In the early days of the COVID-19 pandemic, it became apparent that this coronavirus affected older people more severely than children. Children were also thought to have a very minor role in infection transmission.
But with the new Delta variant quickly replacing older strains of SARS-CoV2, the dynamics of the virus are starting to look different.
In the UK, the transmission of the Delta variant in schools has been rising rapidly in the past two months. In Israel, where more than half the population is fully vaccinated, but after several outbreaks in schools, teenagers are being urged to get their jab.
It is now being reported that Delta is at least 50% more infectious than the Alpha variant. In an unvaccinated population, an increase in transmission rate is expected across all ages, says Professor Fiona Russell, a paediatrician and infectious diseases epidemiologist at The University of Melbourne.
But as more older people are protected by vaccines, the virus predominantly infects people who are naive to the disease and who haven’t been vaccinated, such as children.
“When you start vaccinating, the epidemiology changes because the vaccine works at preventing infections,” says Russell.
In Indonesia, where just 5% of the population is fully vaccinated, the percentage of overall cases in people aged 18 or younger has risen sharply: more than 12% more cases were recorded among children in June, with 24 dying in a single week last month. The COVID-19 daily case count has quadrupled in less than a month, with the country now recording more than 27,000 new infections a day.
Russell allows that Indonesia might not have a solid healthcare system, and that many of these children might have underlying, untreated health conditions that make them especially vulnerable, contributing to this terrible statistic. Certainly, this was the case when a number of deaths were recorded among children in Indonesia at the beginning of the pandemic. “These kids might have untreated heart conditions, or malnutrition, or cancer that isn’t managed well,” she says.
Can there be any upside to these devastating figures? Perhaps a glimmer. Even though the Delta variant is much more transmissible, Russell says we don’t know yet whether it causes a more severe infection. A higher number of people being infected proportionally leads to a higher number of hospitalisations, “but it doesn’t mean it’s more lethal,” she says.
In the UK, where cases are surging among the younger sections of the population, the death rate remains very low.
So far, it does not appear that children are getting sicker than with other variants of this coronavirus, says Russell.
Nonetheless, some rich countries, including the UK, the US and Canada, have started to vaccinate children as young as 12. In Australia, the Therapeutic Goods Administration has approved the Pfizer vaccine for 16-year-olds and older and AstraZeneca for those aged 18 and older.
Russell says that in Australia, where the transmission rate is extremely low, the vaccination campaign priority should continue to protect the most vulnerable – the elderly, and those with underlying conditions.
In the global context, she says, it is horrifying that rich countries are considering vaccinating children when many low-income countries cannot protect their frontline workers and the most vulnerable.
Dr Manuela Callari is a Sydney-based freelance science writer who specialises in health and medical stories.
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