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LENEXA, Kan. — The Moderna COVID-19 trial is a two year blind trial, which means people don’t know if they got the placebo or the vaccine.

Normally, unblinding happens if a participant has a serious medical condition or emergency. Mass unblindings happening now is uncommon.

“We need to get as many people in our society vaccinated as soon as possible, including people who have volunteered for the clinical trials,” Dr. Carlos Fierro, Principal Investigator at Johnson County Clinical Trials, said.

Johnson County Clinical Trials is one of the places that ran the Moderna COVID-19 trial.

Six-hundred people from the Kansas City area participated in Fierro’s trial, contributing to research that has determined, so far, the vaccine is safe and effective.

Bob and Matthew Leisman are father-and-son participants who live together. Bob remained healthy, Matthew contracted the virus in November and spoke to FOX4 during quarantine.

“So at that point, I realized that I more than likely got the placebo, not the vaccine,” the younger Leisman said.

Now unblinded, Bob Leisman found out he too, received the placebo.

“Somewhat of a shock,” Leisman said. “I wanted to make sure they had the record straight, because I spent four and a half weeks, just very close contact with Matthew while he had it, and he was very ill.”

Fierro said it is going to take a few years to fully understand the dynamics of why some people get the virus and others don’t.

The Leisman’s exemplify why controlled trials are so important and often surprising. They and the other participants will continue to be studied for the full length of the Moderna vaccine trial.

“I just feel that it’s something that’s been worthwhile,” Leisman said. “You know, to have helped in the development of this very serious control of a virus.”

People in the placebo group are now receiving the COVID-19 vaccine. Bob Leisman experienced a few side effects like body aches and chills, but nothing unexpected.