Whooping Cough Outbreak Statistics in US 2026 | Worst Since, Cases & Facts

Whooping Cough Outbreak in America 2026

Whooping cough — the common name for pertussis, a highly contagious bacterial respiratory illness caused by Bordetella pertussis — is back with a ferocity that has alarmed public health officials, pediatricians, and infectious disease specialists across the United States. The numbers confirm what clinicians have been seeing in their exam rooms: 2024 recorded 43,321 cases of pertussis across the US, the highest annual total in more than a decade, representing a more than six-fold increase over the 7,063 cases in 2023. Then 2025 added another 28,783 cases — keeping the US in its second consecutive year above 25,000 reported infections, a threshold not crossed since the 2012 peak of 48,277 cases, which itself was the worst year since 1955. The outbreak is not just a number on a surveillance report. It is two-week-old babies airlifted to neonatal ICUs. It is infants in Louisiana dying within their first months of life. It is a child in Washington state — the first pertussis death in that state since 2011. It is an adult in Idaho, dead in February 2025 from a disease that a vaccine can prevent. And as of April 28, 2026, the CDC’s own surveillance page notes that while case counts have declined from the November 2024 peak, 2025 cases remained elevated compared to the pre-pandemic period — and the structural vulnerabilities that caused this surge have not been resolved.

What is driving this resurgence in 2026 is not a mystery. It is a compounding of three simultaneous failures: declining vaccination rates, waning immunity from the acellular pertussis vaccines introduced in the 1990s, and a public health infrastructure stretched thin by the aftermath of COVID-19 funding cuts. Kindergarten vaccination coverage for whooping cough fell from 95% in 2019 to just 92.3% by the 2023–24 school year, according to CDC data. An NBC News / Stanford University investigation of 31 states found that approximately 70% of counties and jurisdictions fell below the vaccination threshold needed for community protection. In Texas, a new law made it easier for parents to claim nonmedical exemptions by allowing downloadable forms that go directly to schools — bypassing health department tracking. Across the nation, the gap between the immunity the population has and the immunity it needs has widened to the point where whooping cough is circulating freely among children, adolescents, adults, and most dangerously of all, newborns who are too young to be vaccinated. That is the whooping cough crisis in America in 2026.

Key Whooping Cough Outbreak Facts in the US 2026

Source: CDC Pertussis Surveillance and Trends (updated April 28, 2026); Contagion Live citing CDC Week 53 data (January 3, 2026); ABC News (April 25, 2025); CBS News (November 19, 2025); Scientific American (December 30, 2025); CIDRAP (April 3, 2025); NBC News / Stanford University investigation (December 17, 2025); CDC 2024 Provisional Pertussis Surveillance Report (January 2025); NFID; JHEAO Winter 2026 journal

The case count data for the US whooping cough surge reads like a public health alarm that went unheeded for too long. 43,321 cases in 2024 is not just a number — it is the clearest demonstration since 2012 that the pertussis control strategy built around the acellular vaccine is under structural strain. The six-fold surge from 7,063 cases in 2023 to 43,321 in 2024 represents the steepest single-year acceleration in pertussis incidence in decades. When a disease that kills through oxygen deprivation — babies turning gray-blue during coughing fits that can last 12 weeks — surges that rapidly, the cause is almost never a change in the bacterium alone. It is a collapse of the protective barrier that vaccine coverage provides. Kindergarten coverage dropping from 95% to 92.3% may seem like a small number, but at a national scale covering millions of children, that gap represents hundreds of thousands of unprotected children circulating through schools, daycare centers, and pediatric waiting rooms annually. The 70% of US counties below the herd immunity threshold confirmed by the NBC News / Stanford investigation is the structural reality behind every hospitalization.

The death toll data demands its own paragraph. In 2024, approximately 10 Americans died of whooping cough — six of them infants under one year old. By December 2025, at least 13 deaths had been confirmed for that year — a higher total than 2024 despite the lower overall case count, reflecting the continued concentration of severe disease in the most vulnerable infants and the real-world consequences of the immunity gap. The deaths in Louisiana, Washington state, South Dakota, Idaho, and Kentucky are not statistical abstractions — they are individually named, confirmed, grieved. Every one of them occurred in a disease for which a vaccine exists, is recommended, is covered by insurance, and is available at essentially every pediatrician’s office and pharmacy in the country. That is what makes the whooping cough outbreak statistics in 2026 so morally urgent alongside being epidemiologically significant.

Whooping Cough Cases by Year — Historical Trend in the US 2026

US PERTUSSIS CASES — HISTORICAL TREND (KEY YEARS)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
  Pre-vaccine peak (1934): ████████████████████████████████████ 265,000 cases
  1940s avg (pre-vaccine): ████████████████████████████         ~200,000/year
  Post-vaccine era (1976): ██                                    1,010 (all-time low)
  2012 (post-vaccine peak):████████████████████████████         48,277 cases
  2014:                    ██████████████████████               28,660 cases
  2019 (pre-COVID):        ███████████████                      18,617 cases
  2020–2022 (COVID era):   ██                                   ~2,000–5,000/year
  2023:                    ██████                               7,063 cases
  2024 (WORST since 2012): █████████████████████████████████    43,321 cases
  2025 (still elevated):   █████████████████████████            28,783 cases
  2026 (YTD as of Apr 28): ████                                Fewer than same period 2025
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Source: CDC Pertussis Surveillance and Trends (updated April 28, 2026); Contagion Live (Week 53 CDC data, January 2026); CDC Pertussis Cases by Year (1922–2023); JHEAO Winter 2026; NBC News (December 17, 2025)

The historical trend line for US whooping cough cases is one of the most instructive graphs in American public health history — showing the miracle of vaccination, the complacency that followed, and the consequences of that complacency in real time. From the pre-vaccine era peak of 265,000 cases and 10,000 deaths in 1934, the introduction of the DTP vaccine in 1948 drove cases down more than 90%, reaching an all-time post-vaccine low of approximately 1,010 cases in 1976. That achievement was genuine and enormous. But pertussis never disappeared — it circulated at background levels, and cases began climbing again through the 1980s and 1990s as the transition to the acellular vaccine created longer gaps between boosters, waning immunity accumulated in the adult population, and vaccination rates began plateauing. The 2012 peak of 48,277 cases was the first major alarm. 2024’s 43,321 is the second — this time amplified by pandemic-era disruptions to vaccine schedules that have not been fully corrected.

The 2024 to 2025 trajectory illustrates why the CDC classifies pertussis as a cyclical disease — one that peaks and then declines as natural infection and post-peak vaccination responses temporarily raise community immunity. After the November 2024 peak, cases trended downward through 2025, and the CDC’s April 28, 2026 update confirms that fewer cases have been reported in 2026 compared to the same period in 2025 — a welcome but cautious signal. The cyclical nature of pertussis means this is the expected pattern: after a major surge year, incidence typically falls for several years before the next peak. But the underlying structural driver — the progressive erosion of vaccine coverage rates — has not been addressed. Cyclical declines do not fix falling vaccination rates. Without meaningful increases in DTaP coverage among young children, Tdap uptake among pregnant women, and booster compliance among adolescents and adults, the conditions for the next surge are already being set in motion during the current post-peak period.

Whooping Cough Cases by State in the US 2026

WORST-AFFECTED STATES FOR PERTUSSIS — US 2024–2025 DATA
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
  TEXAS (2024):              ████████████████████████  1,928 cases
  TEXAS (by Oct 2025):       ████████████████████████████████  3,500+ cases
  MICHIGAN (2024):           ████████████████████████████████  2,081 cases
  MICHIGAN (2025 partial):   ██████                            497 cases (partial year)
  OREGON (2025):             ██████████████████████████████    1,300+ (highest since 1950)
  WASHINGTON:                ████████████████████████          1,000+ in 2024
  IDAHO:                     ████████████████████              1,000+ in 2024
  CALIFORNIA:                █████████████                     High — exact pending
  LOUISIANA (2025, partial):  █████                            110+ cases as of March 2025
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
  Cases confirmed in ALL 50 states (2024–2025 — Nemours Children's Health / ABC News)

Source: CBS News (November 19, 2025); NBC News (December 17, 2025); Oregon Health Authority via PBS News (November 30, 2025); CIDRAP (April 3, 2025); ABC News (April 25, 2025); NBC News (April 22, 2025); Scientific American (December 30, 2025)

The state-by-state data for the US whooping cough outbreak makes unmistakably clear that this is not a regional problem concentrated in any single geographic or political area. Cases were confirmed in all 50 states during the 2024–2025 surge cycle, from Louisiana to Idaho to New York. But the concentration of severity tells a more specific story. Texas and Michigan both hit extraordinary case counts — Michigan’s nearly 1,800% single-year increase from 110 cases in 2023 to 2,081 in 2024 is perhaps the most dramatic state-level acceleration in the data. Texas’s case trajectory is particularly instructive as a policy case study: a state that already had high pertussis burden in 2024 made it procedurally easier for parents to opt out of school vaccination requirements in 2025, at the exact moment when its outbreak was still escalating. By October 2025, Texas had already exceeded 3,500 cases for the year, nearly double its full-year 2024 total.

The West Coast pattern — with Oregon, Washington, Idaho, and California all featuring prominently in the high-case rankings — reflects a combination of geographic population density in major urban corridors, concentrated pockets of vaccine hesitancy in both rural and suburban communities, and the highly efficient transmission dynamics of pertussis in school-age populations. Oregon’s 2025 total of over 1,300 cases was the state’s highest since 1950, a milestone that Oregon’s state health officials highlighted explicitly. The deaths in Louisiana (two infants), Washington state (child under 5), South Dakota (school-age child), Idaho (adult), and Kentucky (unvaccinated infant) span nearly every demographic category and geographic region — confirming that while infants remain the most vulnerable, whooping cough is killing Americans of multiple ages, across all regions, in a disease that vaccination can prevent.

Vaccination Rates, Waning Immunity & Causes in the US 2026

DRIVERS OF THE WHOOPING COUGH SURGE — US 2024–2025 DATA
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
  Kindergarten DTaP coverage (2023–24):      ████████████████████████ 92.3% (↓ from 95%)
  Counties BELOW herd immunity threshold:    ████████████████████████████ ~70%
  Pregnant women receiving Tdap vaccine:     ██████████████████████   ~60% only
  Unvaccinated 6mo–6yr children in 2024:     >7% of all pertussis cases — highest since 2021
  DTaP initial effectiveness:                ~91% after 5-dose series
  Acellular vaccine immunity waning:         Effectiveness decreases annually after each dose
  Adults needing Tdap booster (every 10yr):  Many have not received booster — immunity gone
  Tdap recommendation for pregnancy:         Every pregnancy — not widely followed
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Source: CDC 2024 Provisional Pertussis Surveillance Report (January 2025); NBC News / Stanford University investigation (December 17, 2025); CBS News (November 19, 2025); JHEAO Winter 2026 Pertussis Outbreak Call to Action; CDC 2019 bacterial mutation research; ABC News (April 25, 2025)

The vaccination coverage data is the single most important explanatory variable for the whooping cough outbreak in the US. The drop from 95% to 92.3% kindergarten DTaP coverage may appear modest, but herd immunity for pertussis requires coverage of approximately 92–95% of the population — meaning the US is now operating right at or below the minimum threshold needed to prevent sustained community spread. With ~70% of counties already below that threshold, the outbreak is not a surprise. It is the mathematically predictable consequence of a coverage rate that has been declining for five years without corrective action. The pregnant women Tdap statistic is particularly alarming given its direct life-or-death implications: only ~60% of pregnant women receive the Tdap vaccine, despite a CDC recommendation that they receive it during every pregnancy. Maternal vaccination is the only mechanism that can protect newborns in their first two months of life, before they are old enough to receive their own first DTaP dose. In King County, Washington, public health data showed that none of the 12 infants treated for whooping cough in one period had mothers who received the Tdap during pregnancy — a statistic that is devastating in its specificity.

The acellular vaccine’s structural limitation is the second major driver — and unlike vaccination rates, it cannot be fixed by public messaging alone. When manufacturers switched from whole-cell to acellular pertussis vaccines in the 1990s to reduce adverse reactions including fever and injection-site pain, they created a vaccine that offers excellent initial protection (~91% after the full 5-dose DTaP series) but sees that effectiveness decline annually with each passing year. Adults who received only acellular vaccines as children — the majority of people now in their 20s and 30s — have progressively lost immunity over time and may unknowingly transmit pertussis to infants. The Tdap booster is designed to address this, but it requires a dose every 10 years and carries the challenge of reaching adults who have not thought about pertussis since childhood. A 2019 CDC study also identified evidence of bacterial mutation in Bordetella pertussis — with strains adapting to vaccine pressure in ways that may be reducing vaccine effectiveness at the population level. Meanwhile, rising antibiotic-resistant pertussis strains in China and Peru have not yet taken significant hold in the US, but their existence adds urgency to the development of a more durable next-generation pertussis vaccine. The FDA convened a meeting in 2024 to discuss this need — as of April 2026, no new vaccine has emerged from those discussions.

Demographics and Risk Groups for Whooping Cough in the US 2026

PERTUSSIS RISK BY AGE AND DEMOGRAPHIC — US 2024–2025 DATA
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
  Infants under 6 months:     ████████████████████████████████  38% of positive cases
  Children under 5 years:     ████████████████████████████████████████ 71% of positive cases
  Hospitalization (infants):  ████████████████████  1 in 3 hospitalized
  Pneumonia (infants):        ████████████          1 in 5 develop pneumonia
  Infant fatality rate:       ██                    ~1%
  Adolescents — rising:       ████████              Significant increase; close-quarter spread
  Adults — unknowing carriers:████████████████████  Major source of infant infection
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Source: JHEAO “The 2024 Pertussis Outbreaks in the United States: A Call for Increased Awareness” (Winter 2026); CDC Pertussis Surveillance (April 28, 2026); Contagion Live (May 2026 citing Stony Brook/Nachman); CBS News (November 19, 2025); NFID Whooping Cough data

The demographic data for whooping cough confirms what clinicians have known for decades — this is a disease that is most lethal at the very beginning of life, in a window when the only protection available is what a vaccinated mother passes through her antibodies before birth. 38% of all positive pertussis cases involve infants under 6 months old, and 71% involve children under 5 — the age groups that are either too young to have completed the full vaccination series or early in the multi-dose process. The 1 in 3 infant hospitalization rate and 1 in 5 pneumonia rate represent a level of clinical severity that makes every unvaccinated adult in proximity to a newborn a potential transmission risk. The average of 15 paroxysmal coughing attacks per 24 hours at peak disease — each one a violent, oxygen-depriving episode — is what earns pertussis its reputation as the “100-day cough”: an illness that does not simply make you uncomfortable but dominates every aspect of breathing, eating, sleeping, and functioning for weeks on end.

What is emerging as a newly prominent trend in the 2024–2025 outbreak data is the rising pertussis burden among adolescents. Dr. Sharon Nachman, chief of pediatric infectious diseases at Stony Brook Children’s Hospital, identified three converging factors for this adolescent surge speaking to Contagion Live in May 2026: non-uptake of initial vaccines in some cases, older children not receiving their boosters, and teens in close proximity — in high schools, college dormitories, and athletic teams — to others with active pertussis. The household transmission rate of 80–90% among susceptible contacts and 50–80% classroom transmission rate explain why any community with a coverage gap can sustain an outbreak once a single case enters. The 13.9-day average diagnostic delay for adults — compared to 5.6 days for young children — means adults carry and spread pertussis far longer before treatment begins, making them the invisible driver of infant exposure. The combination of adolescent spread, adult transmission, and infant vulnerability is the epidemiological architecture of the current US outbreak — and none of it will change without meaningfully higher vaccination rates at every age.

Disclaimer: This research report is compiled from publicly available sources. While reasonable efforts have been made to ensure accuracy, no representation or warranty, express or implied, is given as to the completeness or reliability of the information. We accept no liability for any errors, omissions, losses, or damages of any kind arising from the use of this report.

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