The high pre-vaccine IgA seropositivity rate (56%) found in the RV1 cohort (2015–2016) is in agreement with a birth cohort (n = 236 children) carried out in the same setting between 1991 and 1994, in that study >50% of the infants had evidence of past rotavirus infection by the age of 2 months24. This evidence concerns the gene CD79A and Rotavirus infection.