Wyoming Health Department Warns of Whooping Cough Spread

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Published March 11th, 2026

Detected March 17th, 2026

Summary

The Wyoming Department of Health (WDH) has issued a notice regarding the ongoing spread of pertussis (whooping cough) across the state. Officials are concerned about the high number of cases reported in 2025 and early 2026, particularly in Fremont County, and are urging residents to stay up-to-date on vaccinations.

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What changed

The Wyoming Department of Health (WDH) has issued a public health notice highlighting the significant spread of pertussis (whooping cough) within the state. As of March 11, 2026, 26 cases have been confirmed this year, with a notable concentration in Fremont County. This follows a record high of 148 cases in 2025, the highest since 1951. The WDH emphasizes that actual case numbers may be higher due to underreporting and misdiagnosis.

Health officials are urging residents, especially those who care for infants, to ensure they are up-to-date on pertussis vaccinations, including the Tdap booster. Pregnant individuals are also advised to discuss vaccination with their doctors to protect newborns, as infants are particularly vulnerable and can experience severe complications, including hospitalization and death. The notice also recommends seeking medical attention for symptoms consistent with pertussis for potential antibiotic treatment.

What to do next

Review current pertussis vaccination status for all applicable individuals.
Ensure Tdap booster vaccinations are up-to-date for staff and individuals who interact with infants.
Educate staff and patients about pertussis symptoms and the importance of vaccination.

Source document (simplified)

Home » News » Whooping Cough Continues Wyoming Spread

Whooping Cough Continues Wyoming Spread

March 11, 2026

Wyoming Department of Health (WDH) officials are concerned about the ongoing, active spread of pertussis (whooping cough) across the state.

Kaylyn Friesen, vaccine-preventable disease epidemiologist with WDH, said there have been 26 confirmed pertussis cases in Wyoming so far this year. “While roughly two-thirds of the reported cases have been among Fremont County residents, pertussis has also been identified in other counties,” Friesen said.

Friesen noted that 148 cases were reported in Wyoming in 2025, the highest since 1951. “We are continuing to see outbreaks and high monthly case counts,” Friesen said.

Actual case numbers are likely higher because many illnesses are not recognized as pertussis, and others may not be reported. Pertussis typically begins with cold-like symptoms and perhaps a mild cough. Pertussis is often not suspected or diagnosed until a persistent cough with spasms develops after 1 to 2 weeks. Infants and children can cough violently and rapidly with a loud “whooping” sound.

Dr. Alexia Harrist, state health officer with WDH, said, “One-third of infants less than 1 year of age who become ill with pertussis need to be hospitalized, and we know, in some cases, it can be deadly for these babies. Pertussis in the youngest babies can cause them to have pauses in breathing. Infants are simply more vulnerable and don’t yet have all the protection pertussis vaccines offer.”

Harrist said the Tdap adolescent/adult pertussis booster vaccine is especially important for those spending time with new infants, such as parents, grandparents, and other people who take care of them. “Also, if you are pregnant or planning on becoming pregnant, you should talk to your doctor about a Tdap vaccine because that can also help protect newborns,” she said.

Harrist recommends that all residents stay up to date with pertussis vaccines, as those who still become ill with pertussis after vaccination are less likely to have a severe experience. “In addition, people should consider seeing a medical professional for antibiotics if they have symptoms consistent with pertussis,” she said.

More information about pertussis can be found online at https://health.wyo.gov/publichealth/infectious-disease-epidemiology-unit/disease/pertussis/.