Live-attenuated respiratory syncytial virus vaccine with deletion of RNA synthesis regulatory protein M2-2 and cold passage mutations is overattenuated
Citation: Cunningham CK, Karron R, Muresan P, McFarland EJ, Perlowski C, Libous J, Thumar B, Gnanashanmugam D, Moye J Jr, Schappell E, Barr E, Rexroad V, Aziz M, Deville J, Rutstein R, Yang L, Luongo C, Collins P, Buchholz U; International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) 2012 Study Team. Live-attenuated respiratory syncytial virus vaccine with deletion of RNA synthesis regulatory protein M2-2 and cold passage mutations is overattenuated. Open Forum Infect Dis. 2019 May 6;6(6):ofz212. doi: 10.1093/ofid/ofz212. eCollection 2019 Jun. PubMed PMID: 31211158; PMCID: PMC6559275
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The live respiratory syncytial virus (RSV) candidate vaccine LIDcpΔM2-2 is attenuated through deletion of M2-2 and 5 cold-passage mutations.
RSV-seronegative children aged 6-24 months received a single intranasal dose of 105 plaque-forming units (PFU) of LIDcpΔM2-2 or placebo. RSV serum antibodies, vaccine infectivity, and reactogenicity were assessed.
Four of 11 (36%) vaccinees shed vaccine virus with median peak titers of 1.6 log10 PFU/mL by quantitative culture and 4.5 log10 copies/mL by polymerase chain reaction; 45% had ≥4-fold rise in serum-neutralizing antibodies. Respiratory symptoms or fever were common in vaccinees (64%) and placebo recipients (6/6, 100%).