J&J’s COVID-19 Vaccine Booster Increased Antibody, T-Cell Responses

Johnson & Johnson recently announced preliminary results from an independent study, which showed that a booster shot of its COVID-19 vaccine increased both antibody and T-cell responses.

In the Janssen-sponsored COV2008 study, researchers administered Ad26.COV2.S six months after a two-dose primary regimen of BNT162b2. The booster led to a greater increase in CD8+ T-cell responses than boosting with BNT162b2.

Dan Barouch, MD, PhD of Beth Israel Deaconess Medical Center (BIDMC), conducted the study. The T-cell response data suggest differences between immune responses following homologous boosting, and the overall results demonstrate the potential benefits of heterologous boosting.

“These results provide valuable scientific insights for our vaccine when used as a mix-and-match booster and can help inform boosting strategies with the goal to curb the pandemic,” Mathai Mammen, MD, PhD, global head of Janssen Research & Development at Johnson & Johnson, said in the announcement.

“The mix-and-match booster dose of the Johnson & Johnson COVID-19 vaccine successfully increases humoral responses and cellular responses against the original strain of SARS-CoV-2, as well as the Beta and Delta variants,” Mammen continued.

Johnson & Johnson’s COVID-19 vaccine leverages Janssen’s AdVac technology and cell-mediated immunity, including CD4+ and CD8+ responses.

T-cells can target and destroy cells infected by the virus that causes COVID-19. Specifically, CD8+ T-cells can directly destroy infected cells and are aided by CD4+ T-cells, a Johnson & Johnson spokesperson explained.

Preliminary results from the UK COV-BOOST clinical study, which found that a booster dose of the vaccine increased both antibody and T-cell responses following primary vaccination with two doses of either BNT162b2 or ChAdOx1 nCov-19, reinforce the most recent data.

And in October, Johnson & Johnson submitted data to FDA to support its booster in adults 18 years and older.

In the Phase 3 ENSEMBLE trial, a booster shot of the vaccine at two months provided 100 percent protection at least 14 days post-vaccination and 75 percent protection against symptomatic COVID-19 globally.

Barouch stated that this data is early evidence to suggest that a mix-and-match boosting approach may provide individuals with different immune responses against COVID-19 than a homologous boosting approach.