Johnson & Johnson cut its enrollment in its last-stage clinical trial from 60,000 to 40,000 because the virus is so widespread that data on efficacy is coming in faster than the company expected. J&J has so far enrolled more than 42,000 people and will stop recruiting participants later this week, Slaoui said.
The vaccine is the only one among the frontrunners that is given as a single dose. “Because it’s a one dose vaccine, they can really scale up very quickly,” Slaoui said.
The first efficacy readout of AstraZeneca’s vaccine could come in the second half of January, Slaoui estimated, and the company could potentially file for emergency use later in February.