More than 3,500 cases of pertussis, or whooping cough, have been reported across Texas this year, the highest total in more than a decade, according to the Texas Department of State Health Services.

The sharp rise comes amid a drop in vaccination rates, health experts say, warning that the best way to prevent the spread of the disease is to stay up to date on immunizations.

“We practitioners and public health professionals are concerned because we are seeing a year-after-year trend of a significant increase in cases when this is preventable,” said Dr. Hector Ocaranza, a pediatrician and member of the Texas Medical Association’s Council on Science and Health Promotion. “Especially a disease that can have such a severe effect on infants, older people, and those who have chronic conditions.”

State data show that Texas has already reported four times as many whooping cough cases as it had by this time last year — and 10 times more than in all of 2023. This marks the second consecutive year the state has issued a health alert for pertussis.

The most recent alert, published Nov. 3, warned that infections typically spike in November and December, meaning cases could continue to climb through the holidays.

Dr. Jason Bowling, an infectious disease specialist at UT Health San Antonio, said the timing is concerning as families gather indoors.

After unusually low activity during and immediately after the COVID-19 pandemic, whooping cough has rebounded nationwide. More than 35,000 cases were reported in the U.S. last year, up from 7,063 in 2023, and several deaths have been confirmed in Louisiana, South Dakota, and Idaho.

In Texas, about 85% of cases this year have been among children, though no deaths have been reported.

Whooping cough is caused by Bordetella pertussis bacteria, which infect the upper respiratory tract and cause severe coughing fits that can make breathing difficult. The illness is most dangerous for infants under six months old, who are too young to be fully vaccinated. One in three infected babies requires hospitalization, and some develop pneumonia or brain swelling.

“If you think your baby has been exposed, you have to act fast,” said Dr. Joshua Sharfstein, a pediatrician and public health professor at Johns Hopkins University. “Once the coughing and spasms appear, the damage is already done, and it’s too late to treat the bacteria.”

The Texas health department advises that the best protection is vaccination. The Tdap vaccine is recommended for children age 7 and older, while the DTaP vaccine is for those under 7. Pregnant women are also advised to get vaccinated between 27 and 36 weeks to help protect their newborns.

Health experts stress that adults, especially those around babies, should update their boosters every 10 years, as most infant infections come from parents or relatives.

“One of the worst things I’ve seen in my pediatric career is parents watching their child struggle to breathe from pertussis,” Sharfstein said. “It’s awful, but it’s preventable.”

In the 2024–25 school year, 93.4% of Texas seventh graders and 92.9% of kindergarteners were fully vaccinated against pertussis, according to state data. However, coverage rates for required school vaccines have steadily declined in recent years, raising concerns about potential outbreaks.

“The measles outbreak in Texas was a warning bell,” Sharfstein said. “People aren’t getting vaccinated enough.”