Skip to Content

J&J confirms long-lasting protection of coronavirus vaccine

Data suggests booster shot at two months provided 94% protection against COVID-19

NEW BRUNSWICK, N.J. (KYMA, KECY) - Johnson & Johnson (J&J) announces Monday new data reinforcing the strong and long-lasting protection of its COVID-19 vaccine.

“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. Additionally, our Phase 3 trial data further confirm protection against COVID-19-related death,” said Mathai Mammen, M.D., Ph.D., Global Head, Janssen Research & Development, J&J.

Researchers say new data also shows that protection against COVID-19 increases when a booster shot of the J&J vaccine is administered.

Dr. Mammen continues, “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 largest real-world evidence study for a COVID-19 vaccine reported to date in the U.S. shows stable vaccine effectiveness of 79% for COVID-19-related infections and 81% for COVID-19-related hospitalizations.

There was no evidence of reduced effectiveness over the study duration, including when the Delta variant popped up in the U.S. Sequencing data was not available for analysis.

The study included 390,000 people whom received the J&J COVID-19 vaccine versus approximately 1.52 million unvaccinated people matched on age, sex, time, three-digit zip code, comorbidities and predictors for COVID-19 infection severity tested from March to late July 2021.

These data was consistent with the Phase 3 ENSEMBLE trial, where strong protection against severe/critical disease and death was observed at least 28 days post-final vaccination:

  • 75% overall efficacy against severe/critical COVID-19, across all age cohorts and all countries included in the study.
  • 74% efficacy in the U.S. against severe/critical COVID-19; 89% against hospitalization; 83% against COVID-19-related death.

The Phase 3 ENSEMBLE 2 study showed that another shot of the Johnson & Johnson COVID-19 vaccine given 56 days after the first provided:

  • Potentially 100% protection against severe/critical COVID-19 – at least 14 days post-final vaccination.
  • 75% protection against symptomatic (moderate to severe/critical) COVID-19 globally.
  • 94% protection against symptomatic (moderate to severe/critical) COVID-19 in the U.S.
Author Profile Photo

Caleb J. Fernández

Upon earning his bachelor’s degree from The Pennsylvania State University in Advertising/Public Relations, Caleb went straight to New York City where he learned the necessities of production assistance, photography and art direction. Please reach out via email at if you’re interested in collaborating.

Author Profile Photo

Cole Johnson

Cole grew up in a small town of just over 3,000 people called Moravia, NY—home of President Millard Fillmore and Fillmore Glen State Park.

He is eager to wake up every morning with the Desert Southwest and give viewers the greatest coverage to start their day.

Contact Cole at

Skip to content