There is no vaccine currently available for RSV: a common and pervasive cause of severe acute respiratory illness in older adults (infections can occur in all ages by can be potentially life-threatening in infants, the immunocompromised and older adults).
In the US, it is estimated that more than 177,000 adults aged 65 and above are hospitalised each year and 14,000 of them die each year due to RSV. It is a seasonal illness that commonly starts in the fall months: peaking in winter as with colds and other respiratory illnesses.
Pfizer’s RSV vaccine candidate, RSVpreF, builds on research from the National Institutes of Health (NIH), which detail the crystal structure of a key form of a viral protein RSV uses to attack human cells. Antibodies that protect humans from RSV target this viral protein.
The single-dose bivalent prefusion F subunit investigational vaccine candidate, RSVpreF, is entering the Phase 3 'Renoir' trial this month. The global, randomized, double-blind, placebo-controlled study will enroll approximately 30,000 participants 60 years and older. The primary objectives of the study will assess safety and efficacy for the prevention of moderate to severe lower respiratory tract illness (msLRTI-RSV) during the first RSV season.
In July, Pifzer released initial results from a Phase 2a study that evaluated the safety, immunogenicity and efficacy of RSVpreF in a virus challenge model in healthy adults aged 18-50 years old. The candidate showed 100% efficacy against mild to moderate symptomatic infection; with no serious adverse events observed. Detailed results from the Phase 2a study are due to be shared in a future scientific forum.
In April 2020, positive top-line results were achieved for a Phase 2b proof-of-concept study of RSVpreF, which evaluated the safety, tolerability and immunogenicity of RSVpreF in vaccinated pregnant women aged 18 - 49 and their infants. Detailed results from the study will be shared at a future medical conference.
In November 2018, the FDA granted Fast Track status to RSVpreF for prevention of RSV-associated lower respiratory tract illness in infants by active immunization of pregnant women.