group of international experts — including, notably, two outgoing Food and Drug Administration vaccine regulators — argues in a new paper against offering Covid-19 vaccine boosters to the general population.

The paper, published Monday in the Lancet, is based on a review of available data about the durability of vaccine protection. That it was co-authored by Marion Gruber and Phil Krause, two veteran FDA officials who have been leading the agency’s review of Covid-19 vaccine applications, amounts to a strikingly direct rebuff to the Biden administration as it lays plans for booster shots. Gruber and Krause announced last month they would be leaving the agency this fall.

Others authors include experts from the World Health Organization, which has called for countries to delay broad booster plans as many countries are still suffering from a lack of vaccine supply in the face of horrific outbreaks driven by the highly transmissible Delta variant.

“Current evidence does not, therefore, appear to show a need for boosting in the general population, in which efficacy against severe disease remains high,” the authors wrote.