Background

Monkeypox is a zoonotic disease caused by an Orthopoxvirus genus virus. Since 2024, Mpox cases have been reported to have reached more than 100,000 worldwide. Adverse Events Following Immunization (AEFI) information after Mpox vaccination is still limited and requires further research.

Objectives

This study aims to describe the adverse events following immunization (AEFI) among Udayana University Hospital staff after receiving Mpox vaccination.

Material and methods

This was an observational, descriptive study with a cross-sectional approach conducted in November 2024 at Udayana University Hospital. A total of 47 health workers who had received two doses of Mpox vaccination were selected using total sampling. Data were collected via Google Forms and analyzed using SPSS v.25 (IBM).

Results

After the first dose, 55.3% people experienced AEFI, such as pain (42.5%), swelling (19.1%), and drowsiness (19.1%), with symptoms starting < 24 hours in 34.1% cases. Symptom improvement occurred < 24 hours in 8.5%, within 1 day in 19.1%, 2–3 days in 17%, and 4–7 days in 10.7%. With the second dose, 51.1% people experienced AEFI, such as pain (34.04%), swelling (14.8%), and drowsiness (12.7%), with symptoms appearing < 24 hours in 25.5% and within 1 day in 23.4%. Improvement from second-dose AEFI occurred within 2–3 days for 17%, within 1 day for 14.9%, within 4–7 days for 8.5%, and > 7 days for 4.3%.

Conclusions

The study confirms the safety of Mpox vaccination for health workers, with most AEFIs being mild to moderate, resolving within 24 hours to a week. Limitations include a small sample size, self-reported data, and the absence of a control group.