Between April and July of this year, more than 35 countries reported 1,010 cases of severe hepatitis with no apparent cause in children. Almost half of these cases were in Europe, including a quarter in the UK.Also Read – Benefits of Cherry Tomatoes: Top 5 Reasons Why You Should Include Cherry Tomatoes in Your Diet – Watch Video
Usually, childhood hepatitis is caused by infection with one of the hepatitis viruses (such as hepatitis A or hepatitis C). But even though the children were presenting with elevated levels of hepatitis markers in their blood, no traces of the hepatitis virus were found in these children, or in any related cases since. Also Read – Dark Lips Home Remedies: Want naturally pink lips? These effective home remedies will surely help – watch the video
Initial investigations suggested a possible link between these cases of adenovirus infection and hepatitis. Adenovirus is a very common viral infection, especially in children. They usually cause infections such as a mild cold, pink eye (conjunctivitis) or stomach problems. However, they rarely cause hepatitis if they reach the liver.
However, given how common adenoviruses are in children – and because they rarely cause hepatitis in healthy people – it was difficult to say which was the likely cause. Also Read – Disha Patani’s fitness: This is how a villain makes a comeback The actress maintains her lean and fit body – watch video
A new study suggests that cases of severe hepatitis seen in children may be the result of three factors working together: adenovirus, adeno-associated virus 2 (AAV2) and an underlying genetic predisposition to the disease.
Probable cause emerges
In a pre-print study (meaning it hasn’t yet been reviewed by other scientists), a team of researchers looked at nine cases of original hepatitis in April and conducted a large series of tests to detect new or previously discovered viruses. or genetic factors that can cause hepatitis in children.
The team found that all nine children were infected with adeno-associated virus 2. They then compared their findings to 13 healthy children and 12 children who had adenovirus infection but not hepatitis. Adeno-associated virus 2 was not detected in any of these children. This is a strong indicator that AAV2 was the cause of these mysterious hepatitis cases.
Adeno-associated virus 2 belongs to a group of viruses called dependoparvoviruses that infect both humans and some primates. But what is particularly interesting about AAV2 is that in order to infect a host, it requires other viruses to infect the host at the same time. It uses this helper virus to replicate inside human cells. The most common helper viruses of AAV2 are adenoviruses and herpesviruses.
The researchers found that six of the nine patients they looked at had adenovirus, while three had signs of the herpes virus. This makes it likely that this hepatitis infection was caused by a combination of AAV2 and one of these helper viruses.
The immune system and infection
But both AAV2 and infections such as adenovirus and herpesvirus are fairly common in children, and most children infected with these do not develop hepatitis. This means that there must be an additional factor at play here, perhaps even at a genetic level.
The team of researchers then analyzed the children’s genomes to look for specific immune system markers, called human leukocyte antigens. Cells of the immune system use human leukocyte antigens to detect and engulf other viruses and pathogens.
This then sends a signal to other immune cells that come along and destroy the pathogen. There are many different types of human leukocyte antigens, and depending on why a person has the type can determine which infections they may be more susceptible to.
The researchers found that eight of the nine children had a high genetic prevalence of a particular type of human leukocyte antigen, which may increase their likelihood of developing hepatitis symptoms from this viral infection. This type is also more common in people of European descent, which may further explain why cases of this hepatitis were mainly seen in Europe.
Although this study suggests that a combination of factors may explain the sudden, severe cases of hepatitis seen in children, the study itself was small and only conducted on participants from Scotland. Larger, peer-reviewed studies will be needed to understand the exact link and how best to protect children going forward.
Another factor that may have played a role in this was the COVID-19 restrictions, which meant that many children were not exposed to the virus and developed immunity at an age they normally would have. This meant that when restrictions were lifted, children were exposed to the virus at the same time, which would overwhelm their immune systems which were not prepared to deal with it.
However, research will be needed to investigate whether this actually plays a role in cases of severe hepatitis. But if it is shown to be a cause, it is likely that there will be fewer and fewer cases of hepatitis in children as the months pass after the last lockdown.
