The J&J Covid-19 vaccine protects people against dying if they get infected with the Delta variant, Prof Glenda Gray, co-principal investigator of the Sisonke implementation study — which gave nearly half a million healthcare workers J&J jabs — said on Friday.

Healthcare workers had 91% to 96.2% protection against sickness and death she said, presenting the first results in the world to show J&J’s effectiveness against the Delta variant.

Gray and co-principal investigator of the Sisonke implementation, Prof Linda-Gail Bekker, launched Sisonke on Feb. 17 when the national rollout faltered and they vaccinated about 478,000 healthcare workers until May 17.

“We were able to give healthcare workers vaccinations [ahead of] the third wave,” said Gray.

Heath minister Joe Phaahla said, in the same briefing, that fewer healthcare workers had died or been sick during the third wave after being vaccinated with the J&J shot.

“Everywhere we go, even without proper studies, we get reports from healthcare workers themselves and health leadership that very few people have fallen sick, very few people have ended up in hospital and very few in ICUs.”

The Sisonke analysis found that the J&J vaccine protected against both the Delta and Beta variants, with “in fact greater effect against Delta”.

The analysis was based on data from two medical insurers and from the Western Cape government's payroll database.

Most breakthrough infections — an infection 28 days after vaccination — were mild and the reduction in hospitalisation among vaccinated healthcare workers ranged from 66% to 71%.

Gray said the J&J vaccine proved to be safe, with few side effects, in this real-world study.

“The side effects were completely in line with what we are seeing globally, where they have seen rare adverse events.”

Globally, cases of a very rare blood clotting disorder have been reported. Gray said: “We had two cases ... and both people made a complete recovery.”

Sisonke will continue to monitor safety for two more years and Bekker urged people to get in touch with their safety desk if they had any concerns.

Research on the J&J vaccine showed it had good durability up to eight months, said Gray. “We do not believe there is a need for a booster at this stage and will continue to evaluate this,” she said.

She said more data on durability would be available at the end of August.

“In conclusion, we have provided the world’s first evidence that the Ad26.COV2.S vaccine [J&J] is effective against the Delta variant of concern. It protects against severe disease and death and has an ... immediate and sustained response.”

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