Two dose Johnson & Johnson vaccine option shows 94% efficacy against COVID-19, study

Johnson & Johnson said Tuesday a two-dose version of the pharmaceutical company's coronavirus vaccine provides 94% protection against symptomatic infection, putting its in line with those offered by Pfizer and Moderna.

Additionally, the company said that adding a booster dose of the vaccine to a single J&J shot should also be effective in protecting people against infection. 

"Our large real-world-evidence and Phase 3 studies confirm that the single-shot Johnson & Johnson vaccine provides strong and long-lasting protection against COVID-19-related hospitalization," said the global head of Janssen Research & Development Dr. Mathai Mammen. 

He continued, "Our single-shot vaccine generates strong immune responses and long-lasting immune memory. And, when a booster of the Johnson & Johnson COVID-19 vaccine is given, the strength of protection against COVID-19 further increases."

The company's ongoing Phase 2 trial of its two-dose regimen indicates that giving two doses of the vaccine a little less than two months apart provides a 100% protection against severe COVD cases, and a 94% protection against moderate-to-severe cases in the U.S.

A second study showed that the later an individual receives a booster shot, the more protection the shot will provide. Those in the study given the booster shot six months or longer after their first J&J shot saw a 12-fold increase in antibodies, while those given the second shot after two-months saw four-fold increase.

The single-dose Johnson & Johnson vaccine has been given to around 15 million Americans, according to data from the CDC.