Patients '29% less likely to be hospitalised with Omicron'

Data from a real-world study South Africa has indicated that the Omicron variant of COVID-19 is 29% less likely to cause hospitalisation among infected adults than other strains – although the researchers behind the work stress the findings are preliminary.

The results – released by healthcare insurance group Discovery SA and the South African Medical Research Council – back up speculation among experts that Omicron may be less virulent than other variants even though it seems to have a frighteningly high level of transmissibility.

The real-world study of more than 211,000 positive COVID-19 PCR test results was carried out in the Gauteng area of South Africa where Omicron first took hold, and also includes some other encouraging findings.

Top of the list is that while two doses of the Pfizer/BioNTech Comirnaty vaccine only seems to provide 33% protection against infection by Omicron, two doses prevents 70% of hospitalisations compared to unvaccinated people.

The researchers stress that the results come from just three weeks of data since the Omicron outbreak was first identified in South Africa and Botswana, so the numbers could change. Moreover, the study also revealed that Omicron poses a higher risk of reinfection for people who have previously had COVID-19.

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Around 41% of the 211,000 PCR tests were conducted in people who were double vaccinated with Comirnaty.

The protection against hospitalisation is still lower than the 93% efficacy on this measure shown by Comirnaty on the Delta variant, but still a reasonable level of protection and above the 50% threshold for efficacy set by the World Health Organization for COVID-19 vaccine early on in the pandemic.

Pfizer and BioNTech have already reported data showing that a third booster dose of Comirnaty provides a similar level of neutralising antibodies to Omicron that was comparable to two doses against wild-type COVID-19 and other variants.

The 70% protection from hospitalisation with two doses was observed across all adult age groups, but does track down with older age, reaching 59% in the 70 to 79 bracket. That could be because older people were vaccinated first and there has been more time for immunity to wane than with younger people.