Birth Outcomes Related to Prenatal Zika, Dengue, and Other Flavivirus Infections in the Zika en Embarazadas y Niños Prospective Cohort Study in Colombia.

Zika virus (ZIKV) infection in pregnancy is associated with severe abnormalities of the brain and eye and other adverse outcomes. Zika en Embarazadas y Niños was a prospective cohort study conducted in multiple Colombian cities that enrolled pregnant women in their first trimester. Specimens collected from pregnant women (n = 1,519) during February 2017-September 2018 and their infants (n = 1,080) during June 2017-March 2019 were tested for prenatal ZIKV infection by nucleic acid amplification tests or IgM antibody testing. Zika virus infection in pregnancy was present in 3.2% of pregnant women (incidence rate [IR] per 1,000 person-months = 5.9, 95% CI: 4.3-7.8). Presumptive ZIKV infection was present in 0.8% of infants (IR = 1.6, 95% CI: 0.7-2.9). Five percent of infants with prenatal ZIKV exposure or infection presented with Zika-associated abnormalities; 4.7% were small for gestational age. Understanding the risk of ZIKV infection during pregnancy and associated adverse outcomes can help inform counseling efforts.

Evaluation of Serologic Cross-Reactivity Between Dengue Virus and SARS-CoV-2 in Patients with Acute Febrile Illness - United States and Puerto Rico, April 2020-March 2021.

The diagnosis of dengue disease, caused by the dengue virus (DENV) (a flavivirus), often requires serologic testing during acute and early convalescent phases of the disease. Some symptoms of DENV infection, such as nonspecific fever, are similar to those caused by infection with SARS-CoV-2, the virus that causes COVID-19. In studies with few COVID-19 cases, positive DENV immunoglobulin M (IgM) results were reported with various serologic tests, indicating possible cross-reactivity in these tests for DENV and SARS-CoV-2 infections (1,2). DENV antibodies can cross-react with other flaviviruses, including Zika virus. To assess the potential cross-reactivity of SARS-CoV-2, DENV, and Zika virus IgM antibodies, serum specimens from 97 patients from Puerto Rico and 12 U.S.-based patients with confirmed COVID-19 were tested using the DENV Detect IgM Capture enzyme-linked immunosorbent assay (ELISA) (InBios International).* In addition, 122 serum specimens from patients with confirmed dengue and 121 from patients with confirmed Zika virus disease (all from Puerto Rico) were tested using the SARS-CoV-2 pan-Ig Spike Protein ELISA (CDC).† Results obtained for DENV, Zika virus IgM, and SARS-CoV-2 antibodies indicated 98% test specificity and minimal levels of cross-reactivity between the two flaviviruses and SARS-CoV-2. These findings indicate that diagnoses of dengue or Zika virus diseases with the serological assays described in this report are not affected by COVID-19, nor do dengue or Zika virus diseases interfere with the diagnosis of COVID-19.