How much and how long will one dose of COVID vaccines prevent virus variants?

In December, distinct SARS-CoV-2 virus variants with multiple mutations in the spike (S) protein were reported in the UK (“B.1.1.7”) and South Africa (“B.1.351”), and then, on Jan. 10, in travelers from northern Brazil arriving in Japan (“B.1.1.248”).  A crucial question is whether any COVID vaccine will have a less protective effect against these variants. The answer to this question carries major public policy, as well as public health, ramifications. This answer must include how much  (what %) — protection, and for how long (# months) is protection provided after only one dose, of a two-dose vaccine? To date the focus has been on protection after two doses of vaccine.

Preliminary reports in the media and in unpublished manuscripts have been optimistic that the variants found in the UK and S. Africa will be protected against by the Pfizer and Moderna vaccines.

For example, a recent not-yet-peer-reviewed manuscript reported that sera from 20 people who had received two doses of the Pfizer vaccine, administered three weeks apart, neutralized a specific N501Y mutant (only) virus as well as the virus without the N501Y mutant. Much needed more complete data would include at least two additional analyses:

1. Comparing one dose with two doses of the vaccine and,
2. Using the entire variant viruses with many mutations, rather than only one key mutation.

These two analyses should be part of a standard template for evaluating the predictable and certain future variants of SARS-CoV-2.