School-aged children with SARS-CoV-2 infection had only a few mild symptoms and typically recovered in 6 days, with more than 98% recovering in 8 weeks, a large U.K. study of smartphone data reassuringly reports.
In a small proportion (4.4%), however, COVID-19 symptoms such as fatigue, headache, or loss of smell persisted beyond a month, highlighting the need for ongoing pediatric care, according to Erika Molteni, PhD, a research fellow at King’s College, London, and colleagues.
The results, published online in The Lancet Child & Adolescent Health, also indicated that some children who had non-COVID infections were also susceptible to prolonged symptoms. “Our data highlight that other illnesses, such as colds and flu, can also have prolonged symptoms in children and it is important to consider this when planning for pediatric health services during the pandemic and beyond,” Michael Absoud, PhD, a senior coauthor and a King’s College consultant and senior lecturer, said in a news release. “All children who have persistent symptoms – from any illness – need timely multidisciplinary support linked with education, to enable them to find their individual pathway to recovery.”
Using a “citizen science” approach, the study extracted data from a smartphone app for tracking COVID symptoms in the ZOE COVID Study. The researchers looked at 258,790 children aged 5-17 years whose details were reported by adult proxies such as parents and carers from March 24, 2020, to Feb. 22, 2021. Of these, 75,529 had undergone a valid SARS-CoV-2 test.
The study also assessed symptoms in a randomly selected, age- and sex-matched cohort of 1,734 children in the app database who tested negative for COVID-19 but may have had other illnesses such as colds or flu.
In the 1,734 children testing positive for COVID-19 (approximately 50% each boys and girls), the most common symptoms were headache (62.2%) and fatigue (55.0%). More than 10% of the entire cohort had underlying asthma, but other comorbidities were very rare.
To assess the effect of age, the children were assessed in two groups: 5-11 years (n = 588) and 12-17 years (n = 1,146).
While unable to cross-check app reporting against actual medical records, the study suggested that illness lasted longer in COVID-positive than COVID-negative children, with a median of 6 days (interquartile range, 3-11) versus 3 days (IQR, 2-7). Furthermore, illness duration was positively associated with age: older children (median, 7 days; IQR, 3-12) versus younger children (median, 5 days; IQR, 2-9).
In 77 (4.4%) of the 1,734 COVID-positive children, illness persisted for at least 28 days, again more often in older than younger children: 5.1% of older children versus 3.1% of younger children (P = .046).
In addition, those with COVID-19 were more likely than children with non-COVID illness to be sick for more than 4 weeks: 4.4% versus 0.9%. At 4 weeks, however, the few children with other illnesses tended to have more symptoms, exhibiting a median of five symptoms versus two symptoms in the COVID-positive group.
Dr. Sindhu Mohandas
“I tend to agree with the U.K. findings. COVID-19 in most school-age children is asymptomatic or a brief, self-limiting illness,” Sindhu Mohandas, MD, a pediatric infectious disease specialist at the Children’s Hospital Los Angeles, said in an interview. “The few children who need hospitalization have also mostly fully recovered by the time they are seen for their first outpatient clinic follow-up visit.”
Dr. Mohandas, who was not involved in the U.K. study, added that in her experience a small percentage, particularly adolescents, have some lingering symptoms after infection including fatigue, loss of appetite, and changes in smell and taste. “Identifying children with persistent illness and providing support and multidisciplinary care based on their symptomatology can make a positive impact on patients and their families.”
Recent research has suggested that long symptoms can persist for 3 months in 6% of children with COVID-19. And data from China have indicated that the prevalence of coinfection may be higher than in older patients.
In an accompanying comment, Dana Mahr, PhD, and Bruno J. Strasser, PhD, researchers in the faculty of science at the University of Geneva, said the app-based study “illustrates the potential and challenges of what has been called citizenship science,” in which projects rely on data input from nonscientists.
But while potentially democratizing participation in medical research, this subjective approach has the inherent bias of self-reporting (and in the case of the current study, proxy reporting), and can introduce potential conflicts of interest owing to the politicization of certain diseases.
In the case of the current study, Dr. Mahr and Dr. Strasser argued that, since the COVID-19 test result is known to participants, a pediatrician using objective criteria is better positioned to control for reporting biases than a parent asking a child about symptoms. “Entering data on a smartphone app is not equivalent to discussing with a pediatrician or health care worker who can answer further questions and concerns of participants, an especially important factor for underserved communities,” they wrote. “Citizen science will continue to require a close interaction with professional medical researchers to turn unique illness experiences into research data.”
This study was funded by Zoe Limited, the U.K. Government Department of Health and Social Care, Wellcome Trust, the U.K. Engineering and Physical Sciences Research Council, the U.K. Research and Innovation London Medical Imaging and Artificial Intelligence Centre for Value Based Healthcare, the U.K. National Institute for Health Research, the U.K. Medical Research Council, the British Heart Foundation, and the Alzheimer’s Society. Several study authors have disclosed support from various research-funding agencies and Zoe Limited supported all aspects of building and running the symptom-tracking application. Dr. Mahr and Dr. Strasser declared no competing interests. Dr. Mohandas disclosed no competing interests with regard to her comments.