One high school in Lane County had so many students with pertussis -- or whooping cough -- that the public health department is investigating the cause.

Twelve people at Sheldon High School, a public high school in Eugene, contracted pertussis, a highly contagious bacterial infection. Pertussis is also highly preventable through vaccination.

According to The Oregonian/OregonLive's database of vaccination rates for Oregon schools last school year, Sheldon High has enough students vaccinated that contagious diseases should have a hard time spreading. However, any adults or students who aren't vaccinated are susceptible to contracting pertussis, according to the local health authorities.

One case of pertussis can cause up to 16 new ones, said Dr. Patrick Luedtke, chief health officer for Lane County Public Health. So to have 12 in such a short time span is troublesome, he said.

"Fortunately, we have had great team effort with the school, now it's time to ask our community members for help by getting vaccinated," Luedtke said.

Oregon has some of the lowest vaccination rates in the country, according to the U.S. Centers for Disease Control and Prevention. Only 83 percent of Oregon adults in 2017 had received the Tdap, a booster shot against tetanus, diphtheria and pertussis.

The federal government recommends that infants start their immunization shots at 2 months old. They then receive four follow-up booster shots: At 4 months, 6 months, between 15 and 18 months and when the child enters school, or between 4 and 6 years old.

Public health authorities say that some parents don't know that the booster shots are needed to be fully vaccinated. Some children also contract the disease because adults either don't know they are unvaccinated or choose not to be and then pass it to unvaccinated children or babies too young to be vaccinated.

Pertussis can be fatal, following days of gagging, gasping, coughing, spasming and sometimes vomiting. At the least, it is debilitating for two weeks to 90 days. Anyone with pertussis is asked to stay home from work or school for up to 21 days and see a doctor.

Doctors can prescribe antibiotics that can allow people to return to normal activities after five days.

Most health insurance plans cover immunization shots and can be gotten several places outside of doctors offices, such as pharmacies.

-- Molly Harbarger

mharbarger@oregonian.com

503-294-5923

@MollyHarbarger