The Omicron variant of Covid-19 is highly unlikely to fully evade immunity offered by vaccines, a senior World Health Organization official said on Tuesday, according to AFP.

Micheal Ryan, the Executive Director of the global health body’s emergencies programme, told the news agency that the variant does not seem to cause more severe disease than earlier detected strains of the coronavirus. Ryan said that preliminary data indicated that infections caused by the Omicron variant were less severe.

“We have highly effective vaccines that have proved effective against all the variants so far, in terms of severe disease and hospitalisation,” Ryan said. “The preliminary data from South Africa wouldn’t indicate that we will have a catastrophic loss of efficacy.”

The official, however, said that it was possible that Omicron could replace Delta as the dominant strain of Covid-19. He added that there was evidence to suggest that reinfection with Omicron was more common than with previous variants.

The Omicron variant was first detected in South Africa in November and has spread to many other countries. The World Health Organization classified it as a variant of concern on November 26. It noted that it has a large number of mutations, some of which are concerning.

India’s first two cases of the Omicron variant had been detected in Karnataka on December 3. Till Monday, a total of 23 cases of the variant had been found in India.

‘Omicron unlikely to be more severe than Delta’: Top US scientist

Anthony Fauci, the chief medical advisor to United States President Joe Biden, told AFP that early indications were that the Omicron variant was “almost certainly” not more severe than Delta.

“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,” the official told the agency.

Fauci, however, said that the new variant was highly transmissible and was likely to be more so than the Delta strain.