Vaccine Take of RV3-BB Rotavirus Vaccine Observed in Indonesian Infants Regardless of HBGA Status.

BACKGROUND: Histo-blood group antigen (HBGA) status may affect vaccine efficacy due to rotavirus strains binding to HBGAs in a P genotype-dependent manner. This study aimed to determine if HBGA status affected vaccine take of the G3P[6] neonatal vaccine RV3-BB. METHODS: DNA was extracted from stool samples collected in a subset (n = 164) of the RV3-BB phase IIb trial in Indonesian infants. FUT2 and FUT3 genes were amplified and sequenced, with any single-nucleotide polymorphisms analyzed to infer Lewis and secretor status. Measures of positive cumulative vaccine take were defined as serum immune response (immunoglobulin A or serum-neutralizing antibody) and/or stool excretion of RV3-BB virus. Participants were stratified by HBGA status and measures of vaccine take. RESULTS: In 147 of 164 participants, Lewis and secretor phenotype were determined. Positive vaccine take was recorded for 144 (97.9%) of 147 participants with the combined phenotype determined. Cumulative vaccine take was not significantly associated with secretor status (relative risk, 1.00 [95% CI, .94-1.06]; P = .97) or Lewis phenotype (relative risk, 1.03 [95% CI, .94-1.14]; P = .33), nor was a difference observed when analyzed by each component of vaccine take. CONCLUSIONS: The RV3-BB vaccine produced positive cumulative vaccine take, irrespective of HBGA status in Indonesian infants.

Australian Rotavirus Surveillance Program Annual Report, 2022.

Abstract: This report from the Australian Rotavirus Surveillance Program describes the circulating rotavirus genotypes identified in children and adults during the period 1 January to 31 December 2022. After two years of a lower number of stool samples received as a result of the coronavirus disease 2019 (COVID-19) pandemic, this reporting period saw the highest number of samples received since the 2017 surveillance period, with samples received from all states and territories. During this period, 1,379 faecal specimens had been referred for rotavirus G- and P- genotype analysis, of which 1,276 were confirmed as rotavirus positive. In total, 1,119/1,276 were identified as wildtype rotavirus, 155/1,276 identified as the Rotarix vaccine strain and 2/1,276 that could not be confirmed as vaccine or wildtype due to sequencing failure. Whilst G12P[8] was the dominant genotype nationally among wildtype samples (28.2%; 315/1,119), multiple genotypes were identified at similar frequencies including G9P[4] (22.3%; 249/1,119) and G2P[4] (20.3%; 227/1,119). Geographical differences in genotype distribution were observed, largely driven by outbreaks reported in some jurisdictions. Outbreaks and increased reports of rotavirus disease were reported in the Northern Territory, Queensland, and New South Wales. A small number of unusual genotypes, potentially zoonotic in nature, were identified, including: G8P[14]; G10[14]; caninelike G3P[3]; G6P[9]; and G11P[25]. Ongoing rotavirus surveillance is crucial to identify changes in genotypic patterns and to provide diagnostic laboratories with quality assurance by reporting incidences of wildtype, vaccine-like, or false positive rotavirus results.

Rotavirus-Specific Maternal Serum Antibodies and Vaccine Responses to RV3-BB Rotavirus Vaccine Administered in a Neonatal or Infant Schedule in Malawi.

High titres of rotavirus-specific maternal antibodies may contribute to lower rotavirus vaccine efficacy in low- and middle-income countries (LMICs). RV3-BB vaccine (G3P[6]) is based on a neonatal rotavirus strain that replicates well in the newborn gut in the presence of breast milk. This study investigated the association between maternal serum antibodies and vaccine response in infants administered the RV3-BB vaccine. Serum was collected antenatally from mothers of 561 infants enrolled in the RV3-BB Phase II study conducted in Blantyre, Malawi, and analysed for rotavirus-specific serum IgA and IgG antibodies using enzyme-linked immunosorbent assay. Infant vaccine take was defined as cumulative IgA seroconversion (≥3 fold increase) and/or stool vaccine shedding. Maternal IgA or IgG antibody titres did not have a negative impact on vaccine-like stool shedding at any timepoint. Maternal IgG (but not IgA) titres were associated with reduced take post dose 1 (p < 0.005) and 3 (p < 0.05) in the neonatal vaccine schedule group but not at study completion (week 18). In LMICs where high maternal antibodies are associated with low rotavirus vaccine efficacy, RV3-BB in a neonatal or infant vaccine schedule has the potential to provide protection against severe rotavirus disease.

Australian Rotavirus Surveillance Program: Annual Report, 2021.

Abstract: This report from the Australian Rotavirus Surveillance Program describes the circulating rotavirus genotypes identified in children and adults during the period 1 January to 31 December 2021. During this period, 521 faecal specimens had been referred for rotavirus G- and P- genotype analysis, of which 474 were confirmed as rotavirus positive. Of these, 336/474 were wildtype rotavirus strains and 138/474 were identified as vaccine-like. Of the 336 wildtype samples, 87.5% (n = 294/336) were identified as G8P[8], and were detected in five of the six jurisdictions that provided samples for the reporting period. Two rotavirus outbreaks, located in the Northern Territory and Western Australia, were also attributed to G8P[8]. As with the 2020 reporting period, a low number of stool samples were received for this reporting period as a result of the COVID-19 pandemic. However, an unexpectedly high proportion of samples with unusual genotypes were identified which were potentially zoonotic in nature, including feline G3, P[9], bovine-like G8, P[14], and porcine-like G4, G6, P[1], and P[6]. Ongoing rotavirus surveillance is crucial to identify changes in genotypic patterns and to provide diagnostic laboratories with quality assurance by reporting incidences of wildtype, vaccine-like, or false positive rotavirus results.