Children under the age of two account for about 10 per cent of total hospital admissions in the omicron epicentre Tshwane in South Africa, according to the National Institute for Communicable Diseases.
More children are being admitted than during the early stages of the country entering the current fourth wave of infections, although a similar trend occurred during the third wave when Delta was dominant, said Dr Waasila Jassat, public health specialist at the institute.
South African scientists were last week the first to identify the new variant now known as Omicron, and while symptoms have been described as mild, the exact risk from the new strain is still uncertain.
Governments across the globe stepped up travel restrictions in response, and the World Health Organisation warned that the variant could fuel a fresh surge in infections.
"The very young children have an immature immune system and they are also not vaccinated, so they are more at risk," said Dr Jassat, who was part of developing and managing South Africa's national hospital surveillance system for Covid-19.
She said that part of the increased rate of admissions may reflect extra precaution on the part of parents given the new concern about the mutation. A paediatric report due later this week should provide more information.
In Tshwane, the municipality that includes the capital Pretoria, 52 children under the age of two diagnosed with the coronavirus have been admitted and one has died, Dr Jassat said.
It's not yet clear whether they contracted Omicron, currently the region's dominant strain.
"People are more likely to admit children as a precaution because if you treat them at home something can go wrong - especially very young children because there is a higher proportion of death," Dr Jaffat said.
Scientists in South Africa said on Monday (Nov 29) that existing vaccines are still likely to protect against severe illness, though very small children are not able to get shots yet.
About a third of the country's population is fully vaccinated.
During the Delta-driven third wave, hospital admission for those under the age of 19 jumped 43 per cent, and the country has since opened up vaccinations to adolescents between 12 and 17 years old.
"It does however appear that in this early part of this wave a higher proportion of children are being admitted than they were in the past," Dr Jaffat said.