Johnson & Johnson, the only major drug maker developing a single-dose vaccine for Covid, announced on Friday that its shot provided strong protection against Covid-19, potentially offering another powerful tool in a desperate race against a worldwide rise in virus mutations.

But the results came with a significant cautionary note: The vaccine’s efficacy rate dropped from 72 percent in the United States to 57 percent in South Africa, where a highly contagious variant is driving most cases.

Continue reading “Johnson & Johnson’s Vaccine Offers Strong Protection but Fuels Concern About Variants” →

Novavax, a little-known company supported by the U.S. federal government’s Operation Warp Speed, said for the first time on Thursday that its Covid-19 vaccine offered robust protection against the virus. But it also found that the vaccine is not as effective against the fast-spreading variant first discovered in South Africa, another setback in the global race to end a pandemic that has already killed more than 2.1 million people.

That could be a problem for the United States, which hours earlier reported its first known cases of the contagious variant in two unrelated people in South Carolina. And it came just days after Moderna and Pfizer said that their vaccines were also less effective against the same variant.

Continue reading “Novavax’s Vaccine Works Well — Except on Variant First Found in South Africa” →

In late December, scientists in California began searching coronavirus samples for a fast-spreading new variant that had just been identified in Britain.

They found it, though in relatively few samples. But in the process, the scientists made another unwelcome discovery: California had produced a variant of its own.

That mutant, which belongs to a lineage known as CAL.20C, seemed to have popped up in July but lay low till November. Then it began to quickly spread.

Continue reading “New California Variant May Be Driving Virus Surge There, Study Suggests” →