As a dad-to-be, you’re thinking of all the things you hope to pass on to your child: maybe your sense of humor, your love of sports or music, or your eye color. One thing you don’t want to pass on to your new baby is whooping cough, or pertussis, a highly contagious disease that can be deadly for infants. As we honor dads this Father’s Day, the physicians of Texas Medical Association (TMA) urge dads- and grandfathers-to-be to get vaccinated, before baby arrives.

“Vaccinating dads and others who will come into contact with the baby is the best way to ensure they will not get pertussis and inadvertently infect the infant,” said C. Mary Healy, MD, of Houston, a pediatric infectious disease specialist and member of TMA’s Committee on Infectious Diseases. “The vaccination is safe, and everyone should be vaccinated against whooping cough to protect themselves and their baby.”

Whooping cough is especially dangerous for infants younger than 1 year of age. The Texas Department of State Health Services (DSHS) says more than half of babies under 1 year of age who get pertussis must be hospitalized. Many will have serious complications, like pneumonia or apnea (slowed or stopped breathing), and some become so sick they will die.

The Tdap vaccination (a combination vaccination that protects against tetanus, diphtheria, and pertussis) is recommended for adolescents and adults — including dads, siblings, and grandparents — who will have contact with the infant, according to the Centers for Disease Control and Prevention (CDC).

For the best protection, the CDC recommends the vaccine be administered to family members at least two weeks before they have contact with the baby. And because babies don’t always arrive on their due date, getting vaccinated a few weeks before the anticipated birth is best, said Dr. Healy.

“Every mom should be vaccinated during pregnancy to help protect the baby from pertussis,” Dr. Healy explained. “Vaccinating all of the newborn’s family members prior to the baby’s arrival provides even better protection.”

Physicians call it “cocooning,” vaccinating those who will be around a newborn to surround the infant in a vaccination “cocoon.” That, together with immunizing pregnant women, is the best way to protect the baby, said Dr. Healy, because, in most cases, infants catch pertussis from a family member or caregiver whose symptoms were so mild they didn’t know they had the illness.

Family members and caregivers around babies must defend the little ones against whooping cough because newborns cannot protect themselves yet. And because babies require a series of pertussis vaccinations, they are not fully protected until they’re close to 18 months of age. Until that time, babies rely on the vaccinations of those around them to avoid catching the disease.

Texas reported 3,985 pertussis cases in 2013, the most cases in a year since 1959, according to DSHS. Eleven percent of those patients (most of them children under age 1) ended up in the hospital, and all five of the people who died of pertussis in 2013 were infants. In 2014, the number of cases decreased slightly with 2,576 cases of pertussis and two infant deaths (based on preliminary data).

If you’re expecting a baby, physicians urge you to ask your doctor about the Tdap vaccine. TMA has published a fact sheet about the importance of pertussis vaccination, in English and Spanish.

TMA is the largest state medical society in the nation, representing more than 48,000 physician and medical student members. It is located in Austin and has 110 component county medical societies around the state. TMA’s key objective since 1853 is to improve the health of all Texans.

TMA actively works to improve immunization rates in Texas through its Be Wise — ImmunizeSM program. Be Wise works with local communities to give free and low-cost shots to Texans, and educate people about the importance of vaccination. More than 277,000 shots have been given to Texas children, adolescents, and adults through the Be Wise program since 2004.