Increasing COVID-19 Vaccination Rates Among Patients With Serious Mental Illness: A Pilot Intervention Study

This quality improvement project was implemented with 193 patients who had serious mental illness in an outpatient clozapine treatment clinic housed in a community mental health center in Boston. The study was approved by the institutional review boards of Massachusetts General Hospital and North Suffolk Mental Health Association.

Starting in February 2021, our clinic held monthly COVID-19 literature–based educational sessions to share vaccine knowledge and strategies for motivational interviewing and nudging with other psychiatrists and psychiatric nurse practitioners. Topics covered included evidence-based communication strategies to promote vaccine acceptance, counter messages to common vaccine hesitancies, and monitoring of misinformation (9).

The authors created a population-based vaccination-monitoring tool (available in an online supplement to this report) with questions based on literature review of vaccine hesitancy. The tool comprises a set of questions to track patients’ vaccine uptake and reported vaccination intention (on a 5-point scale, ranging from 1, very unlikely, to 5, very likely). This tool was embedded in patients’ electronic medical records (EMRs) to serve as a basis for semistructured interviews, which were conducted during each outpatient visit by psychiatric providers between February 1, 2021, and June 30, 2021. Each interview took 2–3 minutes. After a general open-ended question about COVID-19 vaccination to initiate the conversation, each item of the population-management tool was read aloud. When vaccine hesitancy was detected, patients were encouraged to share their vaccine-related concerns. Their concerns were addressed by psychiatric providers and were documented in their EMR. When practical challenges prevented vaccination of people who were willing to get vaccinated, psychiatric providers did their best to coordinate with family and care teams to assist with scheduling, transportation, and remembering vaccine appointments. The interview was repeated at each visit during this 5-month period. The clinical team reviewed the progress of the vaccination effort in monthly medical-psychiatric integration team rounds.

The project included only adult patients (ages >18 years) who received clozapine treatment and had a DSM-5 axis I diagnosis of schizophrenia, schizoaffective disorder, unspecified psychotic disorder, bipolar disorder, or persistent major depressive disorder. Most of the 193 patients were men (N=137, 71%), and the mean±SD age was 46.4±13.5 years (range 19–81). Nearly all (N=187, 97%) had schizophrenia spectrum disorders. Living situations of the patients included living with family (N=60, 31%); independently (N=44, 23%); in a group home (N=41, 21%); independently with community support, such as a visiting nurse or case manager (N=34, 18%); and in a shelter or being homeless (N=14, 7%).

Statistical quantitative data summaries were generated with SPSS, version 25, software. Recurrent qualitative observations were summarized thematically.

To set a baseline vaccination rate, we considered the general population of comparison to be adults in the state of Massachusetts. By June 30, 2021, a total of 4,283,434 people were fully vaccinated in the state (12). Given Massachusetts’ population of 6,892,503 (as of 2019 per the U.S. Census Bureau), the state’s vaccination rate was 62.1%. However, this approximation represented a low estimate of the vaccination rate of adults given that the state population includes children, who were ineligible at the time for vaccines. Specifically, given that 19.6% of the residents in the state were ages <18 years in 2019 per the U.S. Census Bureau, 80.4% of the population of 6,892,503 were adults, that is, about 5,541,572. The fully vaccinated 4,283,434 persons of the 5,541,572 adults represented 77.3%; however, this calculation likely resulted in a somewhat high estimate because the number of fully vaccinated people would include some children ages 16–18 years who became eligible for vaccines in April 2021. Thus, we conservatively estimated that between 62.1% and 77.3% of the state’s total adult population were fully vaccinated.

By comparison, by the end of June 2021, the full vaccination rate in our cohort of patients treated with clozapine was higher than the estimated state rate (84%, N=163); 4% (N=7) were partially vaccinated (only first dose), and 11% (N=22) were not vaccinated (for N=1, vaccination status was unknown). As shown in Table 1, although vaccination rates increased with age within this sample, even those younger than 40 years had a high vaccination rate compared with the rate in Massachusetts. Those experiencing homelessness or living in shelters had the lowest vaccination rates.

Before widespread COVID-19 vaccine availability in February 2021, many patients reported vaccine hesitancy in semistructured interviews. The most commonly given reasons included concerns about adverse effects and safety of vaccines due to their rapid development. Few patients believed that COVID-19 did not pose a serious threat or that vaccines were unnecessary. Others believed they were immunized against the disease without vaccination because they had contracted COVID-19. Some expressed mistrust of government and pharmaceutical companies or endorsed conspiracy theories (e.g., two patients raised the idea that vaccines contained microchips). By the end of the study period on June 30, most initially hesitant patients had received a COVID-19 vaccination.

Among the 22 individuals still not vaccinated by the end of the study, several patients (N=8, 36% of the unvaccinated, 4% of the total sample) reported vaccine hesitancy, defined as 1 or 2 on the 5-point scale of the vaccination-monitoring tool, due to concerns about the safety and adverse effects of the vaccines. Some (N=3) communicated that they just “didn’t want” the vaccine but did not provide any specific reasons for their refusal.

Practical barriers to vaccination were commonly observed among many (N=9, 41%) of the patients who were still unvaccinated by the end of study, including unintentionally sleeping through appointments or not knowing how to schedule an appointment. Some patients were unaware that a series of vaccine shots was needed for full immunization.

A large proportion of vaccinated patients with serious mental illness received help from others who managed their appointments or provided transportation (e.g., family members or group home staff members). Many found mobile clinics and walk-in vaccination sites convenient.

Proactive intervention by psychiatric providers who systemically addressed COVID-19 vaccine–related concerns and encouraged vaccinations at routine outpatient visits resulted in higher COVID-19 vaccination rates among patients with serious mental illness compared with the estimated vaccination rate in the state. Vaccine hesitancy of our sample was similar to that of the broader U.S. population. In a study reporting perceptions of the COVID-19 vaccine among U.S. adults (13), those who did not intend to get vaccinated as indicated in survey responses in September 2020 expressed concern about the rapid speed of vaccine development. By December 2020, their cited reasons for not getting vaccinated centered mainly on the adverse effects and safety of vaccines, consistent with the concerns voiced in our sample of patients.

In an international survey of members of Clubhouse International with serious mental illness (14), logistic and administrative details such as scheduling appointments or transportation were cited as prominent barriers to vaccination. Clubhouses provided additional support, and their members subsequently had high vaccination rates, similar to the rates observed in this study. These higher vaccination rates after proactive interventions are in contrast to findings of studies from the United Kingdom (7) and Israel (5), which reported overall lower rates of COVID-19 vaccination among patients with serious mental illness.

We note some limitations. This study reports results from a quality improvement project without a control group; thus, we could not establish causation, and the state of Massachusetts, in which this study was conducted, attempted to vaccinate vulnerable groups in congregate settings, including those with serious mental illness, very early in the pandemic. Even if our efforts increased vaccination rates, it is unclear which of the research-based approaches (motivational interviewing, nudging, helping with practical barriers, and connecting with the broader care team) contributed to this increase.

Another limitation was that the study sample comprised patients treated with clozapine and was therefore not representative of the larger population with serious mental illness. Eligibility for clozapine treatment requires a history of compliance with regular follow-up and blood work; this selection may have led to a sample of patients predisposed to a higher level of compliance with medical instructions than the broader population with serious mental illness, who may have been less likely to engage with this intervention and to follow up with its vaccination recommendations.

By making discussions about vaccines part of the routine clinical procedure at each outpatient psychiatric visit, psychiatric providers may help increase vaccination rates among patients with serious mental illness. Such patients may face many barriers to vaccination and could benefit from psychiatric providers encouraging them to get fully vaccinated. Enhanced monitoring and targeted interventions for this population may be best provided by psychiatric providers who already have a close relationship and frequent contact with their patients (8). Resolving vaccine hesitancy and providing accurate vaccine information may be critical. Not using psychiatric providers would be a missed opportunity, given their expertise with motivational interviewing and nudging. In addition, because of pronounced practical barriers, developing strategies to ensure completed vaccination series, such as working with family and the broader care team, could be important. A policy change that would allow “shots in arms” at the site of mental health practices would be the most effective way to make vaccines more accessible.

Incorporating preventive care such as vaccinations in mental health settings and expanding the role of psychiatrists will protect the health of marginalized patients with serious mental illness who are otherwise hard to reach. Future efforts should move beyond COVID-19 vaccinations to include other vaccine-preventable illnesses such as influenza, given an increased mortality rate from pulmonary infections among patients with schizophrenia (15).