A major public health implication of this interference is the accumulation of a cohort of susceptible

subjects long before the age recommended for revaccination. That could possibly affect disease control, particularly of yellow fever, for which revaccination every 10 years is recommended, disregarding the age at primovaccination and the weaker immune response in infants [6], [20] and [25]. Similar to the results of this study, a multicenter study with the 17DD substrain vaccine showed 88% seroconversion in children aged 12–23 months and 72% in infants aged 9–11 months [6]. At the time that study was conducted the monovalent measles vaccine was administered at 9 months of age. As the study outcomes relied on serological tests the implications of their accuracy results should be considered briefly. PRNT is the “gold standard” for detection Selleckchem GSK2118436 of measles [38] and of yellow fever antibodies [39], but for yellow fever it lacks the level of standardization of measles PRNT [15] and commercial tests such as those used for rubella and mumps antibodies.

The proportion of reduction in number of plaques with neutralization, for instance, might affect the sensitivity of the PRNT and partly explain the variability of GMT across studies. Nevertheless, seroconversion may be a more robust measure of response to immunization. The pre-vaccination seropositivity for Target Selective Inhibitor Library concentration yellow fever could indicate false positive results of the PRNT, previous vaccination held outside the Federal District where the vaccine is given at 9 months of age, and to maternal antibodies

[40]. Randomization safeguarded against selection bias but misclassification of seropositivity might have weakened the differences between groups. However, with seroconversion as the outcome we focused on the variation in the immune status after vaccination and made because allowance for pre-vaccination seropositivity. Systemic adverse events following simultaneous administration of the vaccines had a similar pattern observed after the vaccine against yellow fever was given separately. The time of onset of symptoms, as well as its duration is compatible with events related to vaccination, but there is no way to distinguish them from signs and symptoms of coincidental clinical conditions. The frequency of adverse events following immunization was consistent with that reported in the literature for yellow fever [41], except for fever, which was about twice as high. The higher frequency of signs/symptoms was a plausible outcome of simultaneous vaccination with four viral agents. Neutralizing antibodies against rubella are generally considered the protective immune response [42]. As titration of these antibodies is not routinely available, antibody levels (≥15 IU) measured by other methods are considered to protect against rubella infection [43].