Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: Igor on 13/09/2006 17:24:38

Title: Lifetime probabllity of contracting Mumps?
Post by: Igor on 13/09/2006 17:24:38
Can anyone tell me what is the probability of contracting Mumps in ones entire life ? (living in UK or USA).

(Is it approximately 1:1000 ?)

If possible please include a link to your source of statistics.

Thank you in advance
Title: Re: Lifetime probabllity of contracting Mumps?
Post by: rosy on 13/09/2006 18:34:46
I don't know any of the stats, but it's going to depend a lot on where you're living etc because if you're near a lot of people who've been vaccinated you'll benefit from herd immunity even if you're not vaccinated yourself.
As such, "lifetime probability" is going to be pretty meaningless since we cannot know, now, whether vaccination levels will go up or down in the next 70 or so years... and it'll depend particularly, I think, on the uptake of vaccination in the school cohort of the individual (because kids spend a lot of time with their chronological peers in the first 15-20+ years of life.
Title: Re: Lifetime probabllity of contracting Mumps?
Post by: another_someone on 13/09/2006 22:28:57
quote:
Originally posted by rosy

I don't know any of the stats, but it's going to depend a lot on where you're living etc because if you're near a lot of people who've been vaccinated you'll benefit from herd immunity even if you're not vaccinated yourself.
As such, "lifetime probability" is going to be pretty meaningless since we cannot know, now, whether vaccination levels will go up or down in the next 70 or so years... and it'll depend particularly, I think, on the uptake of vaccination in the school cohort of the individual (because kids spend a lot of time with their chronological peers in the first 15-20+ years of life.



I would have thought the bigger risk is exaectly because of vaccination in schools, making it less likely that you will become infected in childhood, and thus attaining immunity by that path, thus leaving you more exposed in adulthood, which may well be more dangerous.



George
Title: Re: Lifetime probabllity of contracting Mumps?
Post by: iko on 13/09/2006 22:42:26
A little piece for your puzzle:
 
quote:
...Although mumps is generally considered "less contagious" than measles and chickenpox, this difference may be more apparent than real because many mumps infections (at least 25 percent) tend to be inapparent clinically.  In some surveys, 80 to 90 percent of an adult population had serologic evidence of previous mumps.
Harrison's Principles of Internal Medicine  13th edition

This may further complicate your statistical analysis...
Enjoy it!
iko
Title: Re: Lifetime probabllity of contracting Mumps?
Post by: Igor on 15/09/2006 15:35:23
Thank you everyone for your contributions.

I found this graph on Mumps incidence in Maryland (USA)

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fi67.photobucket.com%2Falbums%2Fh300%2Fsotohp_photos%2Fmumps2.gif&hash=2d40109f99d51fee5be89ceddee73970)

http://edcp.org/html/mumpsb.html

Title: Re: Lifetime probabllity of contracting Mumps?
Post by: ROBERT on 21/09/2006 16:30:29
quote:
Originally posted by iko

A little piece for your puzzle:
 
quote:
...Although mumps is generally considered "less contagious" than measles and chickenpox, this difference may be more apparent than real because many mumps infections (at least 25 percent) tend to be inapparent clinically.  In some surveys, 80 to 90 percent of an adult population had serologic evidence of previous mumps.Harrison's Principles of Internal Medicine  13th edition

This may further complicate your statistical analysis...
Enjoy it!
iko



Isn't this high figure due to vaccination against mumps ?
In the UK 80 - 90 % of people under 40 have been vaccinated against mumps.
Title: Re: Lifetime probabllity of contracting Mumps?
Post by: rosy on 21/09/2006 17:09:20
quote:
I would have thought the bigger risk is exaectly because of vaccination in schools, making it less likely that you will become infected in childhood, and thus attaining immunity by that path, thus leaving you more exposed in adulthood, which may well be more dangerous.

The question was about total probability of contracting mumps, rather than any sort of time-integrated consideration of likely damage due to infection...
Title: Re: Lifetime probabllity of contracting Mumps?
Post by: iko on 21/09/2006 18:50:45
quote:
...Although mumps is generally considered "less contagious" than measles and chickenpox, this difference may be more apparent than real because many mumps infections (at least 25 percent) tend to be inapparent clinically. In some surveys, 80 to 90 percent of an adult population had serologic evidence of previous mumps.Harrison's Principles of Internal Medicine 13th edition

My textbook edition is 1994 and from USA.
The point here should be that 'subclinical' mumps infections could total more than 25 percent (I knew almost 65 percent from older pediatrics books).  Without vaccination.
Unfortunately I'm not exactly sure about that.
If you sold a vaccine for this, you would't believe it.
Enjoy your calculations!
iko
Title: Re: Lifetime probabllity of contracting Mumps?
Post by: chris on 09/10/2006 11:30:01
I don't think one can realistically offer a lifetime probability of catching mumps because this will strongly depend upon the people around you, and their behvaiour.

The majority of people in western countries are now immunised against mumps, usually with the MMR (measles, mumps and rubella) vaccine given at 1 year and again pre-school. This live triple vaccine drives very powerful immunity against these infections and gives protection to about 90% of vaccinees.

But not everyone is vaccinated and some people cannot be for medical reasons, such as impaired immunity. But they are nonetheless protected by so-called "herd immunity". In other words, because the majority of the population are immunised there are too few susceptible individuals in a population to allow these viruses to circulate, and so the disease burden remains low.

That's why certain infections tend to come in cycles several years apart. A flare-up occurs and lots of people are infected. They then all become immune and the virus runs of of human "fodder" and disappears for a while. Then, four years later, enough young children have been born to have created a sufficiently large pool of susceptible individuals to allow the virus to re-kindle and circulate.

In this regarde, the worry we face at the moment is that ill-founded concern over the safety of the MMR vaccine, in particular with respect to an alleged link to autism, has led to a reduction in the numbers of individuals being vaccinated. As a result our herd immunity is at risk of breaking down. We are already seeing measles and mumps outbreaks, and measles is serious illness with serious consequences, which can be fatal.

Chris

"I never forget a face, but in your case I'll make an exception"
 - Groucho Marx
Title: Re: Lifetime probabllity of contracting Mumps?
Post by: Mjhavok on 10/10/2006 01:04:15
Yes Chris I hate when the media makes a big situation out of something when they don't fully understand the consequences. If any risk exists with the MMR vacine then it should be looked at definitely but I got the MMR vacine at school and all of my friends got it. I don't know anyone who had any side effects. How can they prove the alleged link to autism? As far as I know autism is fairly rare and it has many factors attributed to its cause, how could they tell if it was a MMR vacine and not something else? On a case by case basis.
Title: Re: Lifetime probabllity of contracting Mumps?
Post by: chris on 11/10/2006 09:41:54
Well actually no. The best way to study any association is by looking at big groups with a well documented exposure history. Then the natural variation and glitches in the data will be swamped by the real findings.

This has been done for the MMR / autism association. By comparing the autism rates in the groups of children who do receive MMR and those who don't it's possible to spot whether there is a general trend.

A recent study in Japan looked at over 30,000 children and found an increased frequency of autism amongst the unvaccinated group!

There is no evidence linking MMR with autism or inflammatory bowel disease. On the other hand there is strong evidence linking lack of MMR vaccination with fatalities due to measles, sterility due to mumps, and congenital malformation due to intra-partum rubella infection.

The individual who made these claims in the first instance owned a patent on monovalent vaccines for these agents. He stood to profit financially if parents could be pursuaded to eschew the MMR in favour of the monovalent equivalents.

Chris

"I never forget a face, but in your case I'll make an exception"
 - Groucho Marx