Sixth child in US dies of unexplained hepatitis as global cases top 600

A sixth child has died in the United States from puzzling liver inflammation—aka hepatitis—and the number of unexplained cases has risen to 180 across 36 states, according to the Centers for Disease Control and Prevention.

The latest death was announced in a press briefing Friday, led by CDC Deputy Director for Infectious Diseases Jay Butler, who said it was reported to the agency Thursday. He did not indicate in which state the death occurred.

In addition to the deaths, 15 of the 180 cases required liver transplants, Butler reported. The cases all occurred in children under the age of 10 but skewed to preschool-age children, with the median age being around 2 years.

The latest US tallies feed into a global phenomenon that now includes over 600 cases across 31 countries, including 15 deaths. But, despite the growing numbers, international health experts are still scrambling to understand what's behind the illnesses after eliminating the most obvious possibilities, such as hepatitis viruses A, B, C, D, and E.

Tricky numbers

In today's briefing, Butler was cautious to note that while the latest total of 180 cases may seem like a concerning rise from the 109 cases CDC reported two weeks ago, most of the 71 newly reported cases were retrospectively identified and actually occurred weeks to months ago. In fact, only 7 percent of the 180 cases occurred in the last two weeks, Butler said.

He was also careful to avoid saying that the cases were part of an outbreak, noting that the agency is not detecting an overall increase in the number of unexplained hepatitis cases it usually sees. And the 180 cases over the past seven months have not clustered geographically or by time. They've been somewhat evenly dispersed among the 36 states, and the month-to-month case totals have been generally flat, Butler reported.

Though pediatric hepatitis cases are not monitored at a national level, the CDC estimates that there are somewhere between 1,500 to 2,000 cases each year, according to Umesh Parashar, chief of CDC's Viral Gastroenteritis Branch, who also spoke at the briefing. Butler added that about 30 percent to 50 percent of those pediatric hepatitis cases go unexplained each year. Thus, the 180 unexplained cases over a seven-month period don't ring statistical alarm bells.

It's possible, Butler speculated, that the cases being highlighted now have always been there and simply weren't identified and scrutinized previously.