Measles and Whooping Cough Are Back. Vaccination Rates Explain Why.
Measles, whooping cough, and rotavirus cases are climbing in the U.S. as vaccination rates fall, with children bearing the heaviest burden.
The Diseases We Nearly Eliminated Are Returning
Measles was declared eliminated from the United States in 2000. That declaration now feels fragile. By late May 2026, the CDC had recorded 1,983 measles cases across 30 outbreaks — and those numbers arrived just one year after 2025 logged 2,288 confirmed cases across 48 outbreaks. The pattern is not a blip. It is a trend with a clear driver: fewer people are vaccinated than were a decade ago.
The diseases re-emerging are not exotic or obscure. Measles, whooping cough (pertussis), rotavirus, and chickenpox are illnesses that immunization programs had pushed to historically low levels. Each has an effective vaccine. Each is now climbing.
Children are absorbing the most damage.
What the Numbers Actually Show
This year’s measles data carries several details worth sitting with. Approximately 72% of 2026 cases involve people 19 and younger. Children under 5 account for roughly 21% of cases — an age group that includes infants too young to complete the full vaccine series and who depend on the immunity of those around them. The CDC reports that 92% of cases this year involve unvaccinated individuals or those with unknown vaccination status.
The geographic spread is uneven but wide. South Carolina leads with 669 cases as of late May 2026, followed by Utah at 484, Texas at 182, and Florida at 139. These are not isolated rural clusters — they reflect communities where vaccination coverage has fallen below the threshold needed to prevent sustained spread. For measles, that threshold sits at roughly 95% of the population having received two doses of the MMR vaccine. When coverage dips below that level, outbreaks become possible; when it drops further, they become likely.
Hospitalization rates offer a complicated signal. About 6% of measles cases this year required hospital care, compared to 11% last year. No deaths have been reported so far in 2026; three deaths were recorded in 2025. Lower hospitalization and death figures this year might seem reassuring, but they exist alongside a high absolute case count — and the year is not finished.
Beyond Measles: Whooping Cough and Rotavirus
William Schaffner, MD, a professor of medicine at Vanderbilt University in Tennessee and a specialist in infectious diseases, put the situation plainly: measles outbreaks have received significant media attention, but increases in whooping cough and rotavirus infections in children have gone less noticed. Clusters of chickenpox have also appeared.
Whooping cough is not a mild inconvenience. In infants especially, the prolonged coughing fits can last weeks and cause oxygen deprivation. Rotavirus, a leading cause of severe diarrheal illness in young children worldwide, had been dramatically reduced in the U.S. after routine infant vaccination was introduced — a reduction that appears to be reversing. Schaffner noted that all of these diseases share a common feature: they can make children seriously ill, require hospitalization, and in some cases cause death.
The increase is not limited to children. Officials have also noted a rise in unvaccinated adults requiring hospitalization, including some who have declined tetanus shots and, in rare cases, blood transfusions — decisions that carry serious medical consequences in trauma and surgical settings.
The Policy Context Shaping This Moment
Understanding why vaccination rates have declined requires looking at the policy environment around vaccines, which has shifted considerably. In January 2025, the Department of Health and Human Services, under Health Secretary Robert F. Kennedy Jr., released a revised childhood vaccination schedule recommending vaccination against 11 diseases, with six others designated as recommendations only for children at higher risk.
This came against a backdrop of an executive order signed by President Donald Trump reaffirming an HHS assessment examining whether U.S. vaccine practices align with “scientific evidence and best practices from peer, developed countries.” The executive order referenced a notable comparison: in 1980, the CDC recommended 23 vaccine doses in seven shots against seven diseases. By 2024, the recommended schedule had grown to at least 84 doses in at least 57 shots covering 17 diseases — more than any other developed nation.
Kennedy framed the revised schedule as the product of an “exhaustive review of the evidence” aimed at aligning U.S. practices with international consensus while improving transparency and informed consent. Whether the revised schedule itself has directly influenced coverage rates is not yet established by published data, but the broader cultural shift in how some families approach vaccination predates and extends beyond any single policy change.
What Physicians Are Saying
Schaffner’s assessment was direct: “I am very concerned about the increase in cases of vaccine-preventable infections in children in the United States.” He described the measles outbreaks as well-publicized but said the simultaneous increases in whooping cough, rotavirus, and chickenpox represent a fuller picture of what declining coverage produces. Across all four diseases, his conclusion was the same — hospitalization and death are real outcomes, not theoretical risks.
The CDC has stated that vaccination remains a critical tool for preventing measles infection. Physicians dealing with rising caseloads are making the same point at the patient level, with an emphasis on communicating both the safety record and effectiveness of vaccines to families who have questions or concerns.
That communication task has become more demanding. Hesitancy is not uniform — it comes in different forms, from skepticism about specific ingredients or scheduling, to broader distrust of health institutions, to philosophical objections. Addressing it requires more than repeating statistics, though the statistics remain important.
The Math Behind Herd Immunity
One aspect of vaccine-preventable disease that is easy to misunderstand is how quickly protection can erode when coverage drops. Measles is among the most contagious infectious diseases known — one infected person can transmit it to 12 to 18 others in an unvaccinated population. This is why the 95% coverage threshold is not arbitrary; it accounts for the virus’s extraordinary ability to find susceptible hosts.
When vaccination rates fall even a few percentage points below that threshold in a given community, the math shifts. An introduction of a single case — often from international travel — can seed an outbreak that grows faster than contact tracing can contain it. The 30 outbreaks recorded by late May 2026 reflect exactly this dynamic playing out across multiple communities simultaneously.
Infants under 12 months cannot yet receive the MMR vaccine. Immunocompromised individuals may not be able to. Their protection relies entirely on the vaccination choices of the people around them.
A Concrete Look at Where Things Stand
As of late May 2026, the United States is navigating the second consecutive year of large-scale measles outbreaks, alongside less-publicized but real increases in pertussis and rotavirus. The 1,983 measles cases recorded so far in 2026 already represent a historically high count for a country that eliminated the disease 26 years ago.
Parents and caregivers with questions about their child’s vaccination schedule should consult their pediatrician or family physician directly — schedules and recommendations can vary based on a child’s age, health history, and risk factors, and official guidance from the CDC and the American Academy of Pediatrics is updated as evidence develops. As of publication, the CDC maintains its recommendation for two MMR doses: the first at 12–15 months, the second at 4–6 years.
The South Carolina outbreak, the largest in the country this year at 669 cases, is still active.
This article is for general informational purposes only and does not constitute personalized medical advice. Vaccination schedules, case counts, and public health guidance are subject to change. Consult a licensed healthcare provider and refer to the CDC (cdc.gov) or your country’s public health authority for current recommendations and decisions about your care.