Enhanced contact investigations for nine early travel-related cases of SARS-CoV-2 in the United States

Coronavirus disease 2019 (COVID-19), the respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in Wuhan, China and has since become pandemic. In response to the first cases identified in the United States, close contacts of confirmed COVID-19 cases were investigated to enable early identification and isolation of additional cases and to learn more about risk factors for transmission. Close contacts of nine early travel-related cases in the United States were identified and monitored daily for development of symptoms (active monitoring). Selected close contacts (including those with exposures categorized as higher risk) were targeted for collection of additional exposure information and respiratory samples. Respiratory samples were tested for SARS-CoV-2 by real-time reverse transcription polymerase chain reaction at the Centers for Disease Control and Prevention. Four hundred four close contacts were actively monitored in the jurisdictions that managed the travel-related cases. Three hundred thirty-eight of the 404 close contacts provided at least basic exposure information, of whom 159 close contacts had ≥1 set of respiratory samples collected and tested. Across all actively monitored close contacts, two additional symptomatic COVID-19 cases (i.e., secondary cases) were identified; both secondary cases were in spouses of travel-associated case patients. When considering only household members, all of whom had ≥1 respiratory sample tested for SARS-CoV-2, the secondary attack rate (i.e., the number of secondary cases as a proportion of total close contacts) was 13% (95% CI: 4-38%). The results from these contact tracing investigations suggest that household members, especially significant others, of COVID-19 cases are at highest risk of becoming infected. The importance of personal protective equipment for healthcare workers is also underlined. Isolation of persons with COVID-19, in combination with quarantine of exposed close contacts and practice of everyday preventive behaviors, is important to mitigate spread of COVID-19.

Enhanced contact investigations for nine early travel-related cases of SARS-CoV-2 in the United States

Coronavirus disease 2019 (COVID-19), the respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in Wuhan, China and has since become pandemic. In response to the first cases identified in the United States, close contacts of confirmed COVID-19 cases were investigated to enable early identification and isolation of additional cases and to learn more about risk factors for transmission. Close contacts of nine early travel-related cases in the United States were identified and monitored daily for development of symptoms (active monitoring). Selected close contacts (including those with exposures categorized as higher risk) were targeted for collection of additional exposure information and respiratory samples. Respiratory samples were tested for SARS-CoV-2 by real-time reverse transcription polymerase chain reaction at the Centers for Disease Control and Prevention. Four hundred four close contacts were actively monitored in the jurisdictions that managed the travel-related cases. Three hundred thirty-eight of the 404 close contacts provided at least basic exposure information, of whom 159 close contacts had ≥1 set of respiratory samples collected and tested. Across all actively monitored close contacts, two additional symptomatic COVID-19 cases (i.e., secondary cases) were identified; both secondary cases were in spouses of travel-associated case patients. When considering only household members, all of whom had ≥1 respiratory sample tested for SARS-CoV-2, the secondary attack rate (i.e., the number of secondary cases as a proportion of total close contacts) was 13% (95% CI: 4-38%). The results from these contact tracing investigations suggest that household members, especially significant others, of COVID-19 cases are at highest risk of becoming infected. The importance of personal protective equipment for healthcare workers is also underlined. Isolation of persons with COVID-19, in combination with quarantine of exposed close contacts and practice of everyday preventive behaviors, is important to mitigate spread of COVID-19.

Active Monitoring of Persons Exposed to Patients with Confirmed COVID-19 - United States, January-February 2020

In December 2019, an outbreak of coronavirus disease 2019 (COVID-19), caused by the virus SARS-CoV-2, began in Wuhan, China (1). The disease spread widely in China, and, as of February 26, 2020, COVID-19 cases had been identified in 36 other countries and territories, including the United States. Person-to-person transmission has been widely documented, and a limited number of countries have reported sustained person-to-person spread.* On January 20, state and local health departments in the United States, in collaboration with teams deployed from CDC, began identifying and monitoring all persons considered to have had close contact^† with patients with confirmed COVID-19 (2). The aims of these efforts were to ensure rapid evaluation and care of patients, limit further transmission, and better understand risk factors for transmission.

Active Monitoring of Persons Exposed to Patients with Confirmed COVID-19 - United States, January-February 2020

In December 2019, an outbreak of coronavirus disease 2019 (COVID-19), caused by the virus SARS-CoV-2, began in Wuhan, China (1). The disease spread widely in China, and, as of February 26, 2020, COVID-19 cases had been identified in 36 other countries and territories, including the United States. Person-to-person transmission has been widely documented, and a limited number of countries have reported sustained person-to-person spread.* On January 20, state and local health departments in the United States, in collaboration with teams deployed from CDC, began identifying and monitoring all persons considered to have had close contact^† with patients with confirmed COVID-19 (2). The aims of these efforts were to ensure rapid evaluation and care of patients, limit further transmission, and better understand risk factors for transmission.

Active Monitoring of Persons Exposed to Patients with Confirmed COVID-19 - United States, January-February 2020

In December 2019, an outbreak of coronavirus disease 2019 (COVID-19), caused by the virus SARS-CoV-2, began in Wuhan, China (1). The disease spread widely in China, and, as of February 26, 2020, COVID-19 cases had been identified in 36 other countries and territories, including the United States. Person-to-person transmission has been widely documented, and a limited number of countries have reported sustained person-to-person spread.* On January 20, state and local health departments in the United States, in collaboration with teams deployed from CDC, began identifying and monitoring all persons considered to have had close contact^† with patients with confirmed COVID-19 (2). The aims of these efforts were to ensure rapid evaluation and care of patients, limit further transmission, and better understand risk factors for transmission.

Use of tobacco retail permitting to reduce youth access and exposure to tobacco in Santa Clara County, California

OBJECTIVE

To target youth smoking, the impact of a local tobacco retail permit was evaluated on the number and location of tobacco retailers, and on the level of enforcement and compliance with tobacco sales regulations from 2010 to 2012 within unincorporated Santa Clara County, California.

METHODS

Geographic Information Systems (GIS) mapping of each of 36 tobacco retailers pre- and post-intervention, observational surveys of tobacco retail environments pre- and post-intervention, and post-intervention enforcement surveys to measure location of sales, level of enforcement action, and compliance with laws governing sale of tobacco products were conducted.

RESULTS

Eleven (30.6%) of the initial 36 retailers selling tobacco at the start of the intervention stopped selling tobacco post intervention. Of these 11 retailers, one was within 500feet of another retailer, and three were within 1000feet of a K-12 school. Ten (91%) of the retailers who stopped selling tobacco were non-traditional retailers.

CONCLUSION

An immediate reduction in the number of stores selling tobacco occurred following implementation of tobacco retail permitting. Post-implementation, all retailers who underwent compliance checks were in compliance with laws prohibiting sales of tobacco to minors. Compliance with laws governing the sale of tobacco has potential to reduce access and use of tobacco products by youth.

Viral meningitis in child care center staff and parents: an outbreak of echovirus 30 infections

OBJECTIVE

A report of five cases of viral meningitis among adults with children enrolled in a child care center prompted an investigation of risk factors for viral transmission from children to adult household members.

METHODS

To determine recent echovirus 30 (E30) infections, the authors conducted a serologic survey. To determine risk factors for infection among adult household members, they conducted a retrospective cohort study using written questionnaires.

RESULTS

Recent E30 infections were found in 84% of children tested, 57% of adult household members tested, and 47% of staff members tested. Infected adults were more likely than infected children to have clinical meningitis. Among adult household members, changing diapers was a risk factor for recent infection. Women who changed > or = 90 diapers per month had a higher infection rate than women who changed fewer diapers; in contrast, men who changed > or = 90 diapers per month had a lower infection rate than men who changed fewer diapers. Handwashing was protective: there was a negative correlation between handwashing after diaper changes and E30 infection among adults with infected children in diapers.

CONCLUSIONS

Because child care centers can be a source of enteroviral infections among adult household members, adults with viral meningitis should be questioned about their children's day care or preschool attendance. The importance of handwashing should be stressed to adults with children in day care.

Continuing high prevalence of HIV and risk behaviors among young men who have sex with men: the young men's survey in the San Francisco Bay Area in 1992 to 1993 and in 1994 to 1995

Several recent studies have shown high rates of HIV infection and risk behavior among young men who have sex with men (MSM). To assess the direction of the epidemic in this population, we replicated a venue-based study performed in the San Francisco Bay Area during 1992 and 1993. From May 1994 to September 1995, we surveyed 675 MSM aged between 17 and 22. After statistical adjustment for age, ethnicity, residence, and site of recruitment, seroprevalence did not change significantly between the 1992 to 1993 (8.4%) and the 1994 to 1995 (6.7%) surveys. Similarly, no significant changes were found in the rates during the previous 6 months of unprotected receptive anal intercourse (23.4% versus 24.9%), injection drug use (8.0% versus 7.8%), or needle sharing among injection drug users (56.3% versus 64.5%) between the two surveys. Despite the increased attention that the problem of high risk behavior among young MSM has received, effective prevention interventions for MSM are needed as profoundly now as they had been several years ago.

Development of a population-specific risk assessment to predict elevated blood lead levels in Santa Clara County, California

OBJECTIVES

To determine: (1) the prevalence of a blood lead level (PbB) of 10 micrograms/dL or greater and 20 micrograms/dL or greater among children aged 6 to 72 months attending the Santa Clara County (SCC), California, public clinics, (2) risk factors for elevated PbB in this population, and (3) whether an SCC public clinic population-specific risk-assessment tool and a five-question lead poisoning questionnaire developed by the Centers for Disease Control and Prevention are useful for prospectively identifying children at higher risk for elevated PbB.

METHODS

We tested for PbB 3630 children aged 6 to 72 months attending SCC public outpatient clinics between August 8, 1991, and September 1, 1992. We then conducted two matched case-control studies. Five local risk-factor questions were combined with the CDC's five-question lead poisoning questionnaire, and from May 1, 1993, to June 30, 1993, we conducted risk assessments on 247 children tested for PbB.

RESULTS

Two hundred twenty-two of 3630 children (6.1%) had a PbB of 10 micrograms/dL or greater. Thirty-nine (1.1%) had a PbB at least 20 micrograms/dL. Seventy-nine percent of the children screened and 91.0% of the children with PbB at least 10 micrograms/dL were Hispanic. Twenty percent of Mexican-born Hispanic children had a PbB of 10 micrograms/dL or greater, versus 7% of U.S.-born Hispanic children. Several factors were associated with elevated PbB among Hispanic children. For identifying children with a PbB of at least 10 micrograms/dL, the sensitivity and predictive value negative for the CDC's "high risk" definition were 30% and 93%, respectively, whereas for the SCC population-specific high-risk definition, the sensitivity was 90% and the predictive value negative was 98%.

CONCLUSIONS

Hispanic children attending SCC public clinics have risk factors for elevated PbB that were not included in the CDC's lead poisoning questionnaire. Methods for prioritizing the frequency of lead screening may be improved by combining the CDC's questions with a population-specific risk assessment.

School-based screening for tuberculous infection. A cost-benefit analysis

OBJECTIVE

To compare tuberculin screening of all kindergartners and high school entrants (screen-all strategy) vs screening limited to high-risk children (targeted screening).

DESIGN

Decision, cost-effectiveness, and cost-benefit analyses.

SETTING AND SUBJECTS

Students in a large urban and rural county.

DEFINITIONS

High risk of tuberculosis infection was defined as birth in a county with a high prevalence of tuberculosis. Low risk was defined as birth in the United States.

OUTCOME MEASURES

Tuberculosis cases prevented for 10, 000 children screened. Net costs, net cost per case prevented, benefit-cost ratio, and incremental cost-effectiveness.

RESULTS

The screen-all strategy would prevent 14.9 cases per 10,000 children screened; targeted screening would prevent 84.9 cases per 10,000 children screened. The screen-all strategy is more costly than no screening; the benefit-cost ratio is 0.58. Targeted screening would result in a net savings; the benefit-cost ratio is 1.2. Screening all children is cost saving only if the reactor rate is 20% or greater. The cost per additional case prevented for screening all children compared with targeted screening (+34 666) is more than twice as high as treatment and contact tracing for a case of tuberculosis (+16 392).

CONCLUSIONS

Targeted screening of schoolchildren is much less costly than mass screening and is more efficient in prevention of tuberculosis.

Prevalence of measles antibodies in adults with HIV infection: possible risk factors of measles seronegativity

OBJECTIVES

To determine the prevalence of measles (rubeola) immunity in a group of HIV-1-infected adults and to examine predictors of measles seronegativity in this population.

SETTING

County hospital outpatient clinic and public-health department early HIV intervention clinic.

PATIENTS

A total of 262 HIV-infected adults presenting to outpatient clinics between September 1990 and January 1991.

INTERVENTIONS

Patients were screened for the presence of measles immunoglobulin G antibody, as measured by an enzyme-linked immunosorbent assay (ELISA). Pertinent clinical and immunologic information was recorded. Univariate and multivariate analyses were performed to identify possible risk factors for measles seronegativity.

MAIN OUTCOME MEASURE

Measles seronegativity, as defined by a lack of detectable antibody (ELISA predicted index value < 1.0).

RESULTS

Thirteen (5%) patients lacked serologic evidence of immunity. Risk factors for measles seronegativity included year of birth in 1957 or later, Caucasian (non-Hispanic) race and oral hairy leukoplakia. Factors associated with progressive HIV disease (other than hairy leukoplakia) were not associated with a lack of existing immunity.

CONCLUSIONS

A high prevalence (95%) of measles antibody was found in this large group of HIV-infected adults. Young, white individuals born in 1957 or later were at the greatest risk for measles seronegativity, but declining immunity due to progressive HIV infection did not appear to be associated with a lack of antibody. Self-reported histories of measles infection or immunization were not reliable predictors of measles immunity.

Targeting AIDS prevention and treatment toward HIV-1-infected persons. The concept of early intervention

We propose establishing private and public outpatient facilities where persons with human immunodeficiency virus, type 1 (HIV-1), infection can receive state-of-the-art clinical and behavioral follow-up, treatment, and assistance. The possible advantages of enrolling HIV-1-positive persons into long-term follow-up are early treatment of clinical conditions and resulting gains in life quality and life expectancy, decreased transmission of HIV-1 to uninfected persons, more efficient use of scarce patient-care resources, and improved estimates of the total number of HIV-infected persons. The possible disadvantages of such a program are adverse psychological reactions to knowledge of HIV-1 infection, adverse societal actions against infected persons, and, finally, the economic cost of the program. These facilities, with the proper expertise and safeguards of confidentiality and trust, could prolong and improve the lives of infected persons while preventing infection of others.