Scientists have been working for decades to develop a vaccine for RSV.
Drugmaker Pfizer reports its RSV vaccine is safe for pregnant women and is effective in helping to protect their newborn babies.
The vaccine could be available next year.
As health officials all over Southern California deal with an onslaught of viruses affecting mainly children, news of this potential vaccine offers hope on the horizon.
Respiratory syncytial virus is a common infection that affects the respiratory tract. Its severity can range from mild to life-threatening but young children and the elderly are the most vulnerable.
Pediatric cases are starting to skyrocket in Los Angeles County
Flu and RSV cases were practically non-existent during the past two winters. Now, L.A. County Health officials report we're getting an early and fast start.
"We have surpassed the 5% threshold and the amount of influenza we're seeing is increasing sharply," said Dr. Muntu Davis, L.A. County's health officer. "This is the earliest start to the flu season we've experienced in the past five years."
The most recent data shows about 21% of 5 to 11 year olds brought to the emergency rooms had influenza-like illnesses. In September, RSV cases rose sharply.
"About 20% of specimens are testing positive for RSV," said Davis.
Officials can't predict if an early peak means a long and severe season. But there is a potential respite for babies born next winter in the form of an RSV vaccine.
"This is good news because it provides a high level of protection during the period of life when infants are most vulnerable," said Dr. William Gruber, senior vice president of Pfizer vaccine clinical research and development.
The vaccine would be given to expectant mothers. They would then pass the antibodies to their babies.
The pharmaceutical company says early studies show 82% efficacy in preventing severe sickness during the first 90 days of life and 69% efficacy through the first six months.
In Orange County pediatric hospitals beds are filled to capacity. County officials on Monday declared a health emergency in the face of rising cases of RSV and other infections.
"It's already spreading like wildfire," said Dr. Jennifer Birkhauser with Hoag Medical Group.
Unlike other viruses, RSV doesn't peak until the fifth or sixth day, making it contagious for much longer, Birkhauser explained. Many parents are fooled into thinking their kids' illness is improving, but the symptoms gradually get worse.
"A lot of times we think it's bad, but it just keeps getting worse. And I think that's where RSV kind of plays into more of an epidemic more of really hurting our kids because it doesn't follow the typical viral course that we see," Birkhauser said.
If the FDA approval process goes smoothly, it'll still be about a year before we see an RSV vaccine for pregnant women and their unborn children.
For now, doctors advise you to protect yourself and your family with the vaccines we have for other common infections. It's not too late to get a flu shot and the new COVID-19 bivalent booster. Both provide protection for the viruses currently circulating.