Measles Returns: Why Thailand Should Brace for Waning Herd Immunity
A leading US infectious disease expert warns the world may have entered a “post-herd immunity” era for measles as vaccination gaps spark renewed outbreaks. The United States is contending with its worst measles surge in decades, with more than 930 cases reported this year. The warning underscores how gaps in vaccination can erode community protection and fuel transmission even in previously controlled regions.
For Thai readers, this development matters because declining vaccine coverage worldwide raises the risk of measles returning to countries that had long controlled the disease. Measles had been declared eliminated in many regions thanks to sustained vaccination campaigns, but recent disruptions and misinformation have dented uptake. In the United States and parts of Europe, vaccination rates have fallen below the 95 percent threshold needed for herd immunity, raising concerns about localized outbreaks and spillover to other regions, including Southeast Asia.
