The United States has recorded more than 2,371 confirmed measles cases by the end of July, the highest tally in three decades, as outbreaks in Arizona, South Carolina, and Utah drive the surge. The rising numbers are putting unprecedented pressure on state and local health departments, underscoring the critical need for early identification and rapid response.
Delaware's first outbreak in over a decade
In July, Delaware reported its first measles case in more than ten years. Within two days, officials declared an outbreak after confirming five cases. The cluster emerged in Kent County, where the first four patients were unvaccinated men; the fifth patient had been vaccinated and experienced only mild symptoms, illustrating the vaccine's protective effect.
Vaccination rates in Delaware have slipped from 98.5% of kindergartners receiving the MMR vaccine in 2016 to 94.1% today. This drop places the state below the 95% threshold considered essential for herd immunity, which protects vulnerable populations such as infants and cancer patients who cannot be vaccinated.
Officials stress vaccine safety and effectiveness
Robert Rosenbaum, Delaware's medical director for emergency medical services and preparedness, emphasized the dangers of falling below the threshold. "We don't want to be below that threshold. And the lower we get, the more likelihood there is that someone who can't be vaccinated yet – because of their age or because of their immune status – is going to come into contact with someone who has unfortunately contracted measles," he said.
Rosenbaum also addressed the misinformation surrounding vaccines, noting that the disproven link between autism and vaccination has caused confusion. He added that the pandemic amplified existing anti-vaccine sentiments, with some people now viewing all vaccines as optional.
William Chasanov, an infectious disease physician at Beebe Healthcare in Lewes, Delaware, observed a "pendulum swing" during Covid. "There was a shift in thought that 'maybe I don't need vaccines for things that I haven't seen,'" he said. The measles vaccine has become a victim of its own success, as many have never witnessed the disease's severity.
Health secretary's stance draws criticism
Health Secretary Robert F. Kennedy Jr., who has a long history of vaccine misinformation, has framed measles vaccination as a personal choice and falsely claimed that healthy children rarely die from measles. Rosenbaum countered, "Anyone who isn't advocating that is not following science consistently." He reiterated that two doses of the MMR vaccine are highly effective and safe.
Measles: a severe but preventable disease
Measles can cause high fevers, breathing difficulties, extreme lethargy, and encephalitis, which may lead to lasting health effects or death, sometimes years later. Chasanov stressed the importance of education: "Understanding what the consequences could be is part of that education. And it's important to know that the measles vaccine is one of the most highly effective vaccines that we've had on the market for decades … Measles is highly contagious, but it's also highly preventable."
In response to the outbreak, Delaware's public health clinics administered over 60 MMR vaccinations within a day. Chasanov noted that local cases spur healthy conversations with clinicians about vaccination needs.
Vaccination recommendations and public health response
Public health officials are not currently recommending early vaccination for children under one or those under four with only one dose, unless they have been exposed. Rosenbaum said, "What we don't have at this point is a large-scale epidemic where we might be changing some of those vaccine recommendations. Certainly, if the numbers change or for some indication to change it, we would revisit that."
Adults born before 1989 may need a second measles shot, as the two-dose schedule became standard in the late 1980s. One dose is about 93% effective, while two doses are about 97% effective. Those born before 1957 are likely immune from natural infection.
Contact tracing and vaccination efforts
Delaware's response combines vaccination and contact tracing, the mainstays of public health. After the first case, health workers traced contacts, prioritizing high-risk individuals such as unvaccinated children, pregnant women, and immunocompromised people. Rosenbaum praised the effort: "The contact tracing has really done a nice job of identifying the at-risk contacts. So the good news is, I would say, if people haven't heard from us, we're not actively looking for them."
Officials are also reaching out to those with poor healthcare access, including the uninsured. "The public health safety net is an important one," Rosenbaum said. "We don't want anyone who wants to get vaccinated to feel like they're unable to do so because of insurance status … That's the function of public health, right? To help people who are at risk and may be vulnerable."
The field of public health has been battered by pandemic stress, chronic underfunding, and growing threats. Yet, Rosenbaum remains hopeful: "We have a process that we follow. And when we follow that process well, we have the opportunity to stem the outbreak."
