Depressive symptoms associated with endorsement of COVID-19 vaccine misinformation

People with moderate or severe depressive symptoms are more likely to endorse misinformation about coronavirus disease 2019 (COVID-19) vaccines, and those who embrace vaccine misinformation are half as likely to be vaccinated, a study in the US has shown.

In the study, researchers analyzed responses to two waves of the COVID State Project survey conducted between May and July 2021. The online survey contained four common vaccine-related statements of misinformation, including: 1) “The COVID-19 vaccines will alter people’s DNA”; 2) “The COVID-19 vaccines contain microchips that could track people”; 3) “The COVID-19 vaccines contain the lung tissue of aborted fetuses”; and 4) “The COVID-19 vaccines can cause infertility, making it more difficult to get pregnant”. The responders were asked to rate the statements as accurate, inaccurate or not sure, and to complete the Patient Health Questionnaire 9-item (PHQ-9) as a measure of major depressive symptoms. [JAMA Netw Open 2022;5:e2145697]

Among 15,464 respondents (mean age, 47.9 years; women, 63.6 percent), 26.9 percent were identified to have moderate or greater depressive symptoms (ie, PHQ-9 score≥10), while 19.2 percent believed in ≥1 vaccine-related statements of misinformation. Presence of depression was significantly associated with an increased likelihood of believing in vaccine misinformation (adjusted odds ratio [OR], 2.15; 95 percent confidence interval, 1.91 to 2.43).

“In general, negative biases are apparent in information processing even in the absence of depression. Individuals with major depressive symptoms often exhibit a more pronounced negativity bias,” pointed out the researchers.

At the end of the survey, the respondents were asked if they had received at least one dose of COVID-19 vaccine to determine their resistance to vaccination. If they had not received COVID-19 vaccination, they were then asked, “If you were able to choose when to get a COVID-19 vaccine, would you get it …”, with options including “as soon as possible”, “after at least some people I know”, “after most people I know”, or “I would not get the COVID-19 vaccine”.

As expected, individuals who believed in ≥1 statement of misinformation were significantly less likely to be vaccinated (adjusted OR, 0.45; 95 percent CI, 0.40 to 0.51) and more likely to report vaccine resistance (adjusted OR, 2.68; 95 percent CI, 2.89 to 3.31).

Moreover, among 2,809 individuals who responded to a subsequent survey in July 2021, presence of depression in the first wave of the survey was associated with worsened belief in misinformation (ie, increased number of misinformation statements labelled accurate) compared with the prior survey (adjusted OR, 1.63; 95 percent CI, 1.14 to 2.33).

“It bears noting that individuals with depression may exhibit a lack of positive interpretation bias (ie, less optimistic belief), which could lead them to underestimate the potential benefit of vaccination,” the researchers noted.

“Mood disorders have been associated with worse COVID-19 outcomes among hospitalized patients. While this study’s design cannot address causation, the association between depression and the spread and impact of misinformation merits further investigation,” they continued. “If causation could be established, it might suggest another potential benefit of public health efforts to address depressive symptoms, such as reducing susceptibility to misinformation.”