How safe is J&J’s single-shot Covid-19 vaccine? FDA says it's effective and meets ‘favorable safety profile’
Johnson & Johnson’s coronavirus vaccine is a step closer to reaching the Americans after the US Food and Drug Administration (FDA) confirmed that the single-dose shot was safe and effective against Covid-19. Vaccine efficacy against moderate to severe/critical coronavirus across all geographic areas in which the trial was conducted was 66.9% at least 14 days after the single-dose vaccination and 66.1% when considering cases occurring at least 28 days after vaccination, reveals analysis.
According to the researchers, the vaccine was 85.4% effective at preventing severe cases of Covid-19. The FDA concludes that the Johnson & Johnson vaccine has “known benefits” in reducing both symptomatic and severe illness. This paves the way for it to become the third Covid-19 vaccine that could be authorized for emergency use in the US after Pfizer and Moderna.
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“Safety analysis through the January 22, 2021 data cutoff included 43,783 randomized participants 18 years of age and older with 2-month median follow-up. The analysis supported a favorable safety profile with no specific safety concerns identified that would preclude issuance of an EUA,” says the 62-page document. It adds, “Analyses of secondary endpoints demonstrated vaccine efficacy against central laboratory-confirmed and blind-adjudicated severe/critical Covid-19 occurring at least 14 days and at least 28 days after vaccination of 76.7% and 85.4% respectively.”
On February 4, 2021, Janssen Biotech, Inc. (the sponsor) submitted an Emergency Use Authorization (EUA) request to the FDA for the investigational vaccine known as Ad26.COV2.S. The agency’s Vaccines and Related Products Advisory Committee (VRBPAC) is meeting on February 26 to discuss EUA of the vaccine for Americans 18 years and older.
The FDA may authorize the vaccine by this week, depending on a vote of its vaccine advisory panel on Friday. The company said it would be able to provide 20 million shots by the end of March, with an additional 100 million doses by the end of June.
To explore the possible impact of the circulation of variant strains on vaccine efficacy, a subgroup analysis of vaccine efficacy against moderate to severe/critical and severe/critical Covid-19 was done for the US, South Africa, and Brazil. “There was a lower efficacy against moderate to severe/critical disease endpoints observed in South Africa (52.0% and 64.0%) starting 14 days and 28 days after vaccination, respectively, compared to the US (74.4% and 72.0% starting 14 days and 28 days after vaccination, respectively. But vaccine efficacy against severe/critical Covid-19 at the two timepoints were similarly high in all 3 countries,” the findings state.
According to the safety analysis, the most common solicited adverse reactions associated with Ad26.COV2.S were injection site pain (48.6%), headache (38.9%), fatigue (38.2%), and myalgia or muscle pain (33.2%), which were “predominantly mild and moderate.”
Reports of such reactions were less common among participants 60 years of age and above. “Non-fatal serious adverse events, excluding those attributed to Covid-19, were infrequent and balanced between study groups with respect to rates and types of events (0.4% in both groups). One serious event of a hypersensitivity reaction, not classified as anaphylaxis, beginning two days following vaccination was likely related to receipt of the vaccine,” write authors.
There appeared to be more incidents related to blood clotting and ringing in the ears among those who received the vaccine compared with those who did not, but the FDA notes that data at this time “are insufficient to determine a causal relationship between these events and the vaccine.” As of February 5, there were seven Covid-19-related deaths in the placebo group in the J&J trial and no Covid-19-related deaths in the vaccine group.
Johnson & Johnson also looked for asymptomatic infections by checking for coronavirus antibodies 71 days after volunteers got a vaccine or a placebo. The document indicates that the vaccine may prevent Covid-19 infection without symptoms. But since the calculations were based on a small number of volunteers, the FDA says that “there is uncertainty about the interpretation of these data and definitive conclusions cannot be drawn at this time.”