ARLINGTON — Even in the midst of what state health officials have deemed an epidemic of pertussis, also known as whooping cough, Marysville and Arlington are still leading the way in reported cases of the illness in Snohomish County this year, but local health agencies aren’t taking this lying down.

On Wednesday, April 4, the Cascade Valley Hospital served as the site for half a dozen nurses from the Medical Reserve Corps to administer free “Tdap” shots for four hours. “Tdap” is so named because a single shot prevents tetanus, diphtheria and acellular pertussis, a.k.a. whooping cough, and according to those who supervised the afternoon and evening vaccinations, community members demonstrated a remarkable interest in getting protected from the disease.

“Our clinic didn’t start until 4 p.m., but we had people start showing up as early as 1 p.m.,” said Jennifer Egger, community relations coordinator for the Cascade Valley Hospital. “Within our first hour alone, we must have seen between 80-90 people.”

Egger noted that the 4-8 p.m. series of vaccinations was partially funded through a $5,000 grant from the Cascade Valley Hospital Foundation, which she cited as one of the ways in which the foundation is seeking to expand its outreach into the community.

Dr. Robert Russell, an emergency room physician at the Cascade Valley Hospital, explained that ER personnel have become aggressive in screening for pertussis in anyone who comes in for any reason, which is relatively easy since the test is simple and the results come back quick.

“As recently as five years ago, it used to be virtually unheard of for people to be diagnosed with pertussis,” Russell said. “I could go two years without seeing a diagnosis.”

Dr. Gary Goldbaum, health officer for the Snohomish Health District, visited the Cascade Valley Hospital to observe its April 4 “Tdap” shots. Not only did he identify a cyclical nature to regional whooping cough occurrences, but he also confirmed that Marysville and Arlington have been hit earlier and harder by the illness than surrounding areas.

“We started the trend,” Goldbaum said. “We saw an increase in reported cases all the way back in early 2011, even before the infant death on Aug. 27 of last year.”

Of the 200 cases of pertussis reported to the Snohomish Health District for 2012 as of March 30, 64 occurred in Marysville and 31 were in Arlington, but these likely represent the tip of the iceberg. Because a number of adults tend to ignore the possible symptoms of the disease and decline to seek treatment for it, Goldbaum identified the numbers of infant hospitalizations as a truer indicator of the spread of pertussis in the area.

“In just the first three months of this year, six infants in Snohomish County have already been affected, two of whom were hospitalized,” Goldbaum said. “Adults and older children serve as reservoirs of pertussis, passing it on to infants who have no defense. This is why everyone needs to get vaccinated, to protect the youngest and most vulnerable among us.”

This sentiment was shared by many of the folks who rolled up their sleeves for their shots on April 4. Marna Danner’s baby is due in two weeks, so she’s had her “Tdap” shot, but her significant other, Greyson Steinborn, had yet to be vaccinated, which was why she accompanied him to the hospital. David Bergemeier was likewise thinking about his nephew, who’s due to be born on April 16, when he brought Raquel Parker along for moral support, up to and including literal hand-holding, as he braved the needle.

“All of us older folks need a booster,” said Nathan Girard of Marysville, who has no children, but who nonetheless echoed Goldbaum’s warning that childhood vaccinations against whooping cough wear off over time. “When you consider how much it costs to get it anywhere else, free is definitely the best deal.”