Public health priority: Routine.
PHU response time: Enter cases on NDD within 3 working days of notification. Respond to a report of an outbreak in a residential care facility on the same day.
Case management: Not routine.
Contact management: Not routine.
Section 14 - Jurisdiction specific issues - increase to serology cut of levels
Section 2 - Persons at increased risk and Health Care Workers
Section12 - Outbreaks of ILI in RCF
When these Guidelines were first developed in 2009, they were directed specifically at the pandemic influenza virus A/H1N1 influenza 2009 (pH1N1). This 2011 version of the Guidelines is generic for influenza infection of all types because of the many similarities between the pandemic influenza strain and existing seasonal influenza strains, and the likelihood that there will be co-circulation of strains in 2011 and beyond.
Since 1 December 2010 Australia has been in the standby 'ALERT' phase of its pandemic plan. The key element of the ALERT phase is heightened vigilance for a new influenza virus strain or a significant change in a currently circulating strain, which may be of public health concern. This is consistent with the WHO's recommendation for ongoing vigilance in the early post-pandemic period. Further information on the ALERT phase can be found in the
Australian Health Management Plan for Pandemic Influenza.
The best protection against pH1N1 and other influenza strains is vaccination. Annual influenza vaccination is recommended for any person aged six months and over who wishes to reduce the likelihood of becoming ill with influenza. Influenza vaccination is particularly recommended for people at risk of complications from influenza infection, people who may potentially transmit influenza to those at high risk of complications from influenza (e.g. healthcare workers), poultry workers, people providing essential services and some industries, and travellers, as guided by
The Australian Immunisation Handbook. The 2011 trivalent seasonal influenza vaccine again contains the pH1N1 strain and is free under the National Immunisation Program (NIP) for certain groups at risk for severe disease, including older Australians, pregnant women, Aboriginal and Torres Strait Islander People aged ≥15 years, and individuals aged ≥6 months with specified underlying medical conditions predisposing to severe influenza. The influenza vaccine is also available to others if they wish to pay for a prescription or obtain the vaccine through workplace or other programs.
Following the investigation of the excess number of cases of febrile reactions to the 2010 seasonal influenza vaccine in children, the Australian Technical Advisory Group on Immunisation (ATAGI) has advised that children aged between 6 months to less than 5 years should not receive the 2011 Fluvax® vaccine. Fluvax® is not registered for use in this age group in 2011. The alternative influenza vaccines available for paediatric use in the NIP are Vaxigrip® or Influvac®. ATAGI has also advised a strong preference for the use of either Vaxigrip® or Influvac® in children aged 5 years to less than 10 years under the NIP. Fluvax® may be used in children aged 5 years to less than 10 years when no timely alternative seasonal influenza vaccine is available. The
full ATAGI statement includes the rationale for these recommendations.
Enter data within 5 working days - for individual cases in most community-based settings.
Act as soon as possible, generally within one working day - for outbreaks in high-risk settings such as health care facilities, boarding schools, special schools, residential care facilities, and Indigenous communities
or health care workers in high risk settings (see
Section 12. Special situations).
Act as soon as possible, respond within 24 hours - following the identification of a new subtype or an untypable influenza isolate.
Cases will be managed directly by their health care providers, with a focus on patients with influenza-like illness (ILI) who are at increased risk for severe disease, or who have moderate to severe disease.
Public health action will focus on outbreaks in high-risk settings (as above).
None routinely, except in specific high-risk settings.
Remind health care providers to be mindful of appropriate management of close contacts who are in vulnerable groups at increased risk of severe disease, including instructions to present early for testing and treatment should they develop symptoms.
Influenza viruses are composed of an RNA core surrounded by an envelope containing two surface glycoproteins — haemagglutinin and neuraminidase. The RNA encoding these glycoproteins has the ability to rapidly mutate and produce minor or major changes to the antigenic structure, known as antigenic drift and antigenic shift, respectively.
Influenza virus are most commonly spread from person-to-person by inhalation of infectious droplets produced while talking, coughing and sneezing. Transmission may also occur through direct and indirect (fomite) contact. Aerosol transmission within confined spaces may be important. The virus may persist on hard surfaces for 1-2 days, particularly in cold or low humidity conditions. The virus may remain viable on hands for 5 minutes.
The incubation period for infection with influenza ranges from 1 to 7 days, commonly 2-3 days.
Patients may shed influenza virus for up to 24 hours (1 day) before onset of symptoms and until 7 days after the onset of symptoms. Viral shedding in adults peaks in the first 1 to 2 days after symptom onset, then reduces to very low levels by 5 days after onset of symptoms. Not all cases of influenza infection exhibit fever, but when it is present, it is correlated with viral shedding.
Children and younger adults may shed influenza virus for 10 or more days, and immunosuppressed persons may shed virus for weeks. However, the ability to transmit infection is likely to be higher when respiratory symptoms are present.
Patients are considered no longer infectious if 24 hours have elapsed since the resolution of fever, provided either:
Symptoms of influenza typically include fever, cough, fatigue, sore throat, headache, myalgia, and rigors or chills. Diarrhoea and/or vomiting may also occur. Illness can range from asymptomatic infection to severe disease.
Pneumonia may develop directly from influenza infection (primary influenza pneumonia) or from secondary bacterial infection. Acute respiratory distress syndrome (ARDS) may develop several days after disease onset.
Under the NIP, the following groups are regarded as vulnerable groups
at increased risk of severe disease from influenza and are eligible for free seasonal influenza vaccine:
While not eligible for free influenza vaccine under the NIP, otherwise healthy children aged less than 5 years of age can also be considered to be at increased risk for severe disease, compared to other age groups, evidenced by higher hospitalisation rates.
[Note that a NSW-funded
seasonal influenza vaccination program for all children aged 6 months to less than 5 years was offered in 2018]
Similarly, during the 2009 pH1N1 pandemic, people with morbid obesity were identified to be an additional group at risk of complications.
Healthcare workers (HCW), defined as those workers providing clinical care, are considered to be a group of special interest, since vulnerable patients who are exposed to a HCW with influenza can become infected. Additionally, reduction in HCW numbers due to illness will adversely affect the care of vulnerable patients.
[Note that under the NSW
Occupational Assessment, Screening and Vaccination Against Specified Infectious Diseases (PD2018_009) policy directive, influenza vaccination is required annually for NSW Health workers in
Category A High Risk positions by June 1 each year].
The best protection against influenza is vaccination.
Hand hygiene and respiratory/cough etiquette are thought to reduce transmission of influenza and voluntary home isolation of those with the illness may have significant impact on reducing disease transmission.
Key prevention activities may include:
The objectives of surveillance are to:
The methods for achieving the surveillance objectives are as follows:
The severity of influenza will be monitored through: he severity of influenza will be monitored through:
During the Australian influenza season, a
national influenza surveillance report is published fortnightly.
Confirmed cases of influenza, including available data on typing and subtyping, should be entered into jurisdictional notification databases and relayed to the National Notifiable Diseases Surveillance System (NNDSS).
Positive influenza laboratory results should be reported to the State/Territory disease control unit or relevant public health units (PHU) in a timely fashion, and in accordance with specific jurisdictional notification requirements.
PHUs shall inform their central State/Territory disease control unit when notified of an outbreak of influenza in a high-risk setting, or in an area with few previously reported cases.
Where a confirmed case is being managed by a jurisdiction other than that of the case's usual residence, the managing jurisdiction will notify the jurisdiction of residence according to the established protocol for cross-border notification.
A confirmed case of influenza is defined as a person with influenza virus infection identified by one or more of the following tests:
The latest version of the NNDSS influenza case definition is at
Australian national notifiable diseases and case definitions.
Diagnoses of ILI may be used for various purposes, including routine surveillance of influenza activity in the community, case-finding in outbreaks, and for clinical diagnosis and treatment.
The sensitivity and specificity of particular case definitions of ILI vary, depending on the clinical symptoms or signs that are used as inclusion or exclusion criteria. The positive predictive value of a diagnosis of ILI will also depend on the current prevalence of influenza in the setting under surveillance.
The choice of particular criteria to define a case of ILI may vary, depending on the settings and the purpose (surveillance or clinical management).
Common to most case definitions of ILI are an illness, often of rapid onset, with fever and cough. Additional or optional features in case definitions may include chills or rigors, myalgia, fatigue, headache, sore throat and coryza. Note that in the elderly, confusion, anorexia and breathlessness may sometimes be the only signs of influenza.
An example of a case definition for ILI that has been effectively used to guide clinical detection and treatment of individuals during a community influenza epidemic is:
In settings where influenza is being transmitted, this definition is fairly specific but lacks sensitivity, so some influenza cases will be missed.
Laboratory testing of all potential cases of influenza is neither required nor desirable for public health management.
It is not necessary to routinely obtain laboratory confirmation of influenza before commencing anti-influenza medications for individual patients.
Laboratory testing is recommended:
In order to monitor changes in circulating viruses, isolates from both representative and clinically or microbiologically unusual cases of influenza should be provided to the WHO Collaborating Centre for Reference and Research on Influenza for antigenic characterisation and resistance testing.
Follow up is not required routinely for single notifications.
Public health action should focus on outbreaks in high-risk settings (see
Section 12. Special situations).
Anti-influenza medications have been shown to attenuate disease in cases of seasonal influenza if given early in the course of the illness (within 48 hours of developing symptoms). There may be benefit in providing anti-influenza medications to hospitalised patients after 48 hours.
Consideration should be given to commencing anti-influenza medication in anyone suspected of having influenza who presents within 48 hours of symptom onset. Particular emphasis should be given to treating those who are at risk for severe outcomes i.e., those who:
The health care provider should provide the patient with information on the disease, the use of anti-influenza medications (if indicated), and infection prevention and control practices including hand hygiene and respiratory/cough etiquette (see
Section 13. References and additional sources of information for factsheets).
Health care providers should urge patients with ILI to ask close contacts who are at risk of severe disease to present early for treatment should ILI symptoms develop.
Health care providers should counsel patients who have influenza or ILI to stay at home and keep away from work, school and crowded areas or public gatherings until symptoms have resolved. Ideally, they should be advised to wear a surgical mask when seeking medical attention or when in close company of vulnerable people.
Healthcare workers with influenza should stay off work for 5 days after symptom onset, or until they are symptom-free, whichever is longer (see also
Section 2. The disease).
People with ILI who work with pigs or poultry should not attend work while they are likely to be infectious.
People hospitalised with ILI should be nursed in a single room if possible. Where this is not possible, they should be cohorted with other patients with ILI or confirmed influenza infection, maintaining at least 1 m spacing between patients at all times. Patients with ILI should not be co-located with other patients at risk of severe disease.
The risk of further transmission of influenza can be minimised by ensuring compliance with 'standard' infection prevention and control precautions, and 'contact' and 'droplet' transmission-based precautions, as outlined in the NHMRC
Australian Guidelines for the Prevention and Control of Infection in Healthcare (2010). In accordance with droplet transmission-based precautions it is important that infectious patients wear a surgical mask when not in isolation.
In addition to these standard practices, the following should be undertaken:
P2 or N95 respirators should form part of the ensemble of personal protective equipment (PPE) of all HCWs involved in aerosol-generating procedures, e.g. endotracheal intubation, nebulized medication administration, airway suctioning, bronchoscopy, diagnostic sputum induction, positive pressure ventilation via facemask, and high frequency oscillatory ventilation. These procedures should only be performed in a single room with the door closed (note that the taking of throat/nasal swabs is not considered an aerosol generating procedure).
Fit checking is the appropriate minimum standard for HCWs using P2 or N95 respirators and should be conducted each time a respirator is donned. Formal
fit testing is recommended where available.
Daily and on discharge - clean all surfaces and patient equipment as per the recommendations in the
Australian Guidelines for the Prevention and Control of Infection in Healthcare (2010). The room can be used immediately following cleaning, once surfaces are dry.
All staff involved in cleaning procedures should use the appropriate personal protective equipment for contact and droplet transmission-based precautions, both for daily cleaning and for cleaning following patients' discharge, in accordance with the NHMRC
Australian Guidelines for the Prevention and Control of Infection in Healthcare (2010).
Management of laundry and crockery and cutlery should be performed in accordance with standard precautions.
Management of clinical and related waste must conform to relevant state/territory regulations. Healthcare facilities should also refer to AS/NZS 3816.
Used tissues should be disposed of in general waste.
If healthcare- or residential care facility-acquired infection is suspected, the facility's infection prevention and control procedures should be reviewed. Staff conducting the review must have a thorough understanding of infection prevention and control practices, be competent in using PPE and should have been vaccinated.
No public health action routinely required except in high risk settings (see
Section 12. Special situations).
Schools and childcare settings are prone to experiencing rapid transmission of influenza. Children and staff of schools and childcare centres who have risk factors for severe disease should be strongly encouraged to be vaccinated (NB: see notes in Prologue regarding the 2011 vaccination recommendations for children aged under 5 years and for children aged 5 to under 10 years).
Children and staff with confirmed influenza or ILI should not attend school or child care. If a child or staff member becomes sick with an ILI at school they should be sent home.
If an outbreak of ILI is reported in:
Because of the close nature of the students, outbreaks may spread more rapidly, and special control measures may be required, including:
Because there may be large numbers of students with chronic illnesses at risk of severe complications from influenza, special control measures may be required including:
Full or partial school closures are not generally recommended on public health grounds, although it is recognised that they may be considered on logistical grounds by the school.
Outbreaks of influenza or ILI in residential care facilities should be managed with close reference to the CDNA documentGuidelines for the Prevention, Control and Public Health Management of Influenza Outbreaks in Residential Care Facilities in Australia(2017).
[Note that the CDNA RCF influenza outbreak guidelines recommend a case definition for influenza-like illness (ILI) which differs slightly from the example ILI case definition for outbreaks given above in Section 7. Case definition]
Influenza outbreak data should be entered into NCIMS within one day of outbreak notification.
NSW Health is also able to assist with providing antivirals but local supplies should be sourced first. Should local supply of Tamiflu be unlikely within 24 hours of declaring the outbreak, the PHU can obtain Tamiflu from the State stockpile by ordering through the NSW Vaccine Centre.
HCWs with ILI require special consideration because an infectious HCW can expose vulnerable patients to infection and/or be a reflection of a broader outbreak in a health care setting. Patient care may also be adversely impacted by a reduction in health care worker numbers due to illness.
Prevention of transmission of ILI between patients and HCWs can be achieved by using an approach that includes:
Unvaccinated HCWs who are at increased risk of complications from influenza and who are likely to be in direct contact with infectious influenza patients should be offered vaccination and, if they refuse, considered for redeployment to lower risk activities or environments. Where this is not practical:
HCWs must be advised of their responsibility to identify themselves if they believe they are in a group at risk for severe diseases and take appropriate action to protect themselves and others.
During times of influenza activity, healthcare facilities should ensure HCWs are aware to:
If influenza is diagnosed on clinical grounds:
Where clinically appropriate, a negative 'direct' test result (i.e., antigen test or nucleic acid test (NAT)) may allow the HCW to return to work earlier, subject to the risk that they may pose. Note that a negative 'point of care test' result does not have the required sensitivity to be used in this context.
Contact tracing is not routinely required following diagnosis of an ILI in a HCW, unless the HCW was working in certain high risk settings (as described below).
Contact tracing should be considered when patients or staff working in high risk settings have been exposed to a confirmed infectious case of influenza (such high risk settings include hospital wards specifically for people who are immunosuppressed or neonatal wards, but not emergency departments, general wards, theatres or outpatient settings). In these situations:
If an outbreak occurs in a health care facility, an outbreak management team should be convened, including a senior facility manager, an infection control practitioner and appropriate clinical staff, in consultation with PHU staff as required. Control measures may include:
Key factors to be considered regarding influenza risk in Indigenous communities include:
The clinical and public health response to suspected or confirmed influenza outbreaks in the remote community setting should aim to:
* Note - during outbreaks in aboriginal communities it is recommended that the identification of vulnerable community members should include all individuals with risk factors referred to in
Section 3. Routine prevention activities. Children who fall into the 'failure to thrive' category should also be considered as vulnerable to complications of influenza infection.
Cruise ship travel is characterised by large numbers of people in closed and semi-closed settings. As with other close contact environments, these settings can facilitate the transmission of influenza and other respiratory viruses from person-to-person through droplet spread or potentially through contact with contaminated surfaces.
Cruise ships are recommended to:
Passengers and crew who are vulnerable to influenza infection need to be aware that their attendance on a cruise ship increases the risk that they may come into contact with respiratory viruses.
In managing a potential outbreak of influenza on a cruise ship, the following should be considered:
A confirmed case of influenza is defined as a person with influenza virus infection identified by one or more of the following tests:
Persons with additional PCR laboratory results for influenza which identify a different subtype or strain after a 30 day period should be entered as a newly acquired cases of influenza.
Any confirmed cases that are identified within 30 days of a previously confirmed case will continue to be treated as a dual infection.
Any confirmed cases regardless of strain or subtype that are identified using a means other than PCR testing will continue to be treated as a dual infection.
Previously confirmed cases with additional laboratory notifications after 30 days where subtype is not known or unchanged should not be entered as a new case.