Faculty Bibliography

BACKGROUND:Contact tracing is an important public health tool for curbing the spread of infectious diseases. Effective and efficient contact tracing involves the rapid identification of individuals with infection and their exposed contacts and ensuring their isolation or quarantine, respectively. Manual contact tracing via telephone call and digital proximity app technology have been key strategies in mitigating the spread of COVID-19. However, many people are not reached for COVID-19 contact tracing due to missing telephone numbers or nonresponse to telephone calls. The New York City COVID-19 Trace program augmented the efforts of telephone-based contact tracers with information gatherers (IGs) to search and obtain telephone numbers or residential addresses, and community engagement specialists (CESs) made home visits to individuals that were not contacted via telephone calls. OBJECTIVE:The aim of this study was to assess the contribution of information gathering and home visits to the yields of COVID-19 contact tracing in New York City. METHODS:IGs looked for phone numbers or addresses when records were missing phone numbers to locate case-patients or contacts. CESs made home visits to case-patients and contacts with no phone numbers or those who were not reached by telephone-based tracers. Contact tracing management software was used to triage and queue assignments for the telephone-based tracers, IGs, and CESs. We measured the outcomes of contact tracing-related tasks performed by the IGs and CESs from July 2020 to June 2021. RESULTS:Of 659,484 cases and 861,566 contact records in the Trace system, 28% (185,485) of cases and 35% (303,550) of contacts were referred to IGs. IGs obtained new phone numbers for 33% (61,804) of case-patients and 11% (31,951) of contacts; 50% (31,019) of the case-patients and 46% (14,604) of the contacts with new phone numbers completed interviews; 25% (167,815) of case-patients and 8% (72,437) of contacts were referred to CESs. CESs attempted 80% (132,781) of case and 69% (49,846) of contact investigations, of which 47% (62,733) and 50% (25,015) respectively, completed interviews. An additional 12,192 contacts were identified following IG investigations and 13,507 following CES interventions. CONCLUSIONS:Gathering new or missing locating information and making home visits increased the number of case-patients and contacts interviewed for contact tracing and resulted in additional contacts. When possible, contact tracing programs should add information gathering and home visiting strategies to increase COVID-19 contact tracing coverage and yields as well as promote equity in the delivery of this public health intervention.

IMPORTANCE:Contact tracing is a core strategy for preventing the spread of many infectious diseases of public health concern. Better understanding of the outcomes of contact tracing for COVID-19 as well as the operational opportunities and challenges in establishing a program for a jurisdiction as large as New York City (NYC) is important for the evaluation of this strategy. OBJECTIVE:To describe the establishment, scaling, and maintenance of Trace, NYC's contact tracing program, and share data on outcomes during its first 17 months. DESIGN, SETTING, AND PARTICIPANTS:This cross-sectional study included people with laboratory test-confirmed and probable COVID-19 and their contacts in NYC between June 1, 2020, and October 31, 2021. Trace launched on June 1, 2020, and had a workforce of 4147 contact tracers, with the majority of the workforce performing their jobs completely remotely. Data were analyzed in March 2022. MAIN OUTCOMES AND MEASURES:Number and proportion of persons with COVID-19 and contacts on whom investigations were attempted and completed; timeliness of interviews relative to symptom onset or exposure for symptomatic cases and contacts, respectively. RESULTS:Case investigations were attempted for 941 035 persons. Of those, 840 922 (89.4%) were reached and 711 353 (75.6%) completed an intake interview (women and girls, 358 775 [50.4%]; 60 178 [8.5%] Asian, 110 636 [15.6%] Black, 210 489 [28.3%] Hispanic or Latino, 157 349 [22.1%] White). Interviews were attempted for 1 218 650 contacts. Of those, 904 927 (74.3%) were reached, and 590 333 (48.4%) completed intake (women and girls, 219 261 [37.2%]; 47 403 [8.0%] Asian, 98 916 [16.8%] Black, 177 600 [30.1%] Hispanic or Latino, 116 559 [19.7%] White). Completion rates were consistent over time and resistant to changes related to vaccination as well as isolation and quarantine guidance. Among symptomatic cases, median time from symptom onset to intake completion was 4.7 days; a median 1.4 contacts were identified per case. Median time from contacts' last date of exposure to intake completion was 2.3 days. Among contacts, 30.1% were tested within 14 days of notification. Among cases, 27.8% were known to Trace as contacts. The overall expense for Trace from May 6, 2020, through October 31, 2021, was approximately $600 million. CONCLUSIONS AND RELEVANCE:Despite the complexity of developing a contact tracing program in a diverse city with a population of over 8 million people, in this case study we were able to identify 1.4 contacts per case and offer resources to safely isolate and quarantine to over 1 million cases and contacts in this study period.

Understanding SARS-CoV-2 transmission within and among communities is critical for tailoring public health policies to local context. However, analysis of community transmission is challenging due to a lack of high-resolution surveillance and testing data. Here, using contact tracing records for 644,029 cases and their contacts in New York City during the second pandemic wave, we provide a detailed characterization of the operational performance of contact tracing and reconstruct exposure and transmission networks at individual and ZIP code scales. We find considerable heterogeneity in reported close contacts and secondary infections and evidence of extensive transmission across ZIP code areas. Our analysis reveals the spatial pattern of SARS-CoV-2 spread and communities that are tightly interconnected by exposure and transmission. We find that locations with higher vaccination coverage and lower numbers of visitors to points-of-interest had reduced within- and cross-ZIP code transmission events, highlighting potential measures for curtailing SARS-CoV-2 spread in urban settings.

This cross-sectional study examines more than 600 000 household contacts in New York City to characterize the risks of acquiring SARS-CoV-2 infection after household exposure.

BACKGROUND:COVID-19 vaccines have been available to all adults in the USA since April, 2021, but many adults remain unvaccinated. We aimed to assess the joint effect of a proof-of-vaccination requirement, incentive payments, and employer-based mandates on rates of adult vaccination in New York City (NYC). METHODS:We constructed a synthetic control group for NYC composed of other counties in the core of large, metropolitan areas in the USA. The vaccination outcomes for NYC were compared against those of the synthetic control group from July 26, 2021, to Nov 1, 2021, to determine the differential effects of the policies. Analyses were conducted on county-level vaccination data reported by the Centers for Disease Control and Prevention. The synthetic control group was constructed by matching on county-level preintervention vaccination outcomes, partisanship, economic attributes, demographics, and metropolitan area population. Statistical inference was conducted using placebo tests for non-treated counties. FINDINGS:The synthetic control group resembled NYC across attributes used in the matching process. The cumulative adult vaccination rate for NYC (in adults aged 18 years or older who received at least one dose of an authorised COVID-19 vaccine) increased from 72·5% to 89·4% (+16·9 percentage points [pp]) during the intervention period, compared with an increase from 72·5% to 83·2% (+10·7 pp) for the synthetic control group, a difference of 6·2 pp (95% CI 1·4-10·7), or 410 201 people (90 966-706 532). Daily vaccinations for NYC were consistently higher than those in the synthetic control group, a pattern that started shortly after the start of the intervention period. INTERPRETATION:The combination of a proof-of-vaccination requirement, incentive payments, and vaccine mandates increased vaccination rates among adults in NYC compared with jurisdictions that did not use the same measures. Whether the impact of these measures occurred by inducing more people to get vaccinated, or by accelerating vaccinations that would have occurred later, the increase in vaccination rates likely averted illness and death. FUNDING:None.

IMPORTANCE:COVID-19 booster vaccine can strengthen waning immunity and widen the range of immunity against new variants. OBJECTIVE:To describe geographic, occupational, and sociodemographic variations in uptake of COVID-19 booster doses among fully vaccinated US adults. DESIGN, SETTING, AND PARTICIPANTS:This cross-sectional survey study used data from the Household Pulse Survey conducted from December 1, 2021, to January 10, 2022. Household Pulse Survey is an online, probability-based survey conducted by the US Census Bureau and is designed to yield estimates nationally, by state, and across selected metropolitan areas. MAIN OUTCOMES AND MEASURES:Receipt of a booster dose was defined as taking 2 or more doses of COVID-19 vaccines with the first one being the Johnson and Johnson (Janssen) vaccine, or taking 3 or more doses of any of the other COVID-19 vaccines. Weighted prevalence estimates (percentages) were computed overall and among subgroups. Adjusted prevalence ratios (APRs) were calculated in a multivariable Poisson regression model to explore correlates of receiving a booster dose among those fully vaccinated. RESULTS:A total of 135 821 adults completed the survey. Overall, 51.0% were female and 41.5% were aged 18 to 44 years (mean [SD] age, 48.07 [17.18] years). Of fully vaccinated adults, the percentage who reported being boosted was 48.5% (state-specific range, from 39.1% in Mississippi to 66.5% in Vermont). Nationally, the proportion of boosted adults was highest among non-Hispanic Asian individuals (54.1%); those aged 65 years or older (71.4%); those with a doctoral, professional, or master's degree (68.1%); those who were married with no children in the household (61.2%); those with annual household income of $200 000 or higher (69.3%); those enrolled in Medicare (70.9%); and those working in hospitals (60.5%) or in deathcare facilities (eg, funeral homes; 60.5%). Conversely, only one-third of those who ever received a diagnosis of COVID-19, were enrolled in Medicaid, working in pharmacies, with less than a high school education, and aged 18 to 24 years old were boosted. Multivariable analysis of pooled national data revealed that compared with those who did not work outside their home, the likelihood of being boosted was higher among adults working in hospitals (APR, 1.23; 95% CI, 1.17-1.30), ambulatory health care centers (APR, 1.16; 95% CI, 1.09-1.24), and social service settings (APR, 1.08; 95% CI, 1.01-1.15), whereas lower likelihood was seen among those working in food or beverage stores (APR, 0.85; 95% CI, 0.74-0.96) and the agriculture, forestry, fishing, or hunting industries (APR, 0.83; 95% CI, 0.72-0.97). CONCLUSIONS AND RELEVANCE:These findings suggest continuing disparities in receipt of booster vaccine doses among US adults. Targeted efforts at populations with low uptake may be needed to improve booster vaccine coverage in the US.

Understanding SARS-CoV-2 transmission within and among communities is critical for tailoring public health policies to local context. However, analysis of community transmission is challenging due to a lack of high-resolution surveillance and testing data. Here, using contact tracing records for 644,029 cases and their contacts in New York City during the second pandemic wave, we provide a detailed characterization of the operational performance of contact tracing and reconstruct exposure and transmission networks at individual and ZIP code scales. We find considerable heterogeneity in reported close contacts and secondary infections and evidence of extensive transmission across ZIP code areas. Our analysis reveals the spatial pattern of SARS-CoV-2 spread and communities that are tightly interconnected by exposure and transmission. We find that higher vaccination coverage and reduced numbers of visitors to points-of-interest are associated with fewer within- and cross-ZIP code transmission events, highlighting potential measures for curtailing SARS-CoV-2 spread in urban settings.

OBJECTIVE:Because of their increased interaction with patients, healthcare workers (HCWs) face greater vulnerability to COVID-19 exposure than the general population. We examined prevalence and correlates of ever COVID-19 diagnosis and vaccine uncertainty among HCWs. DESIGN:Cross-sectional data from the Household Pulse Survey (HPS) conducted during July to October 2021. SETTING:HPS is designed to yield representative estimates of the US population aged ≥18 years nationally, by state and across selected metropolitan areas. PARTICIPANTS:Our primary analytical sample was adult HCWs in the New York Metropolitan area (n=555), with HCWs defined as individuals who reported working in a 'Hospital'; 'Nursing and residential healthcare facility'; 'Pharmacy' or 'Ambulatory healthcare setting'. In the entire national sample, n=25 909 HCWs completed the survey. Descriptive analyses were performed with HCW data from the New York Metropolitan area, the original epicentre of the pandemic. Multivariable logistic regression analyses were performed on pooled national HCW data to explore how HCW COVID-19-related experiences, perceptions and behaviours varied as a function of broader geographic, clinical and sociodemographic characteristics. RESULTS:Of HCWs surveyed in the New York Metropolitan area, 92.3% reported being fully vaccinated, and 20.9% had ever been diagnosed of COVID-19. Of the subset of HCWs in the New York Metropolitan area not yet fully vaccinated, 41.8% were vaccine unsure, 4.5% planned to get vaccinated for the first time soon, 1.6% had got their first dose but were not planning to receive the remaining dose, while 52.1% had got their first dose and planned to receive the remaining dose. Within pooled multivariable analysis of the national HCW sample, personnel in nursing/residential facilities were less likely to be fully vaccinated (adjusted OR, AOR 0.79, 95% CI 0.63 to 0.98) and more likely to report ever COVID-19 diagnosis (AOR 1.35, 95% CI 1.13 to 1.62), than those working in hospitals. Of HCWs not yet vaccinated nationally, vaccine-unsure individuals were more likely to be White and work in pharmacies, whereas vaccine-accepting individuals were more likely to be employed by non-profit organisations and work in ambulatory care facilities. Virtually no HCW was outrightly vaccine-averse, only unsure. CONCLUSIONS:Differences in vaccination coverage existed by individual HCW characteristics and healthcare operational settings. Targeted efforts are needed to increase vaccination coverage.

This cohort study assesses COVID-19 prevention measures against the Delta variant by measuring the secondary attack rate for cases in students, teachers, and staff of New York City public schools from October to December 2021 and analyzing the likely direction of transmission for secondary cases.