South African health officials said Friday they are investigating a recent surge in cases among younger age groups not seen in previous waves of the virus, as the country battles an "unprecedented" surge of COVID-19 cases it believes is fueled by the Omicron variant.
Officials in South Africa are not saying that there's any evidence the variant poses a greater danger to the youngest children, compared to previous variants - all ages in South Africa are seeing a "steep increase" in infections and hospitalizations.
Instead, some may have incidentally tested positive for COVID-19 after being hospitalized for other reasons, or are being admitted by health care providers as a precaution.
"We are hoping that in the coming weeks we'll be able to also give reasons for why this particular cohort of patient is having increased infections," said Dr. Ntsakisi Maluleke, a health official for South Africa's Gauteng province, at a briefing hosted by the country's health agency on Friday.
Rates of COVID-19 among hospitalized younger children in South Africa under five "is now second highest and second only to the incidence in those over 60."
"The trend that we see now, that's different to what we saw before, is a particular increase in hospital admissions in children under five years," said Dr. Waasila Jassat of South Africa's National Institute for Communicable Diseases.
These children also remain ineligible for vaccination in South Africa, unlike older age groups.
"All these young children being admitted, most of them, the parents have not been vaccinated either. So I think, certainly the value of vaccination in the adults, protecting the children in the homes, is something to keep in mind," said Jassat.
While doctors had suspected earlier in the pandemic that children might be less vulnerable catching and spreading SARS-CoV-2, health officials have since concluded that rates of disease among children "can be comparable, and in some settings higher, than in adults."
During the surge in cases driven by the Delta variant earlier this year, pediatricians reported an unprecedented wave of admissions overwhelming children's hospitals around the country.
A study published by the CDC concluded that hospitalizations had climbed simply due to the sheer number of overall cases, with the actual proportion of sick children who ended up with severe disease remaining unchanged by the Delta variant.
"We don't have the outcome data for those individuals. We haven't seen an increased risk of death yet. So we have to wait to understand how those patients will do," the World Health Organization's Dr. Maria Van Kerkhove said on Friday, when she was asked about reports of rising hospitalizations among young people in South Africa.
Clues from South Africa
U.S. health officials say they are closely tracking data from South Africa and other countries that have seen cases of Omicron, as they look for potential clues to assessing the variant's danger as it begins to spread in the United States.
"Because of the volume of cases that they have thus far, are ahead of us in the sense of being able to take a look at differences in protection, immune evasion, severity of disease in people who have either been vaccinated, people who have been unvaccinated, or people who have recovered from prior infection," Dr. Anthony Fauci, the president's chief medical adviser, told reporters on Friday.
In a study that has yet to be peer-reviewed, South African scientists recently reported seeing an increased risk of reinfection from Omicron.
Officials there said Friday their "limited data" currently suggests the "variant is highly transmissible" and is so far causing mostly mild illness, but warned that could change as Omicron spreads "into older age groups."
Meanwhile out of Hong Kong, the CDC published a study on Friday suggesting Omicron may be transmissible enough to spread, despite the country's already strict quarantine measures.
More data from lab experiments and real-world tracking of the variant are expected in the coming weeks that could help officials assess the risk posed by the highly-mutated strain.
"That's all going to take a matter of maybe a week or two more to get the in vitro data, and maybe another additional week or so to get the clinical data. So we expect we're going to have that information to you over the next few weeks," said Fauci.