Pfizer’s US application for its respiratory syncytial virus (RSV) maternal vaccine candidate to help protect against the complications of the disease in infants has been accepted for priority review by the US Food and Drug Administration (FDA).
The single-dose vaccine is administered in the late second to third trimester of pregnancy. The antibodies triggered by the vaccine are then passed to the foetus to protect infants against RSV from birth to the first six months of life, when they are most vulnerable.
There is currently no US-approved vaccine for RSV, a contagious virus characterised by several mild, cold-like symptoms. Although most people recover within a week or two, the virus can potentially cause severe illness in young infants, older adults and individuals with certain chronic medical conditions.
In the US alone, RSV infections result in around 2.1 million outpatient visits and 58,000 hospitalisations each year among children under the age of five. Worldwide, RSV results in the death of approximately 102,000 children annually, with around half of those being infants less than six months old and with the vast majority happening in developing countries.
Annaliesa Anderson, senior vice president and chief scientific officer, vaccine research and development at Pfizer, said: “If approved, RSVpreF would help protect infants at their first breath from the devastating effects of this infectious disease that, although well known, has been particularly evident throughout this RSV season.”
The company’s FDA application was supported by top line results from the phase 3 MATISSE trial, in which the vaccine demonstrated 81.8% efficacy in preventing severe medically attended lower respiratory tract illness in infants in the first 90 days of life.
In terms of safety, pre-planned reviews conducted at regular intervals throughout the trial indicated that the vaccine was well tolerated, with no safety concerns for both the vaccinated individual and their newborns.
“We look forward to progressing the review of Pfizer’s RSV maternal vaccine candidate with the FDA and other regulatory authorities, given its significant potential to positively contribute to global health in the prevention of RSV in infants,” Anderson added.
The European Medicines Agency has also accepted Pfizer’s application under accelerated application for the RSV vaccine for both older adults and maternal immunisation to help protect infants, with a decision expected in the second half of this year.