Study challenges assumptions about COVID-19 vaccines, long COVID prevention

A recent study conducted by researchers at the Mayo Clinic has found that COVID-19 vaccination may do little to prevent the onset of long COVID, contradicting the widely held belief that vaccines significantly reduce the risk of developing long-term symptoms.

The study, led by Dr. Melanie Swift and published in Open Forum Infectious Diseases, examined the electronic health records of 41,652 patients aged 5 and older who tested positive for COVID-19 between February 2021 and December 2022.

Despite the prevailing assumption that vaccines could lower the risk of long COVID by reducing the severity of the initial infection, the study found no significant difference in long COVID diagnosis rates between vaccinated and unvaccinated individuals.

In total, 6.9% of patients in the study were diagnosed with long COVID, with no observed difference between those who received two doses of an mRNA vaccine, those who received more than two doses, and those who were unvaccinated.

The study did find that long COVID was more commonly associated with older age, female sex, and hospitalization during the initial infection. However, it was inversely associated with infections during the Omicron variant period.

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Dr. Swift explained that while vaccines are still crucial in preventing COVID-19, their role in preventing long COVID may not be as significant as previously thought. “If you don’t get COVID, you don’t get long COVID,” she emphasized, noting that vaccines remain vital tools in preventing severe illness, even if they don’t fully eliminate the risk of long-term symptoms.

The study’s findings have sparked debate within the medical community. Dr. Clifford Rosen, a senior scientist at the MaineHealth Institute for Research, cautioned that the study’s relatively small and homogeneous sample size might limit its applicability. He pointed out that larger studies, such as those based on Veterans Affairs (VA) data, have shown more varied results, with some indicating that vaccination can reduce the risk of long COVID by 40% to 50%.

Dr. Ziyad Al-Aly, a leading researcher on long COVID at the VA St. Louis Health Care System, expressed surprise at the Mayo Clinic study’s results. He suggested that the study may be affected by confounding factors, such as the likelihood that patients seeking a long COVID diagnosis are more engaged with healthcare and are more likely to be vaccinated.

While more research is needed to fully understand the relationship between vaccination and long COVID, Dr. Al-Aly remains confident that vaccines play an important role in reducing the risk of certain long COVID symptoms, particularly those related to pulmonary health.