Children, contagiousness, severity: What we know (and don’t know) about the Omicron COVID variant so far

December 3, 2021, 1:01 PM UTC

The Omicron COVID-19 strain has spread to at least 32 countries, battered financial markets, and spread fear in public health officials since it was first detected a week ago and labeled a “mutation variant of serious concern” by the World Health Organization. But Omicron’s effects and potency have largely remained a mystery.

That is beginning to change, however, as doctors and researchers examine case and hospitalization data from southern Africa, where Omicron was first detected and has spread most widely.

The information about Omicron that’s been gleaned so far is preliminary, or anecdotal. But it paints the picture of a world moving into a new stage of the COVID pandemic.

“Omicron seems to be moving at a faster speed than Delta, but at the same time what seems to be happening is that our hospitalization rate is somewhat more muted,” Shabir Madhi, a vaccinologist at the University of the Witwatersrand, told Bloomberg.

Growing evidence suggests that the new variant is highly contagious and causes high rates of reinfection, and the cases it causes appear to be mildly symptomatic in general. At the same time, drugmakers, scientists, and policymakers have expressed confidence that vaccines seem to be effective at stopping hospitalization and death from Omicron. That’s the good news.

The bad: It appears that Omicron infections among infants might be cause for concern.

In a push to better understand Omicron, an international 450-researcher team led by the WHO has begun a new study to isolate the variant, grow it in the lab, and identify its genomic sequence. The study should be published next Tuesday.

High transmission rate

With the arrival of Omicron, South Africa’s seven-day rolling average of daily new COVID infections has jumped from less than 300 just two weeks ago to 4,840 today. On Thursday alone, South Africa’s National Institute for Communicable Diseases (NICD) reported 11,535 new cases—a 35% jump from the day before.

The epicenter of new cases is Gauteng—South Africa’s most populous province, with a quarter of its population. There, Omicron is spreading faster than the Delta strain or any of the earlier mutations, according to Bruce Mellado, an adviser to the provincial government.

The current R rate in Gauteng, or the average number of secondary infections an infected person will produce, has risen to 2.33, Michelle Groome, head of health surveillance at the National Institute for Communicable Diseases (NICD), said in an online presentation today.

And while previous infections or vaccination may dull the severity of the illness in a patient, there are higher levels of “reinfections” with Omicron, implying the “susceptibility of the population is greater,” said Anne von Gottberg, a clinical microbiologist at the NICD. A preliminary study by South African scientists, which has yet to be peer reviewed, found that the risk of reinfection from Omicron is three times higher than that of any previous variant.

Mellado, the provincial government adviser, predicted active cases in Gauteng will peak in the coming weeks at around 40,000, compared with the 100,000 confirmed cases seen in the third wave of infections in the summer. And hospitalizations are likely to rise to about 4,000 compared with the 9,500 seen last time around.

Across the rest of Africa, infections are also rising. There has been an average 20% increase in COVID-19 cases over the past four weeks, Africa CDC Director Dr. John Nkengasong said at a virtual news briefing Thursday; he attributed the rise to the Omicron variant.

There is no clear picture what this will look like in Europe or the U.S., but the West is bracing for impact. The European Center for Disease Prevention and Control (ECDC) today released a brief in which it noted Omicron could be responsible for “over half” of all coronavirus infections in wider Europe within the next few months, suggesting “a substantial advantage over the Delta variant.”

Mild symptoms

Despite the shocking rise in cases, the symptoms, especially for those vaccinated, seem to be mild.

Drugmaker GlaxoSmithKline reported Thursday that in early testing, COVID-19 antibody treatments were effective against new mutations found in the variant, while the WHO said vaccines are likely to protect against severe cases.

Meanwhile, Australia’s chief medical officer, Paul Kelly, said there wasn’t any indication that the Omicron variant was more deadly than other strains: “Of the over 300 cases that have now been diagnosed in many countries, they have all been very mild or in fact had no symptoms at all.”

Richard Friedland, the chief executive of Netcare, which operates the largest private health care network in South Africa, said if the country had experienced this level of cases in the second or third wave, “we would have seen very significant increases in hospital admissions, and we’re not seeing that. In our primary care clinics it is mainly people under 30 years old.”

Anecdotal evidence from general practitioners in South Africa also suggest milder symptoms. Anthony Smith, a doctor in Cape Town, told Bloomberg, “They are from a younger demographic and presenting with milder symptoms, mainly sore throats and respiratory phenomenon. But even in older people, it’s been relatively mild.” South African Health Minister Joe Phaahla reiterated these findings in a media briefing on Friday, noting there was “a very steep rise” in cases, but they were mostly mild.

Infant caseload

One worrisome sign is the Omicron variant’s effect on really young children.

Data from South Africa’s NICD shows that a high number of hospital admissions in Tshwane, a northern city in Gauteng, were of infants under 2, which has raised concerns that the variant may pose risks to young children. South African scientists have said they cannot confirm whether there is a link between Omicron and the high number of child admissions.

Out of the 452 COVID-19 patients admitted in Tshwane between Nov. 14 and 28, 52 were infants—making them the most represented age group in hospitalizations. However, not all infants were tested for the new variant, and there is no clear understanding of how many might have or have had Omicron.

There is also uncertainty on whether these infants had COVID-19 at all, as all infants with respiratory symptoms are being treated as if they had COVID-19—meaning they could just have the flu, of which Twashne is experiencing an increased caseload.

The good news: Of the hospital COVID admissions of children in the 0 to 4 age range, the percentage with severe disease was significantly lower than those over age 60.

The correlation between the infant caseload and Omicron is still being examined. When asked whether people should be alarmed by the infant admissions numbers, von Gottberg, the clinical microbiologist at the NICD, told Reuters, “Not yet.”

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