Janssen Vaccine Protects Against COVID-19, Effective Against Critical Disease in International Trial

The Ad26.COV2.S COVID-19 vaccine has shown a positive benefit against both symptomatic and asymptomatic disease, as well as critical disease and hospitalizations in a Phase 3, international trial.

The vaccine was created by Janssen Pharmaceuticals, a company of the largest medical device corporation in the world, Johnson and Johnson.

Results from the study were published in The New England Journal of Medicine.

“Our COVID-19 ENSEMBLE data…demonstrate that, with a single shot, our vaccine offers a high level of activity across all variants and regions studied,” Mathai Mammen, Global Head of Janssen Research & Development said. “We believe these data support the important role our COVID-19 vaccine can play in helping to address the global pandemic that continues to threaten people and healthcare systems around the world.”

The international, randomized, double-blind, placebo-controlled, phase 3 trial, called ENSEMBLE, included 19,630 participants who were negative for SARS-CoV-2 and received a single dose of the vaccine, and 19,691 who received a placebo.

The 2-year ongoing, multicenter trial is taking place in Argentina, Brazil, Chile, Colombia, Mexico, Peru, South Africa and the United States. Participants were assigned 1:1 to receive the therapy or a placebo. The randomization was stratified according to trial site, age group, and the presence or absence of coexisting conditions that have been associated with an increased risk of severe COVID-19.

The 2 primary end points included the efficacy of the vaccine against the first occurrence of centrally confirmed moderate to severe–critical COVID-19 with an onset at least 14 and 28 days after administration.

Findings from the study showed that the vaccine had an efficacy of 66.9% on the primary endpoint of onset at least 14 days after administration, and 66.1% of onset at least 28 days after administration.

Against severe-critical COVID-19, the vaccine was found to have a higher efficacy of 76.7% for onset at ≥14 days and 85.4% for onset at ≥28 days.

As it pertains to the South African variant, data from the South African trial site demonstrated a vaccine efficacy of 52.0% and 64.0% against moderate to severe–critical Covid-19 with onset at least 14 days and at least 28 days after administration, respectively.

Additionally, for those participants who experienced breakthrough cases of COVID-19 following a vaccination, they reported fewer and less severe symptoms compared to placebo recipients, which suggests that illness is milder after administration.

“This comprehensive evidence demonstrates that Johnson & Johnson’s single-shot COVID-19 vaccine offers protection and prevents hospitalization and death, including in countries where viral variants are highly prevalent,” Paul Stoffels, Vice Chairman of the Executive Committee and Chief Scientific Officer at Johnson & Johnson said. “Regardless of race and ethnicity, age, geographic location and comorbidities, these results remain consistent. A single-shot vaccine that provides this level of protection represents an important tool in the global fight against COVID-19, as we strive to help end this deadly pandemic. The safety and well-being of every individual who receives a Johnson & Johnson product remains our top priority, and these data reaffirm our confidence in the protective benefits of our COVID-19 vaccine.”