With the Omicron variant spreading its tentacles in 57 countries, WHO Director-General Tedros Adhanom Ghebreyesus on Thursday warned that its certain features, including its global presence and a large number of mutations, suggest it could have a major impact on the course of the Covid-19 pandemic.
In the meantime, a vaccine advisory panel of the global health agency has recommended that people who are immunocompromised or received an inactivated vaccine should receive a booster dose of a Covid-19 shot. Its contention was that vaccines’ efficacy against Covid-19 wanes, with a significant decline seen in older people in particular.
On the Omicron variant, Tedros Adhanom Ghebreyesus said, “We are now starting to see a consistent picture of rapid increase in transmission (rates), although for now the exact rate of increase relative to other variants remains difficult to quantify.”
Emerging data from South Africa suggests increased risk of re-infection with Omicron, but more data are needed to draw firmer conclusions, he added.
While some evidence might suggest that Omicron causes milder symptoms than the earlier Delta variant, it’s still early days to draw any final conclusions, WHO experts have said.
According to Mike Ryan, executive director of the WHO’s Health Emergencies Programme, although the evolutionary nature of the virus makes it more transmissible as it mutates, this doesn’t necessarily make the virus less severe, as has been suggested by some “urban legends”.
Whether or not a mutation turns out to be milder or more lethal is a matter of chance, he said.
As studies of the latest Covid-19 variant are evolving, the WHO said it still needs days or even weeks for global epidemiological data to come in, be analysed and then to draw any firm conclusions.
It’s also still premature to say that Omicron could result in a significant reduction in vaccine effectiveness, according to WHO Chief Scientist Soumya Swaminathan.
The WHO has called on all countries to increase surveillance, testing, and sequencing, and to submit more data to its Clinical Data Platform using an updated online case reporting form.
The WHO’s vaccine advisory panel suggested booster doses for people who are immunocompromised or received an inactivated vaccine.
Many countries have been rolling out booster shots, targeting the elderly and people with underlying health issues, but worries about the new Omicron variant have prompted some to expand their use to larger portions of their populations.
With vaccination rates worryingly low in much of the developing world, the WHO has said in recent months that administering primary doses - rather than boosters - should be a priority.
The recommendation comes after the Strategic Advisory Group of Experts (SAGE) on immunisation held a meeting on Tuesday to evaluate the need for Covid-19 boosters.
Speaking in a briefing, SAGE chair Alejandro Cravioto said emerging data showed that vaccines’ efficacy against Covid-19 wanes, with a significant decline seen in older people in particular.