immune response above and beyond the protein itself. And they may help to broaden the immunity. And obviously the holy grail is to have something that has very broad protection. And obviously the vaccine manufacturers are working all the time to see what they can do. But I think the most likely, in the short term, is to have different forms of the same kind of vaccines, but maybe directed against different variants. And maybe by putting more than one together, we're hoping that you get a broader response that will cover a wider range of whatever variant might emerge over the season.