Nearly 72,000 children across the United States were confirmed to have COVID-19 in one week last month, according to an analysis from the American Academy of Pediatrics and the Childrens Hospital Association.

Children represented 19% of all newly recorded cases for the week ending July 29. The two groups called it a substantial increase from the week prior, when about 39,000 child cases were recorded.

At least 4.2 million U.S. children have contracted the virus since the beginning of the pandemic, the organizations say in their new report . In total, there have been about 35.2 million recorded cases across the nation, although the true total is believed to be higher.

The good news is that children are still very rarely dying of the coronavirus or experiencing severe symptoms, which commonly include difficulty breathing and fatigue. Children and teens are much less likely to require hospitalization; the report found that only 0.1% to 1.9% of all cases in minors have involved a hospital stay. Mortality rates are similarly low of all the people who have died of COVID-19 in the U.S., only up to 0.03% were children.

However, the report advocated for caution, stating that there is an urgent need to collect more data on longer-term impacts of the pandemic on children, including ways the virus may harm the long-term physical health of infected children, along with their mental health.