by Duaa Eldeib and Patricia Callahan, and photography by Sarahbeth Maney

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In the past six months, two babies in Louisiana have died of pertussis, the disease commonly known as whooping cough.

Washington state recently announced its first confirmed death from pertussis in more than a decade.

Idaho and South Dakota each reported a death this year, and Oregon last year reported two as well as its highest number of cases since 1950.

While much of the country is focused on the spiraling measles outbreak concentrated in the small, dusty towns of West Texas, cases of pertussis have skyrocketed by more than 1,500% nationwide since hitting a recent low in 2021 amid the COVID-19 pandemic. Deaths tied to the disease are also up, hitting 10 last year, compared with about two to four in previous years. Cases are on track to exceed that total this year.

Cases had been decreasing in the years before the COVID-19 outbreak and dropped further when schools were closed in response to the pandemic.

Doctors, researchers and public health experts warn that the measles outbreak, which has grown to more than 600 cases, may just be the beginning. They say outbreaks of preventable diseases could get much worse with falling vaccination rates and the Trump administration slashing spending on the country’s public health infrastructure.

National rates for four major vaccines, which had held relatively steady in the years before the COVID-19 pandemic, have fallen significantly since, according to a ProPublica analysis of the most recent federal kindergarten vaccination data. Not only have vaccination rates for measles, mumps and rubella fallen, but federal data shows that so have those for pertussis, diphtheria, tetanus, hepatitis B and polio.

In addition, public health experts say that growing pockets of unvaccinated populations across the country place babies and young children in danger should there be a resurgence of these diseases.

Many medical authorities view measles, which is especially contagious, as the canary in the coal mine, but pertussis cases may also be a warning, albeit one that has attracted far less attention.

“This is not just measles,” said Dr. Adam Ratner, a pediatric infectious diseases doctor in New York City and author of the book “Booster Shots: The Urgent Lessons of Measles and the Uncertain Future of Children’s Health.” “It’s a bright-red warning light.”

At least 36 states have witnessed a drop in rates for at least one key vaccine from the 2013-14 to the 2023-24 school years. And half of states have seen an across-the-board decline in all four vaccination rates. Wisconsin, Utah and Alaska have experienced some of the most precipitous drops during that time, with declines of more than 10 percentage points in some cases.

“There is a direct correlation between vaccination rates and vaccine-preventable disease outbreak rates,” said a spokesperson for the Utah Department of Health and Human Services. “Decreases in vaccination rates will likely lead to more outbreaks of vaccine-preventable diseases in Utah.”

But statewide figures alone don’t provide a full picture. Tucked inside each state are counties and communities with far lower vaccination rates that drive outbreaks.

For example, the whooping cough vaccination rate for kindergartners in Washington state in 2023-24 was 90.2%, slightly below the U.S. rate of 92.3%, federal data shows. But the statewide rate for children 19 to 35 months last year was 65.4%, according to state data. In four counties, that rate was in the 30% range. In one county, it was below 12%.

“My concern is that there is going to be a large outbreak of not just measles, but other vaccine-preventable diseases as well, that’s going to end up causing a lot of harm, and possibly deaths in children and young adults,” said Dr. Anna Durbin, a professor in the Department of........

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