A study by the Sigal lab that was released yesterday showed a significant decline in neutralizing antibodies (nAbs) in those 2x vaccinated, but a very small decrease in those 2x vaccinated + infected. Presumably, this would imply to me that a third dose/booster would bump 2x vaccinated to similar levels of nAbs as the vaccinated + infected.

Indeed today, Pfizer released very promising results. 3 doses offer great protection, similar to previous variants. There is a 25 fold decrease in nAbs with two doses, but T-cell is not significantly affected – so protection from severe illness still exists with two doses.

Children will be fine for now with two doses because it is recent, so will have high levels of nAbs.

Suggests to me that this is going to be three-dose primary series for all.