Johnson & Johnson Says Booster Shot of Its One-Dose Vaccine Makes It 94% Effective Against COVID-19

Johnson & Johnson has said that a booster shot of its single-dose COVID-19 vaccine increases the strength of protection against the virus and is effective against severe illness.

On Tuesday, Dr Mathai Mammen, the global head of research and development at J&J, said: “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 hospitalizations.”

“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,” he added.

The company announced that a second shot administered two months after the first shot increased its effectiveness to 94% against symptomatic and severe illness. This is compared to just 70% protection observed with just one dose of the vaccine.

The latest data will support the company’s case to the U.S. regulators for a booster shot even if the company emphasizes that a single shot of its COVID-19 vaccine is effective as a tool to alleviate the pandemic.

President Joe Biden has been pushing his plans to give booster shots to all Americans as the Delta variant continues to bring a surge of cases and deaths every day across the nation.

J&J, who is the only drugmaker approved with a one-dose COVID-19 vaccine in the U.S., has been under immense pressure to provide evidence of the additional dose’s effectiveness.


“A single-shot COVID-19 vaccine that is easy to use, distribute and administer, and that provides strong and long-lasting protection is crucial to vaccinating the global population,” chief scientific officer Dr. Paul Stoffels of J&J’s said in a statement.

“At the same time, we now have generated evidence that a booster shot further increases protection against COVID-19 and is expected to extend the duration of protection significantly,” he added.

The New Brunswick, New Jersey-based company issued details of three studies that assessed the different aspects of its vaccine.

The first study, a phase III two-dose trial, had over 30,000 participants where the effectiveness of a second dose given after 56 days of getting the first dose in adults 18 and older was observed. The study discovered that a booster shot was 94% effective against symptomatic COVID-19 patients in the U.S. and 100% effective against critical disease at least 14 days after getting the shot.

There was just a single case of COVID-19 in the vaccine group and 14 in the placebo group.

According to the company, the booster shot that will be administered two months after getting the first dose will increase the antibody levels between four-fold and six-fold. If the booster shot is given six months after the first dose, antibody levels increase to nine-fold after a week and 12-fold after four weeks.

The increases were observed irrespective of age. Meanwhile, side effects with two doses were similar to those observed in people who received the single-dose COVID-19 vaccine.

The latest data still needs to be peer reviewed, but data will be submitted for publication in the months to come.

The drugmaker company has already submitted the data to the FDA and is looking to submit it to other regulators, the World Health Organization, and other vaccine advisory groups worldwide as well.

J&J also revealed the data from a real-world study to compare the 390,000 people who got the single-dose J&J COVID-19 vaccine to the 1.52 million people who were unvaccinated from March 2021 to July 2021. The vaccine was discovered to be 79% effective against the coronavirus and 81% effective against hospitalizations.

Also Read: Side Effects From Pfizer Booster Shots Are Similar To Second COVID-19 Vaccine Dose, Drugmaker Tells FDA