Australia’s public health response, and implementation of associated public health measures, was guided by the AHMPPI 2008 and based on the Australian phasing system (see Table 5.1). The phasing system was amended to include a new phase, PROTECT, as an appropriate response to the nature of the pandemic (H1N1) 2009 virus.

WHO announced on 10 August 2010 that the world had moved into the post-pandemic period but that localised outbreaks of various magnitudes were likely to continue. At that time it was considered appropriate that Australia remain in the PROTECT phase, as Australia was still in its influenza season and a late upsurge in pandemic (H1N1) influenza 2009 cases was possible. During the 2010 influenza season Australia experienced a particularly late peak, with levels of influenza cases similar to those reported in 2007 and 2008 and significantly lower than those observed during 2009. The CMO, together with his expert advisory groups, assessed Australia’s pandemic phase status and recommended the change of phase from PROTECT to ALERT from 1 December 2010, the key element of which is heightened vigilance for a new influenza virus or any change in a currently circulating influenza virus which may be of concern.

Table 5.1 Phase changes and duration

PhaseDate commencedDate changedDuration
DELAY28 April 200921 May 20093 weeks
CONTAIN22 May 200917 June 20094 weeks
(Victoria only)
3 June 200917 June 20092 weeks
PROTECT17 June 20091 December 201076 weeks
ALERT1 December 2010ongoingongoing

5.2.1 Identification and classification Case definitions

The Communicable Diseases Network Australia (CDNA) was responsible for developing and reviewing case definitions that described the degree of certainty of infection with pandemic (H1N1) 2009 virus. Case definitions guided the clinical management of cases, disease surveillance, testing protocols and subsequent public health decisions (see Table 5.2).

Cases and contacts were identified at the Australian border during the DELAY and early CONTAIN phases, and in the community during the late DELAY phase and during the CONTAIN and PROTECT phases.

During the DELAY and CONTAIN phases, considerable effort was made to actively identify cases and their contacts. All people meeting the definition for a suspected case were assessed urgently and local public health units (PHUs) were notified. Extensive contact tracing, laboratory testing and treatment or prophylaxis with antiviral medication were undertaken. The management of all cases was the same, as suspected and confirmed cases were all encouraged to quarantine or isolate themselves for a period of seven days (see section 5.2.4 Isolation and quarantine). Media advertisements advised symptomatic people who had potentially been exposed to the virus to seek early medical assistance and to make initial contact by telephone. Information was circulated to GPs and EDs in hospitals regarding the clinical and epidemiological recognition of pandemic (H1N1) 2009 influenza. Doctors were instructed to contact their local PHUs if a suspected case presented.

During the PROTECT phase, the focus was on identifying people vulnerable to developing severe complications of influenza rather than on identifying and managing every case, with a more targeted use of antiviral medication as treatment or prophylaxis where appropriate. This was an appropriate response to the ‘mild in most, moderate overall’ nature of the pandemic. Close contacts who were members of a recognised vulnerable group were advised to present early to a healthcare provider if they developed acute respiratory illness, to enable timely treatment.

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5.2.2 Infection control Personal hygiene messages

Common to all phases was public messaging about personal infection control measures. Hand washing and cough and sneeze etiquette were promoted as the most effective ways for the public to reduce their risk of being infected or of spreading the virus to others, including minimising the potential to infect people vulnerable to severe outcomes from the disease. The messages about these techniques of personal infection control did not change with the different phases. Advice and guidelines

Tailored infection control advice was developed during the response for specific groups and workplaces, including airlines, cruise ships, schools, public transport drivers, government employers and business groups.

5.2.3 Antiviral medication

During the DELAY and CONTAIN phases, antiviral medication was provided to cases for treatment if less than 48 hours since the onset of illness and after this time if clinically indicated, and to household contacts for prophylaxis. This proved to be effective in prevention and in limiting disease duration. During the PROTECT phase, treatment was recommended for those vulnerable to severe outcomes from influenza and for those suffering moderate to severe disease. Vulnerable contacts of suspected cases were considered for antiviral prophylaxis. Antiviral prophylaxis was provided to control outbreaks in high-risk institutional settings such as schools for students with disabilities and aged-care facilities.

Table 5.2 Case definitions – degree of certainty of infection with pandemic (H1N1) 2009
SuspectPeople who were suspected of having the illness but did not yet have test results
Influenza A-positive suspectPeople who were known to be infected with influenza A but whose test results for the subtype of influenza were as yet unknown
ConfirmedPeople whose illness was laboratory confirmed as infection with pandemic (H1N1) 2009

5.2.4 Isolation and quarantine

During all phases, people who were unwell with influenza or with influenza-like illness (ILI) were encouraged to stay at home in isolation.

During the DELAY and CONTAIN phases, people who may have been exposed to the virus and their close contacts, once identified, were asked to voluntarily quarantine themselves at home (or in their hotel room, for non-residents), for a period of seven days – that is, until the infectious period had passed or the diagnosis had been excluded – in order to help control the spread of the disease. This quarantine period was based on an understanding of seasonal influenza viruses.

During these phases, cases were advised that while in isolation, if feasible, they should wear a surgical mask when in the same room as other household members and should stay at least one metre from others. Contacts were instructed to notify PHU staff immediately if they developed symptoms of the illness. With the move to PROTECT, quarantine was no longer recommended for household contacts.

Support for contacts identified in the community was provided by local public health authorities and governments.

A separate system of support was provided for contacts identified at the border, as planning had identified that there may have been a requirement for contact tracing and quarantining of large numbers of people after arrival in Australia. The Home Quarantine Support System (HQSS), which included an automated outbound telephone calling system, was activated from 26 May 2009 to 2 June 2009 following specific international flights that had transported a confirmed case of pandemic (H1N1) 2009 influenza. The HQSS supported people in home quarantine through provision of information to raise awareness of symptoms, direction to contact their GP if they were feeling unwell, and provision of ‘home quarantine support packs’. A total of 4713 calls were made during that time, with 1102 individuals contacted.

Top of Page School exclusions and closures

Early in the 2009 pandemic, reports emerged from overseas that outbreaks had spread rapidly in schools, with high infection rates among students.21 Outbreaks in childcare centres were not reported. The school outbreaks were thought to have seeded wider transmission of the disease in the community, in particular in cities in Japan and in New York City, which is consistent with current knowledge about seasonal influenza outbreaks and the recognition that children may shed influenza virus without becoming obviously unwell.

From the commencement of the CONTAIN phase, Australia introduced a seven-day period of exclusion from school for those students who had recently travelled to areas where there was a high prevalence of the pandemic (H1N1) 2009 virus, including areas overseas and within Australia. School exclusion had not been included in the AHMPPI but was adopted in 2009. The rationale was that a seven-day period of exclusion from attending school after travel to affected areas would reduce the potential to introduce the virus to a school community, thus averting a school outbreak and a possible school closure, and thereby assist in slowing the spread of disease to a community. School exclusion was implemented on a voluntary basis, at the discretion of school principals and local authorities, and was only recommended for primary and secondary schools.

State and territory governments also had the flexibility to close individual schools or classrooms following the identification of a confirmed case or where outbreaks were apparent and if this was considered a useful measure to prevent further outbreak in the school. Decisions to close individual schools or classrooms were made by the states and territories on a case-by-case basis. Closure of childcare centres was not recommended in 2009.

During the PROTECT phase, closure of schools and childcare centres was not considered a proportionate or appropriate intervention, and under these circumstances was, in general, not recommended. Considerations with respect to boarding or residential schools were different, and these were dealt with by the states and territories on a case-by-case basis. Wider community interventions

Wide-scale community-level social distancing measures, such as restricting or cancelling mass gatherings and limiting public transport arrangements, were not considered proportionate to the nature of the pandemic and were not implemented in 2009.

5.2.5 Influenza services

During the 2009 response, many jurisdictions set up influenza-specific services to minimise presentations to hospitals, health services, general practitioners and community health agencies. Implementation varied according to a range of different service provision models and according to evolving jurisdictional need. Services provided included assessment, diagnosis and, as necessary, use of antiviral medication based on the case definition.

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21‘New influenza A (H1N1) virus infections: global surveillance summary, May 2009’ (2009), Weekly Epidemiological Record, 84(20), 173–179.
‘Swine-origin influenza A (H1N1) virus infections in a school – New York City, April 2009’ (2009), Morbidity and Mortality Weekly Report, 58(17), 470–472.
Health Protection Agency and Health Protection Scotland New Influenza A(H1N1) Investigation Teams (2009), ‘Epidemiology of new influenza A(H1N1) in the United Kingdom, April – May 2009’, Eurosurveillance, 14(19).

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