Devin Callinan stands next to the George Brown Boston Marathon starter statue at the Town Common.

More than 15 million people in the United States are in danger of experiencing anaphylaxis, a severe allergic response brought on by contact with specific foods, substances, medicines and insect stings.

Devin Callinan, a Hopkinton resident since 2016, will run his first marathon this year to raise money for the KeepSmilin4Abbie Foundation, an organization dedicated to preventing anaphylaxis. The charity was founded in 2014 in memory of Abbie Benford, a Hopkinton High School student who lost her life after an anaphylaxis reaction just eight days before her 16th birthday.

Callinan and his family know the dangers of anaphylaxis personally. Callinan’s 5-year-old son, Nolan, already has had two anaphylactic reactions. When Nolan was 18 months old, Callinan’s wife, Meghan, a nurse for over 15 years, had to administer an EpiPen injection.

“If you don’t do that within five or six minutes, the odds of survival actually drop precipitously,” Callinan said. “The folks at the hospital told her that she certainly saved his life.”

Callinan did not always realize how severe allergies can be.

“My brother actually had a pretty minor allergy growing up to walnuts, and he might get hives and be a little bit itchy,” Callinan said. “It is not as innocent as getting some hives and being fine, but that is what I always thought it was.”

Through social media, the Callinans learned about KeepSmilin4Abbie. After meeting with foundation co-founder Stephen Benford, Abbie’s father, Callinan was given this year’s bib to run in the Boston Marathon.

“Devin and his family are amazing ambassadors representing exactly who we’re trying to help through our research goals and our awareness programs,” Benford said.

The farthest distance Callinan had run before beginning training was a half-marathon, but running a full marathon had been a bucket list item for him. On the shoelaces of his running shoes, Callinan has tags with Abbie and Nolan’s names on them.

“If I’m struggling up the hill or in crummy weather, looking down at my shoes is good motivation,” Callinan said.

On marathon day, Callinan’s wife and three children will be cheering him from different spots along the way to the finish line.

As of early April, almost $30,000 had been raised for the foundation via Callinan’s fundraising page (givengain.com/activist/689560). The money will go toward anaphylaxis research as well as the foundation’s scholarship program. The organization has partnered with the Wyss Institute at Harvard and the Matthews Lab at Boston Children’s Hospital, which are researching the biomarkers that could lead to a wearable anaphylaxis device that alerts someone at high risk for anaphylaxis and potentially administer epinephrine.

While training on Heartbreak Hill in Newton, Callinan saw many other charity runners for organizations such as Dana-Farber Cancer Institute and Children’s Hospital also training. Callinan realized that running itself is not a difficult task — simply putting one foot in front of the other. The true difficulty lies with families who have lost a loved one or are watching their children battle a serious illness.

“An event like this where you can raise so much money for so many wonderful causes by doing something that a lot of others think is really hard but in comparison to those things is not very hard has just been an incredibly rewarding experience so far,” Callinan said.