Patients with schizophrenia are under‐vaccinated for COVID‐19: a report from Israel

After the first report published in this journal ¹ , several other studies conducted in the US, France, Korea and Israel have confirmed that individuals with severe mental illness (SMI), especially those diagnosed with schizophrenia, are at increased risk for COVID‐19‐related severe morbidity and mortality^e.g., 2, 3. These reports have led to the call to prioritize these patients for early COVID‐19 vaccination ⁴ .

While prioritization is especially pivotal during periods of vaccine deficiency, there are several reasons to suspect that, when vaccinations become widely available, they will not be fully utilized in individuals with SMI. Studies indicate that these patients are less likely to receive available standard levels of care for most of their medical diseases ⁵ , and overall receive less treatment for diseases they are more susceptible to suffer from ⁶ . Furthermore, rates of vaccination for diseases such as influenza, which is mostly available to the public, have been reported to be low among individuals with SMI ⁷ .

Israel has been highly proactive in engaging citizens to follow its mass COVID‐19 vaccination plan ⁸ . Vaccinations became available to all citizens above the age of 16 by the end of January 2021. In a recent study from this country, we found that individuals with schizophrenia were more likely to suffer from COVID‐19 morbidity and mortality compared to age and gender matched controls ³ . To explore whether patients with this diagnosis are being vaccinated to the same extent as their matched controls, we revisited the cohort of patients and updated their medical registry with information regarding vaccination rates.

The original cohort included 25,539 patients with schizophrenia and their matched controls (overall N=51,078). Deceased cases were omitted from the analysis, thus leading to a total of 50,240 cases (25,120 cases of schizophrenia and their age and gender matched controls). The study utilized the databases of Clalit Health Services (CHS), the largest operating health care organization in Israel ⁹ . These databases are regularly updated with real‐time information derived from patients' medical registries, and undergo routine validation procedures for medical and psychiatric diagnoses.

The diagnosis of schizophrenia in this study was made by a senior psychiatrist in the patient's medical registry or was listed on a psychiatric hospital's discharge letter. Matched control participants comprised individuals with no diagnosis of schizophrenia randomly sampled at a 1:1 ratio. The study was approved by the CHS institutional review board, where informed consent was waived due to the anonymous nature of data extraction.

For the purposes of the current analysis, vaccination was considered as implemented if the patient received at least one dose. Univariate logistic regressions were employed to assess the odds of being vaccinated, and odds ratios (ORs) and 95% confidence intervals (CIs) were reported. The dataset was stratified for age and gender groups. All statistical analyses were performed using SPSS software, version 25.

The odds of receiving COVID‐19 vaccination were significantly lower in the schizophrenia group compared to the control group (OR=0.80, 95% CI: 0.77‐0.83, p<0.0001). No significant differences were observed in the 16‐21 age subsample. Differences between the two groups were more profound as age increased: OR=0.90, 95% CI: 0.83‐0.97, p<0.0001 in the 21‐40 age subsample; OR=0.83, 95% CI: 0.79‐0.88, p<0.0001 in the 40‐60 age subsample; and OR=0.61, 95% CI: 0.57‐0.64, p<0.0001 in the subsample at age 60 and above. The odds of being vaccinated were lower in the schizophrenia group for both male and female participants, with males showing slightly greater gaps in vaccination rates (OR=0.79, 95% CI: 0.75‐0.82, p<0.0001) than females (OR=0.82, 95% CI: 0.77‐0.87, p<0.0001).

These results indicate that individuals with schizophrenia, although well known by the scientific community for their medical and social vulnerabilities, are being under‐vaccinated for COVID‐19 in Israel compared to the rest of the population. This inequality is especially pronounced in people aged 60 and above, where the convergence of risk factors may create an additional accumulating mortality risk.

The lack of significant differences in the 16‐21 age subsample may be related to the overall low rates of vaccination in young people. On the other hand, the increasing gap between the schizophrenia and control groups as age increases indicates that, when vaccination is more available (as older age groups could be vaccinated immediately upon the launch of the national plan), schizophrenia patients are more profoundly disadvantaged.

A variety of factors previously described as barriers to immunization in SMI people, such as lack of awareness and knowledge, fear, and lack of active recommendation from primary caregivers ⁷ , may also serve as barriers to COVID‐19 vaccination. Proactive efforts should be made to provide SMI people with easier access to vaccination as part of routine medical care policy. Such access can be obtained by, for example, providing ad‐hoc vaccination to patients presenting for psychiatric examinations or follow‐ups, who are interested in being vaccinated. Patients should also be actively monitored for completing the vaccination plan so as to make sure that they follow through on the recommendations made by the vaccine producers.

The results of this study are based on analyses of associations; therefore, no causality can be inferred from the study design. Future studies should explore whether accessibility to vaccination is associated with specific chronic diseases, as well as with other sociodemographic factors. They should also assess the mediating factors associating schizophrenia with under‐vaccination for COVID‐19.

The lower rates of vaccination among patients with schizophrenia reported in this study should alert public health policy entities to provide better care in the form of easier access to COVID‐19 mitigation/prevention efforts for individuals with schizophrenia.