Rubella elimination goal extended to 2023 in Southeast Asia amid challenges

a recent Weekly Morbidity and Mortality Report described progress toward rubella elimination in the World Health Organization (WHO) Southeast Asia Region (SEAR).

In 2013, the SEAR countries adopted goals to eliminate measles and control congenital rubella syndrome (CRS) and rubella by 2020. In 2019, these countries announced plans to eliminate rubella and measles by 2023.

The authors discussed the progress in eliminating rubella in the SEAR between 2013 and 2021 in the present study.

Study: Progress towards rubella elimination: World Health Organization South-East Asia Region, 2013–2021. Image Credit: NovikovAleksey/Shutterstock.com

Rubella Vaccination Programs

Rubella-containing vaccine (RCV) was only available in Bhutan, Maldives, Bangladesh, Thailand, and Sri Lanka prior to 2013; other SEAR countries introduced the vaccine during 2013-21. Of these, only three countries offered the second dose before 2013; the rest offered the second between 2013 and 2021.

Regional CVR coverage was estimated at 12% in 2013 and 86% in 2021, according to the WHO and the United Nations International Children’s Emergency Fund (UNICEF).

The highest regional coverage (93%) was recorded in 2019 before the coronavirus disease 2019 (COVID-19) pandemic began. Supplementary Immunization Activities (SIA) were initiated during 2013-21 in all SEAR countries except Sri Lanka, covering more than 514 million people.

rubella surveillance

Rubella and measles case-based surveillance had been implemented by 2021 throughout SEAR. A measles-rubella laboratory network was established at SEAR by 2003, comprising 58 laboratories, with at least one laboratory in each country by 2021.

In 2013, only two countries had reached the sensitivity indicator target (≥ two discarded cases without measles and rubella per 100,000 people).

The rate of discarded cases in the region was estimated at 0.91 in 2013 and 1.52 in 2021. However, only five countries reached the goal for 2021.

CRS surveillance was established in all SEAR countries. Thailand, North Korea, and Sri Lanka report CRS through national integrated disease surveillance, while other countries report through sentinel site surveillance. Seven countries reported CRS in 2021, up from six in 2013.

Incidence of CRS and rubella

Rubella cases were reduced by 80% in the SEAR from 10,434 in 2013 to 2,103 in 2021. The annual incidence of rubella was also 80% lower in 2021 with 1.1 cases per 1,000,000 population than in 2013 .

On the other hand, CRS cases increased during 2013-21 due to the improvement or establishment of CRS surveillance. The genotype of clinical rubella virus isolates was 2B in Thailand and India, 1J in India, and 1E in Thailand.

A regional rubella and measles elimination verification commission was established in 2016 and updated the framework to verify elimination by 2020. The commission confirmed (in 2020) rubella elimination in Sri Lanka and the Maldives. Endemic rubella transmission did not occur for more than 36 months in three countries (Timor-Leste, North Korea, and Bhutan) awaiting verification.

conclusions

In summary, SEAR countries made substantial progress in eliminating rubella between 2013 and 2021. CVR vaccination coverage increased by more than 600%, while rubella incidence decreased by 80%. The increased incidence of CRS in this period indicates improvements in surveillance.

Two countries have been verified to eliminate rubella transmission by 2021. However, challenges to eliminate rubella remain prevalent in SEAR.

For example, vaccination coverage decreased during the COVID-19 pandemic, which interrupted surveillance. In 2021, 18% of unvaccinated infants worldwide were on SEAR.

Additional challenges include suboptimal surveillance sensitivity, immunity gaps, funding constraints, and inadequate outbreak preparedness and response. Achieving rubella elimination goals in SEAR countries will require intensified measures to implement interventions in a short period of time.