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The Brazilian Journal of Infectious... 2017
Topics: Brazil; Disease Outbreaks; Humans; Risk Factors; Vaccination; Yellow Fever
PubMed: 28336123
DOI: 10.1016/j.bjid.2017.02.004 -
Viruses Oct 2020Yellow fever (YF) is a re-emerging viral zoonosis caused by the (YFV), affecting humans and non-human primates (NHP). YF is endemic in South America and Africa, being... (Review)
Review
Yellow fever (YF) is a re-emerging viral zoonosis caused by the (YFV), affecting humans and non-human primates (NHP). YF is endemic in South America and Africa, being considered a burden for public health worldwide despite the availability of an effective vaccine. Acute infectious disease can progress to severe hemorrhagic conditions and has high rates of morbidity and mortality in endemic countries. In 2016, Brazil started experiencing one of the most significant YF epidemics in its history, with lots of deaths being reported in regions that were previously considered free of the disease. Here, we reviewed the historical aspects of YF in Brazil, the epidemiology of the disease, the challenges that remain in Brazil's public health context, the main lessons learned from the recent outbreaks, and our perspective for facing future YF epidemics.
Topics: Animals; Brazil; Endemic Diseases; Epidemics; Humans; Primates; Public Health; Viral Zoonoses; Yellow Fever; Yellow Fever Vaccine
PubMed: 33143114
DOI: 10.3390/v12111233 -
Journal of Clinical Microbiology Aug 2022Prior studies have demonstrated prolonged presence of yellow fever virus (YFV) RNA in saliva and urine as an alternative to serum. To investigate the presence of YFV RNA...
Prior studies have demonstrated prolonged presence of yellow fever virus (YFV) RNA in saliva and urine as an alternative to serum. To investigate the presence of YFV RNA in urine, we used RT-PCR for YFV screening in 60 urine samples collected from a large cohort of naturally infected yellow fever (YF) patients during acute and convalescent phases of YF infection from recent YF outbreaks in Brazil (2017 to 2018). Fifteen urine samples from acute phase infection (up to 15 days post-symptom onset) and four urine samples from convalescent phase infection (up to 69 days post-symptom onset), were YFV PCR-positive. We genotyped YFV detected in seven urine samples (five collected during the acute phase and two collected during the YF convalescent phase). Genotyping indicated the presence of YFV South American I genotype in these samples. To our knowledge, this is the first report of wild-type YFV RNA detection in the urine this far out from symptom onset (up to 69 DPS), including YFV RNA detection during the convalescent phase of YF infection. The detection of YFV RNA in urine is an indicative of YFV infection; however, the results of RT-PCR using urine as sample should be interpreted with care, since a negative result does not exclude the possibility of YFV infection. With a possible prolonged period of detection beyond the viremic phase, the use of urine samples coupled with serological tests, epidemiologic inquiry, and clinical assessment could provide a longer diagnostic window for laboratory YF diagnosis.
Topics: Brazil; Disease Outbreaks; Humans; RNA; Yellow Fever; Yellow fever virus
PubMed: 35916519
DOI: 10.1128/jcm.00254-22 -
ELife Mar 2021Yellow fever (YF) is a viral, vector-borne, haemorrhagic fever endemic in tropical regions of Africa and South America. The vaccine for YF is considered safe and...
Yellow fever (YF) is a viral, vector-borne, haemorrhagic fever endemic in tropical regions of Africa and South America. The vaccine for YF is considered safe and effective, but intervention strategies need to be optimised; one of the tools for this is mathematical modelling. We refine and expand an existing modelling framework for Africa to account for transmission in South America. We fit to YF occurrence and serology data. We then estimate the subnational forces of infection for the entire endemic region. Finally, using demographic and vaccination data, we examine the impact of vaccination activities. We estimate that there were 109,000 (95% credible interval [CrI] [67,000-173,000]) severe infections and 51,000 (95% CrI [31,000-82,000]) deaths due to YF in Africa and South America in 2018. We find that mass vaccination activities in Africa reduced deaths by 47% (95% CrI [10%-77%]). This methodology allows us to evaluate the effectiveness of vaccination and illustrates the need for continued vigilance and surveillance of YF.
Topics: Africa; Disease Outbreaks; Global Burden of Disease; Global Health; Humans; Mass Vaccination; Models, Theoretical; Seroepidemiologic Studies; South America; Surveys and Questionnaires; Vaccination; Yellow Fever; Yellow Fever Vaccine
PubMed: 33722340
DOI: 10.7554/eLife.64670 -
Memorias Do Instituto Oswaldo Cruz Jan 2018
Topics: Aedes; Animals; Brazil; Epidemics; Humans; Mosquito Control; National Health Programs; Urbanization; Yellow Fever; Yellow Fever Vaccine
PubMed: 29185597
DOI: 10.1590/0074-02760170361 -
PLoS Neglected Tropical Diseases Jan 2021In the last 20 years yellow fever (YF) has seen dramatic changes to its incidence and geographic extent, with the largest outbreaks in South America since 1940 occurring...
In the last 20 years yellow fever (YF) has seen dramatic changes to its incidence and geographic extent, with the largest outbreaks in South America since 1940 occurring in the previously unaffected South-East Atlantic coast of Brazil in 2016-2019. While habitat fragmentation and land-cover have previously been implicated in zoonotic disease, their role in YF has not yet been examined. We examined the extent to which vegetation, land-cover, climate and host population predicted the numbers of months a location reported YF per year and by each month over the time-period. Two sets of models were assessed, one looking at interannual differences over the study period (2003-2016), and a seasonal model looking at intra-annual differences by month, averaging over the years of the study period. Each was fit using hierarchical negative-binomial regression in an exhaustive model fitting process. Within each set, the best performing models, as measured by the Akaike Information Criterion (AIC), were combined to create ensemble models to describe interannual and seasonal variation in YF. The models reproduced the spatiotemporal heterogeneities in YF transmission with coefficient of determination (R2) values of 0.43 (95% CI 0.41-0.45) for the interannual model and 0.66 (95% CI 0.64-0.67) for the seasonal model. For the interannual model, EVI, land-cover and vegetation heterogeneity were the primary contributors to the variance explained by the model, and for the seasonal model, EVI, day temperature and rainfall amplitude. Our models explain much of the spatiotemporal variation in YF in South America, both seasonally and across the period 2003-2016. Vegetation type (EVI), heterogeneity in vegetation (perhaps a proxy for habitat fragmentation) and land cover explain much of the trends in YF transmission seen. These findings may help understand the recent expansions of the YF endemic zone, as well as to the highly seasonal nature of YF.
Topics: Agriculture; Climate; Humans; Seasons; South America; Yellow Fever
PubMed: 33428623
DOI: 10.1371/journal.pntd.0008974 -
Revista Do Instituto de Medicina... Jul 2019Yellow fever is one of the most important mosquito-borne diseases, which still affects a significant number of people every year, mainly in tropical countries. Mortality... (Review)
Review
Yellow fever is one of the most important mosquito-borne diseases, which still affects a significant number of people every year, mainly in tropical countries. Mortality can be high, even with intensive treatment due to multiple organ failure, including acute kidney injury (AKI). This disease can also be a burden on the health care system in developing countries, without mentioning the number of lives that could be spared with an early diagnosis and adequate monitoring and treatment. The pathophysiology of yellow fever-induced acute kidney injury (AKI) is still to be completely understood, and the best clinical approach has not yet been determined. This manuscript presents the most recent scientific evidence of kidney involvement in yellow fever, since AKI plays an important role in the mortality rate. Recent outbreaks have occurred in Brazil and further studies are required to provide a better clinical control for patients with yellow fever.
Topics: Acute Kidney Injury; Brazil; Humans; Seasons; Yellow Fever
PubMed: 31340247
DOI: 10.1590/S1678-9946201961035 -
Mathematical Biosciences and... Jan 2022We developed a new mathematical model for yellow fever under three types of intervention strategies: vaccination, hospitalization, and fumigation. Additionally, the side...
We developed a new mathematical model for yellow fever under three types of intervention strategies: vaccination, hospitalization, and fumigation. Additionally, the side effects of the yellow fever vaccine were also considered in our model. To analyze the best intervention strategies, we constructed our model as an optimal control model. The stability of the equilibrium points and basic reproduction number of the model are presented. Our model indicates that when yellow fever becomes endemic or disappears from the population, it depends on the value of the basic reproduction number, whether it larger or smaller than one. Using the Pontryagin maximum principle, we characterized our optimal control problem. From numerical experiments, we show that the optimal levels of each control must be justified, depending on the strategies chosen to optimally control the spread of yellow fever.
Topics: Basic Reproduction Number; Cost-Benefit Analysis; Humans; Models, Theoretical; Vaccination; Yellow Fever
PubMed: 35135229
DOI: 10.3934/mbe.2022084 -
BMJ (Clinical Research Ed.) Feb 2002
Topics: Humans; Vaccination; Yellow Fever; Yellow Fever Vaccine
PubMed: 11859033
DOI: 10.1136/bmj.324.7335.439 -
Vaccine Jan 2022Yellow fever (YF) vaccines are highly effective and have a well-established safety profile despite the risk of rare serious adverse events (SAEs), vaccine-associated...
BACKGROUND
Yellow fever (YF) vaccines are highly effective and have a well-established safety profile despite the risk of rare serious adverse events (SAEs), vaccine-associated neurotropic (YEL-AND) and viscerotropic disease (YEL-AVD). This study aimed to describe US civilian YF vaccine usage, the population characteristics and pre-existing immunosuppressive medical conditions among those vaccinated, and to provide updated risk estimates of neurotropic and viscerotropic disease post-vaccination.
METHODS
A retrospective cohort study was conducted using de-identified patient information from Optum Electronic Healthcare Record (EHR) (2007-2019), Optum Clinformatics Data Mart (CDM) (2004-2019) and IBM MarketScan (2007-2019) databases. YF vaccine recipients were identified using relevant vaccination and procedural codes. Demographic characteristics and pre-existing medical conditions were described. Incidence proportions with 95% confidence intervals (CI) of neurotropic and viscerotropic diseases occurring ≤ 30 days post-vaccination, after exclusion of unlikely cases based on current clinical guidelines of YEL-AND and YEL-AVD, were calculated.
RESULTS
A total of 92,205, 46,539 and 125,235 YF vaccine recipients were retrieved from Optum EHR, Optum CDM and IBM MarketScan databases, respectively. The majority of vaccine recipients were aged < 60 years (highest proportion aged 18-29 years) with a higher proportion of females overall. Few vaccine recipients (<1%) had conditions predisposing them to immunosuppression. Four non-fatal cases of neurotropic disease and zero cases of viscerotropic disease were identified. The incidence proportion of post-vaccination neurotropic disease was 1.41 (95% CI: 0.15-6.61) and 3.04 (95% CI: 0.86-8.11) per 100,000 vaccine recipients in Optum EHR and IBM MarketScan, respectively, with no events identified in Optum CDM.
CONCLUSIONS
This study provides updated insights into current YF vaccine usage in US civilian recipients and supports the safety profile of YF vaccines in US practice. The low frequency of pre-existing immunosuppressive medical conditions among vaccine recipients suggests good adherence to vaccination guidelines by healthcare practitioners. The risk of developing neurotropic and viscerotropic disease post-vaccination remains rare.
Topics: Antigens, Viral; Delivery of Health Care; Female; Humans; Retrospective Studies; United States; Vaccination; Yellow Fever; Yellow Fever Vaccine
PubMed: 34996642
DOI: 10.1016/j.vaccine.2021.12.047