Severe breakthrough COVID-19 infections in vaccinated patients with schizophrenia in Israel.

Abstract

Patients with schizophrenia show a substantial reduction in risk of COVID-19 severe illness and related mortality when vaccinated, as compared to non-vaccinated samples. However, the emergence of new variants and the increased frequency of breakthrough infections, especially among vulnerable groups, raise questions regarding the long-term effectiveness of vaccines in reducing overall morbidity and mortality in these patients. To explore whether vaccinated individuals with schizophrenia present a higher risk for breakthrough infections, severe course of illness, and mortality, compared with vaccinated controls from the general population, we utilized the database of Clalit Health Services (CHS), the largest health care organization in Israel. The database was mined at the end of November 2021, almost a year after the launch of the vaccination plan in Israel, and after the fourth infection wave in Israel began to subside. There were 2,233 individuals infected in the total sample (4.59%), with 1,019 in the schizophrenia group (4.18%) and 1,214 in the control group (5.01%). A total of 210 individuals were hospitalized due to COVID-19 (0.43%), including 164 (0.67%) from the schizophrenia group and 47 (0.19%) from the control group. There were 29 deceased cases (0.05%) due to COVID-19, including 23 from the schizophrenia group (0.09%) and 6 from the control group (0.02%). Overall, the results suggest that vaccinated patients with schizophrenia are at increased risk for COVID-19-related hospitalization than are controls from the general population, even after controlling for demographic and clinical factors, and even when accounting for the extent of vaccination coverage through matching. Furthermore, although the overall mortality rates in the total sample were low and therefore affected the magnitude of incidence rate differences between the groups, mortality cases were more frequent in the schizophrenia group, and the RR tended to increase during the fourth infection wave. The increased risk of adverse COVID-19 outcomes for vaccinated individuals with schizophrenia during infection waves highlights the importance of conducting longitudinal studies to continuously monitor the extent of risk for patients with severe mental illness. (PsycInfo Database Record (c) 2022 APA, all rights reserved)