Johnson & Johnson vaccine efficacious upto 8 months after COVID-19 vaccination: NEJM

Interim immunogenicity and efficacy data for the Ad26.COV2.S vaccine for COVID-19 have recently been reported. In the recent study, a team of researchers under Dan H. Barouch, from Center for Virology and Vaccine Research,Boston, USA have described the 8-month durability of humoral and cellular immune responses in 20 individuals who received one or two doses of 5×1010 vp or 1011 vp Ad26.COV2.S and in 5 participants who received placebo.

The team further evaluated antibody and T cell responses on day 239, which was 8 months after the single-shot vaccine regimen (N=10) or 6 months after the two-shot vaccine regimen (N=10). "We also report neutralizing antibody responses against the parental SARS-CoV-2 WA1/2020 strain as well as against the SARS-CoV-2 variants D614G, B.1.1.7 (alpha), B.1.617.1 (kappa), B.1.617.2 (delta), P.1 (gamma), B.1.429 (epsilon), and B.1.351 (beta)." the team elaborated.

Results have revealed some new facts.

• Antibody responses were detected in all vaccine recipients on day 239 .
• The median WA1/2020 pseudovirus neutralizing antibody titer was 272 on day 29, 169 on day 57, 340 on day 71, and 192 on day 239; titers were similar when the analyses were restricted to participants who had received the single-shot vaccine regimen.
• Spike-specific interferon-γ CD8+ and CD4+ T-cell responses were evaluated by intracellular cytokine staining assays and also showed durability and stability over this time period.
• The durability of immune responses elicited by the Ad26.COV2.S vaccine was consistent with the durability recently reported for an Ad26-based Zika vaccine.

"These data suggested an expansion of neutralizing antibody breadth associated with improved coverage of SARS-CoV-2 variants over time, including increased neutralizing antibody titers against these variants of concern."the team concluded.

For full article follow the link: DOI: 10.1056/NEJMc2108829

Source: New England Journal Of Medicine.