Unvaccinated status increases risk of long COVID symptoms

1. Individuals with more severe acute COVID-19 illness and an unvaccinated status prior to infection were more likely to have symptoms one month following infection.

Evidence Rating Level: 2 (Good)

It is well known that COVID-19 infections can result in a wide range of acute outcomes from asymptomatic infection to hospitalization and even death. While new research on clinical presentations and information regarding new variants is regularly released, not much is known about persistent symptoms after several months of infection. This prospective cohort study aimed to investigate the long-term symptoms of COVID-19 and the effect of vaccination on this presentation. This study included 3663 adult participants from the US Military Health System with COVID-19 infection and receipt of a COVID-19 vaccine. All participants were sent surveys at 1, 3, 6, 9, and 12 months after symptom onset to summarize the status of the illness, the duration, and the prevalence of longer-term symptoms. The results of this study showed that 9.8% of participants reported having COVID-19-related symptoms 6 months following infection. Participants who were unvaccinated at the time of infection and reported a moderate or severe initial illness were more likely to report more than one month of symptoms (RR 1.39, 95%CI 1.04-1.85, and RR 2.25, 95%CI 1.80-2.81, respectively). Hospitalized patients had a higher risk of reporting symptoms for longer than a month than patients who were not hospitalized (RR 1.38, 95%CI 1.09-1.74). Commonly reported symptoms included headaches, fatigue, loss of sense of smell, difficulty breathing, and cough. This study conducted among Military Health System beneficiaries shows a greater risk of symptoms six months after COVID-19 infection in participants with more severe initial illness and unvaccinated individuals. There are several limitations to this study that should be noted. Firstly, this study recruited participants based on a voluntary basis in one specific population, specifically the US Military Health Systems. As such, these findings cannot be generalized to a broader population. As well, the self-reported nature of the symptoms through surveys may bias these results. Future multicenter studies with a more rigorous methodology can be informative.

Click to read the study in JAMA Network Open

Image: PD

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