Clinical Trials & Research News

Second Dose of J&J’s COVID-19 Vaccine 94% Effective

The Phase 3 trial found that a booster shot of J&J’s single-dose COVID-19 vaccine was highly effective at protecting against the coronavirus and related adverse events, such as hospitalization and death.

COVID-19 Vaccine

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By Samantha McGrail

- Johnson & Johnson recently announced that a booster shot of its COVID-19 vaccine elicited 94 percent protection against coronavirus in a Phase 3 clinical trial. 

The largest real-world evidence study for a COVID-19 vaccine reported to date in the US, ENSEMBLE, enrolled 390,000 individuals who received the Johnson & Johnson COVID-19 vaccine versus nearly 1.52 million unvaccinated individuals.

In the trial, a booster shot of Johnson & Johnson’s COVID-19 vaccine at two months provided 100 percent protection at least 14 days post-final vaccination and 75 percent protection against symptomatic COVID-19 globally. 

When providers administered a booster of the COVID-19 vaccine two months after the first shot, antibody levels rose four to six times higher than observed after the single shot.

The company noted that the safety profile of the booster shot remained consistent when  administered as a single-shot COVID-19 vaccine. 

For example, a single-shot of the vaccine elicited 79 percent protection against COVID-19-related infections, 89 percent protection against hospitalization, 83 percent protection against COVID-19-related death, and 81 percent protection over total study duration.

The data in the trial included the period when the Delta variant became prominent in the US. 

“Phase 3 trial data further confirm protection against COVID-19-related death,” Mathai Mammen, MD, PhD, global head of Janssen research & development at Johnson & Johnson, said in the announcement.

“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,” Mammen continued. 

Johnson & Johnson provided available data to FDA and expects to submit the data to other regulators, the World Health Organization (WHO), and National Immunization Technical Advisory Groups (NITAGs) globally to inform decision-making on local vaccine administration. 

It is critical to prioritize as many people as possible against hospitalization and death given the spread of the coronavirus. And a single-shot COVID-19 vaccine that provides strong and long-lasting protection is vital to vaccinating the global population, Paul Stoffels, MD, vice chairman of the executive committee and chief scientific officer at Johnson & Johnson, emphasized.