CVirus comments

Great article about a Delta specific booster or a Beta/Delta booster.

The advantage of using an "ancestral" vaccine is that it is related to all variants. But, if 99% of the current infections are Delta, it is likely that he next variant will be related to the Delta variant.

So, I would like to see one or two doses of the ancestral vaccine followed by a Delta booster, or a Beta/Delta booster. While it may not be necessary today, it may help with the next dominant strain. We also need to work on increasing the speed of conception to production.

I partly disagree with @virusrex above.

[quote]"Some people that have no idea about how immunity works mistakenly think the vaccines could be making the variants more likely to appear (even if we are seeing the complete opposite) but that is plainly false. Some even say that soon after vaccination, when the immunity is not yet completely developed, the variants could be selected more easily than in unvaccinated people"[/quote]The background mutation rate is independent of the vaccination status, and thus, there are more unvaccinated people getting the disease, and likely are infectious longer spreading the virus more, and thus more chances of developing significant mutations.

HOWEVER, as a greater percent of the population is vaccinated, we are getting significant numbers of breakthrough infections. Here in the Western USA we are getting about 20% breakthrough infections (more people vaccinated than unvaccinated). These breakthrough infections have the potential of selecting vaccine resistant mutations, either with the primary infection, or developing in vivo.

There is a chance of spreading these potential new mutations to more individuals, either vaccinated or not, or bouncing between vaccinated and unvaccinated individuals, selecting additional vaccine resistant mutations.

So, developing something like the highly infectious Delta variant would be independent of the vaccine. However, developing a vaccine resistant strain may depend on breakthrough infections among vaccinated.

Ultimately, we are better off reducing the number of carriers through vaccination, masking, social distancing, etc.