Amid a global surge in measles cases, new research suggests that undernutrition may be exacerbating outbreaks in areas suffering from food insecurity.

A study involving over 600 fully vaccinated children in South Africa found those who were undernourished had substantially lower levels of antibodies against measles.

Researchers from McGill University, UC Berkeley School of Public Health and the University of Pretoria tracked the children’s growth over time as an indicator of undernutrition and measured their antibody levels through blood tests. Children who were stunted around age three had an average of 24-per-cent-lower measles antibody levels by age five compared to their typical-sized peers.

The findings, published in Vaccine, suggest that undernutrition may affect the duration of vaccine protection.

This indicates that addressing child hunger could be a key piece of the puzzle in preventing viral outbreaks, said senior author Jonathan Chevrier, an Associate Professor in McGill’s Department of Epidemiology, Biostatistics and Occupational Health and Canada Research Chair in Global Environmental Health and Epidemiology.

A growing threat worldwide

Measles is a highly contagious viral infection that causes symptoms such as a rash, fever and cough, and can lead to severe complications, especially in young children. The disease is a threat in regions where it was once under control, including Canada, which in 2024 reported its highest number of cases in nearly a decade.

“Global measles cases declined from 2000 to 2016, but the trend reversed in 2018, driven in part by under-vaccination and the impact of the pandemic. Measles is now making a strong comeback in many parts of the world despite being preventable with vaccination and adequate immunity,” said co-author Brian Ward, Professor in McGill’s Department of Medicine.

“We need to vaccinate children against infectious diseases that are preventable and ensure they are protected,” said first author Brenda Eskenazi, Professor Emerita of Public Health at the University of California, Berkeley. “This is especially important now, given that many known diseases are expected to spread with climate change.”

About 22 per cent of children under age five worldwide — approximately 148 million — were stunted in 2022, Chevrier added, with the highest rates in Asia and sub-Saharan Africa.

The team plans to monitor the children in the study as they grow older to understand whether the effects of early-life undernutrition persist.

This study was funded by the U.S. National Institute of Environmental Health Sciences and the Canadian Institutes of Health Research.