Omicron variant more resistant to vaccines but causes less severe covid, major South African study concludes

Omicron variant more resistant to vaccines but causes less severe covid, major South African study concludes

A woman gets vaccinated at a Johannesburg clinic on Dec. 6. (Shiraaz Mohamed/AP)

CAPE TOWN, South Africa — Omicron appears to cause less severe illness than earlier variants of the coronavirus but is more resistant to the two-dose Pfizer-BioNTech vaccine widely used in South Africa, according to the first major private study since omicron was first detected last month.

Get the full experience.Choose your plan

The study by Discovery Health, South Africa’s largest health insurer, of 211,000 positive coronavirus cases showed that risk of hospital admissions among adults who contracted covid-19 was 29 percent lower than in the initial pandemic wave that emerged in March 2020.

However, the study found that the Pfizer-BioNTech vaccine provided just 33 percent protection against infection, much less than the level for other variants detected in the country so far. At the same time, the vaccine provided 70 percent protection against severe complications that would require a patient to be hospitalized, the study found, calling that “very good protection.”

The study comes as omicron has become the dominant variant in South Africa less than three weeks since its existence was confirmed, on Nov. 25. The World Health Organization warned Monday that omicron, now detected in 63 countries, poses a “very high” global risk.

Story continues below advertisement

The drop in the protection of two doses of the Pfizer vaccine against any symptomatic infection is similar to what a British preprint study released late last week showed, namely that it dipped below 40 percent.

The British study, however, could not answer pressing questions about whether vaccine protection against severe disease would erode just as steeply. The South African data provides a first hint, showing that protection against severe illness requiring hospitalization after two doses was diminished from its more than 90 percent protection against the delta variant but remained relatively robust, at 70 percent.

Carolyn Y. Johnson contributed to this report.

Read more: