An increasing number of children have been hospitalised with COVID-19, raising concerns about the Omicron variant causing more severe infection in young children.
Omicron is much more transmissible than previous variants, leading to many more children being exposed to and infected with it. But the increase of paediatric hospitalisations might not be a sign that the variant is a greater threat to young children.
Are we seeing more hospitalisations with Omicron in kids?
Early surveillance data from South Africa showed that children and teens under 20 represented 17% of all hospital admissions during the Omicron wave. Children younger than five years represented 10% of all hospitalisations.
According to The Economist, the US has seen a nearly 50% increase in hospitalisations per 100,000 cases in children aged four or younger since Omicron was first detected and a 70% increase in unvaccinated children aged five to 11.
This increase in hospital admission might suggest that Omicron may not be as mild in young children as in older children and adults.
There were similar fears about the Beta and Delta variants, but the rise in paediatric hospitalisations was more a consequence of the transmissibility of the variants. With Omicron, the rise might also be a reflection of increased contagiousness across all age groups.
In addition, children younger than five years remain unvaccinated, which increases their likelihood of contracting the infection.
“They’re going to be really vulnerable because everyone else is vaccinated,” says Dr Kirsty Short, a virologist at the University of Queensland. “That speaks to the benefits of rolling out paediatric vaccination.”
Is Omicron infection worse for kids than other variants?
The risk of severe disease is still lower in children than in adults, and even when requiring hospital care, young children seem less likely to need ventilators or ICU care.
“On the whole, most children are either asymptomatic or have a very mild illness,” Associate Professor Asha Bowen, a paediatrician at Perth Children’s Hospital and head of Skin Health at the Wesfarmers Centre of Vaccines and Infectious Diseases at the Telethon Kids Institute, told the ABC. She said children generally recover quickly and don’t need medical or hospital care.
Because the sheer numbers are high, she said, more children will end up in hospital. But so far, there is no sign that paediatric hospitalisations are worryingly increasing in Australia.
“As far as I’m aware, the numbers remain relatively similar to what we might expect with a normal respiratory virus in a winter period in Australia,” Bowen said.
The rise in paediatric hospitalisations might also be due to more children incidentally testing positive for COVID-19 during routine screening when being admitted to hospital for other reasons.
An alternative hypothesis for the rise in hospitalisations among young children is the emergence of different symptoms compared with previous variants. Omicron seems to attack the lungs much less frequently and reside instead in the upper respiratory tract – nose, throat, and trachea.
Young children are particularly vulnerable to infections in the upper airway. We know that from other pathogens such as the respiratory syncytial virus or other coronaviruses that cause the common cold.
The ZOE COVID-19 study, which allows people to report their COVID-19 symptoms, has shown that children often present cold-like symptoms, including runny nose, sore throat, sneezing, fever, cough, headache and fatigue, all typical of an inflammation of the upper airways.
Will vaccination help?
Vaccinating children remains the best way to protect children from severe infection and slow the overall spread of the virus. In Australia, the vaccination program to vaccinate children aged five to 11 has begun this month, while older children have been eligible since last September. However, vaccines have not yet been approved for children younger than five years.