Johnson and Johnson One shot vaccine prevents COVID-19

Johnson & Johnson’s long-awaited 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 Friday that in the US and seven other countries, the single-shot vaccine was 66% effective overall at preventing moderate to severe illness, and much more protective — 85% — against the most serious symptoms, Associated Press reports.

There was some geographic variation. The vaccine worked better in the US — 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 one-dose 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, at question is whether somewhat less protection is an acceptable tradeoff to get more shots in arms quickly.