Data from people infected with SARS-CoV-2 early in the pandemic add to growing evidence suggesting that vaccination can help to reduce the risk of long COVID1.
Researchers in Israel report that people who have had both SARS-CoV-2 infection and doses of Pfizer–BioNTech vaccine were much less likely to report any of a range of common long-COVID symptoms than were people who were unvaccinated when infected. In fact, vaccinated people were no more likely to report symptoms than people who’d never caught SARS-CoV-2. The study has not yet been peer reviewed.
“Here is another reason to get vaccinated, if you needed one,” says co-author Michael Edelstein, an epidemiologist at Bar-Ilan University in Safed, Israel.
People with the debilitating condition called long COVID continue to experience symptoms — such as fatigue, shortness of breath and even trouble concentrating — weeks, months or years after SARS-CoV-2 infection. Some estimate that up to 30% of infected people, including many who were never hospitalized, have persistent symptoms.
Vaccination reduces long COVID’s incidence by preventing people from getting infected in the first place. In theory, the shots could also protect against the condition by minimizing the length of time the virus has free rein in the body during breakthrough infections. But so far, the few studies that have looked into whether vaccines protect people from long COVID have had mixed results, says Akiko Iwasaki, a viral immunologist at the Yale School of Medicine in New Haven, Connecticut.
To examine the pandemic’s long-term effects, between July and November 2021, Edelstein and his colleagues asked more than 3,000 people whether they were experiencing the most common symptoms of long COVID. All had been tested for SARS-CoV-2 between March 2020 and the study period.
The researchers compared the prevalence of each symptom to self-reported vaccination status and found that fully vaccinated participants who had also had COVID-19 were 54% less likely to report headaches, 64% less likely to report fatigue and 68% less likely to report muscle pain than were their unvaccinated counterparts.
A shot for long-haul COVID?
Edelstein says his team’s study is the most “comprehensive and precise” to date on vaccination and long COVID, and that the results echo those of other research, including a UK-based study2 from last September that found that vaccination halved the risk of long COVID.
Claire Steves, a geriatrician at King’s College London who led the UK study, agrees that the Israeli data support earlier findings. “It’s really good to see different study designs correlating, with the same results,” she says.
Although the results of both the UK and Israel studies show that vaccination reduces the risk of long COVID, she says, even fully vaccinated people are still at risk of developing the condition. And whether vaccination protects people from Omicron-induced long COVID is still unclear.
Regardless, Iwasaki says these findings are encouraging. “Long COVID is a terrible and debilitating disease. Any measures we can take to prevent long COVID are key to limiting more suffering in the future,” she says. “One more reason to get vaccinated.”