Efficacy

A health worker prepares a booster dose of a coronavirus disease (Covid-19) vaccine, as vaccinations jump in Italy after the government made inoculation mandatory for all workers, in Rome, Italy. Photo: Reuters
Coronavirus chronicle

Covid booster efficacy wanes significantly by fourth month: US study

Vaccine efficacy against hospitalization was 91 percent in the first two months, but fell to 78 percent by the fourth month after a third dose

A sign of Sinopharm is seen at the 2020 China International Fair for Trade in Services (CIFTIS), following the COVID-19 outbreak, in Beijing, China September 5, 2020. REUTERS/Tingshu Wang
Coronavirus chronicle

Peru study finds Sinopharm Covid vaccine 50.4% effective against infections