Evidence for Congenital Zika Virus Infection From Neutralizing Antibody Titers in Maternal Sera, Northeastern Brazil.

Reliable diagnosis of congenital Zika virus (ZIKV) infection is challenging. Here, we assessed ZIKV-specific neutralizing antibodies in 28 mothers of children with microcephaly (cases) and 122 controls from northeastern Brazil using plaque reduction neutralization tests. ZIKV-specific antibody titers were significantly higher in cases than in controls (t test, P < .0001). We identified a putative case of congenital Zika syndrome retrospectively by unusually high ZIKV-specific antibody titers. High ZIKV-specific antibody titers in cases were unrelated to prior dengue virus infection. Our data suggest a strong immunological stimulus from prolonged placental or transplacental ZIKV shedding and potential utility of maternal antibody titers to corroborate congenital ZIKV infection.

High Zika Virus Seroprevalence in Salvador, Northeastern Brazil Limits the Potential for Further Outbreaks.

During 2015 to 2016, Brazil reported more Zika virus (ZIKV) cases than any other country, yet population exposure remains unknown. Serological studies of ZIKV are hampered by cross-reactive immune responses against heterologous viruses. We conducted serosurveys for ZIKV, dengue virus (DENV), and Chikungunya virus (CHIKV) in 633 individuals prospectively sampled during 2015 to 2016, including microcephaly and non-microcephaly pregnancies, HIV-infected patients, tuberculosis patients, and university staff in Salvador in northeastern Brazil using enzyme-linked immunosorbent assays (ELISAs) and plaque reduction neutralization tests. Sera sampled retrospectively during 2013 to 2015 from 277 HIV-infected patients were used to assess the spread of ZIKV over time. Individuals were georeferenced, and sociodemographic indicators were compared between ZIKV-positive and -negative areas and areas with and without microcephaly cases. Epidemiological key parameters were modeled in a Bayesian framework. ZIKV seroprevalence increased rapidly during 2015 to 2016, reaching 63.3% by 2016 (95% confidence interval [CI], 59.4 to 66.8%), comparable to the seroprevalence of DENV (75.7%; CI, 69.4 to 81.1%) and higher than that of CHIKV (7.4%; CI, 5.6 to 9.8%). Of 19 microcephaly pregnancies, 94.7% showed ZIKV IgG antibodies, compared to 69.3% of 257 non-microcephaly pregnancies (P = 0.017). Analyses of sociodemographic data revealed a higher ZIKV burden in low socioeconomic status (SES) areas. High seroprevalence, combined with case data dynamics allowed estimates of the basic reproduction number R0 of 2.1 (CI, 1.8 to 2.5) at the onset of the outbreak and an effective reproductive number Reff of <1 in subsequent years. Our data corroborate ZIKV-associated congenital disease and an association of low SES and ZIKV infection and suggest that population immunity caused cessation of the outbreak. Similar studies from other areas will be required to determine the fate of the American ZIKV outbreak.IMPORTANCE The ongoing American Zika virus (ZIKV) outbreak involves millions of cases and has a major impact on maternal and child health. Knowledge of infection rates is crucial to project future epidemic patterns and determine the absolute risk of microcephaly upon maternal ZIKV infection during pregnancy. For unknown reasons, the vast majority of ZIKV-associated microcephaly cases are concentrated in northeastern Brazil. We analyzed different subpopulations from Salvador, a Brazilian metropolis representing one of the most affected areas during the American ZIKV outbreak. We demonstrate rapid spread of ZIKV in Salvador, Brazil, and infection rates exceeding 60%. We provide evidence for the link between ZIKV and microcephaly, report that ZIKV predominantly affects geographic areas with low socioeconomic status, and show that population immunity likely caused cessation of the outbreak. Our results enable stakeholders to identify target populations for vaccination and for trials on vaccine efficacy and allow refocusing of research efforts and intervention strategies.

Seroepidemiology of hepatitis B in individuals born between 1945-1985 on a Brazilian regional metropolis / Soroepidemiologia da hepatite B em indivíduos nascidos entre 1945-1985 em uma metrópole regional Brasileira

Background: hepatitis B prevalence can be influenced by social/cultural behavior and the Baby Boomer (BB) generation(1945-1964) may have been more susceptible to this infection. Objectives: We investigated the seroprevalence of markers for HBV infection and vaccination and its association with main risk factors. Methodology: a random sample of individuals aged 30-70 years old in a public clinical laboratory from a metropolitan area of Bahia/Brazil were tested for HBsAg/Total Anti-HBc/Anti-HBs/Anti-HBc-IgM and a socio-demographic questionnaire was applied. Results: of the650 participants, 349 were 51-70 yo (BB) and 301 were non-BB. The prevalences were HBsAg (2.3%), Total Anti-HBc (17.1%) and Anti-HBs (27.4%). Anti-HBcIgM (2.7%) was performed in 112 participants sera who had contact/infection with HBV. The laboratory profiles were characterized as susceptibility (68%), vaccine response (14.8%) and contact/infection with HBV (17.2%). BB participants were more susceptible and less vaccinated than non-BB. The higher frequency of contact/infection status was observed in the BB generation. Statistically significant differences were found for the contact/infection status in males(50,9%) illicit drug use (11,6%), syringe/needle sharing (7,1%), and blood transfusion (10,7%). Non-BB with contact/ infection profile reported more tattoo/piercing and BB reported higher use of glass syringes. Conclusion: the majority of the study population was susceptible to infection but participants older than 50 years showed both, a higher frequency of this profile and also a higher frequency of contact/infection status, thus suggesting the need for greater health care attention for this age group.

Introdução: a prevalência de hepatite B pode ser influenciada pelo comportamento sociocultural e a geração Baby Boomer (BB) (1945-1964) pode ter sido mais suscetível a esta infecção. Objetivos: Investigar a soroprevalência de marcadores para a infecção pelo VHB e resposta vacinal e associação com fatores de risco. Metodologia: soro de indivíduos de 30 a 70 anos randomicamente selecionados em um laboratório publico de análises clínicas na área metropolitana do Brasil foram testados para AgHBs/ Anti-HBc Total /Anti-HBs/Anti-HBc-IgM. Todos responderam questionário sociodemográfico contendo perguntas sobre fatores de risco para hepatite B. Resultados: dos 650 participantes, 349 eram BB (51-70 anos) e 301 eram não-BB (30-50 anos). As prevalências estimadas foram: HBsAg (2,3%), Anti-HBs (27,4%). Entre os Anti-HBc Total (17,1%) apenas 2,7% foram Anti-HBc IgM. Os perfis laboratoriais foram caracterizados como suscetibilidade (68%), resposta vacinal (14,8%) e contato com VHB (17,2%). Na distribuição por idade, os BB foram mais susceptíveis, menos vacinados e apresentaram maior frequência de contato/infecção que os não-BB. Diferenças estatisticamente significantes foram encontradas no status contato/infecção e as seguintes variáveis: sexo masculino, uso de drogas ilícitas, compartilhamento de seringas de vidro/agulhas e transfusão de sangue. Não-BB com status contato/infecção relataram ter mais tatuagem/piercing e BB relataram maior uso de seringas de vidro. Conclusão: a maioria da população estudada era suscetível ao VHB, mas os participantes com mais de 50 anos apresentaram tanto uma maior frequência desse status quanto do status contato/ infecção, sugerindo a necessidade de maior atenção à saúde para indivíduos desta faixa etária.