While the benefits of vaccination in reducing the severity and mortality of COVID-19 are well-established, its impact on mental health is a less explored area. Following COVID-19, there are reports of persistent mental health issues, including anxiety and depression. In a recent ICMR study, 9% of individuals who survived COVID-19 hospitalisation were found to experience mental health challenges lasting at least one year. These conditions overlap with Long COVID, a spectrum of lingering symptoms affecting about 5% of individuals recovering from COVID-19, regardless of severity. Any intervention that could reduce this burden would therefore be valuable.
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A recent U.K. study by Walker et al. revealed an increased incidence of mental health problems following COVID-19. However, this was less common among vaccinated individuals, when compared to unvaccinated people. The additional risk of depression at 6 months following COVID-19 was 449 per 100,000 among vaccinated individuals, while it was 1009 per 100,000 among the unvaccinated.
The researchers explored the medical records of 17 million people in the U.K., comparing the incidence of eight types of mental illnesses over a timeline that extended from the pre-vaccine era until several months following the vaccine rollout. This enabled the detection of various types of COVID-associated mental illnesses, not only during the time before vaccines were available but also afterward.
Clear difference
During the period following the vaccine rollout, the researchers found a clear difference in mental health outcomes among vaccinated individuals. They suffered less depression, anxiety and serious mental illness following COVID-19, compared to their unvaccinated peers. The effect was independent of whether they had a prior history of mental illness. This is inferred to be due to the decreased severity of COVID-19 among vaccinated people, which could have had an indirect impact on mental health outcomes.
An additional explanation is that vaccination reduces anxiety, creating a sense of safety, as noted in a University of New Hampshire paper. Various studies affirm this, indicating decreased anxiety and depression across age, gender, and occupation among the vaccinated. However, mental health is not a binary topic, and a deeper examination is warranted to shed more light on this.
Unlike physical health and its commonly used markers such as hospitalisation rate and death, mental health is more difficult to measure, and is often understudied. There is no lab test or scan that can diagnose mental illness. Depression, anxiety, suicidal ideation, substance abuse, schizophrenia and personality disorders are part of the spectrum, the diagnosis of which requires expert evaluation. In countries such as the UK, electronic medical records serve as a reliable source of data on the mental illness burden in the population. This is primarily because of the GP system which caters to the general public - where all medical conditions are electronically logged.
Quality of life
Mental ill-health adversely affects quality of life, not only for the individual but also for the dependents. It contributes directly and indirectly to productivity and, consequently, the economy. A person with undiagnosed mental wellness might not be as productive as a healthy person, irrespective of their role, whether a homemaker or a public servant. Mental illness can impair the quality of decisions made in daily life, ranging from personal matters to government policies. It results in inefficiency, absenteeism and attrition, with employees frequently leaving their jobs. A report by Deloitte in the UK estimated that there was a 25% increase in cost to employers in the UK directly attributable to poor mental health during the pandemic.
A paper by the National Bureau of Economic Research, U.S. found that vaccination reduced the burden of anxiety and depression in the population by 30%, leading to an estimated monetary saving of $346 billion. No ‘spill-over effect’ was observed, ruling out benefits for the unvaccinated. Reduced anxiety and depression were thus exclusive to vaccinated individuals.
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At an individual level, better mental health could mean the difference between suicide and being alive, being happy or sad, or being unemployed or otherwise. Unfortunately the stigma associated with mental illness has prevented several people from seeking the help that they need. Unlike diseases such as chickenpox or conjunctivitis with overt clinical features which enable swift identification, mental illnesses can remain undiagnosed for years until a critical event brings them to light.
In any research, it is important to examine the baseline characteristics of the groups being studied. It is possible that there were fundamental differences between people who chose to be vaccinated and individuals who refused.
Marginalised groups
Studies reveal that unvaccinated individuals tend to have relatively lower education levels and belong to socioeconomically and ethnically disadvantaged groups. Within these subgroups, the physical toll of COVID-19 is compounded by uncertainty regarding employment, income drops, job loss, bereavement, domestic stress, and challenges in accessing healthcare. Indirectly impacting mental health, some of these factors may have contributed to the apparent difference between the two groups after experiencing COVID-19.
The U.K. study examined data from 2021, a period during which several mandates were in place in developed nations. Vaccination granted people certain privileges, which were out of reach for the unvaccinated. This discrimination may have contributed to their delayed recovery from a mental health setback.
Another potential explanation is that early vaccination prioritised older people and healthcare workers who had greater baseline anxiety about the outcome of COVID-19. Consequently, such individuals may have felt a sense of relief when vaccines were introduced.
In fact, a 2022 study published in the European Economic Review by the University of Leeds found that the benefits of vaccination on mental health were predominantly observed in older and clinically vulnerable people. They did not find any significant difference in mental health outcomes attributable to vaccination among younger groups. This could be because younger people are less anxious about the outcome of COVID and perhaps did not feel the need for vaccination. Additionally, vaccination may have had a greater impact among the elderly because they were prone to severe forms of COVID.
It is estimated that 50% of all disability benefits in Britain are linked with mental health, the proportion being only 25% two decades ago. Mental health issues, when not sorted out, can aggravate unemployment. The longer a person remains unemployed, the harder it is to get employment in the future.
Children affected too
Mental health was affected during the pandemic in several ways besides COVID-19 infection. The Hindu published a report in October 2020 stating that the pandemic triggered mood disorders among senior citizens in India. During the early part of the pandemic, factors like social isolation, limited access to communication devices and domestic abuse from caregivers created problems among the elderly in India. The untimely deaths of friends and relatives from COVID-19 exacerbated their sadness and anxiety.
It was not only adults who suffered from mental health issues. Children were adversely affected by school closures. Schools provide crucial non-academic services and support systems, including personal safety and nutrition for children, all of which were disrupted during closures. The increase in screen time along with a heightened attraction to video games, diminished quality of education, and lack of social interaction further impacted their mental health.
Among younger adults, working from home during the early part of the pandemic led to family conflicts, excessive alcohol use and social isolation. An entity called Zoom dysmorphia has been described, which is essentially a warped perception of self image. Following prolonged Zoom meetings, some individuals develop a heightened self-awareness and body image dissatisfaction.
A Cambridge U.K. study showed an interesting paradox. Although depression and anxiety were lower among vaccinated individuals in general, the opposite was observed among vaccinated people with lower educational attainment. The authors note that baseline vaccine hesitancy and susceptibility to misinformation in this subgroup contributed to a paradoxical increase in anxiety and depression.
A 2023 meta-analysis by Lee et al. found that although vaccination reduced depression and anxiety overall, people who had a prior history of COVID-19 experienced more severe symptoms of depression and anxiety after being vaccinated. The UK study however did not find such a difference.
In summary, mental ill health during the times of COVID-19 has rightfully been referred to as the second pandemic. Not easy to detect yet having a profound impact on the individual, family, society as well as economic productivity, it deserves greater attention. The overwhelming evidence suggests that vaccination reduced the negative impact COVID-19 had on mental health.
(Dr. Rajeev Jayadevan is co-chairman of the National IMA COVID Task Force.)
