Lower Vaccination Rates Bring Measles Back
2026-05-17
As people turn away from vaccines worldwide, the resurgence of infectious diseases is becoming more visible. Even after the COVID-19 pandemic, vaccination rates have not recovered, and the number of countries with measles outbreaks rose to 59 in 2024, 1.6 times the 22 in 2022. Weakened public health could also weigh on economic growth.
Measles and Lower Vaccination Rates
The measles virus is extremely contagious. If an infected person is in the same space, nearly 100% of unvaccinated people are said to become infected. In addition to complications such as pneumonia and otitis media, it can also become severe through encephalitis.
Vaccination is essential for prevention. Maintaining herd immunity to prevent spread requires a vaccination rate of at least 95%. According to UNICEF, 84 countries and regions exceeded this level for first-dose coverage in 2019, before the pandemic, but that number fell to 69 in 2024.
A Broader Decline Across Infectious Diseases
During the pandemic, movement restrictions led many people to delay other vaccinations. At medical institutions, staff were diverted to COVID-19 response, putting strain on vaccination and treatment systems. With other infectious diseases temporarily suppressed, more people also seem to have underestimated the need for vaccination.
According to the World Health Organization (WHO), measles increased in emerging markets such as India and Indonesia. Even in advanced economies, infections spread in the UK and Canada, removing them from the list of countries that had eliminated measles.
In the United States, more than 2,200 cases were confirmed in 2025, and by May 1, 2026, the total had already topped 1,800. Outbreaks are especially noticeable in states with low vaccination rates, such as Florida and South Carolina. In Japan, infections reached 462 cases as of May 8, and the 2026 total has already surpassed the full-year 2025 figure of 265. Japan's first-dose coverage had stayed above 95% throughout the 2010s, but in fiscal 2024 it fell to 92%, the lowest since fiscal 2008.
In Nagasaki Prefecture, the rate dropped from 99% in fiscal 2018 to 87% in fiscal 2024. A prefectural official says disrupted vaccine distribution, partly due to manufacturing problems at the producer, was a major factor.
Loss of Trust and Policy Effects
The decline is spreading beyond measles. For the combined vaccine against diphtheria, pertussis, and tetanus, 2024 vaccination rates in every region of the world were below the peak seen since 2010. The BCG vaccine for tuberculosis prevention fell to 88% in Latin America and the Caribbean in 2024, about 7 percentage points lower than in 2010. It also declined by about 2 points in the Middle East and Africa. In low-income countries, the disruption from the pandemic continues, and conflict is also believed to be a major factor.
The spread of vaccine hesitancy is another headwind. Emily Housley of the Institute for Health Metrics and Evaluation says, "Trust in vaccines has been damaged in many high-income countries." A Japanese health ministry official also sees the decline in measles vaccination as partly due to "the spread of negative impressions about vaccines."
The Trump administration has appointed Kennedy, a vaccine skeptic, as health secretary. In June 2025, Kennedy dismissed all members of the advisory committee on immunization. In January 2026, the Centers for Disease Control and Prevention (CDC) withdrew recommendations for six childhood vaccines, including those for rotavirus gastroenteritis and hepatitis B.
Jonathan Mosser of the Institute for Health Metrics and Evaluation warns, with diseases such as diphtheria in mind, that "even a drop of a few percentage points in vaccination rates can trigger outbreaks." As the COVID-19 lockdowns showed, infectious diseases pose a risk to the economy that cannot be ignored.
Three years have passed since COVID-19 was reclassified under Japan's Infectious Diseases Control Law as a Category 5 disease. Hantavirus infections also occurred aboard a cruise ship sailing in the Atlantic. The importance of preparing for both old and new infectious diseases has not changed. International cooperation is wavering amid events such as the U.S. withdrawal from the WHO, and the crisis is quietly spreading.
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