Doctors in America believe the inflammatory Kawasaki-like condition caused by coronavirus could be affecting adults in their early 20s.
The mysterious condition is affecting children and has been shown to be linked to previous infection with the SARS-CoV-2 coronavirus, which also causes COVID-19.
Reports in the Washington Post claim several patients in their 20s are being treated for the condition in San Diego and New York.
It appears the patients were been infected with the coronavirus but developed antibodies, indicating they contracted the infection several weeks ago.
It is believed the hyper-inflammatory condition, which resembles Kawasaki disease, is a delayed immune response to the infection.
It is known as PIMS-TS (paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2) in Europe and MIS-C (multisystem inflammatory syndrome in children) in the US.
According to US-based doctors, adult patients expressing symptoms of the new condition have more severe symptoms than children, which can affect the lungs and heart.
Current treatments seem to be effective and involve steroids, anticoagulants, immunoglobulin and, occasionally, ventilation and admission to intensive care.
Younger children have symptoms more closely related to Kawasaki disease, such as inflammation of the blood vessels and rashes.
However, the emerging condition appears to be able to infect a range of people, from infants to those who have lived for a quarter of a century.
Some diseases are known to affect children but not adults, and vice versa. The reason for this remains a scientific enigma, lacking a viable explanation.
Biology does not suddenly change at 18 years old, and the impact of ageing on physiology is a progressive shift which transcends the label of adult and child.
The first wave of coronavirus patients had COVID-19 and this disease targets the respiratory system, particularly affecting people with underlying health conditions.
However, the new condition seems to mostly affect previously healthy individuals who develop a fever, nausea and vomit.
Little is known about the condition at the moment but it is believed to be rare.
However, there have been deaths from the disease. This week, a 14-year-old boy in London died from the disease. There have been reports of four deaths in the US.
The mother of an eight-month-old baby who died of the rare illness urged parents to be ‘vigilant’ to the symptoms, and called for more research into the disease.
Alexander Parsons, from Plymouth, died at Bristol Children’s Hospital last month after being diagnosed with Kawasaki disease, his family said.
Experts believe more than 100 children in Britain have been affected by the new syndrome and more than 20 states have reported cases.
The exact cause of Kawasaki Disease and the coronavirus-related condition are unknown.
However, doctors note that almost all of the patients have tested negative for current infection with the SARS-CoV-2 virus.
These tests are done in a lab and involve a throat swab. They look for the virus itself and a negative test means a person does not currently have the virus.
However, it does not reveal if a person has previously been infected and fought off the virus.
For this, antibody tests are relied upon. Antibodies are produced by the body to destroy an invading pathogen and remain in the person’s body for months.
If an antibody test comes back positive but the swab test comes back negative, it means the person has been infected with, and subsequently fought off, the virus.
A British study conducted in Birmingham assessed eight children with the condition and found they all had the antibodies but tested negative via the throat swab.
It remains unknown why the syndrome develops weeks after infection, but scientists believe it may be due to a severe overreaction from the body’s own immune system.
This ‘immune-mediated pathology’ causes the immune system to go haywire and can cause damage to the body’s own cells.
A similar phenomenon has been seen in adults, dubbed cytokine storm, and can be fatal to the sickest patients.
Theories claim that the immune system of young people is less experienced due to exposure to less pathogens and this may cause it to overreact.