What has WHO said about the covid-19 Omicron variant compared to Delta?
There is promising news from the WHO that the new variant is less severe compared to Delta, but questions still remain on its transmissibility.


The Omicron variant is spreading rapidly across the world, with various travel bans being unable to stop the spread. Due to its transmissibility, the variant is expected to outnumber the Delta variant in cases in the next few months and become the dominant train.
In terms of their other differences, the CDC expects that anyone with Omicron infection can spread the virus to others, even if they are vaccinated or don’t have symptoms. In more positive news, there is emerging evidence that Omicron cases could be less severe compared to Delta, although this has only been shown in South Africa's youthful population.
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Will existing vaccines work?
Researchers in South Africa say there is a "very large drop" in the efficacy of the Pfizer vaccine. While it has yet to be peer-reviewed, the study says it could be up to 40 times less effective against Omicron compared to the original covid-19 strain.
The other main vaccines in use in the west, Moderna and Johnson & Johnson, are yet to be tested.
Lot of people seem to have remarkably confident and clear views on where we're headed with Omicron.
— John Burn-Murdoch (@jburnmurdoch) December 7, 2021
I've spent the last 48 hours immersed in the data and speaking to doctors and public health officials in South Africa, and I've done two complete 180s since this morning 😅
The best protection against the new variant continues to be existing vaccines. Around 47 million people in the United States have now received a booster shot, US Centers for Disease Control and Prevention data shows, almost a quarter of all fully vaccinated adults in the country.
"We have highly effective vaccines that have proved effective against all the variants so far, in terms of severe disease and hospitalization, and there's no reason to expect that it wouldn't be so" for Omicron, Dr Mike Ryan, the WHO's emergencies director, told AFP news agency.
What have experts said about Omicron?
On the question of severity, "it almost certainly is not more severe than Delta," said Anthony Fauci, President Biden's Chief Medical Advisor.
"There is some suggestion that it might even be less severe, because when you look at some of the cohorts that are being followed in South Africa, the ratio between the number of infections and the number of hospitalizations seems to be less than with Delta."
#BREAKING Omicron Covid variant 'almost certainly' not more severe than Delta, top US scientist Fauci tells AFP pic.twitter.com/2mez0stPhh
— AFP News Agency (@AFP) December 7, 2021
"As we get more infections throughout the rest of the world, it might take longer to see what's the level of severity."