Hepatitis of Unknown Origin Affecting Hundreds of Young Children

From January-June 2022, 20 countries in the European Region of the World Health Organization reported an outbreak of 427 total cases of hepatitis of unknown origin in children. Adenovirus was concurrently diagnosed in many of these children at the same time, according to the report, published in Eurosurveillance.

“Adenovirus infection is therefore one of the main aetiological hypotheses under investigation, although a causal relationship has not been proven and additional cofactors are under investigation,” the report authors wrote.

Hepatitis is characterized by severe liver inflammation that can result in hospitalization. Vidal et al. analyzed the demographic, epidemiological, clinical, and microbiological data from The European Surveillance System at the European Centre for Disease Prevention and Control for more information on these cases.

According to the researchers, among the 427 cases in children, those who were 0-5 years of age had the most severe infections at 330. More than half of this population (53%) also tested positive for adenovirus.

In the UK, 68% of children diagnosed with acute hepatitis of unknown origin were concurrently diagnosed with adenovirus. Only a small portion (10%) of this population were also diagnosed with the SARS-CoV-2 at the same time.

Children 0-5 not only suffered from the most severe hepatitis infections, but also the highest proportion of adenovirus tests at 60%. Of this 0-5 age group, 36% were admitted to intensive care or high dependency units (ICU/HDU) compared to 22% ICU admissions for the 6-10 age group and 10% of 11-16 age group. Hospital admissions were mainly due to acute liver inflammation.

The WHO noted that 16 to 18 children younger than 5 years of age received a liver transplant. Children with adenovirus were also more likely to be admitted to the ICU/HDU.

Adenovirus infected 64% of UK children, according to the data, as opposed to 35% in other countries. Children with severe cases of hepatitis in the UK were correspondingly more likely to be infected with adenovirus than children in other parts of Europe.

In the UK, severe hepatitis put 74 of the 140 children with hepatitis of unknown origin in the hospital (53%). Only 8 of 101 children outside of the UK who reported unknown hepatitis were hospitalized.

The authors said there should be more efforts to determine the baseline of severe hepatitis of unknown origins in children and whether these current numbers surpass this baseline. They also hope to establish a better definition of the syndrome and standardize the necessary diagnostic algorithms.

The findings “may indicate a higher likelihood of severe disease in younger children, but what is not clear is whether reported cases across all ages share the same aetiology. It may also prove difficult to identify a definite causative agent,” the study authors wrote.

Reference

European data analysis: looking for the cause of unusual amount of hepatitis of unknown origin among children. EurekAlert! Aug 4, 2022. Accessed on Aug 4, 2022. eurekalert.org/news-releases/960879