Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) outbreaks in nursing homes involving residents who had completed a primary coronavirus disease 2019 (COVID-19) vaccine series-13 US jurisdictions, July-November 2021.

Among nursing home outbreaks of coronavirus disease 2019 (COVID-19) with ≥3 breakthrough infections when the predominant severe acute respiratory coronavirus virus 2 (SARS-CoV-2) variant circulating was the SARS-CoV-2 δ (delta) variant, fully vaccinated residents were 28% less likely to be infected than were unvaccinated residents. Once infected, they had approximately half the risk for all-cause hospitalization and all-cause death compared with unvaccinated infected residents.

Anaplasmosis-Related Fatality in Vermont: A Case Report.

Human granulocytic anaplasmosis is an acute febrile tick-borne illness caused by the bacterium Anaplasma phagocytophilum. An anaplasmosis-related fatality in a Vermont resident with multiple comorbidities is described. Clinicians should be aware of the risk factors for severe outcomes of this emerging disease and promptly treat when suspected.

Addressing silent hypoxemia with COVID-19: Implementation of an outpatient pulse oximetry program in Vermont.

OBJECTIVES: We initiated an outpatient pulse oximetry program to facilitate more rapid detection of clinical deterioration of persons with COVID-19. METHODS: Vermont residents in non-congregate settings with laboratory-confirmed SARS-CoV-2 infection were eligible for inclusion. RESULTS: Acceptance of pulse oximetry occurred more frequently among those who were older or symptomatic, spoke English, or who had underlying medical conditions. CONCLUSIONS: We provide the first description of an outpatient pulse oximetry program for COVID-19 by a state health department in the U.S.

Patterns of Virus Exposure and Presumed Household Transmission among Persons with Coronavirus Disease, United States, January-April 2020.

We characterized common exposures reported by a convenience sample of 202 US patients with coronavirus disease during January-April 2020 and identified factors associated with presumed household transmission. The most commonly reported settings of known exposure were households and healthcare facilities; among case-patients who had known contact with a confirmed case-patient compared with those who did not, healthcare occupations were more common. Among case-patients without known contact, use of public transportation was more common. Within the household, presumed transmission was highest from older (>65 years) index case-patients and from children to parents, independent of index case-patient age. These findings may inform guidance for limiting transmission and emphasize the value of testing to identify community-acquired infections.

Risk Factors for Illness Severity Among Pregnant Women With Confirmed Severe Acute Respiratory Syndrome Coronavirus 2 Infection-Surveillance for Emerging Threats to Mothers and Babies Network, 22 State, Local, and Territorial Health Departments, 29 March 2020-5 March 2021.

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 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS: Pregnant women with SARS-CoV-2 infection confirmed by molecular testing were reported during 29 March 2020-5 March 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 7950 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, prepregnancy 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 can inform targeted public health messaging.

Evaluating Differences in Whole Blood, Serum, and Urine Screening Tests for Zika Virus, Puerto Rico, USA, 2016.

We evaluated nucleic acid amplification testing (NAAT) for Zika virus on whole-blood specimens compared with NAAT on serum and urine specimens among asymptomatic pregnant women during the 2015-2016 Puerto Rico Zika outbreak. Using NAAT, more infections were detected in serum and urine than in whole blood specimens.

Profile of Chronic Comorbid Conditions and Obstetrical Complications Among Pregnant Women With Human Immunodeficiency Virus and Receiving Antiretroviral Therapy in the United States.

BACKGROUND: To evaluate the frequency and associated characteristics of chronic comorbid conditions and obstetrical complications among pregnant women with human immunodeficiency virus (HIV) and receiving antiretroviral therapy (ART) in comparison to those without HIV. METHODS: We compared 2 independent concurrent US pregnancy cohorts: (1) with HIV (International Maternal Pediatric Adolescent AIDS Clinical Trials Protocol P1025, 2002-2013) and (2) without HIV (Consortium for Safe Labor Study, 2002-2007). Outcomes were ≥2 chronic comorbid conditions and obstetrical complications. For women with HIV, we assessed whether late prenatal care (≥14 weeks), starting ART in an earlier era (2002-2008), and a detectable viral load at delivery (≥400 copies/mL) were associated with study outcomes. RESULTS: We assessed 2868 deliveries (n = 2574 women) with HIV and receiving ART and 211 910 deliveries (n = 193 170 women) without HIV. Women with HIV were more likely to have ≥2 chronic comorbid conditions versus those without HIV (10 vs 3%; adjusted OR [AOR]: 2.96; 95% CI: 2.58-3.41). Women with HIV were slightly less likely to have obstetrical complications versus those without HIV (both 17%; AOR: .84; 95% CI: .75-.94), but secondarily, higher odds of preterm birth <37 weeks. Late entry to prenatal care and starting ART in an earlier era were associated with a lower likelihood of ≥2 chronic comorbidities and obstetrical complications; detectable viral load at delivery was associated with a higher likelihood of obstetric complications. CONCLUSIONS: Pregnant women with HIV receiving ART have more chronic comorbid conditions, but not necessarily obstetrical complications, than their peers without HIV.

Staphylococcus aureus antimicrobial susceptibility trends and cluster detection in Vermont: 2012-2018.

Objectives: This study presents demographic and temporal trends in the isolation of Staphylococcus aureus in Vermont clinical microbiology laboratories and explores the use of statistical algorithms and multi-resistance phenotypes to improve outbreak detection.Methods: Routine microbiology test results downloaded from Vermont clinical laboratory information systems were used to monitor S. aureus antimicrobial resistance trends. The integrated WHONET-SaTScan software used multi-resistance phenotypes to identify possible acute outbreaks with the space-time permutation model and slowly emerging geographic clusters using the spatial-only multinomial model.Results: Data were provided from seven hospital laboratories from 2012 to 2018 for 19,224 S. aureus isolates from 14,939 patients. Statistically significant differences (p ≤ 0.05) in methicillin-resistant S. aureus (MRSA) isolation were seen by age group, specimen type, and health-care setting. Among MRSA, multi-resistance profiles permitted the recognition and tracking of 6 common and 21 rare 'phenotypic clones.' We identified 43 acute MRSA clusters and 7 significant geographic clusters (p ≤ 0.05).Conclusions: There was significant heterogeneity in MRSA strains between facilities and the use of multi-resistance phenotypes facilitated the recognition of possible outbreaks. Comprehensive electronic surveillance of antimicrobial resistance utilizing routine clinical microbiology data with free software tools offers early recognition and tracking of emerging resistance threats.

Identification of a Human Immunodeficiency Virus Type 1 and Neurosyphilis Cluster in Vermont.

BACKGROUND: Rates of syphilis in the United States have more than doubled over the last several decades, largely among men who have sex with men (MSM). Our study characterizes a cluster of neurosyphilis cases among people with human immunodeficiency virus 1 (HIV-1) in Vermont in 2017-2018. METHODS: Vermont Department of Health disease intervention specialists conduct interviews with newly diagnosed HIV-1 cases and pursue sexual networking analyses. Phylogenetic and network analyses of available Vermont HIV-1 polymerase (pol) sequences identified clusters of infection. Fishers-exact and independent t-tests were used to compare people with HIV-1 within or outside an identified cluster. RESULTS: Between 1 January 2017 and 31 December 2018, 38 residents were diagnosed with HIV-1 infection. The mean age was 35.5 years, 79% were male and 82% were White. Risk factors for HIV-1 included MSM status (79%) and methamphetamine use (21%). Eighteen cases (49%) had HIV-1 viral loads (VLs) >100 000 copies/mL and 47% had CD4 cell counts <200/mm3. Eleven of the 38 (29%) had positive syphilis serology, including four (36%) with neurosyphilis. Sexual networking analysis revealed a ten-person cluster with higher VLs at diagnosis (90% with VLs > 100 000 copies/mL vs 33%, P = 0.015). Phylogenetic analysis of pol sequences showed a cluster of 14 cases with sequences that shared 98%-100% HIV-1 nucleotide identity. CONCLUSIONS: This investigation of newly infected HIV-1 cases in Vermont led to identification of a cluster that appeared more likely to have advanced HIV-1 disease and neurosyphilis, supported by phylogenetic and network analyses.

Birth and Infant Outcomes Following Laboratory-Confirmed SARS-CoV-2 Infection in Pregnancy - SET-NET, 16 Jurisdictions, March 29-October 14, 2020.

Pregnant women with coronavirus disease 2019 (COVID-19) are at increased risk for severe illness and might be at risk for preterm birth (1-3). The full impact of infection with SARS-CoV-2, the virus that causes COVID-19, in pregnancy is unknown. Public health jurisdictions report information, including pregnancy status, on confirmed and probable COVID-19 cases to CDC through the National Notifiable Diseases Surveillance System.* Through the Surveillance for Emerging Threats to Mothers and Babies Network (SET-NET), 16 jurisdictions collected supplementary information on pregnancy and infant outcomes among 5,252 women with laboratory-confirmed SARS-CoV-2 infection reported during March 29-October 14, 2020. Among 3,912 live births with known gestational age, 12.9% were preterm (<37 weeks), higher than the reported 10.2% among the general U.S. population in 2019 (4). Among 610 infants (21.3%) with reported SARS-CoV-2 test results, perinatal infection was infrequent (2.6%) and occurred primarily among infants whose mother had SARS-CoV-2 infection identified within 1 week of delivery. Because the majority of pregnant women with COVID-19 reported thus far experienced infection in the third trimester, ongoing surveillance is needed to assess effects of infections in early pregnancy, as well the longer-term outcomes of exposed infants. These findings can inform neonatal testing recommendations, clinical practice, and public health action and can be used by health care providers to counsel pregnant women on the risks of SARS-CoV-2 infection, including preterm births. Pregnant women and their household members should follow recommended infection prevention measures, including wearing a mask, social distancing, and frequent handwashing when going out or interacting with others or if there is a person within the household who has had exposure to COVID-19.†.

Symptom Profiles of a Convenience Sample of Patients with COVID-19 - United States, January-April 2020.

Coronavirus disease 2019 (COVID-19) was first detected in the United States in January 2020 (1), and by mid-July, approximately 3.4 million cases had been reported in the United States (2). Information about symptoms among U.S. COVID-19 patients is limited, especially among nonhospitalized patients. To better understand symptom profiles of patients with laboratory-confirmed COVID-19 in the United States, CDC used an optional questionnaire to collect detailed information on a convenience sample of COVID-19 patients from participating states. Symptom data were analyzed by age group, sex, hospitalization status, and symptom onset date relative to expansion of testing guidelines on March 8, 2020 (3). Among 164 symptomatic patients with known onset during January 14-April 4, 2020, a total of 158 (96%) reported fever, cough, or shortness of breath. Among 57 hospitalized adult patients (aged ≥18 years), 39 (68%) reported all three of these symptoms, compared with 25 (31%) of the 81 nonhospitalized adult patients. Gastrointestinal (GI) symptoms and other symptoms, such as chills, myalgia, headache, and fatigue, also were commonly reported, especially after expansion of testing guidelines. To aid prompt recognition of COVID-19, clinicians and public health professionals should be aware that COVID-19 can cause a wide variety of symptoms.

Characteristics of Persons Who Died with COVID-19 - United States, February 12-May 18, 2020.

During January 1, 2020-May 18, 2020, approximately 1.3 million cases of coronavirus disease 2019 (COVID-19) and 83,000 COVID-19-associated deaths were reported in the United States (1). Understanding the demographic and clinical characteristics of decedents could inform medical and public health interventions focused on preventing COVID-19-associated mortality. This report describes decedents with laboratory-confirmed infection with SARS-CoV-2, the virus that causes COVID-19, using data from 1) the standardized CDC case-report form (case-based surveillance) (https://www.cdc.gov/coronavirus/2019-ncov/php/reporting-pui.html) and 2) supplementary data (supplemental surveillance), such as underlying medical conditions and location of death, obtained through collaboration between CDC and 16 public health jurisdictions (15 states and New York City).

Surveillance of antimicrobial resistance and evolving microbial populations in Vermont: 2011-2018.

OBJECTIVE: This study presents trends in organism isolation and antimicrobial resistance in routine microbiology test results from acute-care hospital microbiology laboratories in Vermont. METHODS: Organism identifications and antimicrobial susceptibility test results were captured from acute-care hospital laboratories to monitor geographic and temporal trends in resistance and emerging microbial threats with the free WHONET software. RESULTS: Data were provided from 12 acute care hospital laboratories from 2011 through 2018 for 318,833 isolates from 148,994 patients (70% female, 74% outpatient, and 63% urine). Significant differences (p < 0.05) in age, gender, and antimicrobial susceptibility results (e.g. Escherichia coli and levofloxacin) between outpatient and inpatient isolates were identified with temporal increases in certain species (e.g. Aerococcus urinae) and resistance (e.g. Streptococcus pneumoniae and erythromycin). The use of multi-resistance phenotypes demonstrated significant heterogeneity (p < 0.05) in MRSA strains between facilities, for example Staphylococcus aureus resistant to six priority antimicrobials were found in no critical access hospitals (fewer than 25 inpatient beds) but in all non-critical access hospitals. CONCLUSIONS: Comprehensive electronic surveillance of antimicrobial resistance utilizing routine clinical microbiology data with free software tools offers early recognition and tracking of emerging community and healthcare resistance threats at the local and state level.

Pregnant women co-infected with HIV and Zika: Outcomes and birth defects in infants according to maternal symptomatology.

BACKGROUND: Zika virus (ZIKV) was first isolated in Uganda in 1947. In Brazil, the first reported case of ZIKV infection was in May 2015. Additionally, dengue (DENV) is endemic and there has been a recent outbreak of chikungunya (CHIKV). Since the clinical manifestations of different arboviral infections (AI) can be similar, definitive diagnosis requires laboratory testing. OBJECTIVES: To determine the prevalence of ZIKV, DENV, and CHIKV infections in a Brazilian cohort of HIV-infected pregnant women, to assess clinical/immunological characteristics and pregnancy outcomes of women with evidence of recent AI. STUDY DESIGN: Laboratory diagnosis of ZIKV, DENV and CHIKV infections utilized serological assays, RT-PCR and PRNT. The tests were performed at the first visit, 34-36 weeks of gestation and at any time if a woman had symptoms suggestive of AI. Mann-Whitney tests were used for comparison of medians, Chi-square or Fisher's to compare proportions; p< 0.05 was considered statistically significant. Poisson regression was used to analyze risk factors for central nervous system (CNS) malformations in the infant according to maternal symptomatology. RESULTS: Of 219 HIV-infected pregnant women enrolled, 92% were DENV IgG+; 47(22%) had laboratory evidence of recent AI. Of these, 34 (72%) were ZIKV+, nine (19%) CHIKV+, and two (4%) DENV+. Symptoms consistent with AI were observed in 23 (10%) women, of whom 10 (43%) were ZIKV+, eight (35%) CHIKV+. No CNS abnormalities were observed among infants of DENV+ or CHIKV+ women; four infants with CNS abnormalities were born to ZIKV+ women (three symptomatic). Infants born to ZIKV+ women had a higher risk of CNS malformations if the mother was symptomatic (RR = 7.20), albeit not statistically significant (p = 0.066). CONCLUSIONS: Among HIV-infected pregnant women with laboratory evidence of a recent AI, 72% were ZIKV-infected. In this cohort, CNS malformations occurred among infants born to both symptomatic and asymptomatic pregnant women with Zika infection.

Breast milk transmission of flaviviruses in the context of Zika virus: A systematic review.

BACKGROUND: Since the Zika virus epidemic in the Americas began in 2015, Zika virus transmission has occurred throughout the Americas. However, limited information exists regarding possible risks of transmission of Zika virus and other flaviviruses through breast feeding and human milk. We conducted a systematic review of the evidence regarding flaviviruses detection in and transmission through milk, specifically regarding Zika virus, Japanese encephalitis virus, tick-borne encephalitis virus, Powassan virus, West Nile virus, dengue virus, and yellow fever virus. METHODS: Medline, Embase, Global Health, CINAHL, Cochrane Library, Scopus, Popline, Virtual Health Library, and WorldCat were searched through June 2017. Two authors independently screened potential studies for inclusion and extracted data. Human and nonhuman (animal) studies describing: 1) confirmed or suspected cases of mother-to-child transmission through milk; or 2) the presence of flavivirus genomic material in milk. RESULTS: Seventeen studies were included, four animal models and thirteen observational studies. Dengue virus, West Nile virus, and Zika virus viral ribonucleic acid was detected in human milk, including infectious Zika virus and dengue virus viral particles. Human breast-feeding transmission was confirmed for only yellow fever virus. There was evidence of milk-related transmission of dengue virus, Powassan virus, and West Nile virus in animal studies. CONCLUSIONS: Because the health advantages of breast feeding are considered greater than the potential risk of transmission, the World Health Organization recommends that mothers with possible or confirmed Zika virus infection or exposure continue to breast feed. This review did not identify any data that might alter this recommendation.

Symptomatic Zika Virus Infection in Infants, Children, and Adolescents Living in Puerto Rico.

Importance: Little information is available regarding Zika virus (ZIKV) infection in children. Objective: To describe patients younger than 18 years who were infected with ZIKV and were enrolled in the Sentinel Enhanced Dengue and Acute Febrile Illness Surveillance System (SEDSS). Design, Setting, and Participants: Children infected with ZIKV with 7 or fewer days of fever or emancipated minors aged 14 to 17 years with a generalized maculopapular rash, arthritis or arthralgia, or nonpurulent conjunctivitis were eligible for enrollment on or before December 31, 2016, in Puerto Rico. Patients were evaluated using ZIKV polymerase chain reaction testing at 7 or fewer days after the onset of symptoms. Available ZIKV polymerase chain reaction-positive specimens were evaluated to determine viral loads. Exposures: Confirmed polymerase chain reaction-positive ZIKV infection. Main Outcomes and Measures: Clinical characteristics and viral loads of symptomatic children with confirmed ZIKV infection. Results: Of 7191 children enrolled in SEDSS on or before December 31, 2016, only those with confirmed ZIKV infection (351 participants) were included in this study. Participants who had confirmed ZIKV infection included 25 infants (7.1%), 69 children (19.7%) aged 1 to 4 years, 95 (27.1%) aged 5 to 9 years, and 162 (46.1%) aged 10 to 17 years. Among these, 260 patients (74.1%) presented for evaluation of ZIKV infection at fewer than 3 days after the onset of symptoms, 340 (96.9%) were discharged to home after evaluation, and 349 (99.4%) had fever, 280 (79.8%) had a rash, 243 (69.2%) had facial or neck erythema, 234 (66.7%) had fatigue, 223 (63.5%) had headache, 212 (60.4%) had chills, 206 (58.7%) had pruritus, and 204 (58.1%) had conjunctival hyperemia. Of 480 specimens collected (317 serum and 163 urine specimens) from 349 children, the median number of days after the onset of symptoms was lower for children who had serum specimens (1 day [interquartile range (IQR), 1-2 days]) than for children who had urine specimens (2 [1-3] days) (P < .001). Of 131 children who had both serum and urine specimens collected on the same day, the median viral load was higher in serum than in urine (median [IQR], 23 098 [8784-88 242] copies/mL for serum vs 9966 [2815-52 774] copies/mL for urine; P = .02). When a single serum sample from each of 317 patients was analyzed, there were no statistically significant differences in median viral loads according to age, sex, or disposition. However, the median serum viral load varied significantly according to the number of days after the onset of symptoms (0 days, 106 778 [IQR, 9772-1 571 718] copies/mL; 1 day, 46 299 [10 663-255 030] copies/mL; 2 days, 20 678 [8763-42 458] copies/mL; and ≥3 days, 15 901 [5135-49 248] copies/mL; P = .001). Conclusions and Relevance: This study represents the largest study to date of ZIKV infection in the pediatric population. Most children infected with ZIKV had fever, rash, and conjunctival hyperemia. The children usually presented for evaluation at fewer than 3 days after the onset of symptoms. Viral loads for ZIKV were higher in serum vs urine specimens. Median viral loads in serum specimens differed significantly according to the number of days after the onset of symptoms.

Changing Patterns and Factors Associated With Mode of Delivery Among Pregnant Women With Human Immunodeficiency Virus Infection in the United States.

OBJECTIVE: To describe patterns and factors associated with mode of delivery among pregnant women with human immunodeficiency virus (HIV) infection in the United States in relation to evolving HIV-in-pregnancy guidelines. METHODS: We conducted an analysis of two observational studies, Pediatric AIDS Clinical Trials Group and International Maternal Pediatric Adolescent AIDS Clinical Trials Network Protocol P1025, which enrolled pregnant women with HIV infection from 1998 to 2013 at more than 60 U.S. acquired immunodeficiency syndrome clinical research sites. Multivariable analyses of factors associated with an HIV-indicated cesarean delivery (ie, for prevention of mother-to-child transmission) compared with other indications were conducted and compared according to prespecified time periods of evolving HIV-in-pregnancy guidelines: 1998-1999, 2000-2008, and 2009-2013. RESULTS: Among 6,444 pregnant women with HIV infection, 21% delivered in 1998-1999, 58% in 2000-2008, and 21% in 2009-2013; 3,025 (47%) delivered by cesarean. Cesarean delivery increased from 30% in 1998 to 48% in 2013. Of all cesarean deliveries, repeat cesarean deliveries increased from 16% in 1998 to 42% in 2013; HIV-indicated cesarean deliveries peaked at 48% in 2004 and then dropped to 12% by 2013. In multivariable analyses, an HIV diagnosis during pregnancy, initiation of antiretroviral therapy in the third trimester, a plasma viral load 500 copies/mL or greater, and delivery between 37 and 40 weeks of gestation increased the likelihood of an HIV-indicated cesarean delivery. In analyses by time period, an HIV diagnosis during pregnancy, initiation of antiretroviral therapy in the third trimester, and a plasma viral load of 500 copies/mL or greater were progressively more likely to be associated with an HIV-indicated cesarean delivery over time. CONCLUSION: Almost 50% of pregnant women with HIV infection underwent cesarean delivery. Over time, the rate of repeat cesarean deliveries increased, whereas the rate of HIV-indicated cesarean deliveries decreased; cesarean deliveries were more likely to be performed in women at high risk of mother-to-child transmission. These findings reinforce the need for both early diagnosis and treatment of HIV infection in pregnancy and the option of vaginal delivery after cesarean among pregnant women with HIV infection.

Differences in Prevalence of Symptomatic Zika Virus Infection, by Age and Sex-Puerto Rico, 2016.

Background: During the outbreak of Zika virus (ZIKV) disease in Puerto Rico in 2016, nonpregnant women aged 20-39 years were disproportionately identified with ZIKV disease. We used household-based cluster investigations to determine whether this disparity was associated with age- or sex-dependent differences in the rate of ZIKV infection or reported symptoms. Methods: Participation was offered to residents of households within a 100-m radius of the residences of a convenience sample of 19 laboratory-confirmed ZIKV disease cases. Participants answered a questionnaire and provided specimens for diagnostic testing by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Results: Among 367 study participants, 114 (31.1%) were laboratory positive for ZIKV infection, of whom 30% reported a recent illness (defined as self-reported rash or arthralgia) attributable to ZIKV infection. Age and sex were not associated with ZIKV infection. Female sex (adjusted prevalence ratio [aPR], 2.28; 95% confidence interval [CI], 1.40, 3.67), age <40 years (aPR, 2.39; 95% CI, 1.55, 3.70), and asthma (aPR, 1.63; 95% CI, 1.12, 2.37) were independently associated with symptomatic infection. Conclusions: Although neither female sex nor age were associated with an increased prevalence of ZIKV infection, both were associated with symptomatic infection. Further investigation to identify a potential mechanism of age- and sex-dependent differences in reporting symptomatic ZIKV infection is warranted.