Whooping cough infected more Americans in 2025 than in any year since the pandemic began, with the CDC recording 28,783 provisional pertussis cases through the end of December. That total dwarfs the suppressed counts of 2020 through 2022 and signals a sharp return of a disease many parents assumed childhood vaccines had largely controlled. Falling kindergarten vaccination rates, now below the threshold public health officials consider safe, have left a growing share of young children exposed during what the CDC describes as a cyclical upswing.
A 28,783-case count and what it means for families
The scale of the 2025 pertussis surge becomes clear against the backdrop of recent history. During the first two years of the COVID-19 pandemic, whooping cough reporting dropped to historic lows as social distancing, masking, and reduced contact suppressed respiratory infections across the board. By 2023, the most recent year covered in the CDC’s historical case series, counts had started climbing again but remained well below the peaks recorded in several pre-pandemic years. The 28,783 figure for 2025, drawn from the National Notifiable Diseases Surveillance System’s Week 52 table ending December 27, represents a full-year count that confirms the rebound is no longer tentative.
For parents and caregivers, the practical consequence is direct. Pertussis spreads through close respiratory contact and is most dangerous for infants too young to be fully vaccinated. Prolonged coughing fits can last weeks, and in severe cases the disease causes pneumonia, seizures, or death in newborns. A surge of this size increases the odds that unvaccinated or under-vaccinated children will encounter the bacterium Bordetella pertussis in school, daycare, or at home from an older sibling or adult whose immunity has waned.
The CDC has stated plainly that cases remained elevated in 2025, and the agency attributes part of the pattern to natural cyclical peaks that have historically occurred every three to five years. But cyclical timing alone does not explain why this particular cycle has produced such high numbers relative to the immediate pre-pandemic period.
Kindergarten DTaP coverage fell below 93 percent
One measurable factor behind the surge is a documented decline in childhood vaccination. A CDC analysis published in the Morbidity and Mortality Weekly Report found that national kindergarten coverage for the DTaP vaccine, the standard five-dose series that protects against diphtheria, tetanus, and pertussis, dropped to 92.3 percent in the 2023-24 school year. That figure fell below 93 percent for all reported kindergarten vaccines, a threshold that had held for years and that epidemiologists consider the minimum needed to maintain herd protection against highly contagious diseases.
A 92.3 percent coverage rate means roughly one in thirteen kindergartners entered school without confirmed DTaP protection. In communities where exemption rates run higher than the national average, the effective coverage can drop well below 90 percent, creating pockets where outbreaks gain traction quickly. The hypothesis that the 2025 surge hit hardest in states where DTaP exemption rates climbed most steeply after 2022 is consistent with what immunologists would predict, but publicly available CDC data do not yet pair state-level 2025 case counts with matched exemption figures in a single dataset. Without that linkage, the geographic distribution of the surge cannot be confirmed or ruled out as exemption-driven.
The CDC classifies pertussis cases using a standardized 2020 case definition that requires either laboratory confirmation or epidemiologic linkage to a confirmed case, combined with a compatible cough illness. That definition has not changed during the current surge, which means the 28,783 count reflects the same diagnostic standard applied in prior years and is not inflated by a shift in how cases are classified.
Gaps in state-level data and testing patterns
Several questions remain open despite the headline number. The CDC’s national surveillance pages provide the 28,783 total but do not offer a side-by-side weekly comparison with 2023 and 2024 in the same downloadable file, making it difficult for independent analysts to pinpoint exactly when the 2025 curve diverged from prior years. The agency publishes machine-readable weekly data through its NNDSS dataset, but reconciling provisional counts across reporting lags requires careful handling of revision dates.
A second gap involves testing practices. PCR-based pertussis testing has become more widely available since the pandemic expanded laboratory capacity for respiratory pathogens. If clinicians in 2025 tested more patients with prolonged cough than they did in, say, 2018 or 2019, some portion of the apparent surge could reflect better detection rather than a true increase in infections. The 2020 case definition does not address whether changes in testing volume or sensitivity have altered ascertainment, and the CDC has not yet published a detailed breakdown of how many suspected cases were tested, how many tests were positive, or how those metrics compare with earlier years.
State health departments also vary in how aggressively they promote testing and in how quickly they forward reports to the federal level. In some jurisdictions, clinicians are encouraged to test any patient with a cough lasting more than two weeks, especially if they are in close contact with infants or work in schools or healthcare settings. Elsewhere, testing may be reserved for patients with classic “whoop” symptoms or for those involved in known clusters, a narrower approach that can miss milder or atypical cases. These differences complicate efforts to map the true contours of the 2025 surge.
Despite these uncertainties, the CDC’s own surveillance summaries emphasize that pertussis remains underdiagnosed, particularly in adolescents and adults whose symptoms can resemble a routine bronchitis. That undercounting means the 28,783 confirmed and probable cases likely represent only a fraction of total infections. For families, the implication is that even communities reporting modest numbers may be experiencing a much larger, largely invisible wave.
What parents and clinicians can do now
Public health officials continue to stress vaccination as the primary defense. The standard childhood schedule calls for DTaP doses at 2, 4, and 6 months, a fourth dose between 15 and 18 months, and a fifth between 4 and 6 years. Pregnant people are advised to receive a Tdap booster during each pregnancy, typically in the third trimester, to pass antibodies to the fetus and protect newborns before their own shots begin. Adolescents and adults who have not had a Tdap dose should receive one, followed by periodic Td or Tdap boosters as recommended.
Clinicians, for their part, are being urged to think of pertussis whenever a patient presents with a cough that lingers beyond two weeks, especially if it is accompanied by post-cough vomiting or a whooping sound, or if there is known exposure in a household or school. Early diagnosis allows for antibiotic treatment that can shorten the period of contagiousness and limit spread, even if it does not always dramatically change the course of symptoms for the individual patient.
For families in communities where vaccine coverage has slipped, local action can matter. Schools and pediatric practices can use enrollment and back-to-school visits to check shot records and schedule catch-up doses. Community leaders and health departments can tailor outreach to address specific concerns that have driven exemptions, whether they involve safety questions, logistical barriers, or mistrust of institutions. Because pertussis risk is highly localized, even small gains in a single school district can reduce the chance of an outbreak there, regardless of national trends.
A cyclical disease in a changed landscape
Pertussis has always ebbed and flowed in multi-year cycles, but the 2025 numbers suggest those cycles are now playing out in a population with more immunity gaps than before the pandemic. The combination of disrupted routine care, rising vaccine hesitancy, and uneven recovery of public health infrastructure has left some cohorts of children less protected just as the bacterium enters a natural upswing. Until more detailed state-level data and testing metrics are released, the precise drivers of the current surge will remain partly speculative. What is clear, from the CDC’s outbreak updates to its formal outbreak guidance, is that pertussis has reclaimed a visible place on the list of vaccine-preventable threats.
For now, the 28,783-case tally stands as both a warning and a call to recalibrate expectations. Whooping cough never disappeared; it receded into the background of a well-vaccinated society. As coverage slips, it has room to return. Whether 2025 becomes an outlier or the first in a series of higher-plateau years will depend largely on how quickly communities close their vaccination gaps and how seriously clinicians and families take the disease while the current cycle runs its course.
More from Morning Overview
*This article was researched with the help of AI, with human editors creating the final content.
