With the number of confirmed whooping cough cases in the Worthington schools reaching 46 as of Monday, Columbus Public Health officials are urging parents to have children from age 11 to 18 receive booster shots to guard against pertussis, a bacterial infection that is easily spread by coughing.

Those shots will be offered this Friday from 8 a.m. to 2 p.m. at Thomas Worthington High School; during the same hours next Wednesday at Worthington Kilbourne High School; from 8 a.m. to noon this Saturday at Columbus Public Health, 240 Parsons Ave., Columbus; and from 1 to 4 p.m. on Nov. 20 at the Worthington United Methodist Church, 600 High St.

The shots are also available through family physicians.

Health department spokespersons said they hope to wipe out the disease before Thanksgiving, when children could spread germs to family members including infants, who are at greatest risk for complications and death.

Children are generally vaccinated for the disease as infants and receive a booster before entering kindergarten. However, immunity seems wane at adolescence, putting teens at greater risk.

The Worthington outbreak started three weeks ago at Worthington Kilbourne, then spread to Thomas Worthington. Cases have also been reported at Wilson Hill, Worthington Park, and Evening Street elementary schools.

The youngest victim is a third-grader at Evening Street.

Students who have a cough for three days are being pulled from school and their parents are being instructed to get them tested for pertussis. If they test positive, they should be treated with an antibiotic and not return to the classroom or to extra-curricular activities for five days.

Columbus health commissioner Dr. Teresa Long stressed that those who test positive should also stay away from the mall, the movies, or anywhere else that the infection could spread to others.

Those who have had close contact with someone who is infected are also being prescribed treatment. If they show no symptoms, they may return to school.

"It doesn't seem to be having an impact on school attendance," said school spokesperson Vicki Gnezda. "Nothing has been canceled."

Pertussis causes a severe cough that lasts for several weeks. In worst cases, thick mucus makes it difficult to eat, drink, or breathe.

Nobody in Worthington has been hospitalized, health officials said.

As of Monday, 224 laboratory-confirmed cases have been reported in Franklin County. Last year, there were 156.

The booster shots for pertussis, known as Adacel and Boostrix, have only been available for two years. Parents should check their children's medical records to see if they have received either vaccine.

The schools on Tuesday were preparing to send home forms for students at Thomas Worthington and Worthington Kilbourne.

The shots will be given in coordination with Nationwide Children's Hospital. Some insurance companies will be billed.

Shots given at the Health Department or at the church will cost $25, and minors must be accompanied by guardians. The cost is $25, but nobody will be turned away because he or she cannot pay, said health department spokesperson Jose Rodriguez.