COVID-19 and its effects on children continue to be poorly understood. At the start of the pandemic, it was believed that children are mostly asymptomatic carriers and less likely to have severe forms of the disease.

A few weeks later, a rare inflammatory syndrome similar to Kawasaki disease, was reported in some children with COVID-19 in parts of Europe and most recently in the US. Now a new study has found that the disease may present entirely differently from adults in children. The disease is might begin with diarrhoea and other gastrointestinal symptoms, not cough.

“This case series is the first report to describe the clinical features of COVID-19 with non-respiratory symptoms as the first manifestation in children,” said the authors of the study published in the peer-reviewed journal Frontiers in Pediatrics.

The scientists are from Tongji Hospital in China, where they observed the clinical course of the disease in five children.

The children had been hospitalised and were later confirmed to have COVID-19, between January 23 and February 20, at the Wuhan Children’s Hospital. Four of the patients were boys and one was a girl, and their ages ranged from two months to 5.6 years.

“For three of the five patients, the primary onset disease required an emergency operation or treatment, and included intussusception [bowel obstruction], acute suppurative appendicitis perforation with local peritonitis, and traumatic subdural haemorrhage [bleeding inside the brain] with convulsion, while for the other two it was acute gastroenteritis (including one patient with hydronephrosis and a stone in his left kidney),” said the paper.

The scientists said the reason behind the digestive symptoms could be the distribution of cell receptors for the novel coronavirus. The same receptor, ACE2, through which the virus enters human lung cells is found in the small intestine. The study concludes that the virus might also infect patients through the digestive tract, by contact or faecal-oral transmission.

The possibility of infection should be suspected when children show digestive tract symptoms, especially with fever or exposure history, said the authors. They call for further studies to confirm their findings.