Study finds vaccination against COVID-19 consistently reduced the risk of long COVID symptoms

By Dr. Chinta SidharthanReviewed by Benedette Cuffari, M.Sc.Jan 17 2024

In a recent study published in The Lancet Respiratory Medicine, researchers examine whether coronavirus disease 2019 (COVID-19) vaccines could prevent long COVID symptoms and compare the effectiveness of the Oxford AstraZeneca ChAdOx1 and Pfizer BioNTech BNT162b2 vaccines, which are the two most used COVID-19 vaccines in Europe.

Study: The effectiveness of COVID-19 vaccines to prevent long COVID symptoms: staggered cohort study of data from the UK, Spain, and Estonia. Image Credit: Prostocok-studio / Shutterstock.com

Background

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19, has infected over 800 million individuals worldwide since March 2020.

Since the start of the pandemic, concerted efforts throughout the world led to the rapid development of numerous vaccines and subsequent vaccination of large parts of the global population, particularly the elderly and those at high risk of severe COVID-19 due to the presence of comorbidities. These global vaccination efforts successfully reduced the transmission and severity of SARS-CoV-2 infections, thereby significantly lowering mortality rates.

In addition to the Oxford-AstraZeneca ChAdOx1 and Pfizer-BioNTech BNT162b2 vaccines, Ad26.COV2.S and mRNA-1273 developed by Janssen and Moderna, respectively, were the four most commonly used COVID-19 vaccines in Europe. However, the persistence of COVID-19 symptoms and long-term complications affecting multiple organ systems, now cumulatively referred to as long COVID, remains a significant health burden.

To date, the impact of COVID-19 vaccines in preventing the development of long COVID is unclear.

About the study

In the present study, researchers used electronic health records and primary care data from the United Kingdom, Spain, and Estonia to evaluate whether COVID-19 vaccination prevented long COVID symptoms.

Data registries comprised information on the demographic characteristics of patients, as well as their medical histories, comorbidities, lifestyle factors, diagnoses, prescriptions, insurance claims for procedures, laboratory tests, clinical measurements, and secondary care referrals. Regional and national registries linked to these databases were used to obtain information on vaccination status and the type of vaccine administered.

Study participants were divided into four cohorts based on the enrollment period, which also corresponded to the priority groups, with cohort one primarily consisting of individuals above the age of 75 years with no history of COVID-19. Individuals above the age of 65, those who were considered clinically vulnerable, and those above the age of 18 with underlying health conditions that increased the risk of COVID-19 were included in cohort two. Cohort three comprised individuals above the age of 50, whereas the fourth cohort included individuals 18 years of age or older.

Long COVID was defined as the presence and persistence of any one of the 25 symptoms, such as fatigue, dyspnea, or cognitive dysfunction 90-365 days after a clinical COVID-19 diagnosis and with no indication of those symptoms during the six months before infection. Alternate definitions of long COVID, with varying time intervals for the presence of persistent symptoms, were used for sensitivity analyses.

Study findings

The current study included over 20 million vaccinated and unvaccinated individuals across three European countries and showed that vaccination against SARS-CoV-2 had a 29-52% effectiveness in reducing the risk of long COVID risk. These findings were consistent across numerous sensitivity analyses and varying definitions of long COVID based on clinical diagnoses and differing symptom durations.

The comparative analyses between the effectiveness of BNT162b2 and ChAdOx1 indicated that BNT162b2 was associated with slightly greater long COVID preventative effects than the adenoviral vector vaccine ChAdOx1. Other studies have reported similar results while comparing the efficacies of BNT162b2 and ChAdOx1 in preventing SARS-CoV-2 infection.

The younger population was believed to be at a lower risk of severe SARS-CoV-2 infection than adults above the age of 65 years, which led to lower vaccination uptake rates among younger age groups. However, these individuals are equally vulnerable to long COVID; thus, there remains an urgent need for vaccination across all age groups to reduce the risk of developing long COVID.

Conclusions

COVID-19 vaccination reduces the risk of severe SARS-CoV-2 infection and effectively decreases the risk of developing long COVID. Furthermore, as compared to the adenoviral vector vaccine ChAdOx1, the mRNA vaccine BNT162b2 was more effective in preventing COVID-19 severity and long COVID symptoms.