Early evidence suggests that the Omicron Covid variation is more likely than earlier versions to reinfect persons who have already had the virus or been vaccinated, but it may also cause milder symptoms, according to the WHO.
“Emerging data from South Africa suggests an increased risk of Omicron reinfection,” Tedros Adhanom Ghebreyesus, the World Health Organization’s director-general, told reporters, adding that “there is also some evidence that Omicron produces milder disease than Delta.”
However, he emphasised that more evidence was needed before making definite conclusions, and he urged countries throughout the world to step up their surveillance to help create a fuller picture of Omicron’s behaviour.
The optimistic assessments came as worldwide anxiety over the significantly mutated version intensified, forcing dozens of countries to re-impose border restrictions and raising the prospect of a return to economically painful lockdowns.
Even if Omicron does turn out to produce less severe sickness, Tedros cautioned against losing track of the virus.
He cautioned, “Any complacency now will cost lives.”
Michael Ryan, WHO’s director of emergencies, agreed, saying that the data shows the variant is “efficiently spreading, and perhaps more efficiently transmitting even than the Delta version” so far.
He said, “That does not mean the infection is unstoppable.”
“However, this indicates that the virus is more effective in spreading between humans. As a result, we must redouble our efforts to disrupt those transmission links in order to safeguard ourselves and others.”
Even if the new variation is less harmful than earlier forms, if it spreads faster, it might sicken more people, strain health systems, and cause more deaths, he warned.
The WHO experts emphasised the significance of vaccination, stating that even if vaccinations are less effective against Omicron, as some research suggests, they should still provide significant protection against severe disease.
Soumya Swaminathan, the chief WHO scientist, warned against overreacting to early research suggesting that the Pfizer-BioNTech vaccine may have had reduced efficiency against the new type.
She noted that the investigations so far had been limited, and that the reduction in “neutralising activity” varied drastically between trials, ranging from four to five fold in some to up to 40 fold in others.
They also focused solely on antibody neutralisation, despite the fact that “we know the immune system is considerably more sophisticated than that,” she added.
“I believe it is premature to conclude that this loss in neutralising activity would result in a major decrease in vaccine effectiveness,” she said. “That is something we are unaware of.”
