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On Tuesday, South African researchers released encouraging data based on real-world COVID-19 infections in the country during the current fourth wave of coronavirus infections, driven almost entirely by the new Omicron variant. The preliminary analysis of data gathered by the insurer Discovery shows the standard 2-dose regimen of Pfizer-BioNTech’s COVID-19 vaccine has been about 70% effective at preventing hospitalization over the last 3-weeks, as Omicron has swept across the country. Both vaccinologists and the pharmaceutical companies that make the vaccines said the Omicron variant does appear to have a significant ability to evade the vaccines to cause infection. The data released on Tuesday suggests 2 shots of the Pfizer jab are only about 33% effective at preventing infection. The findings mirror other preliminary research presented over the last week or so by Pfizer, and scientists in South Africa, testing the vaccines against the new variant.

Last week, Pfizer said its own lab work showed the third dose, or booster, of its vaccine, was highly effective at preventing symptomatic COVID-19 infection with Omicron about as potent as just 2 shots had been with the previous, Delta variant. However, the US and other wealthy countries race ahead to administer booster shots and many developing regions are still struggling to get people their first 2 jabs. Less than 10% of the overall population of Africa is fully vaccinated to date. Only around 30% have been fully vaccinated in South Africa, but the real-world evidence emerging from the country where Omicron was first detected and has been prevalent for weeks, particularly regarding serious illness, is encouraging. Data show the hospitalization rate for adults during the current wave of COVID infections has been about 29% lower than during the previous Delta wave.

Moreover, the health experts in South Africa have said hospitals are a lot less full now than they were when the Delta variant tore through the population. But the head of the South African Medical Research Council and one of the leaders of the preliminary study, Glenda Gray announced results on Tuesday. It echoed other experts in the country and said that the lower hospitalization rates now are likely thanks in large part to the huge proportion of people who carry some immunity to COVID-19 from the previous infection. She said that in some parts of South Africa, up to 80% of the local population has had COVID-19. However, it remains unclear how much the previous infection may help to prevent an infection or severe illness with Omicron, but any natural immunity has come at a high price.