More babies are going into hospital with Omicron compared to previous waves of the pandemic, but their illness is milder, according to the first analysis of hospital data for the variant.
The data, compiled for the government’s SAGE committee, finds that babies under one-year-old make up the majority of admissions among the under-18s.
In the Alpha and Delta waves, 30% of paediatric hospital admissions were babies under one year of age.
So far in the Omicron wave it’s 42%.
Despite the increase in cases, however, fewer babies are being admitted to intensive care units (ICU) than in previous waves and fewer are needing oxygen.
In the Delta wave, around 20% of under-ones admitted to hospital required supplementary oxygen, compared to 12% for Omicron.
There have been no deaths recorded among babies under-one infected with Omicron since the variant began circulating in the UK.
Professor Calum Semple of the University of Liverpool, whose team carried out the analysis, said the data was “reassuring”.
“What’s really reassuring here, is these babies are having a very short hospital stay – typically less than two days – and they don’t appear to need intensive care,” he said. “They’re requiring relatively little oxygen, so in fact these babies have the mildest of illness that brings them in to hospital.”
What sort of symptoms are babies experiencing?
The main symptoms recorded among babies are a high fever and a runny nose.
In some cases, they have croup – a barking cough common in infants with an upper respiratory infection – which can lead to breathing difficulties.
Experts think the shift in hospitalisation patterns may be because Omicron seems to affect the upper airway more than previous strains of COVID.
What could be behind the rise in admissions?
It’s likely the trend is also due to the sheer number of Omicron cases and patterns of population immunity.
Because the new variant is so much more infectious than previous strains, infection levels due to Omicron are at least four times higher now than in previous waves.
Many children over five have already been infected with the virus at school, and most adults have been vaccinated.
That means the part of the population with the lowest levels of immunity are likely to be babies and toddlers.
“We would expect a larger proportion of admissions to be among this population, which is what is demonstrated in this data,” according to Dr Alasdair Munro, a clinical research fellow in paediatric infectious diseases at the University of Southampton.
In addition, because babies are more vulnerable to any kind of illness, they are far more likely to be referred to hospital by GPs or the 111 system than other age groups.
The younger the baby, the more likely they are to be referred to hospital, even as a precaution.
Most of the cases of hospitalisation recorded in the latest analysis are babies less than three months of age.
How could the risk of hospital admission be reduced?
While the risk of serious illness is low, one thing that could reduce the chances of babies needing hospitalisation is for more pregnant women and breastfeeding mothers to get vaccinated, according to the researchers.
“They can pass on their immunity to the babies both in the womb and also by breastfeeding,” Prof Semple said. “So there is an important message here that vaccinating pregnant mums or mums planning to get pregnant is a good idea.”
Paediatricians say there is plenty of capacity to deal with any increase in admissions due to Omicron – in part because they were already preparing for a spike in admissions this winter due to other common respiratory viruses.
Due to lockdowns, it was anticipated that many children hadn’t been exposed to the same number of common respiratory viruses as usual – reducing the overall level of immunity in the population.
Dr Camilla Kingdon, president of the Royal College of Paediatrics and Child Health, added: “We are accustomed to having busy winters where we see lots of under-ones with high fevers or with some kind of respiratory distress. The pattern this winter is very similar.”