COVID-19 vaccines probably protect against severe illness from Omicron variant: South African expert

JOHANNESBURG: Existing COVID-19 vaccines are probably effective at preventing severe disease and hospitalisation from the newly identified Omicron variant, a top South African infectious disease expert said on Monday (Nov 29).

Professor Salim Abdool Karim, who served as the government's chief adviser during the initial response to the pandemic, also said it was too early to say whether Omicron led to more severe clinical symptoms than previous variants.

However, it did appear more transmissible and more likely to infect people with immunity from vaccination or prior infection.

"Based on what we know and how the other variants of concern have reacted to vaccine immunity, we can expect that we will still see high effectiveness for hospitalisation and severe disease, and that protection of the vaccines is likely to remain strong," Abdool Karim told a news conference.

Preventing severe disease is mainly a function of T-cell immunity, different from the antibody immunity that often blocks infections, "so even if there's some escape from antibodies it's very hard to escape T-cell immunity", he said.

The discovery of the variant in southern Africa has caused a strong global reaction, with countries limiting travel from the region and imposing other restrictions for fear it could spread quickly, even in vaccinated populations.

In Geneva, the World Health Organization (WHO) said on Monday that the variant posed a very high global risk of infection surges, although further research was needed to assess its potential to evade protection against immunity induced by vaccines and previous infections.

On Sunday, a South African doctor who was one of the first to suspect the presence of a new variant, said Omicron appeared so far to be producing mild symptoms.

However, Abdool Karim, a professor at South Africa's University of KwaZulu-Natal and Columbia University in the United States, said it was too early to draw firm conclusions because doctors can only comment on patients who they treat.

"In terms of clinical presentation, there's not enough data yet," he said.

South Africa's government is doing everything possible to prepare its health facilities to cope with the variant, Health Minister Joe Phaahla told the news conference.

Phaahla said officials were engaging with countries that imposed travel restrictions on southern African countries to try to get them reversed.

Public health specialist Waasila Jassat told the same briefing that Gauteng province, the urban central area where cases have surged since the variant's discovery, had so far not seen an increase in COVID-19 deaths.