Ongoing UK survey reveals a reduced likelihood of developing long COVID after a second infection, though the risk remains non-negligible
Recent research indicates that the risk of developing long COVID—a range of symptoms including exhaustion and shortness of breath—falls sharply between the first and second COVID-19 infections. Daniel Ayoubkhani, a statistician at the Office for National Statistics in the United Kingdom, explains that although the risk is significantly lower after the second infection, it does not disappear entirely.
The UK Study: A Closer Look at Long COVID
An ongoing survey of over 500,000 people in the UK up to March 5 has been tracking long COVID symptoms such as fatigue, muscle aches, shortness of breath, and concentration issues. Fatigue and concentration problems were the most common reported symptoms.
The survey found that among adult participants, 4% reported long COVID symptoms persisting for at least four weeks after their first infection. In contrast, only 2.4% of those who hadn’t developed lingering health problems after their first infection reported ongoing symptoms after their second case. Ayoubkhani describes this reduction in odds as significant.
Possible Explanations for Reduced Risk
The study did not examine why the risk for long COVID might be lower after a second infection than a first. However, Ayoubkhani suggests several possible reasons. One hypothesis is that immunity developed from previous infections could reduce the risk of developing long COVID from subsequent infections.
Another possibility is that the study excluded those who had experienced long COVID after their first infection, indicating that individuals who didn’t develop long COVID after their first infection might be innately less prone to it for some reason.
“It could have something to do with someone’s predisposition,” Ayoubkhani explains.
The study did not investigate whether a second infection exacerbates symptoms in those already experiencing long COVID.
Implications for the US
Although the study was conducted in the UK, Ayoubkhani believes there is no reason the results wouldn’t apply to the US. In fact, the findings align with an earlier study that analyzed data from hundreds of thousands of patients treated through the US Veterans Administration.
That study, published in November, found that the risk of still experiencing health problems one year after contracting COVID fell from about 10% after a first infection to around 6% after a second infection.
Dr. Ziyad Al-Aly, an epidemiologist at Washington University in St. Louis who led the earlier study, says that the reduced risk may be partly due to immunity from the first infection. Another factor could be that later strains of the virus, such as omicron, tend to cause milder disease and are therefore less likely to result in long COVID.
Improved treatments that lessen the severity of COVID may also contribute to the decreased risk.
Beyond Second Infections
Neither study examined the risk of long COVID after a third or fourth infection. However, Al-Aly hopes that the risk would continue to decline with each subsequent infection.
“All these things are pointing in the right direction that makes me optimistic that at some point in time, re-infection may add trivial risks or non-consequential risks,” he says.
However, Al-Aly cautions that as many people are still contracting the virus, the overall number of individuals suffering from lingering health problems continues to increase, even with a lower risk from second infections.
“I sort of liken it to Russian Roulette,” Al-Aly says. “The odds at the individual level of getting long COVID after a second infection versus the first is lower for any individual person.”
But, he adds, “that risk is not zero,” meaning that at a population level, the number of long COVID cases in the community continues to grow, placing an increasing burden on caregivers and society as a whole.
The Importance of Continued Precautions
These findings underscore the need for continued precautions against COVID-19, even for individuals who have already experienced an infection. While the risk of long COVID may decrease with subsequent infections, it remains present and poses a threat to both individual health and public healthcare systems.
Vaccination efforts, maintaining good hygiene practices, and following public health guidelines can help mitigate the risk of COVID-19 infections and the subsequent development of long COVID.
Looking Forward: The Future of Long COVID Research
As the pandemic continues to evolve, further research is crucial to understanding long COVID’s causes, risk factors, and potential treatments. Longitudinal studies can help to monitor the progress of individuals with long COVID over time, identifying patterns and trends that may inform future medical interventions.
Moreover, an international collaboration between researchers and healthcare professionals can facilitate the sharing of data, knowledge, and best practices, enabling a more comprehensive understanding of long COVID and its global impact.
In conclusion, while the risk of developing long COVID may decrease with second infections, it remains a significant concern for public health. Continued research, preventive measures, and collaborative efforts are essential to addressing the challenges presented by long COVID and ensuring the well-being of affected individuals and communities.