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PAEDS provides important data on COVID-19 in children during the 2021 Delta outbreak

A study supported by the PAEDS network has examined the severity and clinical spectrum of SARS-CoV-2 infection in Australian children during the 2021 Delta outbreak and found the majority of children with SARS-CoV-2 infection (Delta variant) had asymptomatic or mild disease. Hospitalisation was uncommon and occurred most frequently in unvaccinated adolescents with comorbidities, and more children were hospitalised for social reasons than for medical care. Some infants were hospitalised for feeding guidance, given lockdowns closed community nursing services, or for observation and investigation in the context of mild fevers.

The collaboration between researchers from the PAEDS network, the Sydney Children’s Hospitals Network, the National Centre for Immunisation Research and Surveillance and the University of Sydney found 1 in 5 children with SARS-CoV-2 infection remained asymptomatic during the 2021 Delta outbreak. Of those who did have symptoms, rhinorrhoea (a runny nose) was the most common symptom. Cough was the most frequent symptom in those requiring hospitalisation, yet 82% of these patients did not require any respiratory support. 

Hospitalisation was uncommon and more likely to occur due to social or welfare reasons than for medical care. For every 100 infections in children aged <16yrs, 1.26 (95% CI: 1.06–1.46) required hospital admission for medical care, while 2.46 (95% CI: 2.18-2.73) required admission for social reasons. Social admissions were often necessitated by parents/carers being hospitalised for COVID-19 themselves (prior to Australia’s high uptake of adult vaccination) or due to services (out-of-home care, disability support etc.) being unable to care for children with COVID-19.

Of the admitted children, 4.6% were admitted for other diagnoses and were incidentally SARS-CoV-2 positive. Incidental infections are rarely delineated in hospital data yet are important to bear in mind, particularly with rising community prevalence due to Omicron.

Young infants exhibited symptoms common to many viruses in children, such as fever, gastrointestinal symptoms, and reduced oral intake. For those who needed medical hospital admission, stays were often brief (median length of stay for non-ICU admissions: 2 days)

The more typical lower respiratory tract symptoms of COVID-19 were largely restricted to teenagers. Obesity was a risk factor for admission to hospital and ICU, but asthma was not.

Only 7 children presented with paediatric inflammatory multi-system syndrome temporally associated with SARS-CoV-2 (PIMS-TS, also known as multi-system inflammatory syndrome MIS-C), with a median age of 3.2 years (around 1 in 2,500 infections). 5 were well enough to be managed on the ward, and all children recovered without complications.

To support this study PAEDS surveillance nurses actively reviewed clinical and laboratory records of children with SARS-CoV-2 infection or PIMS-TS/MIS-C and liaised with clinical teams to identify and subsequently monitor eligible children presenting to participating hospitals. This resulted in comprehensive, individual case data collated within a national electronic database hosted at the University of Sydney that facilitated analyses and reporting.

Read the paper here

Read more about PAEDS COVID-19 and PIMS-TS surveillance.