Two major pharmaceutical companies have their eyes set on approval from the Food and Drug Administration for their respective vaccines for respiratory syncytial virus (RSV).

Both Pfizer and GSK have received positive votes from the FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) for their RSV vaccines this week. The two companies expect an FDA decision on approval in May.

On Tuesday, VRBPAC voted 7 to 4 on both safety and effectiveness in support of RSVpreF, Pfizer’s RSV bivalent vaccine candidate. RSVpreF is currently under FDA review for preventing RSV in adults over the age of 60. 

The VRBPAC recommendation was based on RSVpreF’s Phase 3 clinical trial data released in August, which Pfizer said it intends to publish in a peer-reviewed scientific journal. 

“We are encouraged by the outcome of today’s VRBPAC meeting as it is a testament to the strength of our science and dedication to bringing this important vaccine candidate to the market. We look forward to working with the FDA as it completes the review of our application,” said Annaliesa Anderson, Ph.D., SVP and chief scientific officer, vaccine research and development at Pfizer, in a statement

The next day, VRBPAC voted unanimously that the data from GSK’s vaccine candidate proved its effectiveness and voted 10 to 2 on its safety profile. Similar to Pfizer, GSK’s vaccine candidate received the VRBPAC recommendation based on top-line results from a Phase 3 trial that were also published in the New England Journal of Medicine

“Today’s vote brings us an important step closer to delivering one of the world’s first vaccines for RSV, a respiratory virus that causes potentially debilitating disease and imposes a major burden on healthcare systems,” said Phil Dormitzer, global head of vaccines R&D at GSK, in a statement. “We’re delighted that the Advisory Committee recognised the strength of our vaccine’s data and its potential to make a positive public health impact with a unanimous vote on the effectiveness of the vaccine.”

The adcomm votes are the latest signal that competition in the RSV vaccine space is heating up. 

At the end of January, the FDA granted a breakthrough designation for mRNA-1345, Moderna’s RSV vaccine candidate. The FDA granted mRNA-1345 Fast Track designation in August 2021 and now Moderna said it plans to submit a license application for regulatory approval during the first half of 2023. 

RSV has been a challenging public health concern for the U.S. since the start of the fall, when worries arose about the confluence of RSV, a severe flu season and lingering COVID-19 infections creating a ‘tripledemic.’