• Vaccine Name: RSV/ΔNS2/Δ1313/I1314
• Target Pathogen: Human Respiratory Syncytial Virus
• Target Disease: Respiratory tract disease
• Manufacturer: Charles River Laboratories
• Type: Live, attenuated vaccine
• Status: Research
• Host Species for Licensed Use: Human
• F protein gene engineering:
  • Type: Gene mutation
  • Description: (Karron et al., 2020)Has a 523 nucleotide deletion of the NS2 gene. RSV/ΔNS2/Δ1313/I1314L was derived from a recombinant version of wt RSV strain A2 with the further modification of a 112 nucleotide phenotypically silent deletion in the SH noncoding sequence that stabilizes the complementary DNA (cDNA) during propagation in bacteria.
  • Detailed Gene Information: Click Here.
• F protein gene engineering:
  • Type: Codon deletion
  • Description: (Karron et al., 2020)A codon deletion in the L gene (Δ1313; deletion of S1313) plus the adjacent missense mutation I1314L that prevents the compensatory deattenuating mutation I1314T. RSV/ΔNS2/Δ1313/I1314L was derived from a recombinant version of wt RSV strain A2 with the further modification of a 112 nucleotide phenotypically silent deletion in the SH noncoding sequence that stabilizes the complementary DNA (cDNA) during propagation in bacteria.
  • Detailed Gene Information: Click Here.
• Immunization Route: Intramuscular injection (i.m.)
• Storage: (Karron et al., 2020)CTM was stored at −70°C and diluted to dose on site using Leibovitz L15 medium.
• Description: (Karron et al., 2020)RSV/ΔNS2/Δ1313/I1314L contains 2 attenuating elements: (1) deletion of the interferon antagonist NS2 gene and (2) deletion of codon 1313 of the RSV polymerase gene and the stabilizing missense mutation I1314L.

Human Response

• Host age: 12-59 months
• Host gender: Male and female
• Vaccination Protocol: (Karron et al., 2020) Children were given a dose of 10^6 PFU and in RSV-seronegative children at a dose of 10^5 or 10^6 PFU (Figure 1). Children were randomized 2:1 to receive vaccine or placebo, administered as nose drops
• Side Effects: (Karron et al., 2020)In RSV-seropositive participants, URI was observed in 2 and cough was observed in 1 of 10 vaccinees during the 28-day postimmunization reporting period (Table 1); in each case, rhinovirus was detected in NW samples at the time of illness. None of the vaccinees shed vaccine virus, indicative of attenuation.
• Efficacy: The vaccination showed statistically significant differences in log-fold plaque reduction neutralization antibody titers and the presence of 4-fold increase in RSV F IgG response in both seropositive and seronegative responses. However, 16/20 seropositive and 17/20 seronegative children in the placebo group did have RSV neutralizing antibody responses occured in 16 of 20 and F IgG responses in 17 of 20 RSV-seronegative children who received 106 PFU . For recipients of 105 and  106 PFU, the mean postvaccination PRNT was  1:37 and 1:64, respectively. (Karron et al., 2020)