Effectiveness of a school district closure for pandemic influenza A (H1N1) on acute respiratory illnesses in the community: a natural experiment.

BACKGROUND: Following detection of pandemic influenza A H1N1 (pH1N1) in Dallas/Fort Worth, Texas, a school district (intervention community, [IC]) closed all public schools for 8 days to reduce transmission. Nearby school districts (control community [CC]) mostly remained open. METHODS: We collected household data to measure self-reported acute respiratory illness (ARI), before, during, and after school closures. We also collected influenza-related visits to emergency departments (ED(flu)). RESULTS: In both communities, self-reported ARIs and ED(flu) visits increased from before to during the school closure, but the increase in ARI rates was 45% lower in the IC (0.6% before to 1.2% during) than in the CC (0.4% before to 1.5% during) (RRR(During)(/Before) = 0.55, P < .001; adjusted OR(During/Before) = 0.49, P < .03). For households with school-aged children only (no children 0-5 years), IC had even lower increases in adjusted ARI than in the CC (adjusted OR(During/Before) = 0.28, P < .001). The relative increase of total ED(flu) visits in the IC was 27% lower (2.8% before to 4.4% during) compared with the CC (2.9% before to 6.2% during). Among children aged 6-18 years, the percentage of ED(flu) in IC remained constant (5.1% before vs 5.2% during), whereas in the CC it more than doubled (5.2% before vs 10.9% during). After schools reopened, ARI rates and ED(flu) visits decreased in both communities. CONCLUSIONS: Our study documents a reduction in ARI and ED(flu) visits in the intervention community. Our findings can be used to assess the potential benefit of school closures during pandemics.

Emergency health risk communication during the 2007 San Diego wildfires: comprehension, compliance, and recall.

In October 2007, wildfires burned nearly 300,000 acres in San Diego County, California. Emergency risk communication messages were broadcast to reduce community exposure to air pollution caused by the fires. The objective of this investigation was to determine residents' exposure to, understanding of, and compliance with these messages. From March to June 2008, the authors surveyed San Diego County residents using a 40-question instrument and random digit dialing. The 1,802 respondents sampled were predominantly 35-64 years old (65.9%), White (65.5%), and educated past high school (79.0%). Most (82.5%) lived more than 1 mile away from the fires, although many were exposed to smoky air for 5-7 days (60.7%) inside and outside their homes. Most persons surveyed reported hearing fire-related health messages (87.9%) and nearly all (97.9%) understood the messages they heard. Respondents complied with most to all of the nontechnical health messages, including staying inside the home (58.7%), avoiding outdoor exercise (88.4%), keeping windows and doors closed (75.8%), and wetting ash before cleanup (75.6%). In contrast, few (<5%) recalled hearing technical messages to place air conditioners on recirculate, use High-Efficiency Particulate Air filters, or use N-95 respirators during ash cleanup, and less than 10% of all respondents followed these specific recommendations. The authors found that nontechnical message recall, understanding, and compliance were high during the wildfires, and reported recall and compliance with technical messages were much lower. Future disaster health communication should further explore barriers to recall and compliance with technical recommendations.

Non-pharmaceutical interventions during an outbreak of 2009 pandemic influenza A (H1N1) virus infection at a large public university, April-May 2009.

Nonpharmaceutical interventions (NPIs), such as home isolation, social distancing, and infection control measures, are recommended by public health agencies as strategies to mitigate transmission during influenza pandemics. However, NPI implementation has rarely been studied in large populations. During an outbreak of 2009 Pandemic Influenza A (H1N1) virus infection at a large public university in April 2009, an online survey was conducted among students, faculty, and staff to assess knowledge of and adherence to university-recommended NPI. Although 3924 (65%) of 6049 student respondents and 1057 (74%) of 1401 faculty respondents reported increased use of self-protective NPI, such as hand washing, only 27 (6.4%) of 423 students and 5 (8.6%) of 58 faculty with acute respiratory infection (ARI) reported staying home while ill. Nearly one-half (46%) of student respondents, including 44.7% of those with ARI, attended social events. Results indicate a need for efforts to increase compliance with home isolation and social distancing measures.

Likely transmission of norovirus on an airplane, October 2008.

BACKGROUND: On 8 October 2008, members of a tour group experienced diarrhea and vomiting throughout an airplane flight from Boston, Massachusetts, to Los Angeles, California, resulting in an emergency diversion 3 h after takeoff. An investigation was conducted to determine the cause of the outbreak, assess whether transmission occurred on the airplane, and describe risk factors for transmission. METHODS: Passengers and crew were contacted to obtain information about demographics, symptoms, locations on the airplane, and possible risk factors for transmission. Case patients were defined as passengers with vomiting or diarrhea (> or =3 loose stools in 24 h) and were asked to submit stool samples for norovirus testing by real-time reverse-transcription polymerase chain reaction. RESULTS: Thirty-six (88%) of 41 tour group members were interviewed, and 15 (41%) met the case definition (peak date of illness onset, 8 October 2008). Of 106 passengers who were not tour group members, 85 (80%) were interviewed, and 7 (8%) met the case definition after the flight (peak date of illness onset, 10 October 2008). Multivariate logistic regression analysis showed that sitting in an aisle seat (adjusted relative risk, 11.0; 95% confidence interval, 1.4-84.9) and sitting near any tour group member (adjusted relative risk, 7.5; 95% confidence interval, 1.7-33.6) were associated with the development of illness. Norovirus genotype II was detected by reverse-transcription polymerase chain reaction in stool samples from case patients in both groups. CONCLUSIONS: Despite the short duration, transmission of norovirus likely occurred during the flight.

Comparison of 3 infrared thermal detection systems and self-report for mass fever screening.

Despite limited evidence regarding their utility, infrared thermal detection systems (ITDS) are increasingly being used for mass fever detection. We compared temperature measurements for 3 ITDS (FLIR ThermoVision A20M [FLIR Systems Inc., Boston, MA, USA], OptoTherm Thermoscreen [OptoTherm Thermal Imaging Systems and Infrared Cameras Inc., Sewickley, PA, USA], and Wahl Fever Alert Imager HSI2000S [Wahl Instruments Inc., Asheville, NC, USA]) with oral temperatures (≥ 100 °F = confirmed fever) and self-reported fever. Of 2,873 patients enrolled, 476 (16.6%) reported a fever, and 64 (2.2%) had a confirmed fever. Self-reported fever had a sensitivity of 75.0%, specificity 84.7%, and positive predictive value 10.1%. At optimal cutoff values for detecting fever, temperature measurements by OptoTherm and FLIR had greater sensitivity (91.0% and 90.0%, respectively) and specificity (86.0% and 80.0%, respectively) than did self-reports. Correlations between ITDS and oral temperatures were similar for OptoTherm (ρ = 0.43) and FLIR (ρ = 0.42) but significantly lower for Wahl (ρ = 0.14; p < 0.001). When compared with oral temperatures, 2 systems (OptoTherm and FLIR) were reasonably accurate for detecting fever and predicted fever better than self-reports.

Reporting patterns and characteristics of tuberculosis among international travelers, United States, June 2006 to May 2008.

BACKGROUND: As part of efforts to prevent the introduction of communicable diseases into the United States, the Centers for Disease Control and Prevention (CDC) conducts surveillance for selected diseases in international travelers. One of these diseases, tuberculosis (TB), received substantial attention in May 2007 when the CDC issued travel restrictions and a federal isolation order for a person with drug-resistant TB who traveled internationally against public health recommendations. METHODS: Reports of TB in international travelers in the CDC's Quarantine Activity Reporting System (QARS) from 1 June 2006 through 31 May 2007 (year 1) were compared with reports from 1 June 2007 through 31 May 2008 (year 2). These reports were classified using the CDC and American Thoracic Society guidelines and analyzed for epidemiologic characteristics and trends. RESULTS: Among QARS reports, 4.6% were classified as active TB disease and 1.7% as no TB disease. Active TB disease reports increased from 2.5% of QARS reports in year 1 to 6.4% in year 2 (p < .001). The proportion of active TB disease reports leading to a federal travel restriction increased from 6.8% in year 1 to 15.4% in year 2 (p = .08). CONCLUSIONS: The significant increase in reports of international travelers with TB disease likely represents more attention to and a higher index of suspicion for TB. The increased use of federal travel restrictions was associated with the development of new procedures to limit travel for public health reasons. Continued efforts are needed to decrease the number of persons with TB who travel while potentially contagious.

Nonpharmaceutical interventions implemented by US cities during the 1918-1919 influenza pandemic.

CONTEXT: A critical question in pandemic influenza planning is the role nonpharmaceutical interventions might play in delaying the temporal effects of a pandemic, reducing the overall and peak attack rate, and reducing the number of cumulative deaths. Such measures could potentially provide valuable time for pandemic-strain vaccine and antiviral medication production and distribution. Optimally, appropriate implementation of nonpharmaceutical interventions would decrease the burden on health care services and critical infrastructure. OBJECTIVES: To examine the implementation of nonpharmaceutical interventions for epidemic mitigation in 43 cities in the continental United States from September 8, 1918, through February 22, 1919, and to determine whether city-to-city variation in mortality was associated with the timing, duration, and combination of nonpharmaceutical interventions; altered population susceptibility associated with prior pandemic waves; age and sex distribution; and population size and density. DESIGN AND SETTING: Historical archival research, and statistical and epidemiological analyses. Nonpharmaceutical interventions were grouped into 3 major categories: school closure; cancellation of public gatherings; and isolation and quarantine. MAIN OUTCOME MEASURES: Weekly excess death rate (EDR); time from the activation of nonpharmaceutical interventions to the first peak EDR; the first peak weekly EDR; and cumulative EDR during the entire 24-week study period. RESULTS: There were 115,340 excess pneumonia and influenza deaths (EDR, 500/100,000 population) in the 43 cities during the 24 weeks analyzed. Every city adopted at least 1 of the 3 major categories of nonpharmaceutical interventions. School closure and public gathering bans activated concurrently represented the most common combination implemented in 34 cities (79%); this combination had a median duration of 4 weeks (range, 1-10 weeks) and was significantly associated with reductions in weekly EDR. The cities that implemented nonpharmaceutical interventions earlier had greater delays in reaching peak mortality (Spearman r = -0.74, P < .001), lower peak mortality rates (Spearman r = 0.31, P = .02), and lower total mortality (Spearman r = 0.37, P = .008). There was a statistically significant association between increased duration of nonpharmaceutical interventions and a reduced total mortality burden (Spearman r = -0.39, P = .005). CONCLUSIONS: These findings demonstrate a strong association between early, sustained, and layered application of nonpharmaceutical interventions and mitigating the consequences of the 1918-1919 influenza pandemic in the United States. In planning for future severe influenza pandemics, nonpharmaceutical interventions should be considered for inclusion as companion measures to developing effective vaccines and medications for prophylaxis and treatment.

Evaluation of effectiveness of a continuing education program on antimicrobial susceptibility testing.

OBJECTIVE: To evaluate the effectiveness of a course designed to increase use of the most recently published Clinical and Laboratory Standards Institute (CLSI) standards for antimicrobial susceptibility testing (AST) and reporting. DESIGN: A one-day continuing education course in AST was designed and delivered at multiple sites. Data collected from course evaluations, pre- and post-tests, and pre- and post-practices assessments were used to evaluate the effectiveness of the training. SETTING: The same course was held in 31 cities across the United States (US). PARTICIPANTS: Clinical laboratory scientists who attended the courses. MAIN OUTCOME MEASURES: Participant satisfaction; AST knowledge; number of labs using most recent CLSI standards; compliance with 28 specific CLSI AST recommendations. RESULTS: Data indicate a high level of participant satisfaction, a gain in AST knowledge, an increase in the number of laboratories acquiring the most recently published CLSI guidelines, and improvement in 4 of 28 specific AST practices.

Evaluation of the status of laboratory practices and the need for continuing education in medical mycology.

A survey to determine the need for training in medical mycology was sent to 605 US laboratories. Training needs were determined by comparing actual laboratory mycology practices with recommended practices, documenting the extent of mycology training reported by employees, and asking respondents to specify the fungi they considered most difficult to identify. The response rate was 56.7% (with only 316 laboratories providing sufficient information). Results showed a large degree of interlaboratory variation in practices and suggested that more judicious practices could lower costs and improve clinical relevance. Only 55.6% of laboratories reported that at least 1 employee attended a formal mycology continuing education program in the 4 years before the survey. Species of dermatophytes, dematiaceous fungi, and non-Candida yeasts were the most difficult to identify. Training may be needed in basic isolation procedures and in advanced topics such as identification of problematic molds and yeasts and antifungal susceptibility testing. Educators should consider clinical relevance and cost-containment without sacrificing quality when designing courses. Support for additional mycology training may improve if hospital and laboratory administrators are alerted to potential dangers and costs involved in treating patients with invasive fungal infections.

Assessing physician utilization of laboratory practice guidelines: barriers and opportunities for improvement.

OBJECTIVES: To assess physician utilization of laboratory practice guidelines (LPGs)³ to improve LPG uptake and use. DESIGN AND METHODS: A statewide survey of 4987 primary care physicians (PCPs) and 75 infectious disease (ID) specialists was conducted in 2005-2006 to correlate guideline source with users' awareness, utilization, and perceived usefulness of LPGs. We compared LPGs developed by the Centers for Disease Control and Prevention (CDC) to LPGs developed by the Washington State Department of Health through its Clinical Laboratory Advisory Council (CLAC). RESULTS: Physician awareness of LPGs was a major impediment to utilization of CLAC LPGs, and they were perceived as inaccessible, too numerous and unhelpful. However, once aware, respondents tended to use LPGs and there were no important differences in impediments or the ways CDC and CLAC LPGs were used. Of the PCPs who had a computerized physician order entry system (CPOE), a majority (92%) found, or expected that they would find, the integration of guidelines into their system helpful. CONCLUSIONS: For both CDC and CLAC LPGs, the greatest impediments to uptake were awareness and familiarity, which depended upon LPG source, physician specialty, and practice setting. There was no apparent impediment to uptake of CLAC or CDC LPGs based upon their credibility. Because better promotion could increase uptake, CLAC LPGs are now promoted by the Washington State Medical Association. Integration of LPGs into CPOE and smart phone applications could address major impediments to clinician use. The Cabana paradigm would be useful for any organization seeking to improve LPG impact.

A randomized, double-blind, controlled trial of the 17D yellow fever virus vaccine given in combination with immune globulin or placebo: comparative viremia and immunogenicity.

We evaluated whether coadministration of the yellow fever (YF) virus vaccine with human immunoglobulin (Ig) that contained YF virus-neutralizing antibodies would reduce post-vaccination viremia without compromising immunogenicity and thus, potentially mitigate YF vaccine-associated adverse events. We randomized 80 participants to receive either YF vaccine and Ig or YF vaccine and saline placebo. Participants were followed for 91 days for safety and assessments of viremia and immunogenicity. There were no differences found between the two groups in the proportion of vaccinated participants who developed viremia, seroconversion, cluster of differentiation (CD)-8(+) and CD4(+) T-cell responses, and cytokine responses. These results argue against one putative explanation for the increased reporting of YF vaccine side effects in recent years (i.e., a change in travel clinic practice after 1996 when hepatitis A prophylaxis with vaccine replaced routine use of pre-travel Ig, thus potentially removing an incidental YF vaccine-attenuating effect of anti-YF virus antibodies present in Ig).

Deaths in international travelers arriving in the United States, July 1, 2005 to June 30, 2008.

BACKGROUND: The Centers for Disease Control and Prevention's (CDC) Quarantine Activity Reporting System (QARS), which documents reports of morbidity and mortality among travelers, was analyzed to describe the epidemiology of deaths during international travel. METHODS: We analyzed travel-related deaths reported to CDC from July 1, 2005 to June 30, 2008, in which international travelers died (1) on a U.S.-bound conveyance, or (2) within 72 hours after arriving in the United States, or (3) at any time after arriving in the United States from an illness possibly acquired during international travel. We analyzed age, sex, mode of travel (eg, by air, sea, land), date, and cause of death, and estimated rates using generalized linear models. RESULTS: We identified 213 deaths. The median age of deceased travelers was 66 years (range 1-95); 65% were male. Most deaths (62%) were associated with sea travel; of these, 111 (85%) occurred in cruise ship passengers and 20 (15%) among cargo and cruise ship crew members. Of 81 air travel-associated deaths, 77 occurred in passengers, 3 among air ambulance patients, and 1 in a stowaway. One death was associated with land travel. Deaths were categorized as cardiovascular (70%), infectious disease (12%), cancer (6%), unintentional injury (4%), intentional injury (1%), and other (7%). Of 145 cardiovascular deaths with reported ages, 62% were in persons 65 years of age and older. Nineteen (73%) of 26 persons who died from infectious diseases had chronic medical conditions. There was significant seasonal variation (lowest in July-September) in cardiovascular mortality in cruise ship passengers. CONCLUSIONS: Cardiovascular conditions were the major cause of death for both sexes. Travelers should seek pre-travel medical consultation, including guidance on preventing cardiovascular events, infections, and injuries. Persons with chronic medical conditions and the elderly should promptly seek medical care if they become ill during travel.

Tuberculosis investigations associated with air travel: U. S. Centers for Disease Control and Prevention, January 2007-June 2008.

INTRODUCTION: Contact investigations conducted in the United States of persons with tuberculosis (TB) who traveled by air while infectious have increased. However, data about transmission risks of Mycobacterium tuberculosis on aircraft are limited. METHODS: We analyzed data on index TB cases and passenger contacts from contact investigations initiated by the U.S. Centers for Disease Control and Prevention from January 2007 through June 2008. RESULTS: Contact investigations for 131 index cases met study inclusion criteria, including 4550 passenger contacts. U.S. health departments reported TB screening test results for 758 (22%) of assigned contacts; 182 (24%) had positive results. Of the 142 passenger contacts with positive TB test results with information about risk factors for prior TB infection, 130 (92%) had at least one risk factor and 12 (8%) had no risk factors. Positive TB test results were significantly associated with risk factors for prior TB infection (OR 23; p<0.001). No cases of TB disease among passenger contacts were reported. CONCLUSION: The risks of M. tuberculosis transmission during air travel remain difficult to quantify. Definitive assessment of transmission risks during flights and determination of the effectiveness of contact-tracing efforts will require comprehensive cohort studies.

Knowledge, attitudes, and practices of US travelers to Asia regarding seasonal influenza and H5N1 avian influenza prevention measures.

BACKGROUND: International travel is a potential risk factor for the spread of influenza. In the United States, approximately 5%-20% of the population develops an influenza-like illness annually. The purpose of this study was to describe the knowledge, attitude, and practices of US travelers to Asia regarding seasonal influenza and H5N1 avian influenza (AI) prevention measures. METHODS: We surveyed travelers to Asia waiting at the departure lounges of 38 selected flights at four international airports in New York, Chicago, Los Angeles, and San Francisco. Of the 1,301 travelers who completed the pre-travel survey, 337 also completed a post-travel survey. Univariate and multivariate logistic regression were used to calculate prevalence odds ratios (with 95% CI) to compare foreign-born (FB) to US-born travelers for various levels of knowledge and behaviors. RESULTS: Although the majority of participants were aware of influenza prevention measures, only 41% reported receiving the influenza vaccine during the previous season. Forty-three percent of participants reported seeking at least one type of pre-travel health advice, which was significantly higher among US-born, Caucasians, traveling for purposes other than visiting friends and relatives, travelers who received the influenza vaccine during the previous season, and those traveling with a companion. Our study also showed that Asians, FB travelers, and those working in occupations other than health care/animal care were less likely to recognize H5N1 AI transmission risk factors. CONCLUSION: The basic public health messages for preventing influenza appear to be well understood, but the uptake of influenza vaccine was low. Clinicians should ensure that all patients receive influenza vaccine prior to travel. Tailored communication messages should be developed to motivate Asians, FB travelers, those visiting friends and relatives, and those traveling alone to seek pre-travel health advice as well as to orient them with H5N1 AI risk factors.