New Johnson & Johnson data shows second shot boosts antibodies and protection against COVID-19 – but one dose is still strong against delta variant - The Conversation US

On Sept 22, 2021, Johnson & Johnson released data that answers two questions many people have likely been wondering about its vaccine: How good is it against the delta variant, and do I need a booster.

Early clinical trial data released in January 2021 showed that four weeks after the first dose, the Johnson & Johnson single-shot vaccine was 66.3% effective at preventing COVID-19 infection.

Studies show that individuals who received a Johnson & Johnson or an mRNA vaccine continue to produce some level of antibodies for at least six months after vaccination.

In addition to the results of the single–shot study, on Sept 21, 2021, Johnson & Johnson also released data about booster shots.

The trial gave people a second dose of the Johnson & Johnson vaccine either two or six months after the first dose.

One important question is whether someone who received the Johnson & Johnson shot should get a second Johnson & Johnson dose or mix and match – get a second dose of a different vaccine.

As of late September, the FDA seems more likely to approve a second dose of the Johnson & Johnson vaccine because there isn’t much data yet about a mix-and-match strategy.

On Sept, 22, 2021, the FDA approved booster shots for people who received the Pfizer vaccine and are 65 years of age and older, at risk of severe COVID-19 illness or whose occupations put them at greater risk of exposure.