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Recent studies have investigated whether the human histo-blood group antigen (HBGAs) could affect the effectiveness of the oral rotavirus vaccines, suggesting secretor positive individuals develop a more robust response. We investigated the Rotavirus A (RVA) shedding in association with the host susceptibility profile in children from a birth community-cohort in Rio de Janeiro, Brazil, from 2014 to 2018. A total of 132 children were followed-up between 0 to 11-month-old, stool samples were collected before/after the 1 st /2 nd RV1 vaccination doses and saliva samples were collected during the study. RVA shedding was screened by RT-qPCR and G/P genotypes determined by multiplex RT-PCR and/or Sanger nucleotide sequencing. The sequencing indicated an F167L amino acid change in the RV1 VP8* P[8] in 20.5% of shedding follow-ups and these mutant subpopulations were quantified by pyrosequencing. The HBGA/secretor status was determined and 80.3% of the children were secretors. Twenty-one FUT2 gene SNPs were identified and two new mutations were observed. The mutant F167L RV1 VP8* P[8] was detected significantly more in Le (a+b+) secretors (90.5%) compared to non-secretors and even to secretors Le (a−b+) (9.5%). The study highlights the probable association between RV1 shedding and HBGAs as a marker for evaluating vaccine strain host susceptibility. After implementation of the rotavirus vaccines, Rotarix ® (RV1, GlaxoSmithKline Biologicals, Rixensart, Belgium) and RotaTeq ® (RV5, Merck Inc., USA), in over 100 countries worldwide 1 , the burden of severe group A rotaviruses (RVA) diarrhea has decreased substantially, with reductions in hospitalizations and deaths in many countries, including Brazil 2-6. However, RVA still are one of major causes of severe viral diarrhea in infants and young children <5-years-old worldwide 6,7. Due to the zoonotic potential, variability of the RVA strains and host genetic factors, the surveillance of circulating RVA strains is necessary for evaluating and monitoring the effectiveness of the implemented immunization programs, mainly in low-income countries 8. Currently, 36 G-and 51 P-genotypes have been described 9 and globally, six G/P combinations are the most prevalent in humans: G1P[8], G2P[4], G3P[8], G9P[8], G4P[8] and G12P[8] 10 .

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Cells from various tissues and species are able to bind to Theiler's virus strain DA and allow it to replicate to some extent. Meanwhile, permissiveness in vitro to BeAn strains has not been well investigated. In this paper, the BeAn 8386 virus was subjected to five passages in BHK-21 cells and showed a persistent profile. In order to follow the in vitro infection, real-time RT-PCR to detect the IRES, L* and 3A3B regions of the Theiler's virus genome was carried out in the first and last passages. In addition, the expression of L* protein was detected. These findings confirm the persistence of the virus in vitro, even in the absence of cytopathic effect (CPE).

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