Health officials across 33 countries have received reports of 920 probable cases of severe acute hepatitis of unknown origin in young children, according to the World Health Organization (WHO).
In a press release on Friday, the health agency said the latest update on the outbreak is an increase of 270 cases since it published data last month that revealed 650 cases of severe acute hepatitis were diagnosed in children between April 5 and May 26.
The majority of the cases are in Europe, totaling 460, with 267 from the United Kingdom alone. About one-third of the probable cases are reported in the United States.
The outbreak was first reported in Britain in April and has since then hit dozens of other countries.
Of the 422 cases in which gender and age-related information are available, close to half occurred in males, with most of them under 6 years of age, according to the report.
The WHO said 45 children with acute hepatitis have required liver transplants, and there have been 18 deaths, most of them occurring in the Americas region.
Researchers have been scrambling to determine the cause of the mysterious rise in severe cases of hepatitis—or liver inflammation—in young children. They have also theorized about a possible link to COVID-19, the disease caused by the CCP (Chinese Communist Party) virus.
In a June 24 risk assessment, the WHO said acute hepatitis at a global level is “currently assessed as moderate,” citing several factors.
- The etiology of this severe acute hepatitis remains unknown and is being investigated;
- Limited epidemiological, laboratory, histopathological and clinical information are currently available to WHO;
- The actual number of cases and the geographical distribution may be underestimated, in part due to the limited enhanced surveillance schemes in place;
- The possible mode of transmission of the etiologic agent(s) has not been determined;
- Although there are no available reports of healthcare-associated infections, human-to-human transmission cannot be ruled out as there have been a few reports of epidemiologically-linked cases.
Health officials in the United States said infection with adenovirus, a common childhood virus called F41, could be the leading hypothesis for most probable cases.
Adenovirus, a viral infection that usually causes the common cold, was detected in 75 percent of confirmed cases tested in the UK in April, according to the UK Health Security Agency (UKHSA).
“The leading hypotheses remain those which involve adenovirus; however, we continue to investigate the potential role of SARS-CoV-2 and work on ruling out any toxicological component,” the UKHSA stated at the time.
The WHO said preliminary reports indicate that adenovirus remains the most frequently detected pathogen among cases with available data.
In the United States, adenovirus infection was detected in 45 percent of cases, while in European regions, it was found in more than half of cases with available results.
Researchers studying a probable link to the CCP virus detected COVID-19 in 15 percent of hepatitis cases of unknown origin in European regions and 10 percent in the United States, according to the WHO report.
Health officials with the CDC and WHO have previously said they do not believe COVID-19 vaccines appear to be linked to the hepatitis cases as many of the children who have developed the condition haven’t received the vaccine. They have also ruled out COVID-19 itself as a cause.
Hepatitis is a term that refers to inflammation of the liver and is generally caused by a viral infection. The viruses hepatitis A, B, and C are commonly associated with the condition, although officials say that liver inflammation can also be caused by long-term or heavy alcohol usage, drug overdoses, prescription drugs, over-the-counter drugs like acetaminophen, and toxins.
Symptoms of hepatitis include jaundice, or the yellowing of the skin or whites of the eyes, as well as nausea, vomiting, diarrhea, dark-colored urine, joint pain, a loss of appetite, fever, and fatigue, according to the Mayo Clinic and other health officials.