The recent emergence and re-emergence of viral infections transmitted by vectors—Zika, chikungunya, dengue, Japanese encephalitis, West Nile, yellow fever and others—is a cause for international ...concern. Using as examples Zika, chikungunya and dengue, we summarise current knowledge on characteristics of the viruses and their transmission, clinical features, laboratory diagnosis, burden, history, possible causes of the spread and the expectation for future epidemics. Arboviruses are transmitted by mosquitoes, are of difficult diagnosis, can have surprising clinical complications and cause severe burden. The current situation is complex, because there is no vaccine for Zika and chikungunya and no specific treatment for the three arboviruses. Vector control is the only comprehensive solution available now and this remains a challenge because up to now this has not been very effective. Until we develop new technologies of control mosquito populations, the globalised and urbanised world we live in will remain vulnerable to the threat of successive arbovirus epidemics.
To describe salient epidemiological characteristics of Zika virus outbreaks across the world and to examine the clinical presentations, complications, and atypical manifestations related to their ...occurrence in recent history.
We conducted a systematic review of the literature by searching through MEDLINE, Embase, and Global Health Library, as well as the epidemiological bulletins and alerts from the World Health Organization, the Pan American Health Organization, and the European Centre for Disease Prevention and Control over the period 1954 to 2016.
The search yielded 547 records. We retained 333 for further analysis, to which we added 11 epidemiological bulletins from various sources. Of these, we systematically reviewed 52 articles and reports, revealing some epidemiological features and patterns of spread of the Zika virus worldwide, as well as pathological outcomes suspected to be linked to Zika outbreaks. Neurologic disorders among zika patients were similar in Brazil and French Polynesia but a causal link is not established. Incidence of zika infection in pregnant women is not known. In Brazil, during the zika outbreak the incidence of microcephaly increased more than 20 times. Among 35 infants with microcephaly, born from women suspected to have Zika infection during pregnancy in northeast Brazil, 74% of the mothers reported rash during the first and second trimester.
On February 1, 2016, The World Health Organization declared the ongoing Zika crisis an emergency and that, although not yet scientifically proven, the link between the virus and growing numbers of microcephaly cases was "strongly suspected." However, the causal relationship between zika and microcephaly is not universally accepted. Public Health Implications. The current situation with regard to Zika is not encouraging, because there is no vaccine, no treatment, and no good serological test, and vector control remains a challenge.
Summary Background Little is known about the possible adverse effects of dengue infection during pregnancy on fetal outcomes. In this systematic review and meta-analysis we aimed to estimate the ...increase in risk of four adverse fetal outcomes in women who had dengue infection during pregnancy. Methods For this systematic review and meta-analysis, we searched Medline, Embase, Global Health Library, and Scopus for articles published before Aug 1, 2015. We included original studies that reported any fetal outcomes for pregnant women who had dengue infection during the gestational period. Case-control, cohort, and cross-sectional studies and unselected case series were eligible for inclusion. We excluded case reports, ecological studies, reviews, in-vitro studies, and studies without data for pregnancy outcomes. We independently screened titles and abstracts to select papers for inclusion and scored the quality of those included in meta-analyses. For each study, we recorded study design, year of publication, study location, period of study, and authors and we extracted data for population characteristics such as the number of pregnancies, dengue diagnostic information, and the frequency of outcomes. We investigated four adverse fetal outcomes: stillbirth, miscarriage, preterm birth, and low birthweight. We estimated the increase in risk of these adverse fetal outcomes by use of Mantel-Haenszel methods. We assessed heterogeneity of odds ratios (OR) with the I2 statistic. Findings We identified 278 non-duplicate records, of which 107 full-text articles were screened for eligibility. 16 studies were eligible for inclusion in the systematic review and eight were eligible for the meta-analyses, which included 6071 pregnant women, 292 of whom were exposed to dengue during pregnancy. For miscarriage, the OR was 3·51 (95% CI 1·15–10·77, I2 =0·0%, p=0·765) for women with dengue infection during pregnancy compared with those without. We did not do a meta-analysis for stillbirth because this outcome was investigated in only one study with a comparison group; we calculated the crude relative risk to be 6·7 (95% CI 2·1–21·3) in women with symptomatic dengue compared with women without dengue. Preterm birth and low birthweight were the most common adverse pregnancy outcomes. The OR for the association with dengue was 1·71 (95% CI 1·06–2·76, I2 =56·1%, p=0·058) for preterm birth and 1·41 (95% CI 0·90–2·21, I2 =0·0%, p=0·543) for low birthweight. Interpretation Evidence suggests that symptomatic dengue during pregnancy might be associated with fetal adverse outcomes. If confirmed, it would be important to monitor pregnancies during which dengue is diagnosed and to consider pregnant women in dengue control policies. Funding National Council for Scientific and Technological Development (CNPq).
There is considerable interest in the waning of effectiveness of coronavirus disease 2019 (COVID-19) vaccines and vaccine effectiveness (VE) of booster doses. Using linked national Brazilian ...databases, we undertook a test-negative design study involving almost 14 million people (~16 million tests) to estimate VE of CoronaVac over time and VE of BNT162b2 booster vaccination against RT-PCR-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severe COVID-19 outcomes (hospitalization or death). Compared with unvaccinated individuals, CoronaVac VE at 14-30 d after the second dose was 55.0% (95% confidence interval (CI): 54.3-55.7) against confirmed infection and 82.1% (95% CI: 81.4-82.8) against severe outcomes. VE decreased to 34.7% (95% CI: 33.1-36.2) against infection and 72.5% (95% CI: 70.9-74.0) against severe outcomes over 180 d after the second dose. A BNT162b2 booster, 6 months after the second dose of CoronaVac, improved VE against infection to 92.7% (95% CI: 91.0-94.0) and VE against severe outcomes to 97.3% (95% CI: 96.1-98.1) 14-30 d after the booster. Compared with younger age groups, individuals 80 years of age or older had lower protection after the second dose but similar protection after the booster. Our findings support a BNT162b2 booster vaccine dose after two doses of CoronaVac, particularly for the elderly.
Brazil has made great progress in reducing child mortality over the past decades, and a parcel of this achievement has been credited to the Bolsa Família program (BFP). We examined the association ...between being a BFP beneficiary and child mortality (1-4 years of age), also examining how this association differs by maternal race/skin color, gestational age at birth (term versus preterm), municipality income level, and index of quality of BFP management.
This is a cross-sectional analysis nested within the 100 Million Brazilian Cohort, a population-based cohort primarily built from Brazil's Unified Registry for Social Programs (Cadastro Único). We analyzed data from 6,309,366 children under 5 years of age whose families enrolled between 2006 and 2015. Through deterministic linkage with the BFP payroll datasets, and similarity linkage with the Brazilian Mortality Information System, 4,858,253 children were identified as beneficiaries (77%) and 1,451,113 (23%) were not. Our analysis consisted of a combination of kernel matching and weighted logistic regressions. After kernel matching, 5,308,989 (84.1%) children were included in the final weighted logistic analysis, with 4,107,920 (77.4%) of those being beneficiaries and 1,201,069 (22.6%) not, with a total of 14,897 linked deaths. Overall, BFP participation was associated with a reduction in child mortality (weighted odds ratio OR = 0.83; 95% CI: 0.79 to 0.88; p < 0.001). This association was stronger for preterm children (weighted OR = 0.78; 95% CI: 0.68 to 0.90; p < 0.001), children of Black mothers (weighted OR = 0.74; 95% CI: 0.57 to 0.97; p < 0.001), children living in municipalities in the lowest income quintile (first quintile of municipal income: weighted OR = 0.72; 95% CI: 0.62 to 0.82; p < 0.001), and municipalities with better index of BFP management (5th quintile of the Decentralized Management Index: weighted OR = 0.76; 95% CI: 0.66 to 0.88; p < 0.001). The main limitation of our methodology is that our propensity score approach does not account for possible unmeasured confounders. Furthermore, sensitivity analysis showed that loss of nameless death records before linkage may have resulted in overestimation of the associations between BFP participation and mortality, with loss of statistical significance in municipalities with greater losses of data and change in the direction of the association in municipalities with no losses.
In this study, we observed a significant association between BFP participation and child mortality in children aged 1-4 years and found that this association was stronger for children living in municipalities in the lowest quintile of wealth, in municipalities with better index of program management, and also in preterm children and children of Black mothers. These findings reinforce the evidence that programs like BFP, already proven effective in poverty reduction, have a great potential to improve child health and survival. Subgroup analysis revealed heterogeneous results, useful for policy improvement and better targeting of BFP.
Dengue virus infection during pregnancy increased the risk for any neurologic congenital anomaly in the infant by roughly 50% and for other congenital malformations of brain 4-fold. Our results show ...an association between dengue during pregnancy and congenital anomalies of the brain, suggesting that flaviviruses other than Zika virus are associated with such malformations.
Abstract
To date, no information has been published on the effectiveness of inactivated whole-virus COVID-19 vaccines plus heterologous booster against symptomatic infection and severe outcomes ...(hospitalization or death) during the dominance of the SARS-CoV-2 Omicron variant period. We evaluated the vaccine effectiveness (VE) of CoronaVac plus BNT162b2 booster during the period of dominance of the Omicron variant in Brazil (January to April 2022). Using a test-negative design, we analysed data for 2,471,576 individuals tested during the Omicron variant’s dominant period using a nationally linked database from Brazil. Compared to unvaccinated, vaccinees maintained protection against severe outcomes, with an estimated VE of 84.1% (95% CI:83.2–84.9) at more than 120 days after BNT162b2 booster. Furthermore, while we detected a high level of protection against severe outcomes for individuals up to 79 years old, waning was observed for individuals aged ≥80 years, with VE decreasing from 81.3% (95% CI:77.9–84.2) at 31–60 days to 72.9% (95% CI:70.6–75.1) at 120 days or more after the booster dose. However, no significant protection against symptomatic infection was observed at this time period. In conclusion, except for individuals aged ≥80 years, CoronaVac plus a BNT162b2 booster dose offered high and durable protection against severe outcomes due to Omicron.
Robust epidemiological and biological evidence supports a causal link between prenatal Zika Virus (ZIKV) infection and congenital brain abnormalities including microcephaly. However, it remains ...uncertain if ZIKV infection in pregnancy also increases the risk for other adverse fetal and birth outcomes. In a prospective cohort study we investigated the influence of ZIKV on the prevalence of prematurity, low birth weight, small-for-gestational-age, and fetal death as well as microcephaly (i.e., overall and disproportionate) in the offspring of women attending a high-risk pregnancy clinic during the recent ZIKV outbreak in Brazil. During the recruitment period (01 March 2016-23 August 2017), urine samples were tested for ZIKV by RT-PCR from all women attending the high-risk pregnancy clinic at Jundiaí University Hospital and from the neonates after delivery. Of the 574 women evaluated, 44 (7.7%) were ZIKV RT-PCR positive during pregnancy. Of the 409 neonates tested, 19 (4.6%) were ZIKV RT-PCR positive in the first 10 days of life. In this cohort, maternal ZIKV exposure was not associated with increased risks of prematurity, low birth weight, small-for-gestational-age, or fetal death. However, relative to ZIKV-negative neonates, ZIKV-positive infants had a five-fold increased risk of microcephaly overall (RR 5.1, 95% CI 1.2-22.5) and a ten-fold increased risk of disproportionate microcephaly (RR 10.3, 95% CI 2.0-52.6). Our findings provide new evidence that, in a high-risk pregnancy cohort, ZIKV RT-PCR positivity in the neonate at birth is strongly associated with microcephaly. However, ZIKV infection during pregnancy does not appear to influence the risks of prematurity, low birth weight, small-for-gestational-age or fetal death in women who already have gestational comorbidities. The results suggest disproportion between neonatal head circumference and weight may be a useful screening indicator for the detection of congenital microcephaly associated with ZIKV infection.
Abstract
Although severe COVID-19 in children is rare, they may develop multisystem inflammatory syndrome, long-COVID and downstream effects of COVID-19, including social isolation and disruption of ...education. Data on the effectiveness of the CoronaVac vaccine is scarce during the Omicron period. In Brazil, children between 6 to 11 years are eligible to receive the CoronaVac vaccine. We conducted a test-negative design to estimate vaccine effectiveness using 197,958 tests from January 21, 2022, to April 15, 2022, during the Omicron dominant period in Brazil among children aged 6 to 11 years. The estimated vaccine effectiveness for symptomatic infection was 39.8% (95% CI 33.7–45.4) at ≥14 days post-second dose. For hospital admission vaccine effectiveness was 59.2% (95% CI 11.3–84.5) at ≥14 days. Two doses of CoronaVac in children during the Omicron period showed low levels of protection against symptomatic infection, and modest levels against severe illness.
Recent outbreaks of influenza, Ebola, and Zika viruses have taught us that pregnant women are uniquely vulnerable to emerging infectious threats. Let’s not fail pregnant frontline workers during the ...covid-19 pandemic, say Elizabeth B Brickley and Enny S Paixão
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