RESUMO
BACKGROUND: The use of 2 live attenuated vaccines (LAV) is recommended to be simultaneous or after an interval of at least four weeks between injections. The primary objective of this study was to compare the humoral response to yellow fever (YF) and measles vaccines among children vaccinated against these two diseases, either simultaneously or separated by an interval of 7-28 days. SUBJECTS AND METHODS: A prospective, multicenter observational study was conducted among children aged 9-15 months. The primary endpoint was the occurrence of positive yellow fever antibodies after YF vaccine by estimating the titers of neutralizing antibodies from venous blood samples. Children vaccinated against YF 7-28 days after receiving the vaccine against measles (test group) were compared with children vaccinated the same day against these two diseases (referent group). RESULTS: Analysis was performed on 284 children. Of them, fifty-four belonged to the test group. Measles serology was positive in 91.7% of children. Neutralizing antibodies against YF were detected in 90.7% of the test group and 92.9 of the referent group (p=0.6). In addition, quantitative analysis of the immune response did not show a lower response to YF vaccination when it took place 1-28 days after measles vaccination. DISCUSSION: In 1965, Petralli showed a lower response to the smallpox vaccine when injected 4-20 days after measles vaccination. Since then, recommendations are to observe an interval of four weeks between LAV not injected on the same day. Other published studies failed to show a significant difference in the immune response to a LAV injected 1-28 days after another LAV. These results suggest that the usual recommendations for immunization with two LAV may not be correct. CONCLUSION: In low income countries, the current policy should be re-evaluated. This re-evaluation should also be applied to travelers to yellow fever endemic countries.
Assuntos
Anticorpos Neutralizantes/sangue , Esquemas de Imunização , Vacina contra Sarampo/imunologia , Vacina contra Febre Amarela/imunologia , Feminino , Guiana Francesa , Humanos , Imunidade Ativa , Lactente , Masculino , Sarampo/prevenção & controle , Estudos Prospectivos , Senegal , Fatores de Tempo , Vacinação , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/imunologia , Febre Amarela/imunologia , Febre Amarela/prevenção & controle , Vacina contra Febre Amarela/administração & dosagemRESUMO
OBJECTIVES: Influenza seasonality remains poorly studied in Equatorial regions. Here we assessed the seasonal characteristics and environmental drivers of influenza epidemics in French Guiana, where influenza surveillance was established in 2006. METHODS: Sentinel GPs monitored weekly incidence of Influenza-like illnesses (ILI) from January 2006 through December 2010 and collected nasopharyngeal specimens from patients for virological confirmation. Times series analysis was used to investigate relationship between ILI and climatic parameters (rainfall and specific humidity). RESULTS: Based on 1533 viruses identified during the study period, we observed marked seasonality in the circulation of influenza virus in the pre-pandemic period, followed by year-round activity in the post-pandemic period, with a peak in the rainy season. ILI incidence showed seasonal autoregressive variation based on ARIMA analysis. Multivariate dynamic regression revealed that a 1 mm increase of rainfall resulted in an increase of 0.33% in ILI incidence one week later, adjusting for specific humidity (SH). Conversely, an increase of 1 g/kg of SH resulted in a decrease of 11% in ILI incidence 3 weeks later, adjusting for rainfall. CONCLUSIONS: Increased rainfall and low levels of specific humidity favour influenza transmission in French Guiana.
Assuntos
Clima , Influenza Humana/epidemiologia , Guiana Francesa/epidemiologia , Humanos , Umidade , Incidência , Nasofaringe/virologia , Orthomyxoviridae/isolamento & purificação , Chuva , Estações do AnoRESUMO
A serological survey for yellow fever virus (YFV), dengue 2 virus (DENV-2), and St Louis encephalitis virus (SLEV) was undertaken using a seroneutralization technique in 27 wild forest mammal species (574 individuals) in French Guiana. Evidence of yellow fever infection was observed in 10 species, with high prevalence recorded in howler monkey (18%) and agouti (20%). Antibodies against DENV-2 and SLEV were found sporadically in various species. This potential host diversity and the range of potential vectors might explain the behaviour of the viruses in epidemic outbreaks and the emergence of periurban loci.
Assuntos
Animais Selvagens/virologia , Dengue/virologia , Reservatórios de Doenças , Encefalite de St. Louis/virologia , Mamíferos/virologia , Febre Amarela/virologia , Animais , Anticorpos Antivirais/sangue , Dengue/epidemiologia , Vírus da Dengue/isolamento & purificação , Reservatórios de Doenças/estatística & dados numéricos , Reservatórios de Doenças/veterinária , Vírus da Encefalite de St. Louis/isolamento & purificação , Encefalite de St. Louis/epidemiologia , Guiana Francesa/epidemiologia , Humanos , Prevalência , Árvores , Febre Amarela/epidemiologia , Vírus da Febre Amarela/isolamento & purificaçãoRESUMO
Surveillance of dengue fever is mainly based on specific laboratory tests. However non-specific systems, such as clinical surveillance, are also required. In French Guiana, we have tested a non-specific laboratory surveillance system where different biological examinations performed for other reasons than the diagnosis of dengue fever were analysed as methods for dengue fever surveillance. The number of negative malaria diagnoses in Cayenne and Kourou was found to be the best indicator of dengue fever infections in these towns. This surveillance system appears to be very simple and reliable, and a test which could serve as an indicator that is likely to be found everywhere.