While the world grapples with the COVID-19 pandemic and its aftermath, a new infectious disease outbreak affecting children is causing worry among parents and medical professionals.
Between October 2021 and July 2022, a sudden uptick in cases of hepatitis among 1-month to 16-year-olds began surfacing around the world.
The most perplexing part of it was that doctors could not figure out the cause of the illness — it was not due to the more common hepatitis A, B, C, D, or E viral infections. Initial investigations also could not identify any common exposures between cases from things like travel or toxic substances.¹
A report published in October 2022 stated that at least 1,643 possible cases from 35 countries have been reported based on data from 22 studies. The vast majority of the cases were surfacing in the UK.²
The severity of the symptoms has also promoted those in the medical community to act fast. Of the identified cases, many had acute liver failure (ALF), 120 (7.3%) needed to undergo liver transplants, while 24 (1.5%) died.
In July 2022, the Centers for Disease Control and Prevention (CDC) reported that 296 probable cases had been identified in the US, with 2 years and 2 months being the average age of the patients. The vast majority of the cases, or 89.9%, had to be hospitalized, while 6.1% needed a liver transplant. So far, 3.7% of them have died.³
Researchers have been perplexed by this surge of hepatitis, but some breakthroughs in understanding its potential causes have been discovered. So, what do you need to know about this latest deadly condition affecting children?
So far, researchers have identified the adenovirus as a possible link in this mystery.⁴
Adenoviruses include a large group of viruses. So far, seven species of the virus have been identified, and there are multiple variants within each of these groups.
They usually result in mild respiratory illnesses like the common cold. But it can also cause more severe issues like bronchitis and pneumonia.⁵
The virus is spread through contact with bodily fluids, such as saliva, mucus, or blood, from an infected person.
As adenovirus was present in a substantial portion of the children with hepatitis of unknown origin (in the US, it was in 45% of 224 cases), it prompted researchers to investigate it as a possible cause of the outbreak.
What puzzled experts was how exactly the virus was related to this current hepatitis outbreak.
This is because adenoviruses are common and usually don’t cause hepatitis in healthy individuals.
So far, several adenoviruses have been identified as possible culprits in the outbreak:⁶
Adenovirus subtype 41, which usually results in gastroenteritis symptoms like diarrhea and vomiting that can be mild to moderate
Adeno-associated virus 2 (AAV2), which cannot replicate without another virus being present
Some experts suggest that COVID-19 lockdowns could be to blame for the reduced immunity in children, which in turn leads to milder viruses causing serious illness.
"During the lockdown period when children were not mixing, they were not transmitting viruses to each other. They were not building up immunity to the common infections they would normally encounter," said Prof. Judith Breuer, virologist at University College London and Great Ormond Street Hospital, in an interview with the BBC.
"When the restrictions were lifted, children began to mix, viruses began to circulate freely — and they suddenly were exposed with this lack of prior immunity to a whole battery of new infections."⁷
Despite the progress in understanding this latest hepatitis outbreak, many questions still remain about how to prevent further spread. Most importantly, experts need answers to how exactly the adenoviruses are actually causing hepatitis.
With more research, experts hope that the outbreak can be brought under control and eventually prevented.
To understand more about the current hepatitis outbreak, it's also important to know the facts about the more common forms of the condition.
There are many different types of hepatitis, but they all have one thing in common: they cause inflammation of the liver.⁸ ⁹
Hepatitis can be acute, meaning it comes on suddenly and lasts for a short time. Or, it can be chronic, where it develops over time and leads to long-term liver damage.
The most common symptoms include:
Loss of appetite
Yellowing of the skin and eyes (jaundice)
If left untreated, hepatitis can lead to liver failure and death.
It's important to see a doctor immediately for testing and treatment if you think you may have hepatitis. Early diagnosis and treatment are essential for preventing serious damage to the liver.
When you have hepatitis, your liver becomes inflamed, which interferes with its usual functions. It may not be able to remove toxins from your blood or make enough bile to help with digestion.
The inflammation can also cause scarring, which is termed "cirrhosis." Once the disease has progressed to the stage of cirrhosis, the damage is irreversible.
There is no one test for hepatitis. The disease is diagnosed by a combination of tests that can identify the virus in your body, as well as liver damage.¹⁰
Blood tests can detect antibodies to the virus, as well as elevated liver enzymes, which are markers of liver inflammation.
Your doctor may also order a liver biopsy, which involves removing a small sample of tissue from the liver. This can help to determine the severity of the liver damage and rule out other causes.
Sometimes, your doctor might also perform an ultrasound to look for structural abnormalities or enlargement of the liver.
Hepatitis can be caused by a virus, such as the hepatitis A virus. Or, it can be the result of non-viral factors like drinking too much alcohol and issues with the immune system (although this is rarer).
Here's more information about the different types of viral and non-viral hepatitis:¹¹ ¹²
Hepatitis A is a virus that is commonly spread through contaminated food or water. The virus can also be passed from person to person through direct contact with infected blood or bodily fluids.
There is no cure for hepatitis A, but the disease can be prevented with a vaccine. The hepatitis A vaccine is typically given to children aged 12–18 months in endemic countries, as well as to adults who are at risk for the disease.¹³
Hepatitis B infections are caused by the hepatitis B virus. The virus is found in the blood and bodily fluids of infected people, and it can be spread through contact with these fluids.
It's commonly spread through sexual contact, but it can also be transmitted through shared needles or from an infected mother to her child during childbirth.
Most adults that get infected with the hepatitis B virus get better naturally. But those who get infected in childhood may develop chronic hepatitis B.
There is also a vaccine available that can help to prevent infection, which is often given to healthcare providers and other at-risk populations.
Hepatitis C infections are caused by the hepatitis C virus (HCV). It's a blood-borne virus, which means it can be spread through contact with infected blood. The virus may cause an acute illness, or it may result in chronic illness, including severe liver damage.
In most cases, HCV is spread through sharing needles or other equipment for injecting drugs.
There is currently no vaccine for the prevention of hepatitis C.
Hepatitis D infections are caused by the hepatitis D virus (HDV), but it can only infect a person who already has hepatitis B. The HDV needs hepatitis B to survive in the body.
It's spread through contact with the blood of an infected person or through sharing needles or other equipment used to inject drugs. It can also be sexually transmitted.
There is no vaccine for HDV. However, taking the hepatitis B vaccine can indirectly protect you from hepatitis D.
Hepatitis E is a worrying virus that can cause severe liver damage. The virus typically spreads when a person consumes raw foods (like shellfish and undercooked pork) or contaminated water.
Symptoms of hepatitis E are usually mild but can become severe in people with weaker immune systems.
Always practice good food and water hygiene to prevent hepatitis E infections.
Alcoholic hepatitis is another form of hepatitis that can occur in people who abuse alcohol over many years.¹⁴
It occurs because alcohol causes the liver to release toxic chemicals when trying to break it down, and this leads to liver inflammation.
Although there is no cure for the condition, it is possible to treat it with medication and lifestyle changes.
Autoimmune hepatitis occurs when the body's own immune system starts attacking the liver cells.
It is also a rare form of hepatitis, and its exact causes are still unknown.
At present, there is no cure for hepatitis. Treatment focuses on minimizing liver damage and providing symptomatic relief. In some cases, this might involve the use of antiviral medication.
For autoimmune hepatitis, there are medications available to help reduce overactivity in the immune system.
The best way to fight hepatitis is by preventing infections in the first place. This can be done through vaccinations that are currently available for hepatitis A and B (but not C, D, and E). Practicing good general hygiene can also help prevent the transmission of hepatitis viruses.
Most of the time, hepatitis will resolve on its own over time in healthy individuals. But it's still important to seek medical treatment if you experience any hepatitis symptoms.
As the hepatitis outbreak continues, it is important for parents to be aware of the potential risks and take steps to protect their children.¹⁵
First and foremost, all children should be up-to-date on their vaccinations for hepatitis, as this is the best way to prevent infection. Most children in the US are vaccinated against hepatitis A as infants. The vaccine is typically given in a series of two shots, with the second shot given at least six months after the first.
Hepatitis B is another type of hepatitis that can be vaccinated against. The vaccine for this virus is typically given in three shots.
The vaccines for both hepatitis A and B are safe and effective, and they are an important part of protecting children from this serious virus.
It's also important for parents to be aware of hepatitis symptoms and to seek medical treatment immediately if their child shows any signs of illness.
They can also help prevent the spread of hepatitis viruses by teaching their children proper handwashing techniques and emphasizing the importance of covering coughs and sneezes.
By taking these simple precautions, parents can help to keep their families healthy and safe during this outbreak.
There's still a lot unknown about the current hepatitis outbreak in children across the world.
So far, experts suggest two possible explanations:
COVID-19 lockdowns resulted in less mingling amongst children, which led to compromised immunity.
This allowed them to become more susceptible to adenovirus infections (which usually do not cause severe illness).
Beware of misinformation circulating online about COVID-19 vaccines as a possible cause of the outbreak. Experts have refuted this claim as most of the children infected with hepatitis of unknown origin were too young to receive the vaccine.¹⁶
Researchers are working hard to understand more about the outbreak to guide treatment and prevent future spread. In the meantime, parents should ensure their children are up-to-date with vaccinations, continue teaching children about good hygiene, and be aware of hepatitis symptoms.
Multi-country – Acute, severe hepatitis of unknown origin in children | World Health Organization
Characterization of a hepatitis outbreak in children, 2021 to 2022 (2022)
Interim analysis of acute hepatitis of unknown etiology in children aged <10 years — United States, October 2021–June 2022 | Centers for Disease Control and Prevention (CDC)
Hepatitis outbreak in children: explainer on adenovirus type 41, the possible culprit | The Conversation
Adenoviruses: Symptoms | Centers for Disease Control and Prevention (CDC)
Childhood hepatitis surge ‘probably linked to two common viruses’ (2022)
Likely cause of mystery child hepatitis outbreak found | BBC News
What is hepatitis? | Hepatitis Australia
What is viral hepatitis? | Centers for Disease Control and Prevention (CDC)
Diagnosing hepatitis A, B & C | NYU Langone Health
What is hepatitis? | Hepatitis Australia
Hepatitis | NHS
Hepatitis A VIS | Centers for Disease Control and Prevention (CDC)
Alcoholic hepatitis (2022)
What parents should know about the current investigation of hepatitis of unknown cause in children | Centers for Disease Control and Prevention (CDC)
Dawn Teh is a health writer and former psychologist who enjoys exploring topics about the mind, body, and understanding what helps humans thrive.
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