Researchers arranged follow-up interviews with the parents of 518 children admitted with suspected or confirmed Covid-19 to ZA Bashlyaeva Children’s Municipal Clinical Hospital in Moscow, Russia, between April and August 2020.
They discovered a quarter of the children had persistent symptoms several months after returning home, with almost one in 10 experiencing “multi-system involvement”.
At the time of the follow-up interview, ranging from about seven to nine months after discharge from hospital, 24.3 per cent of participants had persistent symptoms, among which fatigue (10.7 per cent), sleep disturbance (6.9 per cent) and sensory problems (5.6 per cent) were the most common.
Parents of some participants also reported emotional and behavioural changes in their children after Covid-19.
According to the team of scientists, which included researchers from the UK, Ireland, Italy, Germany, Russia and the US, children over the age of six appeared to be at greater risk of persistent symptoms, as did those with a history of allergies.
However, the study, which has not yet been peer reviewed, found the prevalence of most symptoms declined over time.
While 15.8 per cent reported fatigue at the time of discharge, this fell to 11.1 per cent six to seven months later, while altered smell fell from 8.7 per cent to 5.4 per cent, and change in sense of taste from 5.6 per cent to 3.8 per cent.
The study authors wrote: “Although many children experienced symptoms, such as fatigue, disturbed smell and taste, sleep and respiratory problems, hair loss and headaches at the time of the hospital discharge, we witnessed a steady decline in the symptom prevalence over time.
“This was particularly evident for fatigue and smell disturbance.
“Prevalence of some symptoms such as headache, and sleep problems did not decline over time, which may be driven by psychological mechanisms rather than pathophysiologic virus infection effects.”
They added: “Age was significantly associated with persistent symptom presence at the time of the follow up, with children above six years of age being at higher risk.”
University College London (UCL) has been awarded funding to study long Covid in 3,000 11- to 17-year-olds who were not hospitalised with the disease.
The research will assess risk factors, prevalence and how long Covid lasts. It will also establish a medical diagnosis and operational definition of the condition, and look at how it might be treated.
Earlier this month, the Office for National Statistics (ONS) revealed more than a million people in Britain were still sufferings signs of long Covid.
The ONS said 1.1 million people had reported symptoms lasting beyond four weeks that were not explained by anything else.
It found the symptoms were affecting the day-to-day lives of 674,000 people, with almost 200,000 people reporting their ability to carry out normal activities had been severely limited.
A review by the National Institute for Health Research (NIHR) in March also found lasting effects from coronavirus infection were more common in women and children than expected.
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