Long COVID Condition Resolves Over Time, Study Suggests

A new study has demonstrated that Long COVID can resolve over time. (Shutterstock)

Research led by the University of New South Wales (UNSW) and St Vincent’s Hospital in Sydney has found that the immune abnormalities in most people with mild or moderate long COVID had largely resolved two years after infection.

In a cohort of patients suffering from long COVID, biomarkers present in patients eight months after contraction largely resolved by 24 months, suggesting that long COVID can settle over time.

Biomarkers are biological molecules that can indicate diseases or health conditions, the U.S. National Cancer Institute states.

Long COVID clinical symptoms are consistent with biomarkers exhibiting a sustained inflammatory response.

Details of the Study

The study participants included people who had contracted COVID-19 in Australia’s first wave and a corresponding control group. The study considered the health information systematically reported by patients and detailed blood tests.

The exact scale of immunological improvement is difficult to quantify because immune function significantly varies from person to person. However, after 24 months there were no observable differences between the study’s control and long COVID group.

Chansavath Phetsouphanh, co-author of the paper and senior lecturer at UNSW’s Kirby Institute, said in a news release that significant improvements have been found.

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“Almost one and a half years later, we are pleased to see that among this same group, significant improvements were found in blood markers,” he said.

Blood markers are an easily accessible, cost-effective, and accurate biomarker.

“For the majority of samples we analysed in the laboratory, the biomarkers previously indicating abnormal immune function have resolved,” Mr. Phetsouphanh said.

This trend was also observable in the self-reported data with 62 percent of participants indicating improvements in health-related quality of life.

Study Limitations

The study is one of a small number that measures clinical data, self-reported health information, and intense blood sampling of the same group over an extensive period.

Professor Anthony Kelleher, director of the Kirby Institute, said that immunology is a complex science.

While the finding was encouraging, he noted it involved just one cohort that experienced an early strain of COVID-19 and whose initial COVID-19 infection was generally considered mild or moderate.

Prof. Kelleher said they cannot say for certain that outcomes in the unvaccinated clinical cohort will be true for vaccinated people. He also said that it’s uncertain whether those infected with a different strain of COVID-19 will experience the same outcomes.

“What we do know is that for most people with long COVID, both their symptoms and their biomarkers improve significantly over time, and this is a cause for optimism,” he said.

“Importantly, we will continue to undertake research to understand more about why some people don’t improve, and what can be done for those people.”

Ongoing Impact on their Life Quality

“While this is very encouraging and a reason for optimism, there are still around one third of patients who identify some ongoing impact on their quality of life,” said Professor Gail Matthews, head of infectious diseases at St Vincent’s Hospital.

Prof. Matthews said some patients may have a range of underlying causes for their long COVID symptoms.

She added that not all of these causes are driven by immunological abnormalities and that some are likely to persist even when the immunological environment has largely returned to normal.