Johnson and Johnson’s COVID-19 vaccine booster dose is 85% effective in preventing hospitalisation from the omicron variant of the virus, a study from South Africa has shown.

This efficacy is achieved one to two months after the shot is received. 

The findings of the study were presented at a South African health ministry briefing on Friday. Glenda Gray, head of South Africa’s Medical Research Council (SAMRC), said, “We saw an 85% vaccine effectiveness and we saw that this kind of vaccine effectiveness is maintained for up to two months. We are very happy to report very high levels of vaccine effectiveness against Omicron,” according to a Reuters report.

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The highly transmissible variant of coronavirus has been driving new waves of COVID infection across the world, including South Africa. 

The SAMRC research looked at 477,234 vaccinated healthcare workers, who had received the J&J shot. Nearly half of them, 236,000 had been given the booster dose. 

The study analysed the number of hospitalisations among these workers during the fourth COVID wave. It found that the booster had reduced the chances of hospitalisation by 63% in the first two weeks after the shot, and 83% after that. 

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“This is the world’s first evidence of vaccine effectiveness (against Omicron) using the J&J vaccine,” Gray said, according to the Reuters report. 

Individuals infected with HIV, who make up nearly 13% of the country’s population, were found to be more vulnerable to being hospitalised, the study showed.

“They (those being hospitalised) are more likely to have HIV and less likely to have other comorbidities as compared to the Beta and Delta period,” Gray said.

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Importantly, this research added to the claims that omicron could possibly evade vaccine protection with respect to the initial infection. Around 30,000 breakthrough infections were reported among the study participants, compared to only 11,000 from the earlier waves.

Meanwhile, 21 million doses of the Pfizer-BioNTech COVID vaccine have been administered in South Africa, which is significantly higher than the seven million J&J jabs. 

However, the latter is pragmatically a better option considering it’s a single-dose vaccine and can reach more people without the need for a follow-up.