During the first 6 months of 2016, large outbreaks of Zika virus disease caused by local mosquito-borne transmission occurred in Puerto Rico and other U.S. territories, but local mosquito-borne transmission was not identified in the continental United States (1,2). As of July 22, 2016, the Florida Department of Health had identified 321 Zika virus disease cases among Florida residents and visitors, all occurring in either travelers from other countries or territories with ongoing Zika virus transmission or sexual contacts of recent travelers.* During standard case investigation of persons with compatible illness and laboratory evidence of recent Zika virus infection (i.e., a specimen positive by real-time reverse transcription-polymerase chain reaction [rRT-PCR], or positive Zika immunoglobulin M [IgM] with supporting dengue serology [negative for dengue IgM antibodies and positive for dengue IgG antibodies], or confirmation of Zika virus neutralizing antibodies by plaque reduction neutralization testing [PRNT]) (3), four persons were identified in Broward and Miami-Dade counties whose infections were attributed to likely local mosquito-borne transmission. Two of these persons worked within 120 meters (131 yards) of each other but had no other epidemiologic connections, suggesting the possibility of a local community-based outbreak. Further epidemiologic and laboratory investigations of the worksites and surrounding neighborhood identified a total of 29 persons with laboratory evidence of recent Zika virus infection and likely exposure during late June to early August, most within an approximate 6-block area. In response to limited impact on the population of Aedes aegypti mosquito vectors from initial ground-based mosquito control efforts, aerial ultralow volume spraying with the organophosphate insecticide naled was applied over a 10 square-mile area beginning in early August and alternated with aerial larviciding with Bacillus thuringiensis subspecies israelensis (Bti), a group biologic control agent, in a central 2 square-mile area. No additional cases were identified after implementation of this mosquito control strategy. No increases in emergency department (ED) patient visits associated with aerial spraying were reported, including visits for asthma, reactive airway disease, wheezing, shortness of breath, nausea, vomiting, or diarrhea. Local and state health departments serving communities where Ae. aegypti, the primary vector of Zika virus, is found should continue to actively monitor for local transmission of the virus.(†).
Background
Pregnant women with coronavirus disease 2019 (COVID-19) are at increased risk for severe illness compared with nonpregnant women. Data to assess risk factors for illness severity among pregnant women with COVID-19 are limited. This study aimed to determine risk factors associated with COVID-19 illness severity among pregnant women with SARS-CoV-2 infection.
Methods
Pregnant women with SARS-CoV-2 infection confirmed by molecular testing were reported during March 29, 2020–March 5, 2021 through the Surveillance for Emerging Threats to Mothers and Babies Network (SET-NET). Criteria for illness severity (asymptomatic, mild, moderate-to-severe, or critical) were adapted from National Institutes of Health and World Health Organization criteria. Crude and adjusted risk ratios for moderate-to-severe or critical COVID-19 illness were calculated for selected demographic and clinical characteristics.
Results
Among 7,950 pregnant women with SARS-CoV-2 infection, moderate-to-severe or critical COVID-19 illness was associated with age 25 years and older, healthcare occupation, pre-pregnancy obesity, chronic lung disease, chronic hypertension, and pregestational diabetes mellitus. Risk of moderate-to-severe or critical illness increased with the number of underlying medical or pregnancy-related conditions.
Conclusions
Older age and having underlying medical conditions were associated with increased risk of moderate-to-severe or critical COVID-19 illness among pregnant women. This information might help pregnant women understand their risk for moderate-to-severe or critical COVID-19 illness and inform targeted public health messaging.
Data on the duration of detectable Zika virus–specific IgM in infected persons are limited. Neutralizing antibody cross-reactivity occurs between Zika virus and related flaviviruses, but the degree to which this confounds diagnosis is uncertain. We tested serum specimens collected 12–19 months after illness onset from patients with confirmed Zika virus disease for Zika virus IgM and Zika virus and dengue virus neutralizing antibodies. Among 62 participants, 45 (73%) had detectable Zika virus IgM and 12 (19%) had an equivocal result. Although all patients tested had Zika virus neutralizing antibodies, 39 (63%) also had neutralizing antibodies against dengue virus; of those, 12 (19%) had <4-fold difference between Zika virus and dengue virus titers, and 5 (8%) had dengue virus titer >4-fold higher than Zika virus titer. Prolonged detection of IgM and neutralizing antibody cross-reactivity make it difficult to determine the timing of Zika virus infection and differentiate between related flaviviruses.
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