As everyone recalls, the Seychelles was lambasted during its Delta outbreak for not having its vaccines confer sterilizing immunity as the Pfizer and Moderna vaccines did in Israel and New York. Today, this all sounds ridiculous, given the outbreaks in Israel, Massachusetts, Canada, etc. And, of course, it had an element of ridiculousness at the time given the fact the majority of cases were among the unvaccinated equated to a total effectiveness of the Sinopharm and AstraZeneca vaccines used in the Seychelles of 90% against symptomatic illness. But at the time it was a useful bit of China-bashing, given the Israeli outbreak was still two months away.
Today, however, Delta is dominant, and all vaccines against it are less than 70% effective (at least, if one doesn’t add a third dose) against infection.
A recent narrative has come up (due in part to Israeli data) that the key problem with the Western vaccines is fading immunity over time. However, the evidence from South Korea (which passed .7 vaccine doses per capita on August 21 and 1 vaccine dose per capita on September 10), this is not the primary problem with the Western vaccines. The primary problem with them is the immune escape properties of the Delta variant, which was obviously not forseen when the vaccines were first designed. Despite reaching 1.2 vaccine doses given per capita on September 28, this was also when cases in South Korea (which has unusually good contact tracing, which sufficiently effective vaccines should be able to help with) reached a record high:
Nevertheless, all COVID vaccines currently in widespread use retain some element of effectiveness against symptomatic disease (generally between 40% and 60%, probably higher for Moderna and lower for Pfizer -the lowest appears to be for Johnson&Johnson). It was, after all, in the region of Arkansas, Missouri, and Louisiana, not New York and Massachusetts, where the Delta outbreak hit first and hardest in the U.S., and heavily college educated White urban areas remain less hit by symptomatic disease than the surrounding countryside: