- Healthcare workers infected with Covid-19 after getting the Johnson & Johnson vaccine have displayed mild symptoms.
- A total of 479 768 healthcare workers received the J&J vaccine as part of the Sisonke trial.
- J&J is effective against the beta and delta variants.
Data released by the South African Medical Research Council (SAMRC) shows that the Johnson & Johnson (J&J) vaccine offers significant protection against severe disease and hospitalisation.
Ninety-four percent of healthcare workers vaccinated as a part of the Sisonke Phase 3b trial with the J&J vaccine exhibited mild symptoms after being infected with Covid-19.
Through the Sisonke implementation study, 479 768 healthcare workers were vaccinated against Covid-19 with the J&J vaccine.
Now, data from the SAMRC and Sisonke showed that the vaccine provided significant protection to healthcare workers with breakthrough infections.
Breakthrough infections are Covid-19 positive cases that occur 28 days post-vaccination.
The SAMRC tracks breakthrough infections through "daily linkages to national Covid-19 registries of laboratory and hospitalisation data and through reports to the Sisonke desk".
The Sisonke team then contacts the healthcare worker and establishes the severity of the infection.
"Consistently, we are finding that 94% of breakthrough infections are mild, 4% are moderate, and only 2% severe," the SAMRC said.
The SAMRC said antibody studies from the US showed that immune responses induced by the J&J vaccine matured and covered variants of concern, such as the beta and delta variants over time.
The delta variant dominates the current third wave in South Africa.
Professor Glenda Gray, co-principal investigator of the Sisonke protocol, said: "The single-dose vaccine, designed for emergency use, is safe and easy to use. We have mounting data to suggest that immunity increases over time and that it retains its efficacy against important variants such as beta and delta."
Professor Linda-Gail Bekker, co-principal investigator, said ensuring people don't end up in the hospital due to infection was important.
"Keeping individuals out of ICU and off ventilators is an important outcome. I'm very reassured that the vast majority of breakthrough infections in Sisonke are mild. We believe that recommending booster top-ups with another vaccine is premature."