This mom signed up her twins for a clinical trial before they were even born. They're now part of an RSV drug breakthrough.

In July, the Food and Drug Administration approved a new treatment to help protect young children against respiratory syncytial virus, or RSV. The drug, called Beyfortus, delivers long-acting antibodies to help lower the risk that recipients will get RSV.

RSV is a common childhood respiratory illness, but it can cause serious complications. Up to 80,000 children under the age of 5 in the U.S. are hospitalized with the virus each year, according to data from the Centers for Disease Control and Prevention (CDC), making this new treatment a welcome tool in the fight against RSV.

But Beyfortus was only approved after years of clinical research, including trials conducted on real children. Two of those kids were New York mom Cheryl Meany's twins, Cassidy and Stella Meany.

Eight years ago, Meany made the decision with her husband to enroll her then-unborn babies in the clinical trial on the advice of Dr. Joe Domachowske, a pediatrician at Upstate University Hospital. Now, she tells Yahoo Life, she's happy with the decision and even encourages other parents to consider enrolling their children in clinical trials. Here's what was behind the decision process, plus what the experience was like for her.

Why did you decide to enroll your daughters in the clinical trial?

Meany's husband was a teacher and had Domachowske's children as students. "We knew him a little bit as an acquaintance," Meany says. Domachowske was involved in research and clinical trials for Beyfortus and approached Meany's husband, knowing that the family was expecting twins. Meany was five months into her pregnancy at the time.

"At first, I was a little apprehensive," she says. "We had a very difficult time getting pregnant with the twins, and there were rollercoaster moments during the pregnancy." But Meany says she sat down with the doctor and asked "all sorts of questions" about the medication and how it worked.

Domachowske had been working on the treatment for "pretty much the entire span of his career," Meany says, noting that she felt comforted that this wasn't an entirely new medication. Meany says she knew that her daughters were likely to be born premature — more than half of twins are born before 37 weeks — which would put them at risk for severe complications of the virus, if they happened to get it. She also had a friend whose child had complications of RSV, which made her nervous about the virus.

"Dr. Domachowske's kids were older at the time, but I said, 'Would you do this for your own children?' He said, 'Absolutely.' That really sealed the deal for me," Meany says.

The only other RSV treatment approved for children, which is called palivizumab, was available at the time, but it's only given to very premature babies, so Meany's children wouldn't qualify, "They were born at 33 weeks. They weren't premature enough," she says.

What was the process like for you?

Meany says that the process was fairly easy for her family. Her twins were born prematurely and spent time in the NICU before they went home. About a month later, the family met with Domachowske at his office. "The twins were weighed, measured and had all their vitals taken," Meany says. After that, they were given the treatment via injection. "We had to watch them for any reactions," she says, noting that the experience was "like any other doctor's visit we had at the time."

Meany's daughters went back to the doctor every few weeks, with appointments being spaced further out with time. "The last time they went, they were about 18 months," she says.

The clinical trial was placebo-controlled and double blind, so Meany didn't know if her daughters were given the actual treatment or a placebo. "It was unblinded when they were 5," Meany says. "I had an inkling that they must have gotten it because they had very little illness in the first year. I'm a teacher, my husband had transitioned to working in the medical field, our daughter was in kindergarten ... our house was a cesspool of germs. The fact that they made it through that first year without getting sick is pretty incredible." Meany says it's her understanding that her daughters were the first children to ever receive Beyfortus.

Meany says her friends and family were supportive of the twins participating in the clinical trial. "Our family knew what we were doing and I would mention it to friends," she says. "They would say, 'Oh, I didn't know that was a thing they were working on.' That was in 2015 and the environment around immunizations was a little different."

Would you do another trial?

Meany says she would do another clinical trial — and her children already have participated in an additional study. "They made the decision to be part of the COVID-19 vaccine trial [for the Pfizer vaccine]," she says. The family also heard about that trial from Domachowske. "We sat down with them, explained it and, without hesitation, all three of my girls [said], 'Absolutely. If it means we can get back to school and playing with our friends, we are totally in,'" Meany says.

Meany encourages other parents to consider participating in clinical trials. "I had the opportunity to not only help my children, but others," she says. "This literally is going to save lives in the whole world and help prevent parents from having to watch their children not be able to breathe."

What an expert says

RSV is a common childhood virus — and nearly all children will get it before their second birthday, according to the CDC.

What is RSV?

RSV is a common respiratory virus that usually causes mild, cold-like symptoms, the CDC says. Most people recover in a week or two, but it can be serious. RSV is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia (an infection of the lungs) in children younger than a year old in the U.S., the CDC says.

"The most severe infection is usually when you get it the first time," Dr. Thomas Russo, an infectious disease expert at the University at Buffalo in New York, tells Yahoo Life.

Who is most at risk?

RSV is more likely to cause serious health complications in infants and older adults, the CDC says. "Those who are at the greatest risk are those that are born prematurely," Russo says. "The more premature you are, the greater the risk."

Children with underlying health conditions, like congenital heart or lung disease, are also at a higher-than-usual risk of severe complications from RSV, Russo says.

Why is a preventative treatment a game-changer?

It's important to note that Beyfortus is not a vaccine. Instead, it's a preventative treatment that delivers long-acting antibodies in a process known as passive immunity, Russo explains. As a result, it doesn't require the immune system to activate to develop antibodies to RSV. "It basically skips a step," Russo says.

"Right now, we don't really have great treatments [for all at-risk children]," Russo says. "Preventing disease would significantly prevent bad outcomes for children involved." The treatment can also help protect grandparents and other vulnerable people who may interact with kids who would typically get RSV, Russo says.

How do parents find out about these trials? What are the risks of doing them?

All clinical trials are listed on the National Institutes of Health's website, Russo points out. "People can actively seek out ongoing trials," he says. If an academic center is doing a trial, they may also actively look for study participants, Russo says.

Clinical trials go through multiple phases and "it's possible that issues can occur," Russo says. "There is always a potential risk in terms of doing a trial," he says. "It's usually discussed and laid out that there are unknown risks."

Russo says the decision ultimately lies with parents. "Parents need to weigh risks and benefits with proceeding with a trial," he says, noting that they can help children get access to medications or treatments earlier than the general public. But Russo stresses the importance of having people participate in clinical trials. "Clinical trials are the foundation of advances in medicine," he says.

Wellness, parenting, body image and more: Get to know the who behind the hoo with Yahoo Life's newsletter. Sign up here.