It's been a constant theme of booster critics that because a booster was necessary after 6 months for mRNA vaccines, this is a pattern that will continue indefinitely. Not only does that not take into account the development of new vaccines, but it also assumes that these inoculation intervals for current vaccines will remain the same. That's not at all necessarily the case as virologists and immunologists have pointed out.

 

A study conducted in Chile shows that a booster shot, a 3rd inoculation,  of Sinovac's Coronavac vaccine produces far strong results than does a 2nd inoculation. The study was small and is still in preprint researchers

https://www.news-medical.net/news/20211121/CoronaVac-vaccine-booster-strengthens-protection-against-SARS-CoV-2.aspx

https://www.medrxiv.org/content/10.1101/2021.11.16.21266350v1.full.pdf

 

This echoes findings from another small study, also in preprint, that shows greatly improved immune response after a 3rd inoculation of an mRNA vaccine, compared to the response from a a second dose.

https://khn.org/morning-breakout/mrna-boosters-may-give-longer-lasting-protection-than-2-shots/

 

 

I believe that in Thailand the recommendation is to use another vaccine for the booster shot after initial vaccination with Sinovac.

Just now, Puccini said:

I believe that in Thailand the recommendation is to use another vaccine for the booster shot after initial vaccination with Sinovac.

Actually, there is a growing consensus that no matter what you started with, it's better to go with something different for a booster. However, this was a study done to evaluate Coronavac.

Sinovac has no doubt saved many lives.  I had a lot of friends who didn't want it.  I strongly encouraged them to get it.  Whatever, it's deficits, it did work, just not as well as some later vaccines. 

 

We will likely find that the current vaccines will require some major upgrades and tweaking in time, similar to what needs to be done with Influenza vaccines.  This virus is circulating way too widely to not eventually get mutations or variants that are much more resistant to current vaccines.