Children may carry the coronavirus for longer than adults and for longer than previously thought, a new study in the United States has found.Researchers at the Children’s National Hospital in Washington analysed the medical records of more than 60 children who had been tested multiple times for Covid-19, the disease caused by the virus, and found the median time it took to test negative was 25 days.That was longer than some previous estimates. A recent study by the National Clinical Research…