J&J vaccine: Get done in one shot

Johnson & Johnson's longawaited vaccine appears to protect against COVID-19 with just one shot -- not as strong as some two-shot rivals but still potentially helpful for a world in dire need of more doses.

J&J said on Friday that in the US and seven other countries, the single-shot vaccine was 66% effective in preventing moderate to severe illness, and much more protective - 85% - against the most serious symptoms.

There was some geographic variation. The vaccine worked better in the U.S. - 72% effective against moderate to severe COVID-19 - compared to 57% in South Africa, where it was up against an easier-to-spread mutated virus.

"Gambling on one dose was certainly worthwhile," Dr. Mathai Mammen, global research chief for J&J's Janssen Pharmaceutical unit, told The Associated Press.

With vaccinations off to a rocky start globally, experts had been counting on a onedose vaccine that would stretch scarce supplies and avoid the logistics nightmare of getting people to return for boosters.

But with some other competing vaccines shown to be 95% effective after two doses, the question is whether somewhat less protection is an acceptable trade-off to get more shots in arms quickly.

The company said within a week, it will file an application for emergency use in the U.S., and then abroad. It expects to supply 100 million doses to the U.S. by June, and expects to have some ready to ship as soon as authorities give the green light.

These are preliminary findings from a study of 44,000 volunteers that isn't complete yet.

Researchers tracked illnesses starting 28 days after vaccination; however, no one who got vaccinated needed hospitalization or died regardless of whether they were exposed to "regular COVID or these particularly nasty variants," Mammen said. When the vaccinated did become infected, they had a milder illness.

Defeating the scourge that has killed more than 2 million people worldwide will require vaccinating billions, and the shots being rolled out in different countries so far all require two doses a few weeks apart for full protection. Early data is mixed on exactly how well all the different kinds work, but shots made by Pfizer and Moderna appear to be about 95% protective after the second dose. But amid shortages, some countries have advised delaying the second dose of certain vaccines with little data on how that would affect protection.