Omicron variant 'almost certainly' not more severe than Delta, Fauci tells AFP

National Institute of Allergy and Infectious Diseases Director Anthony Fauci, pictured on December 2, 2021, at the National Institutes of Health (NIH) in Maryland, told AFP the Omicron Covid-19 variant is possibly milder than the Delta strain

National Institute of Allergy and Infectious Diseases Director Anthony Fauci, pictured on December 2, 2021, at the National Institutes of Health (NIH) in Maryland, told AFP the Omicron Covid-19 variant is possibly milder than the Delta strain

Top US scientist Anthony Fauci said Tuesday early indications suggested the Covid-19 Omicron variant was not worse than prior strains, and was possibly milder, while cautioning it would take weeks to judge its severity.

Speaking to AFP, President Joe Biden's chief medical advisor broke down the knowns and unknowns about Omicron into three major areas: transmissibility, how well it evades immunity from prior infection and vaccines, and severity of illness.

Accumulating epidemiological data from around the world also indicates re-infections are higher with Omicron and it is likely better at evading immunity from vaccination. 

On the question of severity, "it almost certainly is not more severe than Delta," said Fauci.

But he noted it was important to not over-interpret this data because the populations being followed skewed young and were less likely to become hospitalized. Severe disease can also take weeks to develop.

"Then as we get more infections throughout the rest of the world, it might take longer to see what's the level of severity."

"The worst-case scenario is that it is not only highly transmissible, but it also causes severe disease and then you have another wave of infections that are not necessarily blunted by the vaccine or by people's prior infections," he added.

- Mystery origin -

Though it has not yet been linked to any deaths, scientists are particularly concerned by the unique "constellation" of more than 30 mutations on the spike protein that dots the surface of the coronavirus and allows it to invade cells. 

Either it evolved inside the body of an immunocompromised patient, such as a person with HIV who failed to rapidly fight off the virus. 

Asked whether vaccinated people should act more cautiously given the unknowns, Fauci said the public should remain prudent, particularly during travel, and wear a mask when gathering indoors where the vaccination status of others is unknown.

Booster shots have been shown to drastically increase the level of antibodies that bind to the spike and also translate to better disease outcomes in the real world, as seen in Israel, which embarked on its booster campaign earlier than the United States, said Fauci.

- Misinformation concerns -

The 80-year-old physician and scientist stressed that misinformation continued to hamper the country's pandemic response, with the problem particularly acute in Republican-led states.

"We have in this country still 60 million people who are eligible to be vaccinated and have not gotten vaccinated, and much of that is along ideological and party lines, which is very unfortunate." 

"There's no reason for that, that should not be, we should have a uniform public health attitude," he concluded.

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Originally published as Omicron variant 'almost certainly' not more severe than Delta, Fauci tells AFP