understanding measles vaccine strains?

[jules]

I've been in a debate about Measles recently :eek: and we disagreed on measles strains and the vaccine...

With many different strains of Measles known...(I've read anywhere from 8 to 22)

If you get vaccinated with one strain in your country and another person gets vaccinated with another strain in his country..are both protected from each other if they travel?

The person I debated with says you are cause the WHO says you are.:rolleyes: But how could you be when each Measles type presents itself differently and has its own disease characteristics? A does not equal B..or does it?

Does anyone know which countries vaccinate with what strain/type? Like the USA uses Edmonston B strain in their MMR. So does India. Who uses Schwarz?


This is about all I could find on types and transmission and backs up that you aren't protected, if I am reading that correctly...:shrug:

Genetic Diversity of Wild-Type Measles Viruses: Implications for Global Measles Elimination Programs
http://www.cdc.gov/ncidod/eid/vol4no1/bellini.htm

I'm sorry, I just realized I think I put this in the wrong category...

[Momtezuma Tuatara]

Obviously strains do differ, as this article (http://www.nytimes.com/2008/11/11/health/research/11glob.html?_r=1&partner=rss&emc=rss&oref=slogin)shows:

A measles (http://health.nytimes.com/health/guides/disease/measles/overview.html?inline=nyt-classifier) outbreak in Gibraltar has infected almost 1 percent of the territory's 28,000 people in just three months, according to a report by its public health director.
The outbreak, mostly in schoolchildren, made it clear that the authorities had been wrong in assuming that more than 90 percent of children had had measles shots, the report said.
...
There were 276 cases of measles in Gibraltar from August to October, according to the health director, Dr. Vijay Kumar. There were none in the previous 10 years. The patients' age range was 4 months to 58 years. Most cases were mild.
Gibraltar's inhabitants live in modern but unusually crowded conditions for Western Europe.
Gene analysis suggested that the virus came from an outbreak in the nearby Spanish town of Algeciras. Gibraltar began a vaccination campaign this summer, but the vaccine ran out twice because of shortages in Britain.


I'll try and find it, but there was an article somewhere, last year, blaming UK parents for not vaccinated their children, and therefore allowing the development of a new strain of measles, which they said, was the strain which affected vaccinated people elsewhere in the world. I don't know if I kept it or not...

[MinorityView]

wasn't there some comment about moving the goalposts that kept coming up...?

[Momtezuma Tuatara]

It was published in the Medical Observer, but I can't find an original source, just lots of blogs talking about it...

Not that any of these abstracts help, but they are interesting:

http://vir.sgmjournals.org/cgi/content/abstract/81/10/2511

This one is very interesting: http://vir.sgmjournals.org/cgi/content/abstract/83/11/2699

I thought I had the article. If I can find it, I will post it.

[Momtezuma Tuatara]

I suspect the reason why the original Medical Observer article might have disappeared, was that someone might have pointed out this (http://vir.sgmjournals.org/cgi/content/abstract/86/2/365)to them.

It would appear, that supposedly, the measles antigens in the vaccine, do target common groupings in all serotypes.

BUT... if I find the original comment, I will post it.

[Momtezuma Tuatara]

Here is another medical article (http://www3.interscience.wiley.com/cgi-bin/fulltext/121531533/PDFSTART?CRETRY=1&SRETRY=0):


An outbreak of over 1,600 clinical cases of measles
was identified in Ireland in 2000 with three measlesassociated
deaths. Subsequent investigation demonstrated
that only 12% had received theMMR[Coughlan
et al., 2002]. The circulating strain was characterized
as genotype D2, which had been observed previously in
South African isolates, and it was concluded that suboptimal
vaccine uptake and recent migration facilitated
the transmission of the virus [Coughlan et al., 2002].

so that might have fueled speculation since that really doesn't identify WHY 12% of the cases were vaccinated. The rest of the discussion in the article doesn't "say" that the development of new strains is leading to outbreaks in vaccinated populations, but you can't help but think that they are doing their damndest to insinuate that.

[Momtezuma Tuatara]

Here is a discussion about the genotypes (http://www.immunisation.nhs.uk/files/conf_261108_MaryRamsay2.pdf). Interesting that the strain for the last three years appears to have been D4.

The last slide is enough to make you choke. It is, however, so believable that someone like Mary Ramsay would put it on, thereby condoning the absolutely atrocious "advice" to use paracetamol every four hours to "reduce fever". Maybe if the poor guy had been given decent advice, he wouldn't have been nearly so ill.

Just maybe if he'd seen the doctor who forwarded the items in the last two posts to me, he might not have been very sick at all :p

[Moya]

Measles virus is monotypic: there's only one serotype. The genetic differences among strains might cause variations in the clinical manifestations of infection but immunity against one strain provides immunity against all strains. There are different genotypes, but the viral genomes haven't diverged far enough to produce multiple serotypes.

It's the same case with mumps -- when mumps outbreaks started increasing, FDA scientists spent a whole lot of money trying to determine if another serotype had suddenly appeared, and they found that no, mumps virus is still monotypic; turns out the vaccine just really sucks.

[jules]

Measles virus is monotypic: there's only one serotype. The genetic differences among strains might cause variations in the clinical manifestations of infection but immunity against one strain provides immunity against all strains. There are different genotypes, but the viral genomes haven't diverged far enough to produce multiple serotypes.

It's the same case with mumps -- when mumps outbreaks started increasing, FDA scientists spent a whole lot of money trying to determine if another serotype had suddenly appeared, and they found that no, mumps virus is still monotypic; turns out the vaccine just really sucks.

Thanks Moya..that answered my question to a T.:D

But why then..would different countries use different strains and not the same one? If one type protects against all, why not just use one type? I was reading Swartz isn't as good as E-B, so why not switch?

Now I'm off to read MT's links.

[MinorityView]

Maybe they use different strains as a weird sort of nationalism? My vaccine is better than your vaccine?

The search for excuses for vaccine failures is an interesting process, based on one underlying imperative: "never publicly admit that a vaccine sucks."

[Momtezuma Tuatara]

I think Edmonston B caused a whole lot of problems when it was made into a vaccine. Moya might know.

[Moya]

But why then..would different countries use different strains and not the same one? If one type protects against all, why not just use one type? I was reading Swartz isn't as good as E-B, so why not switch? That's just economics, business, capitalism or whatever you want to call it. Different companies make different vaccines. In the U.S. it doesn't matter what's the safest or most effective measles vaccine, you're using Merck's product end of story. Keep in mind that decisions about vaccines are not made with respect to what's best for the public - decisions are always made based on business models. Otherwise, you'd be correct, why not take the best vaccine and just use that one? Because decisions are economic based.