Another 36 cases of mysterious pediatric hepatitis in children aged 10 or younger, health chiefs revealed Wednesday — after six deaths were reported in the outbreak.
It brings the tally of children affected by the liver inflammation to 216 across 37 states, with Mississippi and Utah the latest to be added to the growing list.
No new deaths or liver transplants were reported in the last week, the Centers for Disease Control and Prevention (CDC) said in their weekly update with the totals remaining at 14 and six respectively.
The agency has refused to reveal where the deaths have occurred sighting ‘confidentiality issues’, but at least one was registered in Wisconsin health chiefs in the state say.
Globally, the U.S. has recorded the most fatalities and suspected cases out of any nation — although this may be because of strong surveillance.
Indonesia has reported five deaths in the outbreak, while both Palestine and Israel have registered one each.
Scientists say it will still be weeks before the cause of the cases is revealed, although the CDC continues to consider adenoviruses — which can trigger the common cold — as the most likely source of the illness.
The outbreak may also be the result of weakened immunity due to lockdowns which harmed people’s immunity, some experts warn.
The CDC is now publishing weekly outbreaks on the numbers of suspected cases, liver transplants and deaths reported.
Many of the cases are ‘historic’, having occurred over the seven months since October 2021, but are only just coming to light now as physicians research samples collected from sick children in-post.
The CDC said last week there was no sign that cases were surging in recent months.
A total of 37 states have now reported cases in the hepatitis outbreak. These are: Arkansas, Alabama, Arizona, California, Colorado, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Nebraska, Nevada, New Jersey, North Carolina, North Dakota, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Tennessee, Texas, and Virginia, Washington and Wisconsin.
The territory of Puerto Rico has also recorded at least one case of mysterious hepatitis.
Experts warn lockdowns mean the U.S. may now be heading into a period where it is difficult to know what to expect from infectious diseases.
Dr Marion Koopmans, head of the department of viroscience at the Erasmus Medical Center in Rotterdam, the Netherlands, gave the warning to STAT News and said it was because of less recent immunity.
She said blood tests on children showed they had been on something of an ‘infection honeymoon’ with few antibodies present to normal diseases.
She added: ‘You really see that children in the second year of the pandemic have far less antibodies to a set of common respiratory viruses.
‘They just got less exposed.’
The CDC said last week that an adenovirus infection — which can cause the common cold — was their leading hypothesis for the cause of the illness, although they were also still investigating whether Covid infections played a role.
They have all but ruled out theories suggesting a mutation in the virus may be causing the illness, or that it could be down to exposure to pet dogs. There is no evidence that the Covid vaccine is triggering hepatitis.
The usual causes — hepatitis viruses A, B, C, D and E — have all been ruled out.
Q&A: What is the mysterious global hepatitis outbreak and what is behind it?
What is hepatitis?
Hepatitis is inflammation of the liver that is usually caused by a viral infection or liver damage from drinking alcohol.
Some cases resolve themselves, with no ongoing issues, but a fraction can be deadly, forcing patients to need liver transplants to survive.
What are the symptoms?
People who have hepatitis generally have fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, light-colored stools and joint pain.
They may also suffer from jaundice — when the skin and whites of the eyes turn yellow.
Why are experts concerned?
Hepatitis is usually rare in children, but experts have already spotted more cases in the current outbreak than they would normally expect in a year.
Cases are of an ‘unknown origin’ and are also severe, according to the World Health Organization.
What are the top theories?
Experts say the cases may be linked to adenovirus, commonly associated with colds, but further research is ongoing.
This, in combination with Covid infections, could be causing the spike in cases.
Around three-quarters of British cases have tested positive for the virus.
British experts tasked with investigating the spate of illnesses believe the endless cycle of lockdowns may have played a contributing role.
Restrictions may have weakened children’s immunity because of reduced social mixing, leaving them at heightened risk of adenovirus.
This means even ‘normal’ adenovirus could be causing the severe outcomes, because children are not responding to it how they did in the past.
Other scientists said it may have been the adenovirus that has acquired ‘unusual mutations’.
This would mean it could be more transmissible or better able to get around children’s natural immunity.
New Covid variant
UKHSA officials included ‘a new variant of SARS-CoV-2’ in their working hypotheses.
Covid has caused liver inflammation in very rare cases during the pandemic, although these have been across all ages rather than isolated in children.
The CDC has noted environmental triggers are still being probed as possible causes of the illnesses.
These could include pollution or exposure to particular drugs or toxins.