What is happening in South Africa?
The country is seeing a wave of Covid infections linked to two new forms or “subcategories” of Omicron: BA.4 and BA.5. Dr Nicole Wolter of the National Institute of Communicable Diseases in South Africa said the wave was most likely due to BA.4 and BA.5 mutations in the spike protein, which means the virus could also avoid the body’s immunity to to some extent. as declining immunity from previous waves. “In addition, we were relaxing the restrictions, as well as going into winter and therefore experiencing lower temperatures,” he said.
What do we know about BA.4 and BA.5?
BA.4 and BA.5 are now found in Europe and the United Kingdom – albeit at low levels – as well as in other countries. Wolter said work was continuing to understand their characteristics. “While there has been a slight increase in hospitalizations recently, this is from a very low reference value and at the moment we have no evidence to suggest that these new subcategories will be more serious than other Omicron subcategories,” he said. Omicron subcategories include BA.1, which took off in the UK at the end of 2021, and BA.2, which now dominates the UK. Wolter added that South Africa had high immunity due to previous infection and vaccination and this protects against the risk of developing severe Covid with BA.1. “There is currently no indication that this will change with BA.4 / BA.5, however the situation will continue to be closely monitored,” he said. However, research, not yet peer-reviewed by a team including Professor Alex Sigal of KwaZulu-Natal University, found that unvaccinated people who had previously had BA.1 had little protection against BA.4 infection. or BA.5. In contrast, those who had previously had BA.1 and had been vaccinated had much better protection. Another reprint from a team including Professor Tulio de Oliveira, director of the Center for Epidemic Response and Innovation at Stellenbosch University, suggests that BA.4 and BA.5 have identical spike proteins and appear to have a similar growth advantage. 2 as BA.2 had above BA.1 – although some say it’s too early to appreciate that.
What does this mean for the United Kingdom?
Wolter noted that it was difficult to say how different countries could be affected as they have different levels of immunity. Indeed, the United Kingdom has had a long wave of BA.2 and has higher vaccination rates than South Africa. “South Africa was different, like [it]he did not have a second wave of Omicron and the previous immunity of BA.1 is probably receding “, said De Oliveira. Professor Tom Wenseleers of KU Leuven also pointed to the spread of BA.2 in Europe. “Since the NE.4 [and] BA.5 is genetically very close to BA.2, hopefully our immunity to BA infection [and] BA.5 could be somewhat better and that these variants would have a smaller advantage and cause a smaller wave here than in [South Africa],” he said. UCL Professor Christina Pagel added that the UK was approaching summer, which means more outdoor involvement and lower transmission levels, although Covid restrictions have been lifted, there is declining immunity to vaccination and almost no Community testing. “I think so [it is] very likely [BA.4 and BA.5] will be dominant here, “he said, adding that at best it would be a small wave and at worst similar to those of BA.1 and BA.2, noting that it could burden the NHS, disrupt education and jobs. and cause more long Covid.
What about vaccines?
Professor Sir Andrew Pollard, director of the Oxford Vaccine Group, said the vaccinated populations were in a good position as Covid vaccines offered long-term protection against serious disease, with boosters potentially useful for those at higher risk and at higher risk. approach to future amplifiers. UCL Professor Tim Colbourn suggested that it would be good to switch to a special vaccine for Omicron, although current vaccines still protect against serious effects. However, Pollard noted the high rate of infection from Omicron and therefore immunity against it, means that it is increasingly likely that future spread will include a new variant. “If the new variant was similar to Omicron, an Omicron vaccine might be a sensible choice, but it is difficult today to predict which variant will be next and therefore it is not clear which variant or variants to include in a vaccine,” he said. . .
What happens next?
According to Wenseleers, the situation in South Africa suggests that endemic Covid may have a significant surge every six months – although the impact may depend on how boosters and levels of natural immunity are circulated or updated. But not everyone agrees. “While so far we can be sure that Covid is here to stay, it is not yet clear where the virus transmission rates will be regulated in terms of level, peak intensity or frequency of spread,” Pollard said. “We certainly can not predict a seasonal or periodic pattern yet.”
