Rubella Vaccine for the Last 19 Countries: Nearly a Million Birth Defects Preventable

Summary

• Rubella infection in early pregnancy can cause miscarriage, fetal death or a set of birth defects called congenital rubella syndrome (CRS). By 2023, 175 (90%) of 194 WHO member countries had introduced a rubella-containing vaccine (RCV).
• In the 19 countries that hadn't — where an estimated 24,000 CRS cases occurred in 2019 — modeling found that introducing RCV in 2025–2055 would avert about 986,000 CRS cases.
• On the strength of these and other findings, WHO recommended in 2024 that all 19 introduce the vaccine. Doing so within 5 years could speed progress toward eliminating rubella and CRS worldwide.

Background

Rubella is a leading cause of vaccine-preventable birth defects. It is usually a mild rash illness, but infection during pregnancy — especially the first trimester — can cause miscarriage, stillbirth or CRS. One dose of RCV can protect for life. Countries using RCV rose from 99 of 191 (52%) in 2000 to 175 of 194 (90%) in 2022.

The 80% rule. Since 2011, WHO had advised countries to reach 80% coverage with the first dose of measles vaccine before introducing RCV. The worry: low coverage would reduce but not stop rubella, pushing infection to older ages — including women of childbearing age — and could paradoxically increase CRS.

How RCV is introduced: a catch-up campaign with combined measles-rubella (MR) vaccine for children 9 months to 14 years, then MR in the routine schedule, with follow-up campaigns for young children every 3–4 years.

The 19 countries

Afghanistan, Central African Republic, Chad, Democratic Republic of the Congo, Djibouti, Equatorial Guinea, Ethiopia, Gabon, Guinea, Guinea-Bissau, Liberia, Madagascar, Mali, Niger, Nigeria, Somalia, South Africa, South Sudan and Sudan — 15 in WHO's African Region and 4 in the Eastern Mediterranean; 13 are low income, and 12 are conflict-affected or fragile. They are home to about 25 million infants.

• Measles vaccine coverage in 2019 ranged from 40% to 90%; 12 saw declines of 2% to 33% during the pandemic. By 2023, only three — Liberia, Niger and South Africa — reached 80% through routine vaccination, and nine had met the threshold through routine vaccination or campaigns.
• In 2023, they reported 27,989 (78%) of the world's 35,714 reported rubella cases, led by Chad (5,651 cases per million people), Somalia (1,311) and Guinea-Bissau (1,184).
• In 2019, they had an estimated 24,000 CRS cases — 75% of about 32,000 worldwide — with about 1,000 each in the Democratic Republic of the Congo, Ethiopia, Niger, Nigeria and Sudan.

Figure 1. Estimated CRS cases in 2019, and rubella vaccine introduction by 2023, by country. Figure from the CDC report.

The projections

A rubella transmission model from the UK Health Security Agency (checked against an independent University of Georgia model, with similar results) compared three scenarios from 2025: no vaccine; RCV with a catch-up campaign and follow-ups every 4 years at 90% MR coverage; and the same at 60% coverage.

• Without RCV: about 30,000–34,000 CRS cases every year, about 1.03 million over 2025–2055.
• With RCV: cases fall sharply in 2025–2027 in both vaccination scenarios and stay low, totaling about 40,000–60,000 by 2055.
• Averted: about 986,000 cases over 30 years — about 30,000 a year.

Figure 2. Projected annual CRS cases with and without rubella vaccine introduction. Figure from the CDC report.

The decision

After a review by WHO's Immunization and Vaccines-Related Research Advisory Committee in June 2024, WHO's Strategic Advisory Group of Experts on Immunization (SAGE) in September 2024 dropped the 80% threshold, called for universal RCV introduction in the 19 countries, and kept the advice to run wide age-range catch-up campaigns first. Other recent models agree that introducing RCV cuts rubella and CRS quickly.

What's needed now: support from global partners — including Gavi, the Vaccine Alliance, for low- and lower-middle-income countries, and help for countries not eligible for Gavi — to deliver high-quality campaigns, with strong monitoring in fragile and conflict-affected places so no one is missed.

Limits: measles coverage and rubella case data vary in quality; countries will introduce the vaccine over several years, not all in 2025; and projections depend on model assumptions and inputs.

Sources

Based on Emmaculate Lebo, Emilia Vynnycky, James P. Alexander Jr. and others, "Estimated Current and Future Congenital Rubella Syndrome Incidence with and Without Rubella Vaccine Introduction — 19 Countries, 2019–2055," MMWR, Centers for Disease Control and Prevention; a work of the United States government in the public domain.