Pfizer vaccine 'partially protective' against Omicron

The Omicron variant of the coronavirus can partially evade the protection from Pfizer Inc and partner BioNTech's Covid-19 vaccine, Bloomberg News has reported, citing the research head of a laboratory at Africa Health Research Institute in South Africa.

Its evasion is not complete and a booster shot could provide additional protection, said the report on Tuesday, citing Alex Sigal, head of the lab.

Sigal said on Twitter there was "a very large drop" in neutralisation of the Omicron variant relative to an earlier strain of Covid. 

The lab tested blood from 12 people who had been vaccinated with the Pfizer/BioNTech vaccine, according to a manuscript posted on the website for his lab. The preliminary data in the manuscript has not yet been peer-reviewed.

Blood from five out of six people who had been vaccinated as well as previously infected with Covid-19 still neutralised the Omicron variant, the manuscript said.

According to the manuscript, they observed a 41-fold decline in levels of neutralising antibodies against the Omicron variant.

Sigal said on Twitter that figure is likely to be adjusted after his lab does more experiments.

Global alarm over variant 

The Omicron variant, first detected in southern Africa last month, has triggered alarms globally of another surge in infections, with more than two dozen countries from Japan to the United States reporting cases.

The World Health Organization (WHO) on November 26 classified it as a "variant of concern", but said there was no evidence to support the need for new vaccines specifically designed to tackle the Omicron variant with its many mutations.

There is no indication that Omicron causes more severe disease than previous Covid variants, and existing vaccines should protect people who contract it against the worst outcomes of the disease, a top WHO official told AFP news agency on Tuesday.

"We have highly effective vaccines that have proved effective against all the variants so far, in terms of severe disease and hospitalisation, and there's no reason to expect that it wouldn't be so" for Omicron, Michael Ryan, WHO's emergencies director, told AFP in an interview, stressing that more research was needed.