Imperfect Vaccination Can Enhance Transmission (2015)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4516275/

by johnwdefeo • 5 years ago

17 7 5 years ago

ncbi.nlm.nih.gov

jwilber• 5 years ago

This is more generally known as a “leaky” vaccine, (in case you want a keyword to search for related stuff).

amaccuish• 5 years ago

For additional context on how this article has been abused by some: https://factcheck.afp.com/http%253A%252F%252Fdoc.afp.com%252...

mikem170• 5 years ago

From the linked article:

The viral strains varied from the less virulent HPRS-B14, which killed 60% of unvaccinated birds over 2 mo, to the highly lethal Md5 and 675A, which killed all unvaccinated birds in 10 d

I assume this doesn't relate to covid, which has a comparatively minuscule mortality rate.

lax4ever• 5 years ago

No, the disease in question in this report is Marek's disease and I believe it was being studied in chickens.

andrewdubinsky• 5 years ago

According to some sources, the vaccine reduces COVID symptoms even if you are infected.

So people with COVID think they are only mildly sick and go to work/school/concerts, eat out, don't wear a mask, etc...They might think it's allergies or a mild cold.

This might explain why spikes occur in areas that have very high rates of vaccination.

charbonneau2• 5 years ago

The author of the study:

“We're talking a very different virus and very different vaccines. The details in biology really matter a lot. The chicken vaccines we worked with, the first-generation vaccine, definitely reduced disease, severity and death.” But unlike the COVID mRNA vaccines, the chicken vaccine “didn't stop transmission at all.” And this is one of the key differences between what was being studied in Read’s paper and our current situation with the global pandemic. “Those [vaccinated] chickens just kept churning out the virus for weeks and weeks and weeks.” Again, this is a key difference. “It’s a very different virus from SARS-2. A key issue here is transmissibility.”
“Evolution, at the moment, is all happening in the unvaccinated. That's where the majority of cases are. That's the majority of transmission. Every time a virus replicates, it can mutate. So the evolution is, right now, occurring in the body of people who are not vaccinated."

https://www.forbes.com/sites/andreamorris/2021/08/08/joe-rog...

johnwdefeo• 5 years ago

Thanks for this. I stumbled across the 2015 study and I wasn't aware of the controversy surrounding its recent dissemination. Additionally, here is a recent article published by the author of the study: https://theconversation.com/vaccines-could-affect-how-the-co...

That said, I feel frustrated by how the author alternates between weak and strong wording that may influence a reader's interpretation. For example:

Said then: "When vaccines prevent transmission, as is the case for nearly all vaccines used in humans, this type of evolution towards increased virulence is blocked."

Said now: "...no vaccine is 100% effective...we still need more data to determine how leaky [the mRNA vaccines] are..."

Said then: "The use of leaky vaccines can facilitate the evolution of pathogen strains that put unvaccinated hosts at greater risk of severe disease. The future challenge is to identify whether there are other types of vaccines used in animals and humans that might also generate these evolutionary risks."

Said now: "Individuals and populations have always been better off when vaccinated. At every point in the 50-year history of vaccination against Marek’s disease, an individual chicken exposed to the virus was healthier if it was vaccinated. Variants may have reduced the benefit of vaccination, but they never eliminated the benefit."

If the author believed then what he says now, it would have been beneficial to include in the abstract of the 2015 study something like: In the view of the authors, this data suggests that next-generation vaccines coupled with mass vaccination programs are necessary to combat evolutionary pathogenic risks.

Imperfect Vaccination Can Enhance Transmission (2015)

Related Stories