COVID-19 may increase the risk of glandular fever

Even individuals who did not become seriously ill with COVID-19 may have developed a weakened immune system that could lead to serious illnesses in the future. Research from Örebro University suggests that the coronavirus might have had more far-reaching effects than previously believed.

“We were surprised that even people who did not have severe symptoms but tested positive for COVID-19 appear to develop a weakened immune system and a higher risk of, for example, glandular fever. It may also be that the coronavirus further increases the risk of chronic fatigue,” says Snieguole Vingeliene, researcher in medicine and epidemiology at Örebro University.

In the study, 10 million Swedes aged 3–100 were followed from 2020 to 2022. They were grouped based on whether they had contracted coronavirus and the severity of their infection. The results demonstrate a clear link between the coronavirus and subsequent glandular fever. The study also suggests that the coronavirus may worsen other illnesses.

Snieguole Vingeliene designed the study and conducted the statistical analysis together with Scott Montgomery, professor of medicine, and Ayako Hoyoshi, associate professor of medicine. All three conduct epidemiological research at Örebro University.

Study of ten million Swedes

“We studied people who had been admitted to hospital due to glandular fever caused by Epstein–Barr virus. However, many people who develop glandular fever do not have symptoms severe enough to require hospitalisation, so our results probably only show the tip of the iceberg,” says Snieguole Vingeliene.

More than nine out of ten Swedes carry the Epstein–Barr virus (EBV), which can cause glandular fever, but most people do not develop severe symptoms. If the infection occurs during childhood, it usually results in mild or no symptoms. Among those infected in adulthood, around seven out of ten develop symptoms such as a sore throat, fatigue, and other flu-like symptoms.

“If you have had glandular fever, you have probably noticed it. The disease can lead to several weeks of sick leave and cause exhaustion and fatigue that may persist for several months. Once you have had the virus, it remains in the body for life,” says Snieguole Vingeliene.

Possible long-term consequences

“A large proportion of those we studied were relatively young. This may suggest that the coronavirus had a stronger impact on younger people, particularly concerning the immune system and the risk of glandular fever. It also implies that more effects of the virus might become evident later, mainly through an increase in cases of glandular fever,” explains Snieguole Vingeliene.

Since the pandemic, there has been an increase in diagnoses of multiple sclerosis (MS), but it cannot be confirmed that this is caused by COVID-19. Meanwhile, there is concern that the coronavirus could, in the long term, lead to more people developing MS and other serious neurological conditions.
Although the risk is elevated, developing MS remains rare. Less than one per cent of the population is affected. Anyone who is concerned should contact healthcare services,” says Snieguole Vingeliene.

More:
Multiple sclerosis (MS) and Epstein-Barr virus:

• Multiple sclerosis (MS) is a disease that affects the nerves in the brain and spinal cord. It can cause impaired vision, reduced sensation, and difficulty walking. MS cannot be cured, but medications can slow disease progression and relieve symptoms.
• There is a link between Epstein–Barr virus, which can cause glandular fever, and MS. Almost everyone with MS carries the Epstein–Barr virus, but most people with the virus never develop MS. The infection can trigger an immune response that, in some cases, causes the body’s own immune system to attack the myelin surrounding nerve cells.
• Fewer than 1 per cent of individuals with EBV develop MS. An even smaller number develop Guillain–Barré syndrome, a rare condition that can lead to paralysis.