Unvaccinated People at Risk of Facing Mental Illness Up to a Year After COVID-19

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A new study revealed unvaccinated people had an elevated incidence of mental illnesses for up to a year following severe COVID-19.¹ This suggests a vaccination may lower the mental health struggles of those who contract COVID-19.

“Our findings have important implications for public health and mental health service provision, as serious mental illnesses are associated with more intensive healthcare needs and longer-term health and other adverse effects,” said lead investigator Venexia Walker, PhD, senior research fellow in epidemiology at Bristol Medical School: Population Health Sciences (PHS) at the University of Bristol, in a press release.²

Already, hospital- and population-based studies found associations between COVID-19 and subsequent mental illness.¹ Yet, limited evidence exists on which mental illnesses are linked to COVID-19 by vaccination status. Investigators sought to determine which mental illnesses were associated with a COVID-19 diagnosis based by vaccination status.

Walker and colleagues compared the incidence of mental illnesses after a COVID-19 diagnosis with the incidence before or without COVID-19 for depression, serious mental illness (a composite of schizophrenia, schizoaffective disorder, bipolar disorder, and psychotic depression), general anxiety, posttraumatic stress disorder (PTSD), eating disorders, addiction, self-harm, and suicide.

The team used OpenSAFELY-TPP to access data from 24 million people registered with general practices in England. Participants were registered with these practices for ≥ 6 months, were alive, and had data on sex, deprivation index, region, and age (18 – 110 years). Participants were either hospitalized for COVID-19 or from the general population, and they were excluded if they had COVID-19 before baseline.

Investigators analyzed data from 3 cohorts: 1 before vaccine availability during the wild-type/Alpha variant eras (January 2020 – June 2021) and 2 (vaccinated and unvaccinated) during the Delta variant era (June – December 2021.

The pre-vaccine cohort included 18,648,606 participants with 50.2% females and a median age of 49 years (range: 34 – 64 years). The vaccinated cohort included 14,035,286 participants with 52.1% females and a median age of 53 years (range: 38 – 67 years). The unvaccinated cohort included 3,242,215 individuals with 41.1% females and a median age of 35 years (27 – 46 years).

Investigators collected data on a confirmed COVID-19 diagnosis recorded in primary care settings, testing, or from the death registry. They analyzed the data from July 2022 to June 2024.

The team observed the incidence of most of the mental illnesses was raised during the first and fourth week after a COVID-19 diagnosis, compared with people without COVID-19. The incidence of mental illnesses was lower in the vaccinated group compared to the unvaccinated groups, suggesting people who are vaccinated may be less susceptible to mental health issues after getting COVID-19.

The risk for depression and serious mental illness during weeks 1 – 4 after COVID-19 was 1.93 (95% confidence interval [CI], 1.88 – 1.98) and 1.49 (95% CI, 1.41 – 1.57) in the pre-vaccine availability cohort, respectively.

Post-vaccine availability, the depression and mental illness risk for the first 4 weeks was 1.79 (95% CI, 1.68 – 1.90) and 1.45 (95% CI, 1.27 – 1.65) in the unvaccinated cohort, respectively. As for the vaccinated group, the risk was 1.16 (95% 1.12 – 1.20) and 0.91 (95% CI, 0.85 – 0.98), respectively. Investigators observed mental illness was elevated and persisted longer after hospitalization for COVID-19.

Investigators wrote the study was limited by relying on electronic health records, which may not have accurately captured disease incidence and are biased toward those with greater healthcare contact, such as hospitalized COVID-19 patients, potentially leading to an overestimation of mental health impacts. Additionally, the lack of a negative control group and data on other viruses introduces the possibility of unmeasured confounding and limits the ability to attribute observed mental health effects specifically to COVID-19.

“Our results highlight the importance [of] COVID-19 vaccination in the general population and particularly among those with mental illnesses, who may be at higher risk of both SARS-CoV-2 infection and adverse outcomes following COVID-19,” investigators concluded.

References

1. ^{Walker VM, Patalay P, Cuitun Coronado JI, et al. COVID-19 and Mental Illnesses in Vaccinated and Unvaccinated People. JAMA Psychiatry. Published online August 21, 2024. doi:10.1001/jamapsychiatry.2024.2339}
2. ^{Study of 18 million people finds increased mental illnesses incidence following severe COVID-19, especially in unvaccinated people. News Wise. August 19, 2024. https://www.newswise.com/articles/study-of-18-million-people-finds-increased-mental-illnesses-incidence-following-severe-covid-19-especially-in-unvaccinated-people. Accessed August 21, 2024.}