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Is a Vaccine Strain Causing The Latest Measles Outbreak?

What’s the first question anti-vaccine folks start asking whenever we see a large outbreak of measles?

No, it’s not how can I get my kids vaccinated and protected so that they don’t get measles…

It is whether or not it a vaccine strain of measles started the outbreak.

That’s not how any of this works…

Where do folks get all of this stuff about genotypes and vaccine strains? I wonder…

Dr. Bob had no facts, but still posted that a vaccine strain of measles could have killed a woman who got caught up in the last measles outbreak in Washington.


The usual suspects.

Is a Vaccine Strain Causing The Latest Measles Outbreak?

Why do folks who intentionally don’t vaccinate their kids desperately want these measles outbreaks to be caused by a vaccine strain?

Because then it isn’t their fault that their kids are at risk of getting a life-threatening disease!

It’s never a vaccine strain though.

Remember the Disneyland measles outbreak. A lot of folks were talking about vaccine strains when it first started.

“…California patients were genotyped; all were measles genotype B3, which has caused a large outbreak recently in the Philippines…”

Measles Outbreak — California, Dec 2014–Feb 2015

It wasn’t a vaccine strain.

California2014B3, D8
North Carolina2013D8
Washington, Illinois2008D5, D4

For example, during 2011, 222 cases of measles and 17 outbreaks were reported in the United States, with most cases originating from just five countries (France, Italy, Romania, Spain, and Germany). Six different genotypes were identified, including B3, D4, G3, D8, H1, and D9. No vaccine strains…

And no, it doesn’t matter that the vaccine strain of measles, genotype A, differs from all of the wild strains of measles we see in the outbreaks.

“Vaccine induced immunity protects against all virus strains. Measles is considered a monotypic virus despite the genetic variations.”

Factsheet about measles

Unlike the flu, HPV, and pneumococcal bacteria, in which vaccines only protect against different serotypes, in the case of measles, the genotype simply helps us figure out where the measles case came from.

And no, the latest outbreak, wherever it is, wasn’t caused by shedding from a vaccine.

But if it isn’t the vaccine strain, then why do they that is it important to rapidly identify wild strains vs vaccine strains?

“During measles outbreaks, it is important to be able to rapidly distinguish between measles cases and vaccine reactions to avoid unnecessary outbreak response measures such as case isolation and contact investigations.”

Roy et al on Rapid Identification of Measles Virus Vaccine Genotype by Real-Time PCR

That’s easy to answer.

Outbreaks typically trigger a lot of folks to get vaccinated. While that’s great, one possible problem is that some of those folks might develop a fever and/or rash after their MMR vaccine. So it is important to quickly figure out whether they are part of the outbreak and have a wild strain (maybe they were exposed before their vaccine could start to work) or are having a common, mild vaccine reaction.

But couldn’t they have vaccine-associated measles if they have a rash and fever and a vaccine strain? Theoretically, but then they would likely have true measles symptoms. And even in these rare case reports, the children didn’t spread the measles to anyone else.

So why are you waiting to know the genotype of the measles strain causing the outbreak in your area? Hopefully, it isn’t to help you decide whether or not to vaccinate and protect your kids. While it is interesting to know where the outbreak originated, you can bet that it isn’t a vaccine strain.

More on Vaccine Strains Causing Measles Outbreaks

4 thoughts on “Is a Vaccine Strain Causing The Latest Measles Outbreak?”

  1. “Vaccine induced immunity protects against all virus strains. Measles is considered a monotypic virus despite the genetic variations.” But has the actual effectiveness of the measles portion of the MMR vaccine been demonstrated/proven in any peer reviewed research done on the gold standard. If so, provide these data. We all are familiar with Merck’s lack of integrity from the mumps lawsuit. Now we are supposed to believe that Merck all of a sudden developed integrity for their research done on the measles portion. The question is not what strain it was or is, but how many of the effected children were vaccinated versus those effected who were not. Provide that data, i dare you. More than likely you’ll find that it has been suppressed by the major players. You otherwise have committed a false dichotomy in your argument.

  2. Perhaps anti-vaxxers know that catching measles is normal, and the number of CASES of measles is meaningless. What matters is outcome. Not having a damaged immune system (ie, no vaccines, good nutrition, unvaccinated mother, good hygiene, plenty of vitamin C to keep the leukocytes pumping out the peroxide) means good outcomes, lifelong immunity, and critically: the continued development of intergenerational herd immunity through the transmission of maternal antibodies and epigenetic transfer.

    But keep shooting up the adjuvants and bits of dead babies. I’m sure it will make you glow.

  3. Natalie Ferrell

    The massive efforts made in trying to convince the public of the importantance of vaccines using ridiculous scare tactics is making parents even more suspicious and they are digging deeper. It’d be nice if you’d acknowledge the fact that there IS that small percentage of individuals being sacrificed for the greater good.
    This fact is blatantly ignored by the CDC.
    It is public record . Parents can see all who have been compensated. There is a very small risk, but damn it ….. acknowledge it !
    It is simply misleading to say that all vaccines are safe and effective!!! The government is basically saying that it’s okay to sacrifice a few for the greater good. Because of this fact, mandating is unethical.
    I hope the CDC continues to exaggerate using dramatical commercials to sway the public.
    Marketing at its best will back fire. Again making citizens even more suspicious.
    Profits that CANNOT afford to be lost is the message they are sending.

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