On the Path to Measles and Rubella Elimination Following Rubella-Containing Vaccine Introduction, 2000-2023, Namibia

Abstract

Introduction: The WHO Measles and Rubella Strategic Framework 2021-2030 within the Immunization Agenda 2030 includes both measles and rubella elimination goals and provides guidance to countries for planning and implementing the measles and rubella elimination strategies. Namibia has been implementing measles elimination strategies since 1997.

Methods: We reviewed and described the implementation of measles and rubella elimination strategies and the programmatic and epidemiological situation in Namibia during 2000-2023. Namibia introduced a rubella-containing vaccine (RCV) in 2016 as a combined measles-rubella (MR) vaccine using a MR catch-up campaign, targeting a wide age range based on detailed analysis and triangulation of multiple key data sources including MR vaccination coverage, MR case-based surveillance, detailed measles outbreak investigations, and serosurveys.

Results: In 2020, estimated MCV1 coverage in Namibia reached 90% and has been sustained at 91% in 2021 and 2022. MCV2 was introduced in 2016, and the estimated MCV2 coverage has steadily increased to 79% in 2022. Following the MCV2 introduction and the implementation of the wide age range MR catch-up campaign in 2016, annual measles and rubella incidence decreased substantially. During 2017-2023, the period following the implementation of the catch-up MR vaccination SIA in 2016, average annual measles incidence per million population in Namibia decreased by 97% from the average during 2010-2016. Similarly, the average annual rubella incidence decreased by 95% from 2010-2016 to 2017-2023.

Discussion: Successful implementation of the 2016 wide age range campaign and maintaining high routine immunization coverage likely led to the significant reduction in measles and rubella incidence in Namibia. To sustain the reduction in measles and rubella incidence and attain the elimination targets, Namibia needs to attain and maintain high routine immunization coverage with both doses of the MR vaccine and implement timely and high-quality periodic MR follow-up SIAs. High-quality elimination-standard measles and rubella surveillance will help guide strategies and serve as the basis for the eventual verification of measles and rubella elimination in Namibia according to the WHO-recommended framework.

Keywords: Namibia; elimination; incidence; measles; rubella.

Figure 1

National coverage with the first dose of the measles-containing vaccine (MCV1) and second dose (MCV2), supplemental immunization activities, and reported measles cases, 2000–2023, Namibia. Notes: M = measles, MR = measles–rubella, mos = months, yrs = years; World Health Organization (WHO) and United Nations Children’s Fund (UNICEF) estimates of national immunization coverage; data from the Joint Reporting Form submitted to the WHO and UNICEF by member states with the official number of measles cases in the country for the year, http://immunizationdata.who.int (accessed on 11 June 2024).

Figure 2

National measles immunity profile as of 31 December 2023, Namibia. Notes: MCV1 = first dose of the measles-containing vaccine; MCV2 = second dose of the measles-containing vaccine; SIAs = supplementary immunization activities. The number of measles-susceptible children under 5 years of age was projected to be 42,954 by 31 December 2023, which was 0.64 times the number of children born in the most recent year.