8% against hospitalized diarrhea), but lower than in Belgium (90%) [15]. Two-dose VE remained high for two years. This is similar to other countries with low mortality; but different from some countries selleck inhibitor with high mortality where VE decreases in the second year after vaccination [5]. A recent study in Nicaragua also found no waning for the pentavalent vaccine in children aged 12 months or more with very severe AD [34]. Other reasons for the finding that effectiveness did not decrease in the second year in our study are: we explored VE from time since second dose vaccine
while most countries estimated VE by time since birth; and we estimated VE against severe cases only. Besides, declines observed in other studies could be related to the small numbers
to estimate effectiveness in the second year of life [35]. There is no agreement as to the reasons for the variation in VE and in duration of VE in the literature. The fact that effectiveness in Brazil was similar to other middle income countries in terms of overall protection against hospitalized AD and similar to European countries in relation GDC 973 to waning might help to advance in this exploration. A single dose offered some protection, consistent with the literature (although the VE was higher than in El Salvador [16] and Bolivia [17] and lower than in Belgium (91%)) [15]. The good effectiveness identified Chlormezanone is consistent with the reduction in the rate of
child hospitalization and mortality by AD in Brazil following the introduction of vaccine in Brazil [21]. Genotype-specific VE was high for G1P[8] (89%) and slightly lower for G2P[4] (76%) indicating a degree of cross protection. Animal models shown that immunity to group A rotavirus (RVA) present homotypic and heterotypic components. Repeat RVA infections acquired naturally or by vaccination, increase protective immunity to include multiple serotypes, as indicated by development of cross-neutralizing antibodies and cross-reactive epitope-blocking antibodies specific for VP7 and VP4 antigens. In the human vaccine clinical trials (monovalent, Rotarix®; pentavalent, RotaTeq®) as well as in the follow-up studies, both vaccines presented homotypic as well as heterotypic protection against different RVA genotypes, including G2P[4] and G9P[8] genotypes [12], [19], [36] and [37]. Genotype specific VE also remained high in the second year, in contrast with the findings for middle income countries. VE was 74% for all G1 types, 76% for all G2 types and lower for the non G1/G2 type (63%), although numbers were small. The result of VE against G2P[4] is similar to the two small studies carried out in Brazil (75.4% to 77% to G2P[4]) but unlike them, effectiveness against both G1P[8] and G2P[4] did not fall in the second year [18] and [19].