Impact of the COVID-19 pandemic on the measles elimination status in Armenia

Abstract

Introduction: The coronavirus disease 2019 (COVID-19) pandemic led to a decrease in immunization rates and measles surveillance, resulting in re-establishment of endemic measles transmission in many countries where measles was previously eliminated.

Methodology: We conducted a retrospective study to evaluate the impact of the pandemic on the measles elimination status in Armenia. We studied the prevalence of measles from 2000 to May 2024 and predicted the trend for the coming months. We assessed trends in coverage levels of the mumps-measles-rubella (MMR)1 and MMR2 vaccines in Armenia between 2003 and 2023. The performance indicators of measles surveillance at the national and subnational levels before, after, and during the pandemic (2013-May 2024) were studied.

Results: Endemic transmission of measles in Armenia was interrupted in 2008, and was sustained for many years; however, it was re-established in 2023. A total of 988 measles cases were recorded between February 2023 and May 2024. During the pandemic (2020-2022), MMR1 and MMR2 vaccine coverage decreased from the target level to 94%. Case-based measles surveillance was significantly weakened. Discarded case rate was 0.7 in 2020 and 2021, and 0.9 in 2022. After the pandemic, this indicator improved, reaching 33.3 in 2023 and 17.3 in 2024. The mean values of the numbers of discarded cases were 118 (95% CI, 73-163) in 2013-2019, and 23 (95% CI, 20-26) in 2020-2022 (p < 0.05).

Conclusions: The measles elimination status of Armenia was lost due to immunity gaps and weakening of measles surveillance during the pandemic.

Keywords: elimination; measles; pandemic; surveillance; vaccination.