This article originally appeared on our sister site, Drug Topics.
Receiving a COVID-19 vaccine could reduce the risk of developing long COVID if it’s administered 5 months before an infection, according to new research published in the journal Vaccine.1 The authors of the study said that the findings could help with the formulation of future vaccination strategies as COVID-19 becomes endemic.
Long COVID is a chronic condition that occurs after an infection with COVID-19 and is present for at least 3 months. The condition includes a wide variety of symptoms that can persist for weeks, months or even years.2 According to data from the CDC, 6.9% of adults in 2022 had ever had long COVID, with those aged between 35 and 49 being the most likely to experience the condition. Long COVID is more common in women than in men.3
“Although COVID-19 vaccines have shown to be effective in reducing the risk of severe disease and mortality during acute SARS-CoV-2 infection, their impact on the prevalence of post-COVID-19 conditions is less understood,” the authors wrote. “Several studies have reported that vaccination is generally associated with a lower risk of post-COVID-19 conditions after breakthrough infection, while others have indicated that vaccination does not reduce (or even increases) the risk of sequelae.”
What You Need to Know
Receiving a COVID-19 vaccine within five months before contracting the virus significantly reduces the risk of developing long COVID.
Long COVID affects 11.4% of individuals diagnosed with COVID-19 in the study, with higher prevalence among women and those aged 35–49.
While the study highlights the protective effect of recent vaccination against long COVID, limitations such as reliance on claims data and lack of adjustment for vaccine type or reinfections indicate a need for more comprehensive research to refine booster vaccination strategies.
A team of investigators from Kyushu University and St. Mary’s Research Center in Japan conducted a study to examine the long-term effects of COVID-19 vaccination on the incidence and risk of post-COVID-19 conditions. Data for the study was collected from the Vaccine Effectiveness, Networking, and Universal Safety (VENUS) Study, an ongoing longitudinal multi-region database project that supports research on vaccine safety and effectiveness in Japan.
The cohort in the new study included 84464 individuals who were diagnosed with COVID-19 between August 2020 and December 2022. Of those, 27673 were assigned to a distant vaccine group, 25001 to an intermediate vaccine group, and 31790 to the recently vaccinated group. The distant vaccination group developed COVID-19 365 days or more after their last vaccine dose, the intermediate group developed COVID-19 150 to 364 days after their last vaccine dose, and the recent group developed COVID-19 14 to 149 days after their last vaccine dose.
The study found that 11.4% of the participants developed symptoms associated with long COVID. The group who recently received their COVID-19 vaccine had the highest prevalence of comorbidities during the year before they were vaccinated, but they had the lowest incidence of numerous conditions associated with long COVID. The distant vaccine group had the highest incidence of conditions, including acute upper respiratory disease, acute lower respiratory disease, asthma, dermatitis, ear disease, taste disorder, fatigue, and headache.
Study limitations include that the analyses were conducted using claims data, that all medical conditions were identified using recorded diagnoses from the outpatient and inpatient claims data, that the type, dose, and boosters of COVID-19 vaccines in each individual were not considered, that multiple comparisons were not adjusted for, and that COVID-19 reinfections or disease severity were not considered.
“There is currently insufficient information on the effects of regular booster vaccinations on post-COVID-19 conditions, but our study indicates that the risks of developing these conditions are significantly reduced when vaccinated within 5 months before COVID-19 occurrence,” the authors concluded. “In particular, this effect was more pronounced in older persons. The results of this study may serve as a foundation for formulating future vaccination strategies as COVID-19 transitions from a pandemic to an endemic state.”
References
1. Kim S, Maeda M, Murata F, et al. Post-COVID-19 conditions have emerged as a global health challenge. Effect of COVID-19 vaccination on the risk of developing post-COVID conditions: The VENUS study. Vaccine. Volume 43, Part 2, 2025. https://doi.org/10.1016/j.vaccine.2024.126497.
2. Long COVID Basics. Report. CDC. July 11, 2024. Accessed November 8, 2024. https://www.cdc.gov/covid/long-term-effects/index.html
3. Adjaye-Gbewonyo D, Vahratian A, Perrine CG, Bertolli J. Long COVID in adults: United States, 2022. NCHS Data Brief, no 480. Hyattsville, MD: National Center for Health Statistics. 2023. DOI: https://dx.doi.org/10.15620/cdc:132417.
