This observation may partly be explained by the different enrolment patterns employed during the Phase III trial (Rota-037) in these countries. == Results == Sixteen medical trials met the inclusion criteria. The studies were carried out across Africa (N = 3), Asia (N = 4), Latin America (N = 4), Europe (N = 4) and North America (N = 1). Overall, 46,398 babies were enrolled and among these, 20,099 received placebo. The mean age at pre-dose-1 time point ranged from 6.4 12.2 weeks while the mean age at post-last-dose time point ranged from 13.5 19.6 weeks. The anti-RV IgA seropositivity rates at both time points were higher in less developed countries of Africa, Asia and Latin America (pre-dose-1: 2.1%-26.3%; post-last-dose: 6.3%-34.8%) when compared to more developed countries of Asia, Europe and North America (pre-dose-1: 0%-9.4%; post-last-dose: 0%-21.3%), indicating that rotavirus infections occurred at a younger age in these areas. == Summary == Exposure to rotavirus infection occurred early in existence among infants in most geographical settings, especially in developing countries. These data emphasize the importance of timely rotavirus vaccination within the Influenza Hemagglutinin (HA) Peptide Expanded System on Immunization routine to maximize safety. Keywords:Rotavirus, Early safety, Gastroenteritis, Anti-rotavirus == Background == Rotaviruses are a leading cause of severe acute gastroenteritis, resulting in approximately 453,000 annual deaths among children less than five years of age [1] with over 85% of these deaths happening in the less developed countries of Asia and Africa [1,2]. Children typically encounter multiple rotavirus infections during child years, which may result in slight or asymptomatic illness to severe, life-threatening illness [3]. The 1st rotavirus infection is generally the most severe with subsequent rotavirus infections generally resulting in less severe disease outcomes because of acquisition of protecting immunity, the extent of which varies by location [4,5]. Immunization of babies with oral, live attenuated rotavirus vaccine that mimics natural infection, prior to their first exposure to natural rotavirus illness is considered the best strategy to reduce the global disease burden [3,4]. A live attenuated human being rotavirus vaccine, RIX4414 (Rotarix, GlaxoSmithKline Vaccines, Wavre, Belgium) is definitely administered orally relating to a two dose schedule. The 1st dose can be administered as early as 6 weeks of age with a minimum of 4 weeks Influenza Hemagglutinin (HA) Peptide interval recommended between doses [6]. RIX4414 offers undergone an extensive worldwide evaluation system. More than 30 medical studies have been carried out to evaluate its safety, immunogenicity and efficacy, including over MLH1 100,000 children in five continents. Such security and effectiveness studies in Europe [7], Latin America [8] and Asia [9] have confirmed the vaccine is safe [10], well-tolerated [11] and efficacious (range: 80-96%) in avoiding severe rotavirus gastroenteritis in the 1st two years of existence. RIX4414 is now licensed in over 110 countries [12] and is included in the national immunization programs Influenza Hemagglutinin (HA) Peptide of low income/developing countries as well as with high income/developed countries. From a general public health perspective, it is important to identify the optimal age for the completion of rotavirus vaccination to obtain maximum benefit. To achieve this, we evaluated data from placebo-controlled medical trials carried out by GSK Biologicals using RIX4414 across different regions of the world. From all these studies, data on anti-rotavirus immunoglobulin A (IgA) antibody levels at pre-dose-1 and post-last-dose time points in the placebo recipients (of the total vaccinated cohort) were examined. The data available from your medical trials reported with this review were used to assess the tendency in exposure and age at illness. == Methods == Clinical study reports of all randomized, double-blind and placebo-controlled phase II and phase III trials carried out between 2000 and 2008 using the commercial lyophilized formulation of RIX4414 vaccine were reviewed. Influenza Hemagglutinin (HA) Peptide Only studies with available data on anti-rotavirus IgA antibody seropositivity status at pre-dose-1 and post-last-dose time points for placebo recipients were included. In all the included studies,.