RSV vaccine search could hit third piece of “tripledemic” threat

Fears of a wintertime “tripledemic” have prompted warnings to get flu shots and reformulated COVID boosters — but there are no such options for the third pathogen in circulation: respiratory syncytial virus, or RSV. That could soon change.

Driving the news: Pfizer on Tuesday announced promising topline results of a late-stage clinical trial for an experimental RSV vaccine. The vaccine would offer protection to infants from birth by vaccinating women while they’re still pregnant.

• The vaccine showed 82% efficacy against severe illness through the first 90 days of life and 69% through the first six months of life, the company said in a statement.
• Pfizer officials said they intend to submit for Food and Drug Administration approval by the end of the year.

State of play: This is one of several RSV candidates nearing FDA review, per Nature.

• White House COVID-19 adviser Ashish Jha told CNN he’s “hopeful” there could be an RSV vaccine available by next fall.

Why it matters: We’re experiencing a particularly virulent season when it comes to RSV.

• The virus has symptoms similar to the common cold but can be life-threatening for infants, young children and the elderly. It’s already stretched some pediatric hospitals to capacity.
• The virus is circulating while influenza is off to an early start and new, troubling COVID variants are emerging.

Most of the other RSV candidates are aimed at older adults.

• Last month, GlaxoSmithKline announced promising results from a late-stage trial and said regulatory submissions are expected by the end of the year.
• It came on the heels of Pfizer announcing promising results for another vaccine aimed at older adults that the company is expected to submit for review this year.
• Janssen completed a Phase 2b trial last December and Moderna started a Phase 3 trial for an RSV vaccine in older adults in February.
• Novavax also has an RSV vaccine candidate in a phase 3 trial, as well as shots for kids ages 2–6 years old and adults over 60 in earlier-stage testing.

Yes, but: The company previously ran into devastating failures testing experimental RSV vaccines. Its ResVax wasn’t found effective in one 2019 trial.

The bottom line: All of the work won’t yield an RSV shot this season, but there are options on the horizon, officials say.

• In the meantime, U.S. officials are urging caution for the vulnerable, including using the COVID and flu tools we do have.