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
Updated to align with Guidance for Residential Aged Care Facilities on the Public Health Management of Acute Respiratory Infections (including COVID-19, Influenza and Respiratory Syncytial Virus) and Guidance for Disability Care Facilities on the Public Health Management of Acute Respiratory Infections (including COVID-19, Influenza and Respiratory Syncytial Virus).
Other updates include:
This guideline is based on the Seasonal Influenza Infection – Communicable Diseases Network Australia (CDNA) National Guidelines for Public Health Units. NSW specific influenza guidance and recent updates to the CDNA Series of National Guidelines (SoNGs) are included within these call-out boxes throughout the document. The content of the CDNA SoNG has not been modified.
The Series of National Guidelines ('the Guidelines') have been developed by the Communicable Diseases Network Australia (CDNA) and noted by the Australian Health Protection Principal Committee (AHPPC).
Their purpose is to provide nationally consistent guidance to public health units (PHUs) in responding to a notifiable disease event.
These guidelines capture the knowledge of experienced professionals and provide guidance on best practice based upon the best available evidence at the time of completion.
Readers should not rely solely on the information contained within these guidelines. Guideline information is not intended to be a substitute for advice from other relevant sources including, but not limited to, the advice from a health professional. Clinical judgement and discretion may be required in the interpretation and application of these guidelines.
The membership of CDNA and AHPPC, and the Commonwealth of Australia as represented by the Department of Health ('Health'), do not warrant or represent that the information contained in the Guidelines is accurate, current or complete. CDNA, AHPPC and Health do not accept any legal liability or responsibility for any loss, damages, costs or expenses incurred by the use of, reliance on, or interpretation of, the information contained in the guidelines.
Endorsed by CDNA: 20 September 2018
Noted by AHPPC: 07 January 2019
Released by Health: 18 January 2019
*High-risk settings: boarding schools, special needs schools for children with disabilities, residential care facilities, Aboriginal and Torres Strait Islander communities where practicable, and health care workers in high-risk settings (see Section 12 - Special situations).
High-risk settings can also include healthcare facilities and correctional centres.
Cases are managed individually by their health care providers, with a focus on those who are at increased risk of severe disease or serious complications. Management may include appropriate use of antiviral medications.
Public health action focuses on follow-up of cases infected with novel influenza subtypes or untypable isolates. The advice and support of the Public Health Units should be sought during outbreaks in high-risk settings (see Section 12 - Special situations).
Contact management is not routinely undertaken for seasonal influenza.
In specific high-risk settings* (see Section 1 – Summary: public health priority), persons at increased risk of severe disease should be advised to seek early medical care if symptoms develop.
This guideline applies to seasonal influenza and not to avian or pandemic influenza.
A separate guideline for public health responses to avian influenza can be found on the Department of Health website
Further information on pandemic influenza can be found in the Australian Health Management Plan for Pandemic Influenza (AHMPPI)
Influenza viruses belong to the family Orthomyxoviridae, and are enveloped single-stranded ribonucleic acid (RNA) viruses. There are three types of influenza viruses, A, B and C that can infect humans. They can be distinguished by differences in viral proteins in the envelope.
Seasonal influenza is an acute respiratory infection generally caused by influenza A and/or B viruses which circulate globally causing seasonal epidemics. Influenza C virus is detected less frequently and usually causes mild infections. Therefore it is not included in routine influenza tests.
The envelopes of influenza viruses contain two surface proteins, hemagglutinin (H) and
neuraminidase (N). Influenza A viruses can be classified into subtypes according to combinations of these H and N proteins. The influenza A subtypes currently circulating among humans are influenza A(H1N1) and influenza A(H3N2). Although influenza B possesses H and N proteins, they belong to one of the two lineages: Yamagata or Victoria.
The RNA encoding of influenza viruses easily mutate, resulting in changes to antigenic domains in the H and N surface proteins.
Antigenic drift is responsible for seasonal epidemics of influenza. If the antigenic domains change shape, antibodies that would normally match up to it no longer can, allowing the newly mutated virus to cause infection in the human body. Drift is the reason influenza vaccines need adjustment each season to counter currently circulating influenza viruses.
Antigenic shift is associated with pandemics. It occurs when the genetic re-assortment of RNA from two different strains of influenza A results in the abrupt appearance of an influenza A virus with novel H or N proteins. This genetic change enables the influenza strain to jump from one species to another, including humans (1). Regardless of the species in which it occurred, antigenic shift is only detected in human populations if the resultant virus is transmitted to people and causes disease.
The natural reservoir for influenza A viruses are wild aquatic birds, particularly ducks and other waterfowl. As the virus is generally transmitted between birds via the faecal-oral route, these migratory water birds can potentially facilitate transmission of influenza over long distances and to other birds, animals or human populations (2).
Additionally, humans, pigs and horses are naturally hosts of influenza A virus. Influenza A viruses
co-circulate in human populations. This is especially the case in winter months in temperate climates. In more tropical climates, influenza seasons are less well defined, last longer and peaks coincide less frequently with winter months than in temperate climates (3). In the above instances, the human populations are reservoirs. Similarly, human populations are reservoirs for influenza B viruses.
Although influenza B and influenza C viruses are primarily pathogens of humans, other mammals may also be infected by these viruses.
Influenza viruses are most commonly spread from person-to-person by inhalation of infectious respiratory droplets produced by an infected person while talking, coughing or sneezing. Aerosol transmission is less usual, but can occur within confined spaces and during aerosol generating procedures.
Transmission of influenza viruses can also occur through direct and indirect (fomite) contact. Influenza viruses may remain viable on hands for up to five minutes and persist on hard surfaces for 1-2 days.
The incubation period for infection with influenza is most commonly 2-3 days with a range from 1-7 days.
Patients may shed influenza virus and therefore be infectious for up to 24 hours prior to onset of symptoms and up to seven days after onset of symptoms. Children may shed virus for ten days or more, and immunocompromised persons may shed virus for weeks.
In adults, shedding of influenza virus peaks in the first two days after onset of symptoms then reduces to low levels by five days after onset of symptoms. Not all cases of influenza present with fever, but when present, it correlates with viral shedding. Shedding of the influenza virus is more likely when respiratory symptoms are present.
Adult influenza patients are considered no longer infectious 24 hours after the resolution of fever without anti-pyretic medication provided either:
For infection prevention and control purposes, maintain precautions for longer periods for children and immunocompromised persons with influenza.
The reduction in viral shedding as a result of antiviral treatment is dependent on the time to commencement of therapy after symptom onset. Delayed administration of antiviral therapy (>48hours) diminishes its impact on viral shedding and symptom resolution.
Influenza illness can range from asymptomatic infection to severe disease, such as pneumonia, and even death. Symptoms typically include fever (usually 38°C or greater), rhinorrhoea, chills, cough, headache, myalgia, sore throat and fatigue (4). Diarrhoea and/or vomiting may also occur, more commonly in children.
Influenza presentation in elderly persons may be atypical; fever may be absent and may have atypical signs and symptoms such as anorexia, mental status changes, or unexplained fever.
Influenza infection is usually confined to the upper respiratory tract, but can also involve the lower respiratory tract causing viral pneumonia. Pneumonia can also occur as a result of a secondary bacterial infection. In patients with underlying chronic obstructive lung disease or congestive heart failure, worsening respiratory or cardiac status may be unrecognised complications of influenza.
Serious complications from influenza can develop in some people, including very young children, the elderly, pregnant women, people who are immunocompromised, and those with pre-existing respiratory, cardiac and endocrine disease, and may cause death in healthy adults and children. Acute respiratory distress syndrome (ARDS) may develop in some patients several days after disease onset (5).
The Australian Immunisation Handbook (6), recommends that people who are at increased risk of developing complications from influenza should receive annual influenza vaccination. Under the National Immunisation Program(NIP), the following groups are eligible for free influenza vaccine:
Children aged less than 5 years infected with influenza have high notification and hospitalisation (9) rates and therefore can be considered at increased risk. Free vaccine may be available for this age group under state-based programs.
There are a number of at-risk groups that influenza vaccine is strongly recommended and should be actively promoted although they may not be eligible for free vaccine under the NIP. These groups are listed in the Australian Immunisation Handbook (6).
As of October 2023, the following groups are eligible for free influenza vaccine each year:
For the most current eligibility list see the National Immunisation Program (NIP).
In Australia, influenza epidemiology is characterised by seasonal epidemics of type A and/or B virus, which peak during the winter months in temperate areas, with low rates of detection sustained during inter-epidemic months (10). Activity and disease severity varies from year to year, dependent on the circulating virus, level of immunity of the population (from vaccination and past infection), and effectiveness of the vaccine. In years where the circulating strain is predominantly influenza A (H3N2), elderly groups are more heavily impacted, while in influenza A(H1N1) or influenza B circulating years, children, pregnant women and younger adults have a proportionately increased notification rate.
Over the past century, influenza pandemics have been observed in 1918 (H1N1), 1957 (H2N2), 1968 (H3N2), and most recently in 2009 (H1N1) following emergence of novel influenza A subtypes. The 2009 pandemic was associated with a marked increase in notifications in Australia, which returned to pre- pandemic rates the following year (11). Thereafter, increasing notifications have been observed, which have exceeded 2009 pandemic rates between 2014 and 2017 (10, 11), and have been partly attributed to increased testing and a shift to predominantly polymerase chain reaction (PCR)-based detection methods (12).
On average each year in Australia, seasonal influenza results in an estimated 3,500 deaths, (13) and over 300,000 General Practitioner (GP) consultations and 18,000 hospitalisations (14), although these are recognised as underestimates of the true impact. As previously highlighted, certain population groups are at increased risk of severe disease, with significantly higher rates of influenza notification, hospitalisation and mortality observed in the elderly, children less than 5 years of age, and Aboriginal and Torres Strait Islander peoples.(6, 10, 11) Australian studies have previously estimated that influenza causes at least 13,500 hospitalisations and 3,000 deaths in people aged over 50 years (15), and approximately 10–15 deaths in children <5 years of age from influenza-related complications, each year.
For the latest information on seasonal influenza incidence, severity, transmission and virology in Australia, refer to the:
Refer to the NSW Respiratory Surveillance Report – COVID-19 and Influenza for the latest information on influenza in NSW.
Annual seasonal vaccination is the most important measure to prevent influenza and its complications thus decreasing morbidity and mortality (6). While influenza vaccine effectiveness can vary, vaccination reduces the risk of influenza illness in the overall population when the circulating influenza viruses are matched to the influenza vaccine.
Influenza vaccines can change from year to year as new strains of influenza virus appear. The influenza virus composition of vaccines for use in Australia is determined annually by the Australian Influenza Vaccine Committee following recommendations by the World Health Organization (WHO) based on global influenza epidemiology.
The Australian Immunisation Handbook (6) recommends annual vaccination for anyone aged 6 months or over is desired to reduce the likelihood of becoming ill and particularly for people with medical conditions that put them at risk of severe disease and complications of influenza and for people with occupational risk (see Section 2 - The disease - Vaccination of persons at increased risk of severe disease).
Currently in Australia, only inactivated vaccines are available. Inactivated influenza vaccines contain three ('trivalent' - two A subtypes and one B lineage) or four virus strains ('quadrivalent' - two A subtypes and two B lineages).
For adults aged 65 years and older, there are two higher-immunogenicity trivalent vaccine formulations available and funded under the NIP; one a 'high dose' vaccine and another containing an adjuvant (16, 17).
Seasonal vaccine compositions and strains vary. Refer to the 2023 seasonal influenza vaccination information for immunisation providers for the vaccine compositions currently available under the NIP.
Prevention activities should include:
School and childcare closures and exclusions related to potential exposure are not generally recommended for seasonal influenza outbreaks.
The focus of public health responses will be on control of outbreaks in high-risk settings, such as residential care facilities, correctional facilities, boarding schools, special needs schools for children with disabilities and Aboriginal and Torres Strait Islander communities.
For further information, refer to the Guidelines for the Prevention, Control and Public Health Management of Influenza Outbreaks in Residential Care Facilities in Australia (18).
For infected individuals, measures such as hand hygiene, good respiratory and cough etiquette, voluntary home isolation and cleaning of commonly touched surfaces should help reduce further transmission of influenza.
For information about infection control of hospitalised cases, refer to the Australian Guidelines for the Prevention and Control of Infection in Healthcare(19).
To support timely access to treatment for people who may be at increased risk of severe disease see the Pre-assessment action plan for respiratory infections or for residents of aged care facilities, the Pre-assessment action plan for respiratory infections in aged care facility residents.
See Section 12 – Special situations for NSW specific guidance for outbreaks in residential care facilities and guidance for infection prevention and control.
During the Australian influenza season, the Australian Influenza Surveillance Report is published fortnightly and available at the Department of Health website . Some jurisdictions publish local reports.The National Influenza Surveillance Scheme utilises several sentinel surveillance systems to enhance NNDSS data by providing information on the severity of influenza activity, virological characteristics and population susceptibility (20).
Laboratory-confirmed cases of influenza, including type and subtyping data (if available) should be entered into jurisdictional notification databases usually within one (up to five) working days and relayed to the NNDSS through routine processes.
Cases are counted in the jurisdiction of the case's usual residence. The established CDNA protocol for cross-border notification is used when appropriate.
An influenza infection can occur concurrently with, or subsequent to, infection by another influenza virus. In the instance of subsequent infections, each infection should be notified. In the instance of co-infections, the infection should be notified only once.
Notification data will be electronically transferred from laboratories to the NSW Notifiable Conditions Information Management System (NCIMS) within five working days. For those laboratories that do not have the capacity to notify electronically, Communicable Diseases Branch (CDB) will be responsible for uploading batched data into NCIMS at regular intervals. Refer to NCIMS data entry for ARI outbreak events for further guidance.
From January 2022, serology results received via electronic laboratory reporting are automatically excluded in NCIMS.
The reinfection period set for influenza in NCIMS is 30 days. Any additional laboratory results after 30 days will be treated as a new case (if criteria are met as per case definition). Additional results which identify a different subtype or strain within 30 days of a confirmed case will be treated as a dual infection.
Positive influenza laboratory test results should be notified to the relevant central or regional Public Health Unit (PHU) or state/territory disease control unit in accordance with jurisdictional notification requirements and cross- border protocols.
When notified of an outbreak of influenza in a high-risk setting, PHUs should inform the central state/territory disease control unit in accordance with priority. Liaison may be required with specialist infection control and environmental health protection units.
The CDNA and the National Incident Room (Department of Health), should be informed of cases of influenza caused by a novel virus subtype as soon as possible (within 24 hours). The Department of Agriculture and Water Resources Chief Veterinary Officer is notified through veterinary public health representation on CDNA.
Confirmed influenza cases caused by a novel virus subtype detected in people who work with pigs or poultry, should be investigated in collaboration with state/territory Department of Primary Industry veterinary authorities and may involve a work safety authority. With informed permission from the case, these notifications should use an encoded identifier for the case, and the name and location of the workplace.
When notified of an outbreak of influenza in a high-risk setting, PHUs should inform Health Protection NSW in accordance with priority by entering the outbreak into NCIMS.
When notified of a novel subtype or an untypeable influenza isolate, PHUs should urgently notify Health Protection NSW through Communicable Diseases (CD) OnCall. Health Protection NSW should inform the National Incident Centre, Australian Government Department of Health and Aged Care (DoHAC), of cases of influenza caused by a novel virus subtype as soon as possible (within 24 hours). The Department of Agriculture Forestry and Fisheries Chief Veterinary Officer is notified via DoHAC.
The CDNA influenza case definition was updated 1 January 2022 and no longer includes criteria 5. The latest version can be found at Australian national notifiable diseases and case definitions.
In NSW, case definition criteria 4 is unlikely to be met as electronic influenza notification does not include paired quantitative serology or negative serology results.
Only confirmed cases should be notified.
A confirmed case requires laboratory definitive evidence only.
Case definitions can be found on Department of Health,
Diagnoses of ILI may be used for routine surveillance of influenza activity in the community, case-finding in outbreaks and clinical diagnosis and treatment. The sensitivity and specificity of ILI case definitions vary, depending on inclusion and exclusion criteria. The positive predictive value of ILI diagnosis will depend on the current prevalence of influenza in the setting under surveillance and vaccination status of the person.
There are many definitions of ILI. The WHO case definition for ILI is an acute respiratory infection with measured fever ≥38oC and cough, with onset within the last 10 days. Most case definitions of ILI stipulate rapid onset of illness, with fever and cough. Other criteria may include chills or rigors, myalgia, fatigue, headache, sore throat and coryza. In the elderly, fever may be absent, and confusion, anorexia and breathlessness may be the only signs of influenza infection.
The term acute respiratory infection (ARI) is used in NSW, however ILI may be used in other jurisdictions.
An ARI is defined as a new or worsening acute respiratory symptom including cough, runny nose, breathing difficulty or sore throat, with or without the following:
The preferred test is a direct test; that is, detection of influenza virus antigens or influenza viral nucleic acid from a nasal or throat swab (see Section 7 Case definition).
Isolates of influenza should be typed (influenza A or B), and subtyped if possible (e.g. A/H1, A/H3).
Laboratory testing of all potential cases of influenza is neither required nor desirable for public health management.
To monitor changes in circulating viruses across Australia, isolates from both representative cases of influenza and clinically or microbiologically unusual cases of influenza should be provided to the WHO Collaborating Centre (WHOCC) for Reference and Research on Influenza for antigenic characterisation and antiviral resistance testing.
Rapid (45-90 minutes) NAT test systems are available in Australia that detect influenza A and B. These can be performed in laboratories without other molecular testing facilities, and offer comparable sensitivity and specificity to usual influenza-specific or multiplex NAT assays. A positive influenza rapid NAT result meets the surveillance case definition for notification. Rapid NAT results do not require other laboratory tests for confirmation, but may be submitted for subtyping.
POC antigen tests can be performed in the surgery/clinic, at or near the time of consultation, although in Australia POC antigen tests are usually done in the laboratory rather than at time of consultation.
Negative results of the POC antigen tests should be treated with caution due to their relatively low sensitivity compared to nucleic acid tests (NAT). A positive POC antigen test result has a high predictive value for influenza but only meets the surveillance case definition for notification if the POC test is conducted within an accredited laboratory quality management framework. Further testing should be sought if influenza is suspected on clinical signs in the presence of a negative POC test result (21).
Further testing should also be sought if influenza is suspected on clinical signs in the presence of a positive POC test result not conducted within an accredited laboratory.
Follow up by PHU is not routinely required for single notifications unless a case has a novel influenza subtype or untypable isolate, particularly if the case has died.
Public health actions focus on outbreaks in high-risk settings (see Section 12 - Special situations).
See Section 12 – Special situations for NSW specific response times for outbreaks in high-risk settings.
Act as soon as possible, generally within one working day for outbreaks in high-risk settings such as boarding schools, special needs schools for children with disabilities, residential care facilities, Aboriginal and Torres Strait Islander communities, or in health care facilities (see Section 12 - Special situations).
Respond immediately (within 24 hours) following receipt of WHOCC results identifying a novel influenza subtype or an untypable influenza isolate.
Where a novel influenza subtype or an untypable isolate is identified by the WHOCC, an interview with the case is required to confirm the date of onset of illness, occupation, location of exposure, interstate/overseas visits or visitors, any known infections among contacts, and anyone still ill. If the case has died, the next-of-kin is interviewed.
Case investigation forms are at Appendices 1 and 2.
Investigation by the PHU is not routinely required for single notifications.
The medical management of individual cases is the responsibility of the treating doctor. The PHU is not involved for single notifications.
For further information regarding case treatment, refer to the Therapeutic Guidelines – Influenza (22).
Not routinely required by the PHU for single notifications. Infection control education of a case should be managed by their treating doctor, including advice to stay at home while infectious. See Seasonal Influenza (Flu) Fact Sheet (Appendix 3). Fact sheets are also available on jurisdictional websites.
See the NSW Health Influenza fact sheet for further information.
Isolation and restriction is not routinely required by PHU for single notifications. In general, 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 the symptoms have resolved.
Although not mandatory, isolation of influenza cases is recommended as an effective way to reduce the spread of infection.
Healthcare providers should strongly recommend cases stay at home and avoid entering high-risk settings (such as residential aged care facilities, disability care facilities and hospitals) until their symptoms have resolved and at least 5 days following symptom onset, or 72 hours after commencing antivirals. Cases should be educated about their potential to infect others for up to 7 days after onset of symptoms and should continue to avoid people at high risk of severe disease during this time.
Healthcare workers with influenza should stay off work for 5 days after symptom onset, or until they are symptom-free, whichever is longer.
People with ARI who work with pigs or poultry should not attend work for 5 days after symptom onset, or until they are symptom-free, as there is risk of transmission of influenza from or to birds (avian) or pigs (swine) (See Section 12 Special situations).
Hospitals can refer to their own infection and prevention guidelines for the management of isolation and restriction of patients with influenza.
Not routinely required by PHU for seasonal influenza. See Section 12 - Special situations.
Influenza viruses are commonly spread by inhalation of infectious droplets produced by an infected person while talking, coughing and sneezing. Influenza virus transmission may also occur through contact with contaminated surfaces or objects (fomite).
The risk of further transmission of influenza can be minimised by having readily available hand hygiene materials, increased surface cleaning and laundering or disposal of soiled articles.
For further information, refer to the Guidelines for the Prevention, Control and Public Health Management of Influenza Outbreaks in Residential Care Facilities in Australia (18) and the Australian Guidelines for the Prevention and Control of Infection in Healthcare (19).
For further information refer to Infection Prevention and Control Manual – COVID-19 and other Acute Respiratory Infections.
Specialist infection prevention and control advice can be sought as needed.
Used tissues should be disposed of in general waste.
Definitions of an influenza contact are only required for some high-risk settings (see Section 12 - Special situations).
No public health action required except in high-risk settings (see Section 12 - Special situations).
Antiviral prophylaxis may complement but does not replace other outbreak control measures, such as droplet and contact precautions, hand hygiene, cohorting or isolating ill residents and correct cough/sneeze etiquette.
For further information on antiviral treatment, refer to the Therapeutic Guidelines – Influenza (22).
Not routinely required by the PHU for single notifications.
Not required unless described in special situations below (Section 12 - Special situations).
The public health response to outbreaks of influenza is determined by state or territory legislation, local reporting requirements and available resources Public health agencies will seek to determine the nature of the outbreak to define their role in the investigation.
Public health action should focus on influenza outbreaks in residential care facilities (aged and disability) with close reference to the relevant ARI guidance:
Other high-risk settings, e.g., healthcare facilities, correctional centres, boarding schools, special needs schools for children with disabilities, Aboriginal and Torres Strait Islander communities, and healthcare workers in high-risk settings, may be investigated at the discretion of the PHU Director.
Schools and childcare settings are prone to rapid transmission of influenza. Vaccination should be strongly encouraged for children and staff of schools and childcare centres, especially for those at risk of severe disease.
Children or staff with ILI or confirmed influenza should not attend school or childcare while infectious. If a child or staff member becomes ill with an ILI they should be sent home as soon as possible.
If an outbreak of ILI is reported in school or childcare settings, the PHU should assess the extent of the outbreak and may:
Because of the close nature of the students in residence, outbreaks may spread rapidly and special control measures may be required including:
Students may have chronic illnesses and be at risk of severe complications from influenza, so special control measures may be required. The PHU should consider recommending prophylactic antiviral medication to control influenza spread in specific instances.
Full or partial school closures are not generally recommended on public health grounds, although it is recognised that closures may be considered and implemented on logistical grounds by the school.
For further information, refer to the Therapeutic Guidelines – Influenza (22).
In some residential care settings, antivirals may be used as prophylaxis. Consideration and decisions on antiviral prophylaxis should be made by the treating doctor/s and outbreak management team in collaboration with, or after advice from, the state/territory public health authorities. If antiviral prophylaxis is used, all asymptomatic residents (regardless of vaccination status) and all unvaccinated staff should receive it at the same time.
Outbreaks of influenza or ILI in residential care facilities should be managed with close reference to the CDNA document: A Practical Guide to assist in the Prevention and Management of Influenza Outbreaks in Residential Care Facilities in Australia(18).
Residential care facilities (aged and disability) are recommended to notify outbreaks to their local PHU and seek advice as recommended by the ARI guidance.
The degree of involvement of the PHU should be determined by the PHU Director in consultation with the facility.
Aged care facilities can order oseltamivir (Tamiflu®) directly from the State Vaccine Centre by completing the online RACF influenza antiviral treatment access form.
Once the form is complete, the request will go to the NSW vaccine distribution warehouse to be filled and distributed. Facilities can only order up to 250 doses of oseltamivir using this form. For orders over 250 doses, facilities will need to contact their local public health unit.
Health Care Workers (HCW) with ILI may require special consideration. Although patient-care may be adversely impacted by a reduction in HCW numbers due to absences while ill, an infectious HCW can expose vulnerable patients to influenza virus, and may facilitate a broader outbreak in a healthcare setting.
Hospital-employed HCWs infected with influenza should comply with hospital occupational health and safety and infection control guidelines.
Further information is available in the Australian Guidelines for the Prevention and Control of Infection inHealthcare (2010) (19).
Seasonal influenza vaccination is an important routine prevention measure against healthcare-associated transmission of influenza. The WHO, United States Centres for Disease Control and Prevention Advisory Committee on Immunization Practices (ACIP), and the Australian Technical Advisory Group on Immunisation all recommend annual seasonal influenza vaccination of HCWs.
It is recommended that all HCWs with patient contact have seasonal influenza vaccination (6).
Within NSW Health facilities, all HCWs must be assessed, screened and vaccinated as required by the risk category of their position before they commence employment/engagement or attend clinical placements. All Category A workers and new recruits must receive a seasonal influenza vaccine during the influenza season and by 1 June each year. Annual influenza vaccination is strongly recommended and is free for all workers (Category B) employed in NSW Health facilities. For more information refer to the NSW Health Occupational Assessment, Screening and Vaccination Against Specified Infectious Diseases policy directive.
During influenza seasons, healthcare facilities should ensure HCWs:
Contact tracing is not routinely required following diagnosis of confirmed flu in a HCW, unless the HCW was working in a high risk setting with vulnerable patients.
Where a healthcare facility has an infection control service, that service would lead an outbreak management team. However, for outbreaks in other healthcare facilities, an outbreak management team should be convened. The team would include a senior facility manager, an infection control practitioner and appropriate clinical staff. The team may seek advice and guidance from PHU.
Healthcare facilities include hospitals, clinics, outpatient care centres and specialised care centres, such as psychiatric care centres and birthing centres.
Control measures may include:
Key factors in assessing influenza risk in Aboriginal and Torres Strait Islander communities may include:
The clinical and public health response to suspected or confirmed influenza outbreaks in Aboriginal and Torres Strait Islander communities should:
* During outbreaks in Aboriginal and Torres Strait Islander communities, vulnerable people include all those with risk factors referred to in Section 2 - The disease. Children in the 'failure to thrive' category are also considered vulnerable to complications of influenza.
Broad use of antiviral prophylaxis in a community setting requires consultation between the clinician, PHU and central communicable disease control unit within the relevant state or territory health department.
The term Aboriginal and Torres Strait Islander communities can be used to include groups of people such as families, households and networks that have geographic, kinship and/or social ties. Communities may be in remote, regional and/or metropolitan areas.
Cruise ship travel is characterised by the presence of many people in closed and semi-closed settings, which facilitates the transmission of influenza and other respiratory viruses from person-to-person through droplet and contact spread.
Prior to docking, a ship's captain/master should notify the Department of Agriculture and Water Resources (Agriculture Biosecurity Officers) of any ill travellers (23).
Cruise ship operators are recommended to consider:
In managing an outbreak of respiratory disease, on a cruise ship, the following should be considered:
In NSW, outbreaks of ARI or confirmed influenza on cruise ships or other passenger vessels are usually managed by the ship's medical team with support from the cruise company. Cases of influenza are reported to the NSW Health Cruise Ship Surveillance Program, managed by South Eastern Sydney PHU, which can provide advice on the management of outbreaks if required.
Close contact in boarding and disembarking queues and aircraft cabins can facilitate the spread of influenza viruses from person-to-person through droplet spread or contact with contaminated surfaces.
Passengers with ILI should ideally not travel by public transport, including commercial flights. Incoming passengers who have developed symptoms during a flight should wear a surgical mask (if available), practice good cough and hand hygiene and avoid close contact with others, as much as possible.
No restrictions are placed upon well contacts, and contact tracing is not required.
Captains of aircraft are required to notify the Department of Agriculture and Water Resources (Agriculture Biosecurity Officers) of ill travellers who are on an aircraft before it lands (24).
Pigs and poultry are particularly concerning as they have been associated with zoonotic transmission of influenza between species, and viral recombination events resulting in novel strains of swine flu (pig) or avian flu (bird). Refer to the Avian Influenza Control Guideline for further information.
Confirmed human influenza cases caused by a novel virus subtype detected in people who work with pigs or poultry, should be investigated by NSW Department of Primary Industries (DPI) veterinary authorities in collaboration with One Health Branch within Health Protection NSW. In a circumstance where the PHU is made aware of these cases first, they should notify the One Health Branch for escalation to DPI.
State and Territory Public Health Legislation, the Biosecurity Act 2015 and the National HealthSecurity Act 2007.
Seasonal Influenza Infection CDNA Guideline Appendix 1-4
