The Westport and Fairfield health departments are offering 3-in-1 vaccination shots against whooping cough, diphtheria and tetanus to all who have close contact with infants under the age of 12 months.

Registered nurse Loren Pace at the Westport Weston Health District said the vaccine is provided free — with a $21 vaccination administration fee ­­– through the state Department of Public Health immunization program.

Sands Cleary, the director of the Fairfield Health Department, said there is no fee for the 3-in-1 shot, which is available to eligible people at the Fairfield Well Child Clinics.

“Vaccination with pertussis-containing vaccine is intended for all persons who have close contact with infants,” Pace said. Pertussis is the scientific name for whooping cough.

According to the U.S. Centers for Disease Control and Prevention website, in 2009 nearly 17,000 cases of whooping cough were reported in the United States, “but many more go undiagnosed and unreported.” each year worldwide there are 30 million to 50 million cases and about 300,000 deaths, the CDC reports. Additionally, since the 1980s, there has been an increase in the number of reported cases in the U.S., especially among 10- to 19-year-olds and infants younger than 6 months of age.

“The fundamental strategy of the immunization program, referred to as cocooning, helps to put a protective cocoon of safety around the infants,” Pace said.

“Persons eligible for vaccination include post-partum women, mothers and fathers of premature infants in neonatal intensive care units, adoptive families, siblings, grandparents and household contacts and care givers of infants less than 12 months of age.”

Whooping cough is a very contagious respiratory illness caused by the bacteria Bordetella pertussis.

These bacteria attach to cilia, which are tiny, hair-like extensions that line the upper respiratory tract, and release toxins. the toxins damage cilia and cause inflammation.

* Typical signs and symptoms include uncontrollable, violent coughing and a “whooping” sound, and/or vomiting.

* Any person with a history of cough illness lasting 14 days or more and exhibiting one of the symptoms should be seen promptly by his or her physician.

The CDC reported that more than half of the number of infants less than 1 year of age who get pertussis must be hospitalized and that pertussis is generally treated with antibiotics, which are used to control the symptoms and to prevent infected people from spreading the disease.

For more information or for a vaccination appointment at the WWHD, call Pace at 203-227-9571. for Fairfield information, call 203-256-3020.