Evaluation of Public Health Contact Tracing for Mpox Among Gay, Bisexual, and Other Men Who Have Sex With Men-10 US Jurisdictions, May 17-July 31, 2022.

Objectives. To examine the potential impact of contact tracing to identify contacts and prevent mpox transmission among gay, bisexual, and other men who have sex with men (MSM) as the outbreak expanded. Methods. We assessed contact tracing outcomes from 10 US jurisdictions before and after access to the mpox vaccine was expanded from postexposure prophylaxis for persons with known exposure to include persons at high risk for acquisition (May 17-June 30, 2022, and July 1-31, 2022, respectively). Results. Overall, 1986 mpox cases were reported in MSM from included jurisdictions (240 before expanded vaccine access; 1746 after expanded vaccine access). Most MSM with mpox were interviewed (95.0% before vaccine expansion and 97.0% after vaccine expansion); the proportion who named at least 1 contact decreased during the 2 time periods (74.6% to 38.9%). Conclusions. During the period when mpox cases among MSM increased and vaccine access expanded, contact tracing became less efficient at identifying exposed contacts. Public Health Implications. Contact tracing was more effective at identifying persons exposed to mpox in MSM sexual and social networks when case numbers were low, and it could be used to facilitate vaccine access. (Am J Public Health. 2023;113(7):815-818. https://doi.org/10.2105/AJPH.2023.307301).

Acute health effects after exposure to chlorine gas released after a train derailment.

In January 2005, a train derailment on the premises of a textile mill in South Carolina released 42 to 60 tons of chlorine gas in the middle of a small town. Medical records and autopsy reports were reviewed to describe the clinical presentation, hospital course, and pathology observed in persons hospitalized or deceased as a result of chlorine gas exposure. Eight persons died before reaching medical care; of the 71 persons hospitalized for acute health effects as a result of chlorine exposure, 1 died in the hospital. The mean age of the hospitalized persons was 40 years (range, 4 months-76 years); 87% were male. The median duration of hospitalization was 4 days (range, 1-29 days). Twenty-five (35%) persons were admitted to the intensive care unit; the median length of stay was 3 days. Many surviving victims developed significant pulmonary signs and severe airway inflammation; 41 (58%) hospitalized persons met PO2/FiO2 criteria for acute respiratory distress syndrome or acute lung injury. During their hospitalization, 40 (57%) developed abnormal x-ray findings, 74% of those within the first day. Hypoxia on room air and PO2/FiO2 ratio predicted severity of outcome as assessed by the duration of hospitalization and the need for intensive care support. This community release of chlorine gas caused widespread exposure and resulted in significant acute health effects and substantial health care requirements. Pulse oximetry and arterial blood gas analysis provided early indications of outcome severity.

Panel classification of self-reported exposure histories: a useful exposure index after a mass-casualty event.

OBJECTIVE: Although rapid epidemiologic investigations of toxic exposures require estimates of individual exposure levels, objective measures of exposure are often unavailable. We investigated whether self-reported exposure histories, when reviewed and classified by a panel of raters, provided a useful exposure metric. METHODS: A panel reviewed exposure histories as reported by people who experienced a chlorine release. The panelists received no information about health-care requirements or specific health effects. To each exposure case, each panelist assigned one of five possible exposure severity ratings. When assigned ratings were not in initial agreement, the panelists discussed the case and assigned a consensus rating. Percent agreement and kappa statistics assessed agreement among panelists, Kendall's W measured agreement among panelists in their overall ordering of the exposure histories, and Spearman's rho compared the resultant rankings with individual health outcome. RESULTS: In 48% of the cases, the panelists' initial ratings agreed completely. Overall, initial ratings for a given case matched the consensus rating 69% to 89% of the time. Pair-wise comparisons revealed 85% to 95% agreement among panelists, with weighted kappa statistics between 0.69 and 0.83. In their overall ranking of the exposure histories, the panelists reached significant agreement (W = 0.90, p < 0.0001). Disagreement arose most frequently regarding probable chlorine concentration and duration of exposure. This disagreement was most common when panelists differentiated between adjacent categories of intermediate exposure. Panel-assigned exposure ratings significantly correlated with health outcome (Spearman's rho = 0.56; p < 0.0001). CONCLUSION: Epidemiologists and public health practitioners can elicit and review self-reported exposure histories and assign exposure severity ratings that predict medical outcome. When objective markers of exposure are unavailable, panel-assigned exposure ratings may be useful for rapid epidemiologic investigations.

Public health investigation after the discovery of ricin in a South Carolina postal facility.

OBJECTIVES: In October 2003, a package containing ricin and a note threatening to poison water supplies was discovered in a South Carolina postal facility, becoming the first potential chemical terrorism event involving ricin in the United States. We examined the comprehensive public health investigation that followed and discuss the lessons learned from it. METHODS: An investigation consisting primarily of environmental sampling for ricin contamination, performance of health assessments on affected personnel, and local, regional, and national surveillance for ricin-associated illness. RESULTS: Laboratory analysis of 75 environmental sampling specimens revealed no ricin contamination. Health assessments of 36 affected employees were completed. Local surveillance initially identified 3 suspected cases, and national surveillance identified 399 outliers during the 2-week period after the incident. No confirmed cases of ricin-associated illness were identified. CONCLUSIONS: A multifaceted and multidisciplinary approach is required for an effective public health response to a chemical threat such as ricin. The results of all of the described activities were used to determine that the facility was safe to reopen and that no public health threat existed.