Vaccination with a booster shot among as many people as possible is a good way to protect those most at risk against ever-emerging new Coronavirus variants, Moderna CEO Stephane Bancel said on Sunday.

“We believe that our vaccine will be effective for a comparable period, except that the arrival of variants increases the threat level. This is why we must anticipate and vaccinate all people at risk with a third dose by the end of summer, in particular the residents of nursing homes who received their first dose at the beginning of the year,” Bancel told French newspaper Journal Du Dimanche. The CEO of the US drugmaker further suggested that in order to protect the “fragile unvaccinated people,” all adults and adolescents must also receive a booster jab.