Adverse events were reported in 23% of the Selleck Fluorouracil children and had low or moderate severity: fever (14.2%), vomiting (1.9%), irritability (3.3%), pain (2.8%) and redness (1.5%) at the injection site. The proportion of adverse events was higher in the group vaccinated simultaneously, but this difference was Libraries statistically significant only for fever (16.6% for simultaneous vaccination, 11.8% for vaccination with 30-day interval, p = 0.01) and for any signs/symptoms (27.3% for simultaneous vaccination and 18.8% for vaccination with 30-day interval, p = 0.02). The differences in reactogenicity according

to YFV types were small and not statistically significant (p > 0.05). Local events (pain and redness on the injection site) occurred earlier (1–2 days) than the systemic events (fever, vomiting and irritability) (4–6 days). Adverse events in the group vaccinated simultaneously with MMR

and YFV did not differ in average time of onset of signs/symptoms (p > 0.09). The duration of signs and symptoms was on average 2–3 days, with median of 1–2 days. The difference between groups defined by interval between vaccines was small and not statistically significant (p > 0.10). The expanding arsenal of vaccines given in the first two years of life has been accompanied by extensive research on the possibilities and limitations of combined and simultaneous application of live attenuated vaccines [16]. This study demonstrated that concomitant administration (in separate syringes) of a yellow fever vaccine and a combined GS-7340 vaccine against measles, rubella and mumps induced lower seroconversion rates and GMT compared to the immune

response to the same vaccines given 30 days apart. The reduction in the magnitude of immune response was independent of the substrain of the vaccine against yellow fever and time of blood collection for serology after vaccination. The rate of seroconversion to rubella in the group vaccinated 30 days or more apart was consistent with that observed in other studies with MMR vaccines [17], [18] and [19] but the lower magnitude of the response to the rubella and mumps components of MMR in children vaccinated simultaneously not against yellow fever is unprecedented in the literature. Significant reduction in the response to yellow fever vaccine in children had been observed after administration of combined vaccine against smallpox and measles [20], and simultaneous vaccination against cholera [21] and [22] and hepatitis B [23]. Other studies have not found evidence of interference of YFV simultaneous to or combined with vaccines against smallpox and diphtheria–tetanus–pertussis [24], measles [8], [24], [25], [26], [27] and [28], hepatitis A [29] and [30], hepatitis B [23], [31] and [32], typhoid fever [33] and poliomyelitis [32].