Will a 4th vaccine shot improve your protection?

Who might benefit from a 4th shot — and who might not Some countries are moving ahead with plans to offer a fourth dose of COVID-19 vaccine. But studies are raising questions about the potential advantages of this extra booster. NPR.org

At this point, one thing about the pandemic is clear: The COVID-19 vaccines, even when followed by a booster, aren't going to stop the coronavirus — or provide long-term protection from infections.

Right after the third shot — the booster — antibodies rise up quickly. But then about a month later, they begin to decline. As a result, protection against infection drops down to about 50% three months later.

So the question is: Should you get a fourth dose to beef up protection again?

A preliminary study from Israel, published last Tuesday, suggests that for the general population, the answer is likely no. A fourth shot of the same vaccine — in this case Pfizer-BioNTech or Moderna — offered very little extra protection against infection compared with only three shots.

"Not a third dose, not a fourth dose, not a fifth dose will do anything to stop infections [long term]," says Dr. Gili Regev-Yochay, an infectious disease specialist at Sheba Medical Center in Tel HaShomer, Israel, and lead author of the new study.

But that's not to say that an additional dose is pointless in all circumstances. For older people or those at high risk, an extra dose may be needed to help maintain protection against severe disease, Regev-Yochay says. "A fourth dose probably does have a role in protecting against severe disease. I've seen preliminary data looking into that question." ...