Foram Joshi asked:
Why can we not gain immunity to the common cold?
Chris - I wish I knew the answer to that. Itís actually just simple numbers. There are two reasons for this. One is to be immune to something, your immune system has to see it in the first place. So you have to be infected with the thing, so you then learn to neutralize it in the future. Now, that would be simple if there was one virus, but in fact there are hundreds.
If you look at the rhinovirus family, which is the cause of the common cold, around most of the year, there is about a hundred of those. If you look at the enterovirus family, thereís about a hundred of those. There is 50 or 40 adenoviruses, many of which cause upper respiratory and eye infections. Then there are the corona viruses, the parainfluenza viruses, the influenza viruses and to add insult to injury, these viruses also mutate. So not only are there hundreds of them around for you to get your immune systemís head around but also they are moving target. They are changing their molecular appearance, so even if you have learned to recognize it, thereís no guarantee that youíll recognize it again the next time. And given that there are all these hundreds of viruses and the average person gets about two or three colds per year, thatís three life times worth of cold infections before youíve actually got any chance of being immune to all of them, by which time they probably have changed.
So, I donít think thereís really any prospect of ever being able to cure the common cold with the exception that what scientist including Steven Legit who is a researcher of University of Maryland had done, is theyíve sequenced genetically all of the rhinoviruses so far. And they know how they divide up to a little subfamilies and it might be that if you a made a vaccine based around some members of some of those subfamilies, then every time you immunize someone who gets one of the subfamilies you are protected against all the other members of that family. So you could make a vaccine but it would have probably be based around lots and lots a different members and probably be unfeasible. Who knows, letís hope though that we come up with some kind of common cold cure soon because since you have children youíre into a whole different ball game.
foram joshi asked the Naked Scientists: Dear Naked Scientists, † my question is: why do we catch colds so often? Why do we not become immune to diseases like the common cold? What do you think? foram joshi , Tue, 18th Aug 2009
We do gain immunity to the common cold, we never get the same cold twice!! However there are so many different strains of the common cold, each time we come into contact with a new strain, we have to go through the process of having the cold in order to gain the immunity! Variola, Tue, 18th Aug 2009
Variola, the TNS 'Pox in Residence' has given the definitive answer.
I have never had the common cold OR the flu in my entire life.
If the deffinition of 'flu is " a cold, but so bad you can't get out of bed" then I have never had 'flu. Perhaps serological analysis would tell me something else.
That is actually a very interesting question you've got there foram joshi. Such a common illness and no vaccine?
And let's not forget that virus genomes mutate, so a vaccin has to be reinvented everytime a virus reinvents itself (as long as the mutation occurs in membrane component coding genes) Nizzle, Wed, 19th Aug 2009
When the vaccine is rendered useless depends entirely on how it was constructed and what genes that mutate. If 75% of the genetic make-up is the same for all rhinoviruses, I wouldnt worry about inefficient vaccines just yet. If it does go and get nasty, I see no problem in reinventing the vaccine. Those who wish to stay away from colds probably wont mind either. DrChemistry, Wed, 19th Aug 2009
I dont think a Rhinovirus vaccine would work against enteroviruses either I do not think that is likely at all, but well, I could be wrong. Once again its all in the details
Is it an evolutionary thing?
Thanks for the clear and comprehensive answers you all came up with for this question; I think I also gave a fairly thorough answer on the podcast, which you can access via the link above.
never had a cold ever.i was told it is because i had diptheria as a baby.i am well into my seventys yorkie39, Sat, 11th Apr 2015