Yes, this is clearly an issue. One of the key points here, though, is that with two and, of course, three doses of a vaccine, while the efficacy wanes more significantly for protection against infection, you still see very significant protection with three doses against severe outcomes like hospitalization and death. Having said that, it also starts to wane a little bit, but not as significantly versus getting the infection in the first place.
This is speculation here—we'll let the data drive the policy—but I think we'll see two things. One, we'll probably see annual vaccines similar to what we see with influenza, and not vaccinations every four or five months. On top of that, we'll probably have more updated vaccines reflective of the circulating variant du jour. Currently, we're still using vaccines for the original virus that emerged from Wuhan, but we'll probably see some updated vaccines for omicron or other variants shortly.