Getting First Dose of a COVID-19 Vaccine Improves Mental Health

By Linda Carroll

September 09, 2021

(Reuters Health) - Just receiving the first dose of a two-shot COVID-19 vaccine helps reduce stress for many, a new study suggests.

An analysis of survey data from 8,003 U.S. adults collected between March 2020 and March 2021 revealed a striking reduction in stress levels among those who got their first shot during the first few months of the nationwide vaccine rollout, according to the results published in PLoS ONE.

"There's been a lot of interest in the trajectories of mental health during the pandemic," said the study's lead author, Francisco Perez-Arce, an economist at the Center for Economic and Social Research at the University of Southern California in Los Angeles. "I think this study shows that worry about sickness is part of it for sure, and the vaccines can relieve it," he added.

"One thing that emerged from the beginning of the pandemic was that there were multi-tiered stressors - economic, social and others" Perez-Arce said. "We had the opportunity to start tracking them."

To better understand how the pandemic was impacting Americans, the researchers turned to the Understanding America Study (UAS), a nationally-representative longitudinal study of adults 18 and over. Participants were recruited through address-based sampling from U.S. Postal Service data. Respondents without internet access were provided with a tablet, internet access, and training to use the tablets if necessary. They were paid $20 per 30 minutes of survey time.

The UAS respondents were invited to participate in a bi-weekly tracking survey to understand the impacts of the pandemic, which the researchers dubbed the Understanding Coronavirus in America Study (UCAS).

On March 10, 2020, UCAS participants were invited to answer the first survey, then between April 1, 2020 and February 16, 2021, UCAS participants were invited to answer surveys every fourteen days. After February 16, 2021, the respondents answered questions every four weeks.

The current analysis included 8,003 adults who completed at least two waves of the survey. Respondents answered questions about COVID-19 vaccine status and self-reported mental distress as measured with the four-item Patient Health Questionnaire (PHQ-4), which produces a total score range between 0 and 16, with higher scores indicating greater mental distress.

"The PHQ-4 score is calculated using responses to the following four questions: Over the last two weeks, how often have you been bothered by the following problems? Not being able to stop or control worrying; Little interest or pleasure in doing things; Feeling down, depressed, or hopeless," Perez-Arce explained. "The response options go from Not at all (scored at 0) to Nearly every day (scored at 3)," he added. "The categories of psychological distress are: None (0-2), Mild (3-5), Moderate (6-8) and Severe (9-12)."

Those participants who reported having received one or two vaccine doses by March 14, 2021 were considered "ever-vaccinated" and those who did not report having received a vaccine were "never-vaccinated."

There were differences between the two groups from the start, with the ever-vaccinated being older (60.37 years versus 47.12), more likely to have a college degree (68.4% vs 51.9%), and less likely to be Black or Latino (5.9% vs 10.9% and 17.9%, respectively). And the never-vaccinated exhibited a higher PHQ-4 score than the ever-vaccinated group throughout the study period, the authors note. But the two groups' mental distress trajectories were similar until vaccines started becoming available in December 2020.

When the researchers used fixed effects regression models to analyze changes in PHQ-4 scores and categorical indicators of mental distress after the first dose of COVID-19 vaccine, they found an average effect of receiving the vaccine equivalent to 4% of the standard deviation of PHQ-4, a reduction in 1 percentage point (4% reduction from the baseline level) in the probability of being at least mildly depressed, and of 0.7 percentage points (15% reduction from the baseline level) in the probability of being severely depressed.

The new study is "important and timely," said Neda Gould, an assistant professor in the department of psychiatry and behavioral sciences at Johns Hopkins Medicine in Baltimore.

"It validates what we might have thought would be true, but it's nice to see it rooted in data and thoughtful analysis," Gould said. "The big takeaway for me is that not only is it important to get the vaccine for physical health reasons, but now we know - as we suspected - it impacts mental health as well. It's been such a challenging year for many in terms of mental health its promising to see something that helps."

SOURCE: PLoS ONE, online September 8, 2021.