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The following is a summary of “Antipsychotic exposure and infection risk in people with schizophrenia spectrum disorders during the COVID-19 pandemic: a Danish nationwide registry study,” published in the September 2024 issue of Psychiatry by Nersesjan et al.

People with schizophrenia have a higher infection risk and mortality rate, a trend confirmed during the COVID-19 pandemic. However, we still do not know much about the added impact of antipsychotics, especially the debated safety of clozapine.

Researchers conducted a retrospective study examining how antipsychotics influence the risk of COVID-19 and non-COVID respiratory infections during treatment. 

They used nationwide Danish registers like the National Prescription Registry, National Hospital Registry, Psychiatry Research Register, and more to study adults with schizophrenia (ICD-10: F20-F29) in Denmark from Jan 1 to Mar 1, 2020. Antipsychotic users were split into prevalent and incident groups. From Mar 1, 2020, to Dec 31, 2021, infection risks were assessed for mild (positive SARS-CoV-2 PCR, anti-effective drug prescriptions) and severe (hospitalization, death) COVID-19 and non-COVID respiratory outcomes. Adjustments were made for demographics, socio-economic factors, and comorbidities. 

The results showed that out of 85 083 people with schizophrenia (52.1% men [n=44,293], median age 45.8 [IQR: 31.1-60.2]), 30 984 had antipsychotic exposure periods. SARS-CoV-2 positive risk decreased (HR 0.91 [95% CI: 0.85-0.97]), while anti-infective drug use showed no difference (1.01 [0.97-1.06]). While the risk of COVID-19 hospitalization increased (1.28 [1.07-1.52]), mortality risk was not significant (1.24 [0.82-1.86]). Non-COVID respiratory infection risks rose for hospitalization (1.61 [1.44-1.79]) and death (1.61 [1.18-2.21]). COVID hospitalization increased in people aged more than 70, while non-COVID risks rose in age 40 and older groups. Clozapine had no excess risk compared to other antipsychotics.  

Investigators concluded that people over 40 with schizophrenia on antipsychotics should get preventive measures like pneumococcal vaccines. Patients must stick to treatment guidelines and be more cautious without avoiding specific antipsychotics.

Source: thelancet.com/journals/lanpsy/article/PIIS2215-0366(24)00223-2/abstract#au10