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.
Human herpesvirus 8 (HHV-8) is a newly described herpesvirus that is etiologically associated with all forms of Kaposi's sarcoma (KS). Seroepidemiological studies have shown high prevalence rates of HHV-8 antibodies among men who have sex with men (MSM) and AIDS patients, African children, Brazilian Amerindians, and elderly individuals in certain regions of Europe. The aim of the present study was to determine the prevalence of HHV-8 antibodies in healthy children and young adults from different cities in São Paulo State, and in a population at high risk for HHV-8 infection: HIV-negative MSM, and AIDS patients with and without KS. Antibodies to HHV-8 latency-associated nuclear antigen and lytic-phase antigens were detected by immunofluorescence assays. In 643 healthy children and young adults from the general population attending a vaccination program for yellow fever in ten different cities in São Paulo State, the prevalence of HHV-8 antibodies detected by the presence of latent or lytic antigens ranged from 1.0 to 4.1% in the different age groups (mean = 2.5%). In the MSM group, the prevalence was 31/95 (32.6%). In the group of patients with AIDS, the prevalence was 39.2% (51/130) for non-KS patients and 98.7% (77/78) for AIDS patients with the diagnosis of KS confirmed by histopathological examination. We conclude that HHV-8 has a restricted circulation among healthy children and young adults in the general population of São Paulo State and a high prevalence among MSM and AIDS patients.
Yellow fever (YF), an acute infectious disease, is endemic in the north and central-west of Brazil. This disease can be prevented by the use of a vaccine. In Brazil, four fatal adverse events have been associated with the YF vaccine used in the country (17DD vaccine). We briefly describe the last two fatalities, and estimate the risk of 17DD-associated fatal adverse events under different epidemiological scenarios. Controversies regarding the appropriate denominator that enters the estimation of risk serve as a motivation for each proposed scenario. The statistical procedures used show optimum behaviour when assessing the risk of rare events. Risk estimates vary from 0.043 (95 % CI 0.017-0.110) to 2.131 (95 % CI 0.109-12.071) fatalities per million doses administered. The robust estimates of the risk of fatal adverse events we present constitute an important element in future risk-benefit analysis and point to the need for good quality vaccine coverage and adverse-events surveillance data to assess the risk of vaccination. Although vaccination of YF endemic regions is necessary to maintain low disease prevalence, preventive administration of YF vaccine to the entire population should be cautiously analysed.
The aim of the present study was to assess the prevalence of Haemophilus
influenzae type b (Hib) nasopharyngeal (NP) colonisation among healthy
children where Hib vaccination using a 3p+0 dosing schedule has been routinely
administered for 10 years with sustained coverage (> 90%). NP swabs were collected
from 2,558 children who had received the Hib vaccine, of whom 1,379 were 12-< 24
months (m) old and 1,179 were 48-< 60 m old. Hi strains were identified by
molecular methods. Hi carriage prevalence was 45.1% (1,153/2,558) and the prevalence
in the 12-< 24 m and 48-< 60 m age groups were 37.5% (517/1,379) and 53.9%
(636/1,179), respectively. Hib was identified in 0.6% (16/2,558) of all children in
the study, being 0.8% (11/1,379) and 0.4% (5/1,179) among the 12-< 24 m and
48-< 60 m age groups, respectively. The nonencapsulate Hi colonisation was 43% (n
= 1,099) and was significantly more frequent at 48-< 60 m of age (51.6%, n = 608)
compared with that at 12-< 24 m of age (35.6%, n = 491). The overall resistance
rates to ampicillin and chloramphenicol were 16.5% and 3.7%, respectively; the
co-resistance was detected in 2.6%. Our findings showed that the Hib carrier rate in
healthy children under five years was very low after 10 years of the introduction of
the Hib vaccine.
Objective: to describe occurrence of adverse events following immunization (AEFI) with Tdap vaccine during pregnancy. Methods: this was a descriptive study using data from reports by participants in an effectiveness and immunogenicity study conducted in two hospitals in São Paulo, SP, Brazil, from 2015 to 2016. Results: of the 201 mothers included in the study, 48 (23.9%) had at least one AEFI; 60 symptoms related to Tdap use were identified-pain (22.4%), swelling (2.5%), fever (1.5%), somnolence (1.0%), redness (0.5%), vomiting (0.5%), headache (0.5%), local reaction (0.5%), and fatigue (0.5%); no rare, very rare, or extremely rare adverse events were reported; all events were considered to be expected, as they are described in the vaccine package insert; outcome of all events was recovery without sequelae. Conclusion: Tdap vaccine in the form adopted by the National Immunization Program is safe; no unexpected adverse events were identified among vaccinated pregnant women.
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