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Readiness exercise to combat avian influenza

R.C.-S. Seet, E.C.H. Lim, V.M.S. Oh, B.K.C. Ong, K.T. Goh, D.A. Fisher, K.Y. Ho, K.G. Yeoh
DOI: http://dx.doi.org/10.1093/qjmed/hcn159 133-137 First published online: 10 December 2008


Aim: To examine the readiness of our hospital for the potential pandemic threat of avian influenza, we developed and implemented simulation case scenarios in our hospital.

Methods: Two volunteers, who assumed the identity of ‘actual’ patients, were trained to simulate acute respiratory symptoms following a visit to an avian influenza-affected area, and their identities and locations were kept confidential prior to the readiness exercise. A team of auditors was stationed at high-risk areas to assess adherence to the use of personal protective equipment (PPE) and infection control procedures.

Results: A total of 324 healthcare workers and 84 administrators participated in this hospital-wide exercise. Following disclosure of their symptoms, the ‘patients’ were masked and isolated in negative-pressure rooms. A quarantine order was enforced on 38 inpatients and 45 healthcare workers who were present in the affected wards at the time of the exercise, which mandated the use of PPE. Although all affected healthcare workers were competent in the use of PPE, we observed breaches in PPE and isolation procedures in eight medical and nursing students, and 10 healthcare attendants. The exercise concluded after H5N1 tests returned negative.

Conclusions: We recommend the use of case simulation as an effective means of assessing potential breaches in infection control procedures.


The highly pathogenic avian influenza virus, H5N1, is endemic in East and Southeast Asia, with disease outbreaks recently spreading to parts of central Asia, Europe and Africa.1–3 Continued inter-species transmission to humans has been reported in Asia, and in Turkey, Egypt, Iraq and Azerbaijan, causing concerns of a potential pandemic.1–5 A total of 225 laboratory-confirmed human infections, 128 fatal, have been reported to the World Health Organization (WHO) by public health organizations worldwide,4 between 2004 and the first six months of 2006. Recent estimates suggested that the next pandemic may affect more than 1 billion cases worldwide, with up to 7.4 million deaths.6–8 The implementation of measures to promptly alert authorities to infectious diseases and contain them is critical in efforts to curtail the potential spread of infection to healthcare workers and the public.8 Efforts to develop vaccines against the virus have been hampered by the lack of an immunogenic human H5N1 vaccine matched to the dominant circulating strain, as well as a restricted capacity to produce the vaccine for the global population.9 Limited supplies of oseltamivir and the potential for antiviral resistance10 further confound efforts to find a treatment for the H5N1 virus.

Until an effective treatment strategy is found, early detection and isolation of suspected individuals, through diligent surveillance, form our only available and potentially effective defenses against the H5N1 virus. Although contingency plans have been developed worldwide to contain an outbreak,11,12 there have not been, to our knowledge, exercises incorporating the use of simulation scenarios to assess the preparedness of healthcare workers and institutions to the threat of the H5N1 virus or other infectious diseases. We developed and tested such a scenario, in a hospital-based exercise, to assess our state of preparedness against this emerging infectious threat. We describe our experience, in the hope that similar exercises can be conducted in at-risk areas, to mitigate against spread of the H5N1 virus.

Materials and methods


This exercise was conducted at the National University Hospital, Singapore, a 928-bed acute-care tertiary hospital that provides multidisciplinary medical care to approximately 2 million people in the western part of Singapore. The exercise involved a total of 324 healthcare workers based in 26 wards, comprising doctors, nurses, paramedical staff (including occupational therapists, physiotherapists, social workers and healthcare attendants) and 84 administrators. In light of H5N1-outbreaks nearby Indonesia, they were advised of the need for increased vigilance and the possibility of a mock exercise to assess their readiness.

Training of the index patients

Two volunteers were trained to role-play as index patients and complain of acute respiratory symptoms following their travel to a H5N1-affected area. A period of 3 days was chosen to coincide with the 2–8 days incubation period for the H5N1 virus,13 during which time the affected individual could remain asymptomatic. Our trained ‘index patients’ adopted the identity, demographic and medical profiles of two genuine patients throughout this exercise. Further details were kept confidential throughout the exercise. The genuine patients, whose identities were adopted, were transferred to separate rooms within the same ward, to ensure that their clinical care was not compromised during this exercise. ‘Patient A’ was a 40-year-old male, who had ostensibly earlier suffered an open fracture of the tibia, and had been admitted through the Emergency Room. He had earlier commuted to the Diagnostic Imaging Centre, before being transported to the Operating Theatre for operative reduction and fixation of the fracture. Post-operatively, he was transferred to the orthopedic ward. ‘Patient B’ was a 10-year-old boy, similarly admitted through the Emergency Room with a femoral fracture, sustained during an overseas trip. In both index patients, the history of travel to Indonesia was only provided to the primary physicians on the morning of the exercise.

Hospital alert status

Following the outbreak of SARS in 2002, our hospital adopted a three-level response framework according to the level of risk of transmission. These three levels were color-coded: yellow (no cases or sporadic imported cases but with no local transmission), orange (local transmission confined to close contacts in healthcare settings or households) and red (outbreak in the community where local transmissions are no longer confined to close contacts in healthcare settings or households). The alert level, determined the level of response which included temperature screening, eliciting symptoms and travel history amongst patients and visitors, compulsory use of personal protective equipment (PPE) and daily core temperature recording for healthcare workers.14


Measures taken after identification of ‘index patients’

On the morning of a weekend in July 2006, the ‘index patients’ based in two wards disclosed their complaints of fever, cough and shortness of breath, as well as the crucial details of their recent travel to Indonesia that included a visit to a poultry farm, at which an outbreak of H5N1 virus had occurred. Following these revelations, they were immediately asked to don N95 face masks. Healthcare workers within the same ward were immediately mandated to wear PPE, consisting of N95 face mask, gown, goggles and gloves. An infectious disease physician advised that the patients were likely to have been infected with avian influenza. Arrangements were made to transport both patients to separate negative-pressure rooms. Security guards cleared passageways and corridors to facilitate the smooth transfer of these ‘index patients’.

A command centre, manned by divisional chiefs, epidemiologists and information technologists, was set up within an hour after the ‘index patients’ were identified. A quarantine order was served on the affected adult and pediatric wards. Existing patients (n = 38) and healthcare workers (n = 45) were not allowed to leave, except for emergencies, and only with the use of PPE. Security guards were assigned to enforce the order. Entrances to the hospital were closed, only two main areas staying open. Paraclinical staff and hospital administrators were then deployed to these manned points of entry, in order to screen visitors for symptoms of respiratory illnesses and travel history. All would-be visitors underwent recording of core body temperature, those with a core temperature of more than 37.5°C, or with respiratory symptoms, being denied entry. Non-urgent admissions and elective surgical procedures were cancelled. To facilitate contact tracing, hospital visitors were limited to those with urgent pre-arranged appointments, after registration of personal details, including the identity of the patient or member of staff with whom they would come into contact.

Healthcare workers servicing high-risk areas (quarantined ward, intensive care unit, operating theatre and Emergency Room) donned PPE throughout the exercise. An alert was sent through the island-wide page-messaging system to all healthcare workers to inform them of the impending threat, and the upgrade to ‘yellow’ status. Those who had been in contact with patients in the affected ward were asked to register directly with an assigned officer, who was responsible for monitoring of a daily movement log, respiratory symptoms and temperature, and sick leave of these healthcare workers.

Quarantine enforcement

Security guards were deployed outside affected wards to ensure enforcement of the quarantine. Movement of patients and healthcare workers was minimized, and names of those entering and leaving affected areas registered. Only medications and medical supplies, food, beverages and PPE were allowed to be delivered during this period. Patients in affected wards were briefed, updated and reassured throughout the exercise. A team of nurse clinicians, functioning as auditors, was stationed in high-risk areas to ensure adherence to the use of PPE and infection control procedures, and proper fit-testing of N95 masks. On-the-spot training was provided to those who were not familiar with the use of PPE.

Contact tracing

Efforts to trace and monitor individuals who had been in contact with the affected patients were targeted at three levels: on-duty healthcare workers in high-risk areas, patients and visitors. Each staff member was required to record their temperature and register the presence or absence of respiratory symptoms electronically using a web-based password-protected form. Using a healthcare information integration platform, the movement and time-logs of these ‘patients’ were electronically tracked and generated. The respective heads of the department were informed if the identified ‘H5N1 patients’ had visited their areas of responsibility, and healthcare workers who had been on duty during the period identified. This was to ensure ‘wide-net’ surveillance and thus identify those who needed to be quarantined, in the event of confirmation of H5N1 virus infection in our index ‘patients’.15 The ‘patients’ were asked to provide a list of names of visitors and immediate contacts following the onset of their symptoms. The names of visitors were electronically tagged to the names of patients whom they were visiting, to gather further information should contact tracing prove necessary. During this exercise, a home visit team, led by an epidemiologist, was placed on standby due to pending results of H5N1 testing.

Confirming the presence of avian influenza

Two separate blood and nasal swabs were obtained from each ‘patient’, to diagnose the presence of the H5N1 virus. We used polymerase chain reaction (PCR) and real-time PCR assay primer sets, specific for the hemagglutinin gene of the influenza virus, based on the recommendations of the WHO.16 The tests were performed in a WHO-verified national reference laboratory in Singapore, and results were available within 4 h of receipt of the samples. Results of the PCR tests for H5N1 returned negative, and this information was immediately relayed to the Operations Centre. A decision to step-down the level of alert was made within 5 h of commencement of the exercise. Healthcare workers were again informed of step-down of alert status using the island-wide page-messaging system.

Observed adherence to protocol

Although the majority of our healthcare workers were familiar with the use of PPE, a small proportion was observed to have breached protocol, notably medical and nursing students (n = 10) and healthcare attendants (cleaners) (n = 8). Breaches included improper fit of N95 face masks, poor understanding of isolation procedures and failure to use powered air purifying respirators (PAPR) when obtaining high-risk specimens, such as nasal swabs. Other breaches in protocol included incorrect sequence of de-gowning and failure to clean radiograph plates before leaving the isolation rooms. We were disappointed by an apparent failure of our healthcare personnel to extract specific information about the poultry farm in question (such as its precise location and details of the level of contact with infected birds), which could have proved useful in the management of a real epidemic. We did not observe healthcare worker absenteeism, either due to illness or fear of contagion, during this period.


Early and prompt identification and isolation of a suspected index case forms the cornerstone of public health interventions aimed at reducing the transmission of emerging infectious diseases. Our hospital's readiness exercise is unique, in that it assesses the response of our entire hospital to the threat of avian influenza, commencing with the isolation of the index case, through contact tracing and quarantine of contacts to the examination of biological fluids in the blood and respiratory tract for the avian influenza virus. We chose a scenario of a patient who present atypically for an unrelated medical condition, during the virus’ incubation period, to assess the vigilance of our healthcare workers.

An innovative approach was employed to facilitate contact tracing, temperature recording and dissemination of information to healthcare workers. Information on the movement log of each patient was tracked using a healthcare information integration program, that monitors the mobility of each patient using its cost-billing function, which registers patients’ mobility at the different cost centres, such as the Emergency Room, the outpatient clinic, radiology department, operating theatre, intensive care units and general wards. Healthcare workers were kept informed of the level of alert using the nationwide page-messaging and short-messaging systems (SMS). Body temperature was self-monitored by healthcare workers using thermometers and was self-inputted via our hospital's intranet site, which fed the crucial information to a central command centre.

The direct costs of consumables for the PPE, such as gowns, goggles and face masks amounted to S$11 000 (GBP 4300, 1GBP = S$2.56), and an estimated 500 man-hours was spent by members of the operations centre, security and contact-tracing team on the actual exercise. The indirect costs in terms of man-hours for planning, review of exercise and inconvenience to staff members for using PPE are expected to exceed the initial figure. Having reflected on the lessons learnt from the exercise, we carried out measures to re-educate our staff on the proper use of N95 face masks, isolation procedures, use of PAPR when obtaining high-risk specimens, such as nasal swabs and the correct sequence of degowning.

Encouragingly, we did not observe a high absenteeism by employees during the exercise. A survey of 10 511 healthcare workers during an outbreak of SARS in Singapore revealed that the majority of the respondents perceived a great personal risk of falling ill with SARS and feared ostracism by family members.17 Efforts should also be targeted to reduce the discomfort and adverse effects of the use of PPE, such as allergic skin reactions18 and headaches,19 to ensure compliance to their use.

This readiness exercise which comprised a realistic simulation along with a comprehensive response has provided us with a unique insight into our hospital's preparedness to respond to an avian influenza outbreak. We hope that our experience may be of benefit to other healthcare institutions who may wish to adopt or improve upon our methodology.

Conflict of interest: None declared.


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