More than 400 children worldwide have developed unusual cases of acute hepatitis, and researchers are still searching for the cause of the outbreak, the World Health Organization said May 17.
As of May 15, the WHO reported 429 probable cases in 22 countries, up from 348 cases a week prior, according to Philippa Easterbrook, MD, a senior scientist in the global hepatitis program at the WHO. Another 40 cases are still under investigation, and 75 percent of all affected children are under age 5.
Twelve countries are reporting more than five cases, double the amount from last week. Of these 12 countries, nine are in Europe. In total, six children have died in the outbreak and 26 have required liver transplants, according to Dr. Easterbrook.
As of May 17, researchers were still investigating the cause of the hepatitis outbreak. The leading hypothesis is that an adenovirus and SARS-CoV-2, the virus that causes COVID-19, may be causing hepatitis in children. Scientists are exploring "how these two infections may be working together as co-factors either by enhancing susceptibility or creating an abnormal response," Dr. Easterbrook said.
The WHO is working to develop three tools to help countries standardize their reporting and managing of cases. These tools include a diagnostic flowchart of how to investigate the cases, a clinical case report form that will capture all the clinical information on global cases and guidelines on how to manage acute liver failure in children.
Dr. Easterbrook said these types of hepatitis cases have occurred in children before but were rare.
"We're creating a survey on what that background rate of unexplained hepatitis was to help establish whether the reports we are seeing from different countries is an uptick," she said.