County health officials declared a second outbreak of whooping cough in the Vail School District, as five students at Sycamore Elementary School have tested positive for the highly contagious respiratory disease.

As a result, unvaccinated students at the school will not be allowed to attend classes or school-related activities for at least two weeks. If the students remain unvaccinated, they will not be allowed back for three weeks or longer.

Pima County Health Department Director Dr. Francisco Garcia made the ruling after a third case of whooping cough, also called pertussis, was confirmed at the school southeast of Tucson. Two more cases at Sycamore were confirmed late Tuesday, bringing the total number at that school to five.

The newest cases bring the total confirmed by county health officials for the Vail School District to 18 for this year. The first case was confirmed in May. The outbreak prompted at least one Vail pediatrician to ban unvaccinated children from his practice.

Countywide, confirmed cases are up significantly — 71 already for 2013, compared to 46 for all of 2012.

Last month, Garcia issued the same stay-home directive to unvaccinated students at Empire High School in Vail after three whooping cough cases were confirmed there.

“Obviously we are very concerned for the students at Empire, but the younger the age the more severe the complications can be,” County Health Department spokesman Aaron Pacheco said. “That is our main concern with Sycamore, because it’s an elementary school.”

County health officials have confirmed 18 whooping cough cases in the Vail Unified School District in 2013. The first case was confirmed in May.

If there are three cases in 21 days at a school, students who don’t have immunizations or haven’t received the whole series of shots have to stay home, district spokeswoman Natalie Luna Rose said.

District officials are making arrangements to allow the Sycamore students to continue their studies at a different building, she said.

Vail officials say there have been whooping cough cases at Civano Community School, Empire High School, Andrada Polytechnic High School, Cienega High School, Old Vail and Rincon Vista middle schools and Vail Blended Learning.

The case at Cienega was confirmed Friday, while the Andrada case was confirmed Nov. 5, Luna Rose said.

At least three of the Vail students who have tested positive for pertussis this school year were unvaccinated, health department officials say.

Vail pediatrician Dr. Christopher Hickie said he was troubled by a recent increase in parents who don’t want their children to be vaccinated.

Hickie said this is the first year since he began his Vail practice in 2004 that he’s known of area children, including some of his patients, testing positive for pertussis. On Oct. 8 he took the step of banning unvaccinated children from his practice.

“I don’t want an unvaccinated child infecting a newborn in my waiting room with whooping cough,” Hickie said. “My biggest concern is that the longer we have it out here, the more likely we are going to see it spread to younger children, who are at much greater risk of getting extremely ill or dying of it, especially newborns.”

One or two Arizona infants die of whooping cough each year.

“I’ve seen an increasing number of parents exempting their children voluntarily from vaccines for nonmedical reasons,” Hickie said. “Some have done a lot of reading, but they have been reading the wrong stuff. Some are just absolutely convinced vaccines don’t work, aren’t safe and that diseases like whooping cough aren’t dangerous.”

When someone is infected with pertussis, bacteria attach to the tiny, hair-like extensions called cilia that line part of the upper respiratory system. The bacteria release toxins, which damage the cilia and cause swelling that can be fatal.

Nationally, 48,277 cases of whooping cough were reported last year, the highest number reported in the U.S. since 1955.

Fewer parents are vaccinating their children, and more are starting but not completing the series of vaccinations.

But there are other reasons for a spike in cases, health experts say. The vaccine is effective only about 70 percent of the time. And a switch from what’s called a “whole cell” pertussis vaccine to a more purified “acellular” version appears to be causing the childhood pertussis vaccine to wear off faster than in the past.

Contact Star medical reporter Stephanie Innes at or 573-4134.