Due to the risk of severe vaccine-associated adverse events, yellow fever vaccination in Brazil is only recommended in areas considered at risk for disease. From September 2008 through June 2009, two outbreaks of yellow fever in previously unvaccinated populations resulted in 21 confirmed cases with 9 deaths (case-fatality, 43%) in the southern state of Rio Grande do Sul and 28 cases with 11 deaths (39%) in Sao Paulo state. Epizootic deaths of non-human primates were reported before and during the outbreak. Over 5.5 million doses of yellow fever vaccine were administered in the two most affected states. Vaccine-associated adverse events were associated with six deaths due to acute viscerotropic disease (0.8 deaths per million doses administered) and 45 cases of acute neurotropic disease (5.6 per million doses administered). Yellow fever vaccine recommendations were revised to include areas in Brazil previously not considered at risk for yellow fever.
METHODS: This is a descriptive study of a sylvatic yellow fever outbreak in the Southwestern region of the state from February to April 2009. Suspected and confirmed cases in humans and in non-human primates were evaluated. Entomological investigation in sylvatic environment involved capture at ground level and in the tree canopy to identify species and detect natural infections. Control measures were performed in urban areas to control Aedes aegypti. Vaccination was directed at residents living in areas with confirmed viral circulation and also at nearby cities according to national recommendation.
RESULTS:Twenty-eight human cases were confirmed (39.3% case fatality rate) in rural areas of Sarutaiá, Piraju, Tejupá, Avaré and Buri. The deaths of 56 nonhuman primates were also reported, 91.4% were Allouatta sp. Epizootics was confirmed in two non-human primates in the cities of Itapetininga and Buri. A total of 1,782 mosquitoes were collected, including Haemagogus leucocelaenus, Hg. janthinomys/capricornii, and Sabethes chloropterus, Sa. purpureus and Sa. undosus. Yellow fever virus was isolated from a group of Hg. Leucocelaenus from Buri. Vaccination was carried out in 49 cities, with a total of 1,018,705 doses. Nine serious post-vaccination adverse events were reported.
CONCLUSIONS:The cases occurred between February and April 2009 in areas with no recorded yellow fever virus circulation in over 60 years. The outbreak region occurred outside the original recommended vaccination area with a high percentage of susceptible population. The fast adoption of control measures interrupted the human transmission within a month and the confirmation of viral circulation in humans, monkeys and mosquitoes. The results allowed the identification of new areas of viral circulation but further studies are required to clarify the dynamics of the spread of this disease.
We propose the use of the two tests together as a routine protocol for diagnosis. This would require the provision of local medical services to perform molecular biology techniques and adequate Leishmania antibodies.
A primary 3-dose hepatitis B (HB) vaccination series induces protective serum levels of antibodies to HB surface antigen (antiHBs >10mUI/mL) in 90% of healthy adults and 95% of children and adolescents. A 2 nd full-course vaccination induces protection in >50% of those who did not respond to the 1 st vaccination series Healthcare workers frequently do not perform post-vaccination anti-HBs testing. Although HB vaccination has been recommended for HCW since the 1980s, routine post-vaccination testing has not yet been incorporated in the care of HCW in Brazil. Additionally, the adherence of HCW to vaccination and post-vaccination testing is poor. Furthermore, the frequency of HCW who were vaccinated when they were children or adolescents is increasing, and post-vaccination testing is not recommended in routine HB immunization.In the management of HCW who are anti-HBs-negative after a full-course vaccination, the first step is to check the interval between
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