APC: Third time’s the charm (and here’s why)

August 23, 2021

Third time’s the charm (and here’s why)

Why do we need a possible third dose of an mRNA vaccine? One reason: because we got the first two doses so close together.

That was done to get as many people fully vaccinated as possible, but it sacrificed longer-lasting protection.

In a multi-dose vaccine regimen, a longer interval between doses gives the immune system time to mature. During this time period, a process called affinity maturation takes place, which causes antibodies to improve in quality while dwindling in number.

And that means that a third dose, coming eight or nine months after the first ones, could be it. Emphasis, of course, on “could.”