Texas is currently seeing four times the number of whooping cough cases compared to the same time last year, the state’s health department said in a health alert.

The state has reported more than 3,500 cases this year. This is the second year that Texas has experienced high increases in whooping cough cases. 

Nationally, whooping cough cases have been higher in the past two years than levels seen in prior years and pre-pandemic.

In 2024, the United States experienced roughly six times as many cases compared to 2023, CDC data shows. Cases remain elevated this year but appear to have been trending down since a peak seen last winter, the CDC says.

Federal public health data systems have not been updated amid the government shutdown. The latest available CDC numbers from the end of September show the country has had at least 20,939 pertussis cases so far this year. In comparison, 21,391 cases were reported at the same time last year.

The higher numbers of cases in recent years come as vaccination rates for whooping cough have steadily dropped, CDC data shows. Roughly 92.1% of kindergarteners were vaccinated against whooping cough in the 24-25 school year, compared to about 95% before the pandemic started.

Whooping cough, also known as pertussis, is a very contagious respiratory illness caused by a type of bacteria. People can spread the bacteria from the start of symptoms and for at least 2 weeks after coughing begins. It may begin like a common cold; however, coughing can last for weeks or months. Treatment with antibiotics early on makes the infection less serious.

Data from medical records show Nebraska, Idaho, Oregon and Hawaii are the states with the highest rates across the country, according to more recent data from Epic Research.

Doctor visits, emergency room visits and hospitalizations remain lower than at the peak seen last winter, the data shows.