Easy to Recognize Propaganda About Genotypes from the National Vaccine Information Center
Barb Loe pushing misinformation about vaccine strains causing measles outbreaks.
Can you recognize this propaganda from Barb Loe and her National Vaccine Information Center?
It is true that genotype testing can help determine the source of an outbreak.
And while anti-vaccine influencers always bring this up, it is also true that the genotype is typically available for outbreaks, and it is never a vaccine strain!
For example, among measles cases from 2020 to 2024 in the United States, the CDC reports that:
177 were genotype B3
44 were genotype D8
And while they only genotyped 74% of the cases, none was a vaccine strain!
What about in the Texas outbreak?
In Texas, cases have been found to be from the D8 strain, which is, of course, not a vaccine strain.
But wait, could there be “undetected atypical or asymptomatic wild-type measles circulating in the highly vaccinated U.S. population with waning vaccine acquired immunity?”
Well, for one thing, this outbreak is occurring in a population with very low vaccination rates. And we do not see waning immunity after the MMR vaccine for measles protection!
Most importantly though, most cases are in folks who are not vaccinated!
But could genotyping “help answer questions about what country the original case in the current outbreak reportedly starting in Texas may have come?”
Probably not, even though we know the genotype is D8.
The problem is that of the 24 genotypes that were originally discovered, including 18 that were around in 2003, only 2 remain - the B3 and D8 genotypes.
And these two genotypes can now be found in many different countries and regions of the world.
Knowing the genotype could help you determine if a vaccine strain was causing the outbreak though, right?
Again, we know that Texas outbreak is from the D8 genotype and since the vaccine strains are from the A genotype, that should put the idea of a vaccine induced outbreak to rest.
“Genotyping can also distinguish whether a person has wild-type measles virus infection, or a rash caused by a recent measles vaccination. A small percentage of measles vaccine recipients experience rash and fever 10 to 14 days following vaccination. During outbreaks, measles vaccine is administered to help control the outbreak, and in these situations, vaccine reactions may be mistakenly classified as measles cases. The vaccine strain of measles virus can be distinguished from wild-type viruses by determination of the genotype from clinical specimens or virus isolates. Vaccine strains can also be distinguished from wild-type viruses by real-time RT-PCR.”
Genetic Analysis of Measles Viruses
Also know that when you do see a vaccine strain in an outbreak, it is typically because someone who was recently vaccinated developed a rash and/or fever, and they have testing to make sure they don’t have measles.
This is the part that confuses a lot of people!
Remember, many people get vaccinated during an outbreak, and the MMR vaccine can commonly cause a rash and/or fever. It is an immune reaction though and doesn’t mean that they have measles though.
“Individuals recently vaccinated against MeV may already be incubating wild‐type MeV. This then becomes a challenge when trying to establish whether the resulting symptoms are caused by the vaccine or MeV infection. This is clearly demonstrated in this case, whereby the case was evidently incubating wild‐type MeV just prior to vaccination.”
Is it or is it not? Lessons learned from a case of suspected vaccine strain measles
But since their rash and/or fever can mimic the symptoms of measles, they have testing to see if they have a vaccine strain, confirming that it was just an immune reaction, or a wild strain, which means that they do indeed have measles.
These aren’t cases of vaccine induced measles though.
References
Bankamp, Bettina, Gimin Kim, Derek Hart, Andrew Beck, Myriam Ben Mamou, Ana Penedos, Yan Zhang, Roger Evans, and Paul A. Rota. 2024. "Global Update on Measles Molecular Epidemiology" Vaccines 12, no. 7: 810. https://doi.org/10.3390/vaccines12070810
Genetic Analysis of Measles Viruses https://www.cdc.gov/measles/php/laboratories/genetic-analysis.html
Lord H, Kok J, Fletcher S, Alexander K. Is it or is it not? Lessons learned from a case of suspected vaccine strain measles. Aust N Z J Public Health. 2020 Apr;44(2):160-162. doi: 10.1111/1753-6405.12969. Epub 2020 Mar 19. PMID: 32190947.