WORLD / Science & Health

As rollout falters, scientists debate new vaccination tactics

A nurse receives a COVID-19 vaccine at the Cardiff and Vale Therapy Centre in Cardiff, Wales, on Dec. 8. In the U.K., doctors have been told to postpone appointments for second doses that had been scheduled for January, so that those doses can be given instead as first shots to other patients. | ANDREW TESTA / THE NEW YORK TIMES

By Rebecca Robbins and Katherine J. Wu
The New York Times

Jan 4, 2021

As governments around the world rush to vaccinate their citizens against the surging coronavirus, scientists are locked in a heated debate over a surprising question: Is it wisest to hold back the second doses everyone will need, or to give as many people as possible an inoculation now — and push back the second doses until later?

Since even the first shot appears to provide some protection against COVID-19, some experts believe that the shortest route to containing the virus is to disseminate the initial injections as widely as possible now.

Officials in Britain have already elected to delay second doses of vaccines made by the pharmaceutical companies AstraZeneca and Pfizer as a way of more widely distributing the partial protection afforded by a single shot.