Avian influenza H5N1 screening of intensive care unit patients with community-acquired pneumonia

Economic Burden of Influenza in Thailand: A Systematic Review

Thailand has a high incidence and high mortality rates of influenza. This study summarizes the evidence on economic burden or costs of influenza subsequent to the occurrence of influenza illness in the Thai population by specific characteristics such as population demographics, health conditions, healthcare facilities, and/or cost types from published literature. A systematic search was conducted in six electronic databases. All costs were extracted and adjusted to 2018 US dollar value. Out of 581 records, 11 articles (1 with macroeconomic analysis and 10 with microeconomic analyses) were included. Direct medical costs per episode for outpatients and inpatients ranged from US$4.21 to US$212.17 and from US$163.62 to US$4577.83, respectively, across distinct influenza illnesses. The overall burden of influenza was between US$31.1 and US$83.6 million per year and 50-53% of these estimates referred to lost productivity. Costs of screening for an outbreak of influenza at an 8-bed-intensive-care-unit hospital was US$38242.75 per year. Labor-sensitive sectors such as services were the most affected part of the Thai economy. High economic burden tended to occur among children and older adults with co-morbidities and to be related to complications, non-vaccinated status, and severe influenza illness. Strategies involving prevention, limit of transmission, and treatment focusing on aforementioned patients’ factors, containment of hospitalization expenses and quarantine process, and assistance on labor-sensitive economy sectors are likely to reduce the economic burden of influenza. However, a research gap exists regarding knowledge about the economic burden of influenza in Thailand.

Serological evidence of human infections with highly pathogenic avian influenza A(H5N1) virus: a systematic review and meta-analysis

BACKGROUND

Highly pathogenic avian influenza A(H5N1) virus poses a global public health threat given severe and fatal zoonotic infections since 1997 and ongoing A(H5N1) virus circulation among poultry in several countries. A comprehensive assessment of the seroprevalence of A(H5N1) virus antibodies remains a gap and limits understanding of the true risk of A(H5N1) virus infection.

METHODS

We conducted a systematic review and meta-analysis of published serosurveys to assess the risk of subclinical and clinically mild A(H5N1) virus infections. We assessed A(H5N1) virus antibody titers and changes in titers among populations with variable exposures to different A(H5N1) viruses.

RESULTS

Across studies using the World Health Organization-recommended seropositive definition, the point estimates of the seroprevalence of A(H5N1) virus-specific antibodies were higher in poultry-exposed populations (range 0-0.6%) and persons exposed to both human A(H5N1) cases and infected birds (range 0.4-1.8%) than in close contacts of A(H5N1) cases or the general population (none to very low frequencies). Seroprevalence was higher in persons exposed to A(H5N1) clade 0 virus (1.9%, range 0.7-3.2%) than in participants exposed to other clades of A(H5N1) virus (range 0-0.5%) (p < 0.05). Seroprevalence was higher in poultry-exposed populations (range 0-1.9%) if such studies utilized antigenically similar A(H5N1) virus antigens in assays to A(H5N1) viruses circulating among poultry.

CONCLUSIONS

These low seroprevalences suggest that subclinical and clinically mild human A(H5N1) virus infections are uncommon. Standardized serological survey and laboratory methods are needed to fully understand the extent and risk of human A(H5N1) virus infections.

Outbreaks of Influenza A Among Nonvaccinated Healthcare Workers: Implications for Resource-Limited Settings

We identified 3 outbreaks of influenza A (attack rates, 18%–24%) among Thai healthcare workers in intensive care units. All outbreaks were epidemiologically linked to an index patient with pneumonia due to influenza A virus (subtype H3N2). The investigations of these outbreaks incurred costs that exceeded the estimated costs of healthcare worker influenza vaccination by more than 10-fold.

Reduction of seasonal influenza transmission among healthcare workers in an intensive care unit: a 4-year intervention study in Thailand

OBJECTIVE

To evaluate the feasibility and effectiveness of an influenza control bundle to minimize healthcare-associated seasonal influenza transmission among healthcare workers (HCWs) in an intensive care unit (ICU) equipped with central air conditioning.

METHODS

A quasi-experimental study was conducted in a 500-bed tertiary care center in Thailand from July 1, 2005, through June 30,2009. The medical ICU (MICU) implemented an influenza control bundle including healthcare worker (HCW) education, influenza screening of adult community-acquired pneumonia patients, antiviral treatment of patients and ill HCWs who tested positive for influenza, promotion of influenza vaccination among HCWs, and reinforcement of standard infection control policies. The surgical ICU (SICU) and coronary care unit (CCU) received no intervention.

RESULTS

The numbers of influenza infections among HCWs during the pre- and postintervention periods were 18 cases in 5,294 HCW days and 0 cases in 5,336 HCW-days in the MICU (3.4 vs 0 cases per 1,000 HCW-days; P ! .001), 19 cases in 4,318 HCW-days and 20 cases in 4,348 HCW-days in the SICU (4.4 vs 4.6 cases per 1,000 HCW-days; Pp.80), and 18 cases in 5,000 HCW-days and 18 cases in 5,143 HCW-days in the CCU (3.6 vs 3.5 cases per 1,000 HCW-days; Pp.92), respectively. Outbreak-related influenza occurred in 7 MICUHCWs, 6 SICU HCWs, and 4 CCU HCWs before intervention and 0 MICU HCWs, 9 SICU HCWs, and 8 CCU HCWs after intervention.Before and after intervention, 25 (71%) and 35 (100%) of 35 MICU HCWs were vaccinated, respectively (P ! .001); HCW vaccination coverage did not change significantly in the SICU (21 [70%] of 30 vs 24 [80%] of 30; Pp.89) and CCU (19 [68%] of 28 vs 21 [75%]of 28; Pp.83). The estimated costs of US $6,471 per unit for postintervention outbreak investigations exceeded the intervention costs of US $4,969.

CONCLUSION

A sustained influenza intervention bundle was associated with clinical and economic benefits to a Thai hospital.

A nationally coordinated laboratory system for human avian influenza A (H5N1) in Thailand: program design, analysis, and evaluation

BACKGROUND

The first phase of national surveillance for avian influenza (H5N1) human disease in Thailand occurred over a 4-month period that began on 1 December 2003. Subsequently, a nationally coordinated laboratory system (NCLS) for avian influenza (H5N1) was created to assess population-based surveillance, specimen procurement, case detection, and reporting at the national level.

METHODS

We conducted a pre- and postintervention study to evaluate the NCLS designed during the 6-week interval from 1 April through 15 May 2004. During the pre-NCLS period (1 December 2003 through 31 March 2004), 12 cases of human avian influenza (H5N1) were confirmed. During the post-NCLS period (16 May 2004 through 31 December 2006), interventions were implemented for human avian influenza (H5N1) surveillance, case detection, and expedited, computer-based reporting.

RESULTS

During the pre- and post-NCLS periods, 777 (85%) of 915 and 10,434 (95%) of 11,042 clinical respiratory specimens, respectively, were adequate for confirmatory testing (P<.001), the median time from procurement to results decreased from 17 days (range, 14-24 days) to 1.8 days (range, 0.25-4 days; P<.001), and the duration of specimen shipment decreased from 46.5 h to 21.1 h (P<.001). Thirteen cases of avian influenza (H5N1) were detected during the 31-month postintervention period. H5N1 reverse-transcriptase polymerase chain reaction and real-time reverse-transcriptase polymerase chain reaction sensitivity was 100% and specificity was 99.8%.

CONCLUSIONS

The NCLS exemplifies a systematic approach to national surveillance for avian influenza A (H5N1). This NCLS program in Thailand serves as a model for human avian influenza (H5N1) preparedness that can be adopted or modified for use in other countries.

Issues relevant to the adoption and modification of hospital infection-control recommendations for avian influenza (H5N1 infection) in developing countries

The reemergence of avian influenza (H5N1 infection) has heightened concern for a potential human influenza pandemic. Recommendations regarding preparation for a global avian influenza pandemic are available, and it is imperative that health care workers participate in preparedness planning and training. In developing countries, health care worker preparedness training should address the modes of avian influenza transmission and specify how to implement appropriate infection-control strategies to prevent and control the spread of avian influenza. We provide evidence for avian influenza transmission methods and identify prevention strategies relevant to infection control for hospitals in developing countries. Pandemic influenza preparedness plans must include health care administrative support, mechanisms to rapidly create temporary isolation facilities, systems to restrict access to exposed health care workers, and plans to involve specialists to screen and identify cases early, to provide for continuous monitoring to ensure adherence to optimal infection-control practices, and to provide regular feedback to health care workers.

Risk factors and outcomes of influenza A (H3N2) pneumonia in an area where avian influenza (H5N1) is endemic

We conducted a cohort study to identify the risks and outcomes of influenza A (H3N2) pneumonia. Of the 145 patients studied, 10 (7%) had influenza A pneumonia. Logistic regression identified multiple comorbidities (P<.001) and diarrhea at the initial presentation (P=.001) as associated risks. Infection with influenza A (P=.01) and receipt of inadequate antimicrobial therapy (P=.005) were predictors of mortality.