⏩ Third shot: OK likely on Saturday for J&J vaccine.

Johnson & Johnson’s COVID-19 vaccine was endorsed on Friday by a panel of experts advising the Food and Drug Administration. The agency is expected to formally approve authorization on Saturday, the New York Times reported, citing two people familiar with its plans.

It will be the third shot made available to the United States in the year since the first surge of coronavirus cases began washing over the country, and it will be the first vaccine to require just one dose instead of two.

Johnson & Johnson’s formulation worked well in clinical trials, even though it did not match the skyhigh efficacy rates of the first two vaccines made by Pfizer-BioNTech and Moderna.

The panel, made up of independent infectious disease experts, statisticians and public health researchers, voted unanimously in favor of authorizing the vaccine.

The vaccine had an overall efficacy rate of 72% in the United States and 64% in South Africa, where a concerning variant emerged in the fall. The shot showed 86% efficacy against severe forms of COVID-19 in the United States, and 82% against severe disease in South Africa.

Those are strong numbers, but lower than the roughly 95% efficacy rates of Pfizer-BioNTech and Moderna’s vaccines against mild, moderate and severe cases of COVID.

The scale and size of Johnson & Johnson’s vaccine trial was vast, spanning eight countries, three continents and nearly 45,000 participants.

Peter Parks / AFP via Getty Images Doctors and nurses wait to receive COVID19 vaccinations at a community center in Hong Kong. People age 60 and older and health care workers are among those given priority to receive inoculations.