US measles cases hit 30-year high as officials urge rapid action

The United States is experiencing its most severe measles outbreak in three decades, with confirmed infections reaching 2,371 by the end of July. This surpasses the total recorded last year and reflects ongoing transmission in Arizona, South Carolina and Utah. Health officials warn that with high levels of spread, other states may see cases as well, especially given declining vaccination coverage nationwide.

In Delaware, the first measles case in over a decade was announced in July, and an outbreak was declared two days later. So far, five people have been infected. The state's kindergarten vaccination rate for measles, mumps and rubella has fallen from 98.5% in 2016 to 94.1% now. The widely accepted threshold for herd immunity is around 95%, below which vulnerable people – including infants and cancer patients – face greater risk of exposure.

Officials point to a shift in attitudes and the spread of misinformation as key drivers. The debunked claim linking vaccines to autism created confusion, and some parents have chosen alternative vaccination schedules, believing children receive too many shots. The Covid-19 pandemic amplified these doubts, with negative feelings about Covid vaccines extending to routine vaccinations. Health Secretary Robert F. Kennedy Jr., who has long promoted vaccine misinformation, has described measles vaccination as a personal choice and made false claims about the disease's danger to healthy children.

Doctors emphasize that two doses of the MMR vaccine are highly effective and safe. Measles can cause fever, breathing problems, lethargy, brain inflammation and sometimes death, even years later. At the same time, the measles vaccine is one of the most successful preventive tools available, and the disease is largely preventable. The day after Delaware's first case, more than 60 people received MMR shots at public clinics and mobile units. Those born before 1989 may need a second dose, as that became standard practice in the late 1980s.

Delaware's response relies on vaccination and contact tracing. The first four patients were unvaccinated men in Kent County; the fifth was vaccinated and had very mild symptoms. Contact tracing helped identify additional cases, and officials are monitoring exposed individuals. They are also reaching out to people without insurance or limited healthcare access, stressing that no one should be barred from vaccination because of financial status. Nationwide, health departments are following similar strategies to stem the spread.