Local cases of pertussis, otherwise known as whooping cough, have popped up in Oak Park in higher numbers this year than any year in the previous decade.

According to Michael Charley, public health director of the Oak Park Health Department, as of Dec. 16 there are 10 confirmed cases in Oak Park, which has averaged 3.1 cases per year between 2008 and 2018.

Within public schools, according to Charley, District 200 has five confirmed cases (four students and one teacher) and District 97 has two confirmed cases, both students.

In River Forest, District 90 has three confirmed cases of pertussis as of Dec. 16: two at Roosevelt Middle School and one at Willard School. 

It could not be confirmed at time of publication whether the confirmed cases in D200, D97 or D90 were in vaccinated or unvaccinated children.

In Dec. 10 and Dec. 16 memos to D90 parents, the steps the district was taking to help prevent further infections were outlined, and information from the Cook County Department of Public Health was forwarded.

“Please be assured that all of the district’s nurses are aware of this situation and are monitoring the situation,” read the memo. “Our nurses are following the recommended protocols of the Illinois Department of Public Health and the Centers for Disease Control and Prevention (CDC).”

The custodial staff at all D90 locations have been intensifying disinfection of classrooms, bathrooms, desks, door handles and other common areas throughout the school.

Pertussis, a bacterial infection, is treatable by antibiotics, but it is highly contagious and is often misdiagnosed or, because early symptoms mimic those of the common cold, not diagnosed right away. After the initial symptoms of a runny nose, sneezing, low-grade fever and mild cough, the illness progresses. Coughing fits can become severe, especially at night, and can bring with them the characteristic “whoop” after which the disease was named. Coughing fits can be so intense they can lead to vomiting or difficulty breathing.

Pertussis is spread through coughing and sneezing, and the cough can last for weeks. Symptoms generally occur 5-10 days after exposure but can take up to 21 days, according to the Cook County Department of Public Health in a memo shared by D90.

According to the Centers for Disease Control (CDC) website, pertussis diagnoses have been on the rise since the early 1980s. The CDC has identified several explanations for this, including “increased awareness, improved diagnostic tests, better reporting, more circulation of the bacteria, and waning immunity.”

Additionally, according to the CDC, there is evidence that the bacteria that causes pertussis is “changing at a genetic level,” though studies suggest that the current vaccines are still effective even as the bacteria transforms.

However, the currently used pertussis vaccines may be less effective than those used prior to the 1990s, which could account, in part, for pertussis cases being on the rise since the 1980s. The vaccines currently given, DTaP and Tdap, are acellular vaccines, which contain only some organic material from Bordetella pertussis, the bacteria that causes the disease. These vaccines may not provide protection as effective as DTP, a whole cell vaccine, which contains the entire inactivated B. pertussis organism.

In the 1990s, according to the CDC, doctors in the United States switched from DTP, the whole cell vaccine, to DTaP and Tdap, the acellular vaccines, because they had less major and minor side effects.

But this change may have left Americans slightly less protected against the disease. According to the CDC website, “Acellular pertussis vaccines may not prevent colonization (carrying the bacteria in your body without getting sick) or spread of the bacteria.”

Additionally, waning immunity to the vaccine can leave even vaccinated people less protected than they might believe.

According to the Dec. 10 Cook County Department of Public Health’s memo regarding the Roosevelt Middle School student with pertussis, required vaccinations for the illness should be given at ages 2, 4, 6 and 15 months. A booster should be given between the ages of 4 and 6. 

However, according to the memo, “immunity begins to wane three to five years after the last shot. Protection can be completely gone by the time a child enters middle school.” 

The CDC confirms this, estimating that “in the first year after getting vaccinated with Tdap, it protects about seven out of 10 people who receive it. There is a decrease in effectiveness in each following year. About three or four out of 10 people are fully protected four years after getting Tdap.”

For this reason, states the Cook County Department of Health, a Tdap booster is recommended for preteens at age 11 or 12. The department states that being up to date with Tdap is especially important for teens who will be around babies. 

Recommendations from the CDC also include Tdap for children 7-10 years old who are not fully vaccinated with DTaP, adults 65 years and older who are in close contact with young infants, and health-care workers. It is recommended that pregnant women should receive a dose of Tdap during each pregnancy between 27 and 36 weeks of gestation.

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