Study shows vaccines cut long COVID risk

In a recent study published in the journal JAMA Network Open, researchers conducted a prospective cohort study to investigate at-risk populations and factors associated with extended time to recovery following COVID-19 infections. Particularly, researchers evaluated risk factors contributing to recovery exceeding 90 days (“long COVID”). Their findings from a dataset comprising 4,708 participants elucidate that women and adults with suboptimal pre-pandemic health (especially preexisting cardiovascular conditions) were more likely to suffer from long COVID. Encouragingly, vaccinations both before and during the Omicron variant wave were observed to mitigate these risks.

Long COVID and current knowledge on the role of vaccinations

The United States (US) Centers for Disease Control and Prevention (CDC) defines long COVID as “a chronic condition that occurs after SARS-CoV-2 infection and is present for at least three months.” It is characterized by Coronavirus disease of 2019 (COVID-19) symptoms that persist or, in some cases, develop following recovery and hospital discharge from the initial COVID-19 infection. 1 in 5 COVID-19 survivors (~20%), the frequently termed post–COVID–19 condition (PCC) is a significant public health concern given the debilitating effect it has on its patients and their families.

Unfortunately, given the relative novelty of the condition, research outcomes (particularly epidemiology) of the disease are oftentimes confounding, presumably due to substantial differences in sampling methodologies, outcome definitions, and causative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strain. While vaccination is now almost universally accepted to have restricted the pandemic and saved potentially millions of lives, its impacts on survivors and their risk of developing long COVID are similarly confounding. Some reports highlight its risk-dampening effect, while others show no such association, and others suggest that it may contribute to an increased risk of long-term COVID.

A notable limitation of most literature on long COVID prevalence is that they rely on electronic health records, some of which are devoid of pre-pandemic health data. This prevents these studies from accounting for preexisting health conditions that may exacerbate COVID-19 infections, potentially contributing to the subsequent development of PCC in COVID-19 survivors.

Study findings and conclusions

Of the 53,143 eligible C4R participants, only 4,708 completed both follow-up surveys and were included in the present analyses. The median participant age was found to be 61.3 years, with 62.7% of the participants being women. Infection severity records indicated that 12.6% of participants (597) required hospitalization, and 3.1% (148) required critical care. 966 participants (20.5%) received vaccination before infection, but 5.9% (57) only received one dose.

In summary, the present report reveals that one in five COVID-19 survivors (~20%) developed long COVID, with women and adults presenting preexisting health conditions at the highest risk of the condition. It highlights the benefits of vaccination, especially multiple doses, in attenuating this risk, especially during the Omicron wave.