Travel bans and other restrictions are already in place around the world after the World Health Organization named a strain of covid-19 first detected in Botswana as a variant of concern on Friday, November 26.
Named an omicron in the Greek alphabet, the variant contains more than 30 mutations of its spike protein, which allows it to invade host cells and invite a response from the body’s immune system. At this point, little is known whether it is more contagious or dangerous than other strains, or the effectiveness of current covid-19 vaccines against it. But it may not be long before we do.
Efficacy of the omicron vaccine
There are two main ways of looking at the effectiveness of a vaccine. One is the extent to which the vaccine can reduce the number of cases that might otherwise have occurred, and that is the impact of the vaccine on transmission. The other more pressing question is to what extent vaccines can reduce serious illness and hospitalizations from this strain. It is possible to contract covid despite being vaccinated – a so-called “breakthrough” infection – but with the variants that exist, vaccines mainly protect against serious illnesses.
Penny Moore, Research Chair in Virus-Host Dynamics at the University of the Witwatersrand in South Africa, is leading a team that is already studying how this variant fights antibodies. Moore told the Nature journal they are working at “warp speed” and hope to get answers in as little as two weeks.
Scientists at Pfizer and BioNTech also say they will likely know a lot more about their vaccine’s expected effectiveness in about two weeks.
The comparison with delta
For comparison, the first known samples of delta, first detected in India, date from October 2020. It was labeled a variant of interest on April 4, 2021, and then became “of concern” on May 11. On May 22, Public Health England shared preliminary data on the delta and vaccines. A subsequent study published in June, which used blood samples from vaccinated people to assess the level of antibodies produced against the original strain or against delta, found that delta was much more likely to cause a breakthrough infection, but that vaccines were still effective in preventing serious illness.
More answers on omicron will come from seeing how it is spreading (or not spreading) in countries where the delta is widespread, given its ability to crowd out other strains of the virus and become dominant.
A South African doctor who helped discover omicron said she had observed relatively mild symptoms so far, although it is not clear whether these were from vaccinated or unvaccinated patients. While the data suggests vaccines don’t work as well with omicron, Pfizer and BioNTech say it would be possible to tweak their vaccine in just over three months.