New Data Show Janssen Booster Shot Increases Protection Against COVID-19

NIEUWEGEIN, NETHERLANDS – JUNE 25: Close up view of a Janssen vaccine ready to be used on June 25, 2021 in Nieuwegein, Netherlands. The Dutch government this week made it possible to make an injection appointment for everyone who wants to be vaccinated with Janssen. (Photo by Patrick van Katwijk/BSR Agency/Getty Images)
Vaccine effectiveness was reported to be 79% for COVID-19-related infections and 81% for COVID-19-related hospitalizations, according to real-world data.

Johnson & Johnson shared new phase 3 data and real-world evidence related to the effectiveness of the Janssen COVID-19 vaccine.

The real-world evidence study included 390,517 individuals 18 years of age and older who were newly vaccinated with the Janssen COVID-19 vaccine and 1,524,153 unvaccinated individuals matched by age, sex, date, location, comorbidity index, and 17 COVID-19 risk factors. 

Vaccine effectiveness was reported to be 79% (95% CI, 77-80) for COVID-19-related infections and 81% (95% CI, 79-84) for COVID-19-related hospitalizations. There was no evidence of reduced effectiveness throughout the study, including when the Delta variant became dominant in the United States.

The findings were consistent with those observed in the phase 3 ENSEMBLE trial ( Identifier: NCT04505722), which showed 74% efficacy (95% CI, 39-91) in the US against severe/critical COVID-19, 89% efficacy (95% CI, 24-100) against hospitalization, and 83% efficacy (95% CI, 41-97) against COVID-19-related death.

The randomized, double-blind, placebo-controlled phase 3 ENSEMBLE 2 study ( Identifier: NCT04614948) evaluated the efficacy and safety of a booster dose of the Janssen COVID-19 vaccine in individuals 18 years of age and older. Participants received a booster dose 56 days after the first dose.

Findings showed that the booster dose provided 100% protection (95% CI, 33-100) against severe/critical COVID-19 at least 14 days post-final vaccination and 94% protection (95% CI, 58-100) against symptomatic (moderate to severe/critical) COVID-19 in the US.

When the booster dose was given at 2 months, antibody levels were observed to be 4 to 6 times higher than after the first shot. When the booster dose was administered 6 months after the first shot, a 12-fold increase in antibodies was observed after 4 weeks.

“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,” said Paul Stoffels, MD, Vice Chairman of the Executive Committee and Chief Scientific Officer at Johnson & Johnson.

The Janssen COVID-19 vaccine is currently authorized under the Food and Drug Administration’s Emergency Use Authorization for active immunization to prevent COVID-19 caused by SARS-CoV-2 in individuals 18 years of age and older. 

The Company has submitted the new data to the FDA for review.


Johnson & Johnson announces real-world evidence and phase 3 data confirming strong and long-lasting protection of single-shot COVID-19 vaccine in the US. News release. Johnson & Johnson.–johnson-announces-real-world-evidence-and-phase-3-data-confirming-strong-and-long-lasting-protection-of-single-shot-covid-19-vaccine-in-the-us-301381176.html

This article originally appeared on MPR