The Race for an Adult RSV Vaccine: The Last Leg

Once a pharmaceutical company has completed the required clinical trials of a new vaccine and gotten the desired results, the data and request for approval are sent to the FDA 's Vaccines and Related Biological Products Advisory Committee (VRBPAC). After a positive recommendation by that committee, there are still 3 more steps before general use: approval by the FDA, then approval by the Center for Disease Control and Prevention’s (CDC) Committee on Immunization Practices (ACIP), and finally approval by the CDC.

At the end of February VRBPAC voted in favor of approval for 2 new vaccines against respiratory syncytial virus (RSV) in adults older than 60 years of age and on May 3rd the GSK vaccine Arexvy was approved by the FDA for that indication. The other RSV vaccine recommended by the FDA advisory committee, Abrysvo, is also for adults over the age of 60 and is made by Pfizer. Usually the FDA rubber-stamps the recommendation of its advisory committee, but unlike GSK's RSV vaccine, Pfizer's vaccine did not get full FDA approval at their May meeting but was approved at their June meeting.

Question 1: Why was the GSK vaccine approved ahead of the Pfizer candidate?


Question 2: What were the safety concerns for the 2 vaccines?