COVID-19 vaccinations may only offer limited protection against long COVID symptoms, according to a study published this week in the peer-reviewed Nature science journal.
Researchers for the VA St. Louis Healthcare System reviewed data from the Department of Veterans Affairs national healthcare databases to compare people with breakthrough cases of COVID-19 to individuals with no documented history of testing positive for coronavirus.
Compared to people who appeared to have never had COVID-19, individuals with breakthrough cases were found to have a higher risk of death and a higher risk of developing long COVID symptoms including issues with their heart, their digestive system, kidneys and mental health.
Researchers made these comparisons based on follow-ups six months after initial infection.
However, individuals with breakthrough cases were still observed to be at a lower risk of these effects when compared to unvaccinated COVID-19 survivors.
“Altogether, the findings suggest that vaccination before infection confers only partial protection in the post-acute phase of the disease; hence, reliance on it as a sole mitigation strategy may not optimally reduce long-term health consequences of SARS-CoV-2 infection,” the researchers wrote.
Some researchers had suggested that coronavirus vaccinations could offer protection against long COVID, as they would theoretically reduce a person’s viral load, which has been speculated to be linked to persisting coronavirus symptoms.
COVID-19 antivirals like Pfizer’s Paxlovid and Merck and Ridgeback’s molnupiravir are also being considered as potential treatments for long COVID symptoms.
The findings come after the Centers for Disease Control and Prevention (CDC) released the results of its own study looking into the prevalence of long COVID among survivors of the virus, an estimate that has been hard to pin down.
The CDC’s study estimated that one out of five adults survivors of COVID-19, between the ages of 18 and 64, had at least one lingering symptom that could attributed to coronavirus infection. This rate was slightly higher in adults over the age of 65, with one out four estimated to have at least one long COVID symptom after infection.
Vaccination status was not taken into consideration for the CDC’s study.