Mass Omicron infection could lead to the formation of new and potentially even more dangerous coronavirus variants, officials from the World Health Organization warned on Thursday.

That is despite the fact that the Omicron variant is proving less lethal than its SARS-CoV2 predecessors, such as Alpha, Beta and Delta – which swept through India and then the world beginning in the spring of 2021. 

“We are giving this virus plenty of opportunities to circulate and the more the virus circulates the more opportunity it has to change,” said Dr. Maria Van Kerkhove, WHO’s COVID-19 technical lead, speaking at the first global press briefing of 2022. 

“I think, unfortunately, this will not be the last variant you hear us address. It will not be the last variant of concern.”

Her comments followed on remarks by a WHO European Region Emergencies official, Catherine Smallwood, earlier in the day, who sounded an even more ominous note:  

”The more Omicron spreads, the more it transmits and the more it replicates, the more likely it is to throw out a new variant,” Smallwood told AFP, “Now Omicron is lethal, it can cause death, maybe a little bit less than Delta, but who’s to say what the next variant might throw out.”

At the WHO global briefing later in the day, Mike Ryan, executive director of WHO’s Health Emergencies Program, also recalled having discussions during the previous Delta wave with top scientists who said that the Delta variant was so adept at infecting and replicating, that they could not imagine it mutating much more.  

“Yet it did,” Ryan stressed, “and we have seen a further variant emerge that is even more transmissible than Delta, which was even more transmissible than its predecessors… We are not doing well enough globally to say with any degree of certainty that we can avoid the emergence of new variants.”

Spreading at an unprecedented rate 

Omicron is spreading at an unprecedented pace worldwide. In the United States, it now makes up 95% of cases, the Centers for Disease Control and Prevention said. The United Kingdom has said that one in 15 people are infected with the virus, and Indian health officials said Thursday that the country logged more than 90,000 new COVID cases in a 24-hour period, with a positivity rate of more than 4%. 

Last week also saw record highs in the number of new COVID-19 cases to be reported since the beginning of the pandemic  – “and we know for sure this is an underestimate number of cases,” said WHO Director-General Dr. Tedros Adhanom Ghebreyesus.  He stressed that increased vaccine roll-out in underserved countries 

While Omicron does appear to be less severe compared to Delta, especially in those who are vaccinated, it should not be classified as mild, he warned. 

“Omicron is hospitalizing people and killing people,” Tedros said. “It is overwhelming health systems around the world.”

Moreover, the Delta variant is still dominant in some countries and is mutating too, Van Kerkhove added. 

“Omicron is very efficient, but Delta is evolving as well,” Van Kerkhove said. “There are about 30 sub-lineages of Delta that we are tracking.”

WHO Advice includes more of same: masking, social distancing, vaccination  

While the WHO officials sounded a gloomy prognosis on the massive infection wave underway – and what that could mean for future virus mutations  – there were few new measures that they could suggest. 

And certain thorny questions that countries are struggling with now, such as  whether rapid antigen tests could be a reliable go-to protocol for people that suspect they are infected, or want to be released from quarantine, were not addressed. 

Ryan stressed, however, the need to continue with quarantine policies –  even while in some countries as many as one in 15 people are infected with Omicron. He said that quarantines should remain in place for at least five days, while people are most infectious.   That is generally in line with the revised advice that has been issued by the United States Centers for Disease Control, to respond to the infection surge. 

Ryan added that one of the ways to temper longer periods of isolation is through regular testing.  But he didn’t enter the debate raging now in many countries about reliance on rapid antigen tests, as compared to PCRs, to determine COVID infection status, officially report on COVID cases, and send people to quarantine – or allowing them to exit.  

While positive results of rapid antigen tests, using lateral flow devices, are generally regarded as reliable, negative results are considered far less accurate.

One recent pre-print study found that rapid tests are particularly unreliable at detecting the early stages of infection – leaving many people to walk around infectious for an average of three days after a positive PCR test – before showing a positive antigen test result. See related story:

COVID-19 Could Become Endemic in Africa if 70% Vaccination Coverage is not Achieved by 2022 – Africa CDC

WHO officials reiterated well-worn advice on the value of masking, social distancing and vaccination. Tedros also stressed, once more, the importance of expanding vaccine drives in under-resourced developing countries, where even more variants could otherwise fester. 

“This is about making personal decisions,” Van Kerkhove said, “this is about distancing – keeping your distance from others – wearing a well-fitted, appropriately made mask… Make sure you spend more time in places where there is better ventilation… and stay home if you are unwell.”