In April 2009, 2009 pandemic influenza A (H1N1) (hereafter, pH1N1) virus was identified in California, which caused widespread illness throughout the United States. We evaluated pH1N1 transmission among exposed healthcare personnel (HCP) and assessed the use and effectiveness of personal protective equipment (PPE) early in the outbreak.

Cohort study.

Two hospitals and 1 outpatient clinic in Southern California during March 28-April 24, 2009.

Sixty-three HCP exposed to 6 of the first 8 cases of laboratory-confirmed pH1N1 in the United States.

Baseline and follow-up questionnaires were used to collect demographic, epidemiologic, and clinical data. Paired serum samples were obtained to test for pH1N1-specific antibodies by microneutralization and hemagglutination-inhibition assays. Serology results were compared with HCP work setting, role, and self-reported PPE use.

Possible healthcare-associated pH1N1 transmission was identified in 9 (14%) of 63 exposed HCP; 6 (67%) of 9 seropositive HCP had asymptomatic infection. The highest attack rates occurred among outpatient HCP (6/19 [32%]) and among allied health staff (eg, technicians; 8/33 [24%]). Use of mask or N95 respirator was associated with remaining seronegative (P = .047). Adherence to PPE recommendations for preventing transmission of influenza virus and other respiratory pathogens was inadequate, particularly in outpatient settings.

pH1N1 transmission likely occurred in healthcare settings early in the pandemic associated with inadequate PPE use. Organizational support for a comprehensive approach to infectious hazards, including infection prevention training for inpatient- and outpatient-based HCP, is essential to improve HCP and patient safety.

Thailand is one of 22 countries designated by the World Health Organization as “high burden” with regard to tuberculosis. Preventing nosocomial tuberculosis transmission remains an important, unmet need. We investigated the adequacy of current practices to evaluate hospitalized patients for tuberculosis, which is critical in preventing delayed diagnosis and nosocomial tuberculosis transmission.

Thailand conducts active, population-based surveillance for pneumonia in 2 rural provinces. Case report forms are completed for all persons who are hospitalized and meet a case definition of having clinical pneumonia. We analyzed how frequently patients had an adequate diagnostic evaluation for infectious pulmonary tuberculosis, in accordance with national guidelines. We conducted multivariate analyses to determine patient and health-system factors associated with an inadequate diagnostic evaluation for tuberculosis and with tuberculosis disease.

Of 8,853 cases of clinical pneumonia between September 2003 and March 2006,73% were in patients not adequately evaluated for tuberculosis. Acid-fast bacilli (AFB)–positive tuberculosis was diagnosed in 188 cases, which was 2% of all pneumonia cases and 12% of pneumonia cases in patients adequately evaluated for tuberculosis. Diagnostic evaluations for tuberculosis were less commonly performed among those who were younger than 25 years of age, were female, and lacked cough, sputum production, hemoptysis, and dyspnea. Among patients adequately evaluated, a clinical syndrome of no cough, no hemoptysis, and normal chest radiography findings had a 95% negative predictive value.

The prevalence of AFB-positive, pulmonary tuberculosis was high among adults hospitalized with clinical pneumonia in Thailand. Most patients were not adequately evaluated for tuberculosis. Efforts are needed to improve identification and diagnosis of infectious tuberculosis cases in hospitalized patients.