Critical period for research on Omicron

THE country entered the fourth wave of the Covid-19 pandemic on Friday, with the Omicron variant driving the number of infections.

During a briefing, Health Minister Joe Phaahla said this festive season was no different from last year, when the country had entered the second wave.

“At the time we were introduced to the Beta variant, and now we have entered the fourth wave with a new variant. We knew the fourth wave was coming, but we didn’t know how soon and what special characteristics would accompany it. There is a much steeper upward curve than has ever been seen in the past three waves,” Phaahla said.

According to data from the National Institute of Communicable Diseases (NICD) there were 2 273 infections on Monday, and by Friday there were 16 055. Between Monday and Friday the total number of active cases respectively increased from 24418 to 61361 – a total of 40524 confirmed cases.

Friday’s ratio of positive new cases and total new tests was 24.3%, higher than Thursday’s 22.4%, but the 7-day average was 14.7% on Friday, an increase from the previous day’s 12.6%.

Clinical epidemiology professor Quarraisha Abdool Karim, co-founder and associate scientific director of Caprisa, said the first sequenced Omicron case was reported from Botswana on November 11, and a few days later another case was sequenced from Hong Kong in a traveller from SA.

“The earliest known case of Omicron in the country was November 9, although it is probable that there were unidentified cases in several countries across the world before then,” she said.

Infectious diseases epidemiologist Professor Salim Abdool Karim, former co-chair of the Covid-19 ministerial advisory committee, said although previous variants of concern had emerged in a world where natural Covid-19 immunity was common, Omicron emerged at a time when vaccine immunity was increasing globally.

He said the transmissibility rates between Delta and Omicron were unknown, but since Omicron was rapidly spreading against a backdrop of Delta dominance, Omicron was anticipated to displace Delta as the dominant variant in SA.

Vaccinology Professor Shabir Madhi said it would take between two to three weeks to start receiving information, and then four to five weeks for hard evidence on whether or not natural or vaccine-gained immunity would prevent severe disease and death caused by Omicron.

“I believe we are going to see that past infections and vaccines are not going to perform too well in preventing reinfection or large surges in breakthrough infections in those who are vaccinated. Mutations suggest Omicron would be resistant to B-cell antibody immunity, but most cases would be mild disease. But the big question is whether or not it could progress to severe disease,” Madhi said.

According to the department, 26 263 590 vaccine doses had been administered thus far, but the target remained for about 40 million citizens to be vaccinated by the end of February.