A Global Burden of Disease analysis published in Nature Medicine estimates that measles cases among children under five rose from 11.1 million in 2019 to 15.6 million in 2023, reversing three decades of progress. About 23.7 million infants, one in five worldwide, missed their first dose in 2023. Sub-Saharan Africa accounts for half of them and South Asia for a fifth.
Measles is one of the most contagious diseases known, and one of the most preventable. Two doses of a vaccine that has been in use for more than half a century give lasting protection. Yet a study published on 21 October in Nature Medicine shows that the disruption of the COVID-19 years has left millions of children unprotected and allowed the virus to return.
The analysis, led by researchers at the University of Queensland’s Frazer Institute with collaborators at nine other Australian universities, draws on Global Burden of Disease (GBD) 2023 estimates for children under five in 204 countries and territories from 1990 to 2023. It was funded by the Bill & Melinda Gates Foundation and Gavi, the Vaccine Alliance.
What the study found
The headline numbers describe a sharp reversal:
- Progress, then reversal. Worldwide measles cases fell by nearly 80% between 1990 and 2019.
- Post-pandemic rise. Estimated cases among children under five then rose by about 40%, from 11.1 million in 2019 to 15.6 million in 2023.
- Missed doses. In 2023, about 23.7 million infants, one in five, missed their first measles dose.
- Where the gap lies. Sub-Saharan Africa accounted for 50% of missed first doses and South Asia for 20%.
- Lives saved. Two childhood doses are estimated to have prevented nearly 59 million deaths between 2000 and 2024.
“This has contributed to a global resurgence of measles in young children,” said Associate Professor Benn Sartorius of the University of Queensland, the study’s spokesperson. “The greatest burden occurs in lower-resourced settings, yet recent outbreaks in the United States show measles can re-emerge in high-income countries where immunity gaps develop.”
Why measles exploits gaps so quickly
Measles spreads through the air and can linger in a room after an infected person has left. According to WHO estimates cited in the release, one case can cause up to 18 secondary infections where immunity is low. That is why public-health agencies aim for about 95% coverage with two doses: below that level, the virus finds enough susceptible children to sustain outbreaks.
The disease is not trivial. A 2023 Lancet Global Health study, cited by the researchers, found that in 2019 measles killed as many as three in 100 infected infants under one year old in low- and middle-income countries. Complications include pneumonia, encephalitis and blindness. Measles also causes “immune amnesia”, erasing part of the immune system’s memory of other infections and leaving survivors more vulnerable for months or years, a finding from earlier research.
How the pandemic opened the gap
During 2020 and 2021, routine immunisation was disrupted almost everywhere. Clinics closed or were redeployed, supply chains faltered, health workers were diverted, and families avoided health facilities. Mass vaccination campaigns, which many countries rely on to catch children missed by routine services, were postponed. The children born in those years are now the toddlers and young children in whom measles is spreading.
The study shows that the problem is not confined to poorer countries. Measles, mumps and rubella vaccine coverage among US kindergarten children fell from 95% to 92%. CIDRAP reported on 21 October that the CDC has now recorded a third US measles death this year. At the other end of the scale, Australasia achieved the highest regional coverage, with an estimated 96% of children under five receiving a second dose in 2023.
What it means for India
The release does not name India, but South Asia’s 20% share of missed first doses makes the findings directly relevant. India has one of the world’s largest birth cohorts, roughly 25 million babies a year, so even a high coverage rate leaves a large absolute number of unvaccinated children. WHO and UNICEF estimates have repeatedly listed India among the countries with the most “zero-dose” children, those who have received no routine vaccines at all, although its coverage percentages are high and have recovered since the pandemic.
India’s Universal Immunisation Programme gives two doses of measles-rubella vaccine, at nine to 12 months and 16 to 24 months, and the country has run catch-up campaigns as part of its goal of eliminating measles and rubella. The GBD findings suggest that national averages can hide pockets of low coverage in urban slums, migrant communities and remote districts, where outbreaks begin. Strengthening surveillance and tracking each child, the aim of the government’s U-WIN digital immunisation registry, is as important as the national coverage figure.
The limits of the evidence
GBD figures are modelled estimates, built from surveillance data, surveys and statistical assumptions, rather than direct case counts, and measles is badly under-reported in many countries. The study’s numbers end in 2023, so they do not capture any recovery or further decline since. Country-level estimates were not included in the material NSH reviewed.
What comes next
The researchers call for “urgent action … to restore routine immunisation programs and build resilient health systems”. In practice, that means catch-up campaigns for children who missed doses during the pandemic, better tracking of individual children, and sustained funding at a time when global health budgets are under pressure. Measles is often the first disease to return when immunisation coverage slips, and the new estimates suggest that the warning has already sounded.
