Roughly six decades after the first attempt to develop a vaccine for respiratory syncytial virus, the Food and Drug Administration is poised to approve several shots by next winter.

No RSV vaccine has ever been approved in the U.S. The FDA is reviewing two applications — a vaccine from Pfizer and another from GlaxoSmithKline, both of which are for people ages 60 and up.

Close behind is a monoclonal antibody injection designed to protect babies from the virus. Although it is not technically a vaccine, it would serve the same purpose. The shot, from Sanofi and AstraZeneca, has already been approved in Europe, and the FDA began reviewing the companies’ application in January.

RSV infects most people by age 2, and it is common to contract the virus multiple times throughout life. In the U.S., the virus kills more than 10,000 adults 65 or older and around 300 children under 5 every year.

RSV cases spiked dramatically in the U.S. earlier this winter, which overwhelmed children’s hospitals — a reminder of the virus’s threat. Since then, the pharmaceutical race to get vaccines to market has garnered extra attention.

“There’s a very clear public health need for these vaccines, and we’re going to have to see which vaccines prove themselves in terms of safety and efficacy,” said Dr. Ofer Levy, the director of the Precision Vaccines Program at Boston Children’s Hospital.

On Wednesday, data from two vaccine trials was published in the New England Journal of Medicine. The first showed that the GlaxoSmithKline shot awaiting FDA approval lowered the risk of symptomatic illness by 83% and of severe illness by 94% among older adults.

The second study described phase 2 trial results of a vaccine made by Janssen, J&J’s pharmaceutical arm. That shot was found to reduce the risk of severe disease by 80% among people 65 and up.

In total, 11 RSV vaccines are being actively studied in U.S. trials, according to data provided to NBC News by PATH, a nonprofit global health organization. Seven of them are for older adults, and four are designed to protect infants or children.

“This is kind of the beginning of a new era,” said Dr. Barney Graham, a senior adviser for global health equity at Morehouse School of Medicine.

“I actually think all of [the vaccines] are going to work well enough to be approved, depending on the side effect profiles,” he added.

From zero options to multiple candidates

Graham, who previously was the deputy director of the National Institutes of Health’s Vaccine Research Center, published an editorial alongside the two new studies Wednesday in which he described the advances that have been made since an RSV vaccine trial in the 1960s was linked to two infant deaths.

The failure stalled development for several decades. But now, Graham said, researchers have learned that RSV vaccines must target a specific protein on the virus’s surface before it changes its original shape.

“These are vaccines that are made with atomic-level precision,” he said.

Other notable vaccine candidates in the pipeline include a shot for older adults from Moderna, which the company has said could get submitted to the FDA for approval by July. Another candidate, from Bavarian Nordic, targets the same demographic, with phase 3 data expected by the middle of the year.

Pfizer has also tested a second application of its shot in pregnant people to help protect their infants from RSV. For older adults, Pfizer’s vaccine was shown to reduce the risk of severe illness by 86%, according to the company. When it was administered to pregnant people, the shot was 82% effective against severe illness in infants through their first 90 days of life and 69% effective through six months.

The benefits of vaccine variety

Levy said it will be important to have multiple options.

“You don’t want all the eggs in one basket,” he said. “You don’t want to be dependent on just one manufacturing stream, that’s No. 1. No. 2, in my opinion, it’s favorable to have more than one platform.”

A vaccine platform is the technology used to spur an immune response. Having a variety of platforms on the market is ideal, because people may respond differently to shots based on their age, sex or immune status.

Graham said he eventually hopes an RSV vaccine will be approved for young kids, as well.

“If we could find things that would work and be safe in the 6-month-to-5-year-old child, to me that would kind of complete what we could do for RSV,” he said.

In serious cases, RSV infections can lead to bronchiolitis, which causes airways to become inflamed and clogged with mucus, making it difficult to breathe. If an infection travels to the lung sacs, it can result in pneumonia.

Older adults and infants are particularly vulnerable to such outcomes. For most people, however, RSV symptoms resemble a common cold, so vaccines would not be necessary for everyone, Graham said.