The single-shot Janssen COVID-19 vaccine candidate under development by Johnson & Johnson met all primary and key secondary endpoints in its Phase 3 trial and will be submitted to the FDA for emergency use authorization, the company reports.

Specifically, the vaccine candidate had an 85% overall efficacy at preventing severe disease 28 days after vaccination and a 66% overall efficacy rate in preventing moderate-to-severe COVID-19, according to interim analysis of the Phase 3 ENSEMBLE trial, which observed 468 symptomatic cases of COVID-19 in 43,783 study participants. The 66% overall efficacy included all participants from different geographies and including those infected with the emerging South Africa variant (B.1.351 lineage).

The vaccine also demonstrated complete protection against COVID-19 related hospitalization and death as of Day 28. According to J&J, there was a clear effect of the vaccine on COVID-19 cases requiring medical intervention (hospitalization, ICU admission, mechanical ventilation, ECMO), with no reported cases among participants who had received the Janssen COVID-19 vaccine, 28 days post-vaccination.

The onset of protection was observed as early as day 14. The level of protection against moderate to severe COVID-19 infection was 72% in the United States, 66% in Latin America and 57% in South Africa, 28 days post-vaccination. Efficacy against severe disease increased over time with no cases in vaccinated participants reported after day 49, according to J&J.

The company intends to file for US FDA emergency use authorization in early February and expects to have product available to ship immediately following authorization, J&J said in a press release.

“These topline results with a single-shot COVID-19 vaccine candidate represent a promising moment. The potential to significantly reduce the burden of severe disease, by providing an effective and well-tolerated vaccine with just one immunization, is a critical component of the global public health response,” said Paul Stoffels, MD, vice chairman of the executive committee and chief scientific officer of Johnson & Johnson. “A one-shot vaccine is considered by the World Health Organization to be the best option in pandemic settings, enhancing access, distribution and compliance.”

“Eighty-five percent efficacy in preventing severe COVID-19 disease and prevention of COVID-19-related medical interventions will potentially protect hundreds of millions of people from serious and fatal outcomes of COVID-19. It also offers the hope of helping ease the huge burden placed on healthcare systems and communities,” said Alex Gorsky, board chairman and CEO of Johnson & Johnson.

The safety profile was consistent with other vaccine candidates using Janssen’s AdVac technology among more than 200,000 people to date. Overall fever rates were 9% and Grade 3 fever 0.2%. Overall serious adverse events reported were higher in participants who received placebo as compared to the active vaccine candidate. No anaphylaxis was observed, according to J&J.

Trial participants of the phase 3 ENSEMBLE study continue to be followed for up to two years for assessments of safety and efficacy. Therefore, these data may be updated based on ongoing analysis. The comprehensive available data set will be submitted to a peer-reviewed journal in the coming weeks.