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Pertussis cases in Oregon have reached an all-time high, prompting state officials to urge people to make sure they and their families are up to date on vaccinations—especially those who are pregnant or spend time with babies—and take steps to reduce spread.

In 2025, as of today—Dec. 10—Oregon Health Authority has received a record-high 1,475 reported cases of pertussis, also known as whooping cough, breaking the state’s all-time annual record of 1,420, set in 1950. The current outbreak began in spring 2024, when Oregon recorded 1,252 pertussis cases by year’s end. Other U.S. states have reported similar caseload spikes.

Pertussis can cause severe disease in people of all ages, but babies are most at risk of serious illness, hospitalization and death from infection. To reduce that risk, the American Academy of Pediatrics recommends every pregnant person receive a single dose of Tdap vaccine during their third trimester (weeks 27-36) to protect their newborn from pertussis. That’s because babies’ immune systems are too week to protect against infection until they get vaccinated at 2 months old.

Spouses, partners, grandparents and any adult routinely in the baby’s life should also consider receiving a Tdap dose at least two weeks before the baby is born.

However, vaccination is important for people of all ages, and it’s the best way to prevent severe disease and hospitalization. In addition to pregnant people, pertussis vaccination is recommended for infants and children starting at 2 months through 4 to 6 years old, adolescents at age 11 or 12, and any adult who has not previously been vaccinated.

“I worry people may not fully appreciate the risk pertussis poses as case counts are rising, especially for babies and older adults,” said Howard Chiou, M.D., Ph.D., medical director for communicable diseases and immunizations at OHA’s Public Health Division. “One of the most important things someone can do to protect their newborn is to get the Tdap vaccine during pregnancy. Unfortunately, we’ve seen a statewide decline in maternal Tdap vaccination rates in Oregon, which is a dangerous trend.”

In 2025, 87 cases of infant pertussis (children younger than 12 months)--22 of whom were hospitalized—have been reported in Oregon so far. One infant died in Oregon earlier this year. It is the only death from pertussis reported in Oregon during 2025.

OHA’s new Pregnancy Immunization Data dashboard shows only 69% of pregnant people received Tdap vaccination in 2024, down from 72% in 2020.

Maternal Tdap vaccination rates also vary widely from county to county, with rates as low as 17% and as high as 82%. The lowest rates are largely in rural counties, where it’s often harder to find vaccinations, and where vaccine hesitancy rates are also higher.

Pertussis outbreaks occur regionally about every three to five years and do not necessarily follow seasonal patterns. Because of widespread masking and social distancing during the pandemic, Oregon saw only three reported cases of pertussis in 2021, followed by 17 in 2022 and 40 in 2023. Health officials attribute the skyrocketing cases since then to a return to pre-pandemic norms that coincides with waning immunity and decreased vaccination rates.

Studies show Tdap vaccination during pregnancy is highly effective in preventing pertussis infection and hospitalization. Long-term protection from the pertussis vaccine wanes over time, however, which can create confusion about the vaccine.

“I hear the confusion in my community about pertussis vaccination,” said Benton County Health Officer Carolina Amador, M.D., MPH. “When we use the word ‘booster,’ people may think the vaccine isn’t very effective because protection fades, so they may not want to bother. At the same time, we strongly recommend it for certain people, such as children and pregnant people, because in the short term it does a great job protecting the most vulnerable among us.”

The only way a baby will become infected with pertussis is if they are exposed to someone with pertussis, a bacterial infection that spreads easily through droplets when someone coughs or sneezes.

But pertussis often goes undiagnosed. The illness is tricky to diagnose because not everyone with pertussis will have the trademark “whooping” sound when coughing. For some, pertussis can be severe and result in a trip to the hospital, while others may experience mild symptoms and may not necessarily seek medical care while they still spread disease.

Jennifer Gibbons, N.D., is a naturopathic pediatrician in Portland whose practice attracts many parents who are vaccine hesitant.

“When parents of my little patients also happen to be pregnant, they often tell me their own OBGYN has recommended the Tdap vaccine, and they will ask me, ‘But do you think it’s right for me?’ The answer is always yes,” she said.

“I can say, ‘I’ve seen whooping cough, and its truly awful for infants,’” Gibbons added. “Then I’ll explain how the vaccine merely adds to the suite of protective antibodies that the mother is already providing the baby through the placenta. I’m always exploring ways to change my language with patients to see if I can get them to look at it differently.”

Source: Oregon Health Authority