The novel coronavirus may also be the culprit behind the mysterious cases of hepatitis in children in recent months.

A new study by Israeli researchers presented a theory that long COVID could be why some children developed hepatitis amid the pandemic.

In their study published in the Journal of Pediatric Gastroenterology and Nutrition, the researchers from Tel Aviv University, Schneider Children’s Medical Center, Rambam Medical Center and Rabin Medical Center - Beilinson Hospital analyzed five cases of hepatitis patients hospitalized in Schneider Children’s Medical Center last year due to liver injury.

The first patient was a 3-month-old infant hospitalized for acute liver failure 21 days after testing positive for COVID-19. The child had a liver transplant 11 days after his admission to the hospital, and he tested negative for adenovirus and cytomegalovirus (CMV).

The second patient was a 5-month-old child admitted to the hospital after manifesting fever, jaundice and enlarged liver. He also had a liver transplant due to his deteriorating health. He tested positive for SARS-CoV-2, adenovirus and CMV.

The third patient was an 8-year-old boy rushed to the hospital after presenting abdominal pain, vomiting and jaundice about 130 days after his COVID-19 diagnosis. He had tested positive for SARS-CoV-2 before suffering a liver injury. However, he did not test positive for adenovirus.

The fourth patient was another 8-year-old boy who suffered abdominal pain, diarrhea, vomiting and jaundice about 90 days after testing positive for SARS-CoV-2. Just like the third case, he did not get infected with adenovirus.

The fifth patient was a 13-year-old boy who was healthy before testing positive for COVID-19. He experienced weakness, diarrhea, abdominal pain, and jaundice after contracting the virus.

He was admitted to the hospital 53 days after his diagnosis and presented other complications, including hepatomegaly and liver injury. He had to undergo a liver transplant during his hospitalization. After the procedure, he tested positive for adenovirus and CMV.

The child patients had asymptomatic or mild COVID-19 before the onset of their liver problems. Meanwhile, adult SARS-CoV-2 patients experienced the same liver issues after staying in the ICU for a long period and while battling the severe form of the viral infection, as per the Jerusalem Post.

Other studies that focused on similar issues reported that some COVID-19 patients suffered liver problems weeks or months after contracting the disease.

Previous reports linked the unexplained hepatitis outbreak in children to the adenovirus. However, the World Health Organization (WHO) pointed out that though there have been cases of immunocompromised children with adenovirus infection developing hepatitis, the virus was never linked to hepatitis cases in otherwise healthy children.

The researchers behind the new study also did not link adenovirus to the hepatitis cases since the kids were healthy before experiencing the liver problems. They instead presented theories on the possible mechanisms that could have led to the unexplained acute hepatitis cases in children.

None of the five patients analyzed in the study had severe COVID-19, so the scientists speculated that the liver injury could have been triggered by the direct viral damage caused by SARS-CoV-2.

Another possible mechanism they suggested that could have led to the liver problems was how the immune system reacted to the infection. A post-infection immune reaction or an abnormal immune response to SARS-CoV-2 could have led to acute hepatitis in the patients.

Further research is needed to validate the study findings.