South Africa study shows boosters failed to block omicron, bolstering case for face masks

A study of some of the first breakthrough cases of COVID-19 caused by the highly infectious omicron variant found that booster shots of the mRNA vaccines failed to block that strain.

The study involved a group of seven Germans visiting Cape Town in South Africa who had the first documented breakthrough cases of COVID between late November and early December after receiving three vaccine doses, including at least two of the mRNA shots developed by Pfizer or Moderna. Findings were published in the medical journal the Lancet. The group comprised five white women and two white men between 25 and 39 years of age, four of whom were participating in clinical training at hospitals, while the others were on vacation. All seven developed respiratory symptoms between Nov. 30 and Dec. 2 and tested positive for the omicron variant of the SARS-CoV-2 coronavirus. The study was approved by Stellenbosh University and the University of Cape Town.

“These findings emphasize that non-pharmaceutical measures should be maintained,” the authors wrote. Earlier this week, a preliminary study by a hospital in Israel found that a second booster dose failed to block omicron, even though it lifted antibodies to a higher level than they had been after a first booster shot.