J&J joins COVID-19 booster shot drive, filing with FDA

Johnson & Johnson's COVID-19 vaccine has been a minor player in the US vaccination drive so far, but the company hopes it can have a bigger role as a booster shot.

The drugmaker has filed for approval of a second dose of its one-shot Ad26.COV2.S vaccine for people aged 18 years and older, based on the results of its ENSEMBLE 2 trial.

That study showed that a booster dose given two months after the first had an efficacy of 94% against symptomatic disease in US recipients, with 100% protection against severe or critical COVID-19.

J&J's vaccine has been used to vaccinate around 15 million Americans, compared to 226 million doses and 151 million doses, respectively, of Pfizer/BioNTech and Moderna's two-shot vaccines, as of 30 September.

J&J has also submitted data from a phase 1/2 trial looking at a booster given six months after the original Ad26.COV2.S dose, which showed antibody levels leaped nine-fold seven days later, and were 12-fold higher on average after four weeks.

The FDA has scheduled a meeting of its Vaccines and Related Biological Products Advisory Committee next week to consider booster doses, with Moderna's vaccine considered on 14 October and J&J's shot under scrutiny the following day, along with "mix-and-match" booster data.

Pfizer/BioNTech's Comirnaty has already been approved as a booster shot for people aged 65 years and older, adults at high risk of severe COVID-19, and those exposed to the virus because of their work or living conditions.

Comirnaty was also backed for all adults aged 18 and over by the EMA's human medicines committee earlier this week, while Moderna's jab got a green light for people with weakened immune systems and is also under review in Europe for broader use.

J&J has said it plans to file for approval of a booster dose of Ad26.COV2.S to other regulatory authorities around the world as well as to the World Health Organization (WHO).

"We look forward to our discussions with the FDA and other health authorities to support their decisions regarding boosters," said Mathai Mammen, head of R&D at J&J's Janssen pharma unit.

"At the same time, we continue to recognise that a single-shot COVID-19 vaccine that provides strong and long-lasting protection remains a crucial component to vaccinating the global population," he added.

The company has been pushed onto the defensive by a recent study published by the Centres for Disease Control and Prevention (CDC) which suggested that its vaccine was only 71% effective against hospitalisation from COVID-19, while Pfizer/BioNTech and Moderna offered 88% and 93% protection, respectively.

J&J has said its own real-word study indicates 81% efficacy against COVID-19 hospitalisations, and 79% against infections, with no evidence of reduced effectiveness as the highly transmissible delta variant of SARS-CoV-2 started to predominate in the US.