COVID-19 vaccination pharmacovigilance in Khojaly district, Uzbekistan: an epidemiological evaluation

COVID-19 vaccines are safe and effective, reducing global morbidity and mortality. Strong vaccine safety surveillance systems increase public confidence in vaccines. Regular evaluations are needed to ensure these systems function effectively. We evaluated the adverse events following immunization (AEFI) surveillance system for COVID-19 vaccine in Khojaly District, Uzbekistan.

We analyzed National Vaccine Registry data for April 2021-March 2022 for Khojaly (population: 120,000). The registry captures demographic information for individuals who received or refused COVID-19 vaccination and reported AEFI. An AEFI is any untoward medical occurrence that follows immunization, but does not necessarily have a causal relationship with the vaccine. In June 2022, we also surveyed 30 consenting vaccination providers from five outpatient clinics and reviewed regulatory documents related to COVID-19 vaccination and AEFI reporting. We performed descriptive statistics using R.

A total of 78,453 COVID-19 vaccines doses were administered in Khojaly from April 2021 to March 2022. Of these, 70% were Zifivax (ZF2001), an adjuvant protein vaccine produced in Uzbekistan, 9% were Pfizer-BioNTech, 7% were Moderna, and 14% were others. There were 843 AEFI correctly reported by providers (1,074 per 100,000) during this time, 837 (1,067 per 100,000 doses) of which were reported as mild allergic reactions, 4 (5 per 100,000 doses) as exacerbations of chronic disease, and 2 (3 per 100,000 doses) as anaphylactic shock. Among the providers surveyed (n = 30), 15 (50%) had previously encountered at least one AEFI following COVID-19 vaccination, and 3 (10%) had encountered a severe AEFI. Among all providers, only 13 (43%) submitted an AEFI report, and 10 (33%) did not know where to report an AEFI. The most common barriers to reporting included having a large patient load (20%) and not having access to computers (7%). The AEFI surveillance system lacked a feedback loop to share summary data with healthcare facilities and clinicians for informed decision-making.

The COVID-19 vaccination surveillance system in Khojaly recorded AEFIs, but we identified gaps in AEFI reporting and knowledge among providers. Improving the AEFI registry and training providers on standard operating procedures for identifying, reporting, and investigating AEFI could improve vaccine safety surveillance.