Covid seen more in 10- to 19-year-olds than in younger children

Children and younger people have made up a greater proportion of Covid-19 cases and admissions early in the fourth wave than those in older age groups. However, this “does not necessarily reflect more severe disease in children”.

This is according to University of Cape Town (UCT) professor Mary-Ann Davies, director of the Centre for Infectious Disease Epidemiology and Research.

Medical scientists say it is too early to know how mild or severe symptoms will be from the dominant Omicron variant, but there are concerns that a higher proportion of children are being hospitalised.

“At this stage the major increase in children has been in 10- to 19-year-olds rather than in younger children, though Gauteng has seen an increase in admissions in younger children,” said Davies.

Children and young people often dominate rising infections and admissions at the start of waves because the “spread is initially among those with the greatest numbers of contacts”, she noted.

Waasila Jassat, public health specialist at the National Institute for Communicable Diseases (NICD), told Bloomberg a similar trend — of more children being admitted early in the wave — happened during the Delta-driven third wave.

Davies said children are also more frequently admitted to hospital with flu and “with more influenza at the moment ... they may also have Covid-19 diagnosed as part of routine testing”.

Patients of any age admitted to hospital unrelated to the virus could discover, as part of the admissions process, that they have Covid-19 without knowing they were infected.

“Of course, vaccine coverage, especially in older adults, is now much higher and so adults would have additional protection (compared with children) against severe disease and hospital admission,”  Davies said.

Ntsakisi Maluleke, a public health specialist in the Gauteng, told Reuters at the weekend that healthcare workers could be admitting children “out of an abundance of caution”. “We are comforted by clinicians’ reports that the children have mild disease,” she said.

To test the effectiveness of Covid-19 vaccines in preventing severe disease and death against the latest variant, which is driving a surge of infections, top virologist Prof Penny Moore and her team at the NICD are making a pseudo-virus with Omicron mutations.

“We have three different approaches simultaneously and are pushing tag teams so there are no delays,” she said. “Some of the mutations are old enemies. Some we have seen before in other variants of concern, but a lot of them we have not.

“Though Omicron has an unusually large number of mutations, we do not yet have the lab data to know how it will affect immune recognition,” said Moore.

The spread is initially among those with the greatest numbers of contacts.

—  UCT professor Mary-Ann Davies

Davies, who tracks Covid-19 patterns in the Western Cape, said hospitalisations there were “still very low”, even though there had been an early increase in admissions.

At least the mutations have not compromised the reliability of PCR tests used to pick up SARS-CoV-2, said UCT virologist Martin Hsiao. “The early signals are that our diagnostic tests are working fine.”

To expand swift access to Covid-19 testing, infectious diseases specialist and Covid-19 ministerial advisory committee member Prof Ian Sanne said: “I would make the change to regulations that restrict the sale of Covid tests in pharmacies to enable the persons who have got the economic means to access a Covid self-test kit.

“This (would ensure) that ahead of the holiday period people who are getting together can perform one or more self-administered Covid-19 tests in their homes.”

In an unexpected bonus, one of the commercial PCR brands (used for about a fifth of all tests done in SA) may show the person has Omicron without viral sequencing being needed, said Hsiao, an expert in diagnostics.

“This brand of PCR test targets three parts of the virus and one of the three targets is missing with Omicron. Thus, it has become a surrogate marker for Omicron,” he said. In other words, if the test result shows two positive markers instead of three, it is likely to be the variant.

Despite surprises such as these, Covid-19 experts are reasonably confident the protection of vaccines — of more than 80% to 90% against severe disease and death — will hold up against Omicron, as they have against Alpha, Beta and Delta.

Hospitalisations follow infections by two to three weeks, so South Africans will have a clearer picture of what the Omicron-driven fourth wave means as their summer holidays begin.