Routine rubella vaccination in 19 countries could avert 1 million cases by 2055, data suggest

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*World Bank, Kenneth Pornillos / Flickr cc*

A modeling study of vaccination in the 19 low- and middle-income countries that have not introduced rubella-containing vaccines (RCVs) estimates that rolling out these vaccines could prevent 986,000 cases of congenital rubella syndrome (CRS) in the next 30 years.

As of 2023, 175 of the 194 World Health Organization (WHO) member countries (90%) had included an RCV in their routine immunization programs. In 2024, the WHO recommended universal RCV for the remaining 19 countries, which saw an estimated 28,000 CRS cases—78% of all cases worldwide—in 2023 alone.

This study analyzed data from country reports to the WHO and UNICEF from 2019 to 2023, as well as national vaccine coverage estimates and World Bank economic information. The disease is also called "German measles."

"Rubella virus infection usually produces a mild febrile rash illness in children and adults," the US Centers for Disease Control and Prevention-led research team wrote. "However, infection during pregnancy, especially in the first trimester, can result in miscarriage, fetal death, stillbirth, or a constellation of birth defects known as congenital rubella syndrome."

The findings were published last week in Morbidity and Mortality Weekly Report.

Speeding progress toward rubella elimination

In the 19 countries, an estimated 1.03 million CRS cases are predicted to occur from 2025 to 2055 without RCVs. But with RCV catch-up and follow-up supplemental immunization activities—even if population coverage with measles-containing vaccines were under 80%—fewer than 60,000 cases could occur, averting more than 986,000 CRS infections.

A single dose of rubella-containing vaccine (RCV) can provide lifelong protection against rubella.

"Caring for CRS cases is costly, and rubella vaccination has been shown to be cost-effective in high- and middle-income countries," the authors wrote. "However, no similar studies have been conducted in low-income countries in Africa or Asia."

"A single dose of rubella-containing vaccine (RCV) can provide lifelong protection against rubella," they added. "RCV introduction in these 19 countries during 2025–2030 could rapidly accelerate progress toward rubella and CRS elimination worldwide."

They called for global partners such as Gavi, the Vaccine Alliance, to support the procurement of vaccines and the construction of the infrastructure needed to deliver them.

WHO adds NB.1.8.1 as SARS-CoV-2 variant under monitoring

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Lisa Schnirring

The World Health Organization (WHO) Technical Advisory Group on Virus Evolution (TAG-VE) on May 23 announced that it has designated NB.1.8.1 as a SARS-CoV-2 variant under monitoring (VUM), noting that, although proportions are growing rapidly, the virus seems only marginally more immune-evasive than the more dominant LP.8.1 sublineage.

The experts said NB.1.8.1 is fueling rises in cases and hospitalization in some countries in the WHO Western Pacific region, but there are no reports that illnesses are more severe than those from other circulating variants.

NB.1.8.1 clusters with other JN.1 sublineages and descends from XDV.1.5.1. The earliest sample was collected on January 22. So far sequences have been submitted from 22 countries, and, based on limited sequencing data, officials estimate that the virus made up 10.7% of sequences by the end of April, up significantly from 2.5% in the four previous weeks. The prevalence rose in all three WHO regions that regularly report sequences: Western Pacific, Americas, and European.

Low risk based on limited evidence

TAG-VE said the risk is currently low and that the confidence in the assessment is low, given that only a single study has assessed antigenicity using pseudoviruses with serologic data from two cohorts. It added that more studies are needed to further assess the risk of antibody escape. So far, the evidence doesn't suggest resistance to the antiviral drug nirmaltelvir, which is one of the two components of Paxlovid treatment.

On May 15, the WHO's COVID vaccine composition advisory group said JN.1 and KP.2 remain appropriate vaccine antigens, but monovalent LP.8.1—which seems to show more robust neutralization against newer subvariants—is a suitable alternative. The European Medicines Agency preferentially recommended an LP.8.1 component, and the US Food and Drug Administration also said vaccines should target JN.1, preferentially the LP.8.1 component.

Quick takes: Yellow fever risk, H5N1 avian flu case in China, updated Moderna COVID vaccine

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Stephanie Soucheray, MA

The Pan American Health Organization (PAHO) late last week posted a new yellow fever risk assessment, which puts the threat to the region as high with high confidence. So far this year there have been 221 confirmed human cases in the Americas, including 89 fatal cases in five countries, representing an eightfold increase compared to the same period in 2024. Notably, most cases this year have been detected outside of the Amazon region, posing increased risk of virus introduction into urban settings.
China has reported a human H5N1 avian flu case, involving a 53-year-old woman from Guangxi autonomous region in southern China. The woman has recovered from her illness. This is the first H5N1 human case reported in mainland China since July 2024. Officials said the case was likely imported from Vietnam.
Moderna announced that it has filed for a Food and Drug Administration (FDA) review of its updated COVID vaccine, which targets the LP.8.1 sublineage of JN.1. "The submission is based on guidance from the U.S. FDA, which advised that COVID-19 vaccines should be updated to a monovalent JN.1 lineage, with a preference for the LP.8.1 variant," the company said in a press release.