The Texas Department of State Health Services has issued an alert about pertussis, the highly contagious and potentially deadly disease also known as whooping cough.
DSHS has reported nearly 2,000 pertussis cases, including two deaths so far this year.
"This is extremely concerning if cases continue to be diagnosed at the current rate, we will see the most Texas cases since the 1950s," said Dr. Lisa Cornelius, DSHS infectious diseases medical officer. "Pertussis is highly infectious and can cause serious complications, especially in babies, so people should take it seriously."
Closer to home, the city's health department has also seen a rise in pertussis cases.
"Here in Houston we've had 123 cases since January and we're not even through the end of the year, so this is considerably more than we've seen before, not since the 50s," said Kathy Barton, a health department spokesperson.
Experts say adults and teenagers should get a booster shot, because their immunity wanes with age.
To better protect babies, pregnant women, fathers, siblings and extended family members should also be vaccinated.
"If they're exposed they will get a very serious illness, a very serious respiratory illness that could result in their being hospitalized, and when we see deaths from pertussis, it is from infants," said Barton.
The health warnings came as a surprise to some parents, who say keeping their children vaccinated is their top priority.
"People are making a choice not to vaccinate because they're scared of the vaccine and these diseases that have been almost eradicated are coming back and often times killing children already in a suppressed state," said Julie Miller, a parent who heard about the increased number of pertussis cases.