Why Did ZIKV Perinatal Outcomes Differ in Distinct Regions of Brazil? An Exploratory Study of Two Cohorts

Abstract

The Zika virus (ZIKV) epidemic in Brazil occurred in regions where dengue viruses (DENV) are historically endemic. We investigated the differences in adverse pregnancy/infant outcomes in two cohorts comprising 114 pregnant women with PCR-confirmed ZIKV infection in Rio de Janeiro, Southeastern Brazil (n = 50) and Manaus, in the north region of the country (n = 64). Prior exposure to DENV was evaluated through plaque reduction neutralizing antibody assays (PRNT 80) and DENV IgG serologies. Potential associations between pregnancy outcomes and Zika attack rates in the two cities were explored. Overall, 31 women (27%) had adverse pregnancy/infant outcomes, 27 in Rio (54%) and 4 in Manaus (6%), p < 0.001. This included 4 pregnancy losses (13%) and 27 infants with abnormalities at birth (24%). A total of 93 women (82%) had evidence of prior DENV exposure, 45 in Rio (90%) and 48 in Manaus (75%). Zika attack rates differed; the rate in Rio was 10.28 cases/10,000 and in Manaus, 0.6 cases/10,000, p < 0.001. Only Zika attack rates (Odds Ratio: 17.6, 95% Confidence Interval 5.6–55.9, p < 0.001) and infection in the first trimester of pregnancy (OR: 4.26, 95% CI 1.4–12.9, p = 0.011) were associated with adverse pregnancy and infant outcomes. Pre-existing immunity to DENV was not associated with outcomes (normal or abnormal) in patients with ZIKV infection during pregnancy.

Does the Presence or a High Titer of Yellow Fever Virus Antibodies Interfere with Pregnancy Outcomes in Women with Zika Virus Infection?

“…Most women (83.42%) had no outcomes, with the severity being more frequently evidenced in the first trimester of pregnancy (8/9, 89%). Severe outcomes are associated with and described in the literature in women whose infection occurs in the first trimester of pregnancy [25,29]. The high frequency of people with neutralizing antibodies against YFV (150/169, 89%) evidences the presence of immunity against YFV in the region.…”

Incidence of SARS-CoV-2 over four epidemic waves in a low-resource community in Rio de Janeiro, Brazil: A prospective cohort study

“…It should be noted that fieldwork under these conditions was only possible because the interviewers were residents of the region hired during our cohort studies. 11 , 12 , 13 , 14 , 15 …”

“…The present investigation, which was built upon our accompaniment of previous cohorts in this community, 11 , 12 , 13 , 14 is part of an ongoing prospective SARS-CoV-2 study. 15 We offered study participation to all household contacts of children aged 13 and under who were seen at a primary health care centre for any reason including routine vaccinations and preventative care.…”

Evidence of co-circulation of multiple arboviruses transmitted by Aedes species based on laboratory syndromic surveillance at a health unit in a slum of the Federal District, Brazil

“…Cidade Estrutural is hyperendemic for arboviruses transmitted by Aedes sp. mosquitos, with the population exposed to the risk of secondary infection, co-infection, and severe clinical outcomes in areas where this “arboviral soup” occurs [ 13 ], despite cross-immunity being observed among flavivirus infections [ 39 , 40 ]. The site is a potential area for the spread of these arboviruses to other ARs, given the cosmopolitan presence of Ae.…”