The bivalent prefusion F respiratory syncytial virus (RSVpreF) vaccine is effective against symptomatic RSV infection and viral shedding, new research in the New England Journal of Medicine found.

Beate Schmoele-Thoma, M.D., from Pfizer Pharma in Berlin, and colleagues conducted a phase 2a study involving healthy adults aged 18 to 50 years who were randomly assigned to receive a single intramuscular injection of either the RSVpreF vaccine or placebo. Participants were inoculated intranasally with the RSV A Memphis 37b challenge virus at about 28 days after injection and were observed for 12 days.

The researchers found that for symptomatic RSV infection confirmed by any detectable viral RNA on at least two consecutive days, the vaccine efficacy was 86.7 percent after inoculation with the challenge virus. The median area under the curve for the RSV viral load as measured by reverse transcriptase-quantitative polymerase chain-reaction in nasal wash samples was 0.0 and 96.7 hours×log10 copies per milliliter in the vaccine and placebo groups, respectively. At 28 days after injection, the geometric mean factor increase from baseline in RSV A-neutralizing titers was 20.5 and 1.1 in the vaccine and placebo groups, respectively. Compared with the placebo group, the vaccine group had more local injection-site pain. Neither group had serious adverse events. Read more here.

Global Burden of RSV

Respiratory syncytial virus (RSV) was associated with significant global morbidity and mortality in children and infants younger than 5 years, according to findings published in The Lancet.

Researchers conducted a systematic literature review of studies published between January 2017 and December 2020 that reported estimates of morbidity and mortality among children younger than 5 years with RSV-associated acute lower respiratory infection (LRI). The primary outcomes were RSV-attributable mortality and RSV-associated all-cause mortality, as well as mortality due to acute LRI. Overall, 481 studies were included in the final analysis.

In meta-analyses performed at the regional level in 2019, the estimated global rate of RSV-associated acute LRI among children younger than 5 years was 33.0 million (uncertainty range [UR], 25.4-44.6 million). Of note, 1 in 5 of these infections occurred in infants and children aged between 0 and 6 months. Read more here.