In March, the Food and Drug Administration’s advisory committee voted in favor of approving the world’s first respiratory syncytial virus (RSV) vaccine for adults 60 and up from Pfizer.
Respiratory syncytial virus, also called human respiratory syncytial virus and human orthopneumovirus, is a common, contagious virus that causes infections of the respiratory tract. It is a negative-sense, single-stranded RNA virus.
In a close decision, the FDA’s independent Vaccines and Related Biological Products Advisory Committee (VRBPAC) voted 7 to 4 on safety and 7 to 4 on effectiveness with one member abstaining.
Several of the specialists who did not vote in favor on the basis of the vaccine’s efficacy were concerned that there were not enough people infected with respiratory syncytial virus (RSV) during the trial to properly evaluate the shot, NBC News reported.
Specialists who voted against the vaccine based on its safety profile were concerned that it might increase the risk of Guillain-Barré syndrome (GBS), a rare neurological disease that can kill nerve cells and lead to muscle weakness or paralysis.
“It was a 1 in 9,000 risk of GBS, which is concerning,” said Dr. Hana El Sahly, the FDA advisory committee chair, who voted against the shot based on its safety profile but in favor based on efficacy.
The VRBPAC claimed that the available data is “adequate to support the safety and effectiveness of its respiratory syncytial virus (RSV) bivalent vaccine candidate PF-06928316 or RSVpreF. ”
Scientists recommend that older people who received Pfizer’s RSV vaccine should be monitored for Guillain-Barre syndrome.
This comes after two older adults who received the shot during clinical trials developed Guillain-Barre syndrome, scientists said in clinical trial results published in the New England Journal of Medicine per CNBC.
“If RSVpreF vaccine is approved and recommended, these adverse events warrant close monitoring in future studies and with real-world data and postmarketing surveillance,” the scientists wrote. The study, which published Wednesday, was supported by Pfizer.
The clinical trial results, published in the New England Journal of Medicine, concluded that the vaccine effectively prevented lower respiratory tract illness in adults aged 60 and older without any evident safety concerns. However, the scientists flagged the Guillain-Barre cases as a possible cause for concern moving forward.
Guillain-Barre syndrome is a rare disorder in which the body’s immune system mistakenly attacks the nerves, causing symptoms ranging from brief weakness to paralysis. While most people recover, even from severe cases, the scientists are calling for close monitoring for a possible link between the vaccine and Guillain-Barre.
The FDA has asked Pfizer to include Guillain-Barre as an “important potential risk” of the vaccine and to develop a safety study to monitor for potential cases if the shot is approved in May. Pfizer has agreed to conduct a safety study.
In the New England Journal of Medicine article, the scientists noted that the two cases occurred in patients in an age group with an increased risk of developing Guillain-Barre. Read the full Study here
While potential factors other than the vaccine could have caused the individuals to develop the syndrome, the FDA views the cases as possibly related to the vaccine because the patients developed the syndrome shortly after receiving the shot. Pfizer concluded that the cases were unrelated, and the clinical trial’s data monitoring committee did not identify any safety concerns with the vaccine.