Epidemiology and costs of dengue in Brazil: a systematic literature review.

OBJECTIVES: Dengue infection is a growing public health problem, with the number of reported cases increasing in the Americas and worldwide. This review characterized the epidemiological and economic burden of dengue in Brazil. METHODS: Embase, MEDLINE, evidence-based review databases, and gray literature sources were searched for published literature and surveillance reports on epidemiology (between 2000 and 2019) and costs (between 2009 and 2019) of dengue in Brazil. Studies were included if they reported data on incidence, seroprevalence, serotype distribution, expansion factors, hospitalization, mortality, or costs. Data were summarized descriptively and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: A total of 344 publications were included (167 peer-reviewed and 177 gray literature). Dengue outbreaks increased in incidence and frequency, with the highest incidence observed in 2015 at 807 cases per 100,000 population. Outbreaks were related to alternating predominant serotypes. Dengue was more frequent in young adults (aged 20-39 years) and in the Midwest. Cost and societal impacts are substantial and varied across regions, age, and public/private delivery of healthcare services. CONCLUSION: The burden of dengue in Brazil is increasing and likely underestimated. Therefore, developing and implementing new strategies, including vaccination, is essential to reduce the disease burden.

Prevalence and incidence of dengue virus and antibody placental transfer during late pregnancy in central Brazil.

BACKGROUND: Maternal dengue antibodies are considered to play a significant role in dengue pathogenesis among infants. Determining the transplacental specific antibody transfer is invaluable for establishing the optimal vaccination age among infants in endemic regions. METHODS: We conducted a cross-sectional study among pairs of maternal and corresponding umbilical cord blood samples in public hospitals. The prevalence and incidence of dengue infection were determined in 505 pairs of pregnant women and neonates during a large outbreak (2009-2010) in central Brazil. The women were interviewed at late pregnancy to assess current or past symptoms of dengue. All parturients and their neonates were screened using Dengue IgG Indirect ELISA (Panbio) to assess previous dengue exposure. A semi-quantitative measurement of the IgG antibody expressed by the index ratio was calculated using optical density (OD) values according to the manufacturer's instructions. The studied population of parturients and their offspring was also screened for recent dengue infection by the Dengue IgM-capture ELISA (Panbio). Those participants with history of fever and two or more symptoms of dengue at least 10 days before the delivery were also tested for the dengue NS1 antigen using the Dengue Early ELISA (Panbio) and RT-PCR. RESULTS: The mean maternal age was 25.8 (SD = 6.4), and 83.6% of deliveries were between 37 and 41 weeks. Approximately half of the 505 women and neonates were IgG-seropositive, yielding 99.3% co-positive mother-child frequency of antibody transfer (Kappa = 0.96). The incidence of dengue infection was 2.8% (95% CI 1.4-4.4%) among the women considering 14 IgM-positive results and one DENV2 detected by RT-PCR. The dengue NS1 antigen was undetectable in the matched pairs. CONCLUSION: This study provides critical data on the prevalence of transplacental transferred maternal-infant anti-dengue antibodies and incidence of infection. The design of future vaccine trials should consider diverse regional epidemiological scenarios.

Laboratory surveillance of dengue virus in Central Brazil, 1994-2003.

BACKGROUND: In Brazil, dengue endemic and epidemic patterns indicate an upward trend in incidence and hospitalization in the past decade. OBJECTIVE: To report dengue circulating serotypes from 1994 to 2003 and the role of distinct serotypes on dengue clinical outcomes in Central Brazil. METHODS: Virological surveillance for dengue cases was conducted in the city of Goiania ( approximately 1,200,000 population) from 1994 to 2003. Samples were tested using dengue IgM antibody (MAC-ELISA) and/or virus isolation. Circulating subtypes and genotypes were identified by reverse transcriptase PCR (RT-PCR) and by restricted site-specific PCR (RSS-PCR) patterns in selected samples. RESULTS: Adults (87.4%) were the most affected group and dengue fever accounted for the majority of the cases. Laboratory surveillance identified mainly DEN 1 serotype from 1994 to 2002 shifting to a high circulation of DEN 3 in 2003. The ratio of dengue fever to dengue with complications/DHF remained constant following the introduction of DEN 3. Diagnosis of dengue was confirmed in approximately 50% of the suspected cases enhanced by RT-PCR. RSS-PCR patterns for DEN 1 and DEN 3 corresponded to the circulating subtypes in the country. CONCLUSIONS: The result of virological surveillance did not suggest a major role of infecting DEN 3 serotype in increasing disease severity during its first-year spread in Central Brazil.