Metro South Public Health Unit Influenza Dr Bhakti Vasant Public Health Physician Metro South Public Health Unit Source of image: CDC. Influenza images. Available from URL: https://www.cdc.gov/flu/images/h1 n1/3d_influenza/3d_influenza_bl ue_no_key_full_lrg2.jpg
Outline Background Epidemiology At risk groups Symptoms & complications Transmission Diagnosis Prevention Treatment Source of image: Clancy S. Genetics of the influenza virus. Nature Education 2008; 1(1): 83
Background Acute resp illness Recognised since 16 th century Spreads rapidly in communities in outbreaks Caused by a virus (A, B, C or D) Seasonal / epidemic (antigenic drift) Pandemic (antigenic shift) Source: Paules. Influenza. The Lancet 2017; 390: 697 708, World Health Organization. Influenza (seasonal) fact sheet. Available from URL: http://www.who.int/mediacentre/factsheets/fs211/en/
Background: the viruses Influenza A Influenza B Influenza C Influenza D Classified as per haemagluttinin (HA) and neuraminidase (NA) Includes H1N1 and H3N2 Known to have caused pandemics Not classified into subtypes Divided into B/Yamagata or B/Victoria lineage Causes mild infections Not known to cause illness in humans Source: World Health Organization. Influenza (seasonal) fact sheet. Available from URL: http://www.who.int/mediacentre/factsheets/fs211/en/
300000 Number of laboratory-confirmed influenza notifications, Australia 2001-2017 Number of notifications 250000 200000 150000 100000 50000 0 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 Year Source of data: National Notifiable Disease Surveillance System. Available from URL: http://www9.health.gov.au/cda/source/rpt_2.cfm
Impact of 2017 flu season: Australia (data from 1 Jan until 22 Nov 2017) High rate of GP consultations Sentinel GP ILI consultations 14.8 per 1000 consults vs prev 5yr average: 10.3 per 1000 consults Increased hospitalisations Admissions to sentinel hospitals were 2.3 times the prev 5yr average Higher number of deaths Deaths in 2017 (to 22 Nov 17): 745 Prev 5 yr average: 176 Median age of death: 86 years (range 3 to 107y) 91% of deaths in people age 65y or older Source: Australian Government Department of Health. 2017 Influenza season in Australia. Source: http://www.health.gov.au/internet/main/publishing.nsf/content/cda-surveil-ozflu-flucurr.htm/$file/2017-season-summary-22112017.pdf
Laboratory-confirmed influenza notifications in Queensland by week of onset, 1 Jan 2012 to 22 Oct 2017 Source of data: Queensland Health Statewide Weekly Influenza Surveillance Report. Available from URL: https://www.health.qld.gov.au/ data/assets/pdf_file/0034/656494/influenza-qld-2017.pdf
Queensland influenza notifications and hospitalisations, 2016 (full yr) and 2017 (1 Jan 22 Oct) 2016 2017 (partial yr) All influenza notifications 23,261 53,451 Influenza A A(H1N1)pdm09 A/H3N2 Subtype unavailable 21,415 833 2,214 18,368 35,962 538 2,532 35,962 Influenza B 1,846 17,489 Type unavailable 0 0 Influenza hospitalisations (public) Intensive care admissions 3,197 402 5,710 678 Source: Queensland Health. Statewide weekly surveillance reports. Available from URL: https://www.health.qld.gov.au/clinicalpractice/guidelines-procedures/diseases-infection/surveillance/reports/flu
Laboratory confirmed influenza admissions to Queensland public hospitals by age group and gender, 1 Jan to 22 Oct 2017 Source of data: Queensland Health Statewide Weekly Influenza Surveillance Report. Available from URL: https://www.health.qld.gov.au/ data/assets/pdf_file/0034/656494/influenza-qld-2017.pdf
Metro South region: lab-confirmed influenza according to year Year Number of cases 2013 1,402 2014 4,434 2015 7,395 2016 5,783 2017 13,163 Source of data: Queensland Health. Notifiable Conditions Annual Reporting. Available from URL: https://www.health.qld.gov.au/clinical-practice/guidelinesprocedures/diseases-infection/surveillance/reports/notifiable/annual
At risk groups Age Increased risk of death in 65y of age Increased risk of hospitalisation in <2y Increased risk of death in 20 40y (pandemic flu) Pregnancy Immunocompromised state Medical comorbidity Any: neuromuscular disease, cognitive dysfunction, pulmonary disease, cardiovascular disease, renal disease, liver disease, diabetes, etc Genetic susceptibility Source: Paules C. Influenza. The Lancet 2017; 390: 697 708
Signs and symptoms Fever May be absent in the elderly Respiratory Usually non-productive cough Sore throat Rhinorrhoea Constitutional Headache, myalgia, chills, fatigue and anorexia Gastrointestinal Less common (usually in children) Source: Bresee JS. Inactivated Influenza Vaccines. From Plotkin s Vaccines, 7 th edition, Elsevier 2018
Signs and symptoms: influenza in the elderly Fever may be absent May have anorexia, lassitude or confusion Source of text: Bresee JS. Inactivated Influenza Vaccines. From Plotkin s Vaccines, 7 th edition, Elsevier 2018, source of image: Daily Mail (Australia). Available from: http://www.dailymail.co.uk/health/article-3552181/why-flu-deadly-elderly- Older-people-s-immune-systems-fail-detect-infection-t-mount-response.html
Signs and symptoms: case definition of influenza-like illness (ILI) in RACF Source: Communicable Diseases Network Australia. Guidelines for the prevention, control and public health management of influenza outbreaks in residential care facilities in Australia. CDNA 2017. Available from http://www.health.gov.au/internet/main/publishing.nsf/content/27be697a7fbf5ab5ca257bf0001d3ac8/$file/rcf_g uidelines.pdf
Symptoms and complications Source: Ghebrehewet. The BMJ 2016; 355:i6258, doi: 10.1136/bmj.i6258
Transmission is efficient Aerosol Droplet Generated from coughing or sneezing Can remain airborne for minutes to hours Detected in the air from patients rooms Also generated from coughing or sneezing Contact transmission The virus is infectious on hands for a short period Can remain infectious on non-porous environmental surfaces for up to 48 hours Source: Paules C. Influenza. The Lancet 2017; 390: 697 708
Transmission of seasonal influenza A person with seasonal influenza will infect, on average, 1.28 other people. [Of 57 studies, the median R0 = 1.28 (interquartile range: 1.19 1.37)] Source of text: Biggerstaff M. BMC Infectious Diseases 2014;14:480 https://doi.org/10.1186/1471-2334-14-480, source of image: https://sites.psu.edu/siowfa15/2015/09/07/d oes-your-heart-really-stop/
Incubation period and infectious period Average incubation period = 2 days (range 1 4 days) Infectious period = 1 day before illness onset + Viral shedding is greatest 3 5 days post onset (Can be longer in children and severely immunocompromised people) Source: Communicable Diseases Network Australia. Guidelines for the prevention, control and public health management of influenza outbreaks in residential care facilities in Australia. CDNA 2017. Available from http://www.health.gov.au/internet/main/publishing.nsf/content/27be697a7fbf5ab5ca257bf0001d3ac8/$file/rcf_g uidelines.pdf
Diagnosis Nucleic Acid Amplification Test (NAAT) GeneXpert Point of Care Testing Source: Communicable Diseases Network Australia. Guidelines for the prevention, control and public health management of influenza outbreaks in residential care facilities in Australia. CDNA 2017. Available from http://www.health.gov.au/internet/main/publishing.nsf/content/27be697a7fbf5ab5ca257bf0001d3ac8/$file/rcf_g uidelines.pdf
Prevention Source of image: CDC. Seasonal influenza (flu) preventive steps. Available from URL: https://www.cdc.gov/flu/consumer/prevention.htm
Prevention Influenza vaccination Most important step in preventing influenza infection Even with reduced vaccine effectiveness, may prevent some flu illness, medical visits and hospitalisations Important for elderly residents and RACF staff Infection control and cough etiquette Ill staff should be excluded for at least 5 days after symptom onset or until they are symptom free, whichever is longer Antiviral medications Role in treatment and prophylaxis in aged care Source: CDC. Seasonal influenza (flu) preventive steps. Available from URL: https://www.cdc.gov/flu/consumer/prevention.htm, Communicable Diseases Network Australia. Guidelines for the prevention, control and public health management of influenza outbreaks in residential care facilities in Australia. CDNA 2017. Available from http://www.health.gov.au/internet/main/publishing.nsf/content/27be697a7fbf5ab5ca257bf0001d3ac8/$file/rcf_guidelines.pdf
Treatment Healthy individuals Supportive: adequate fluids, antipyretics, rest, exclusion from work for at least 5 days from symptom onset Antivirals are recommended for the following groups: Patients at high risk of developing severe or complicated disease, including the elderly Patients with severe or progressive clinical illness Source: Ghebrehewet. The BMJ 2016; 355:i6258, doi: 10.1136/bmj.i6258, World Health Organization. Influenza (seasonal) fact sheet. Available from URL: http://www.who.int/mediacentre/factsheets/fs211/en/
Antiviral prophylaxis The widespread use of antivirals in institutions that house residents at high risk of severe disease and death from influenza is supported by observational cohort studies and one randomised controlled trial. Antivirals are NOT a substitute other OB control measures! Need to commence promptly for all targeted residents & staff (ideally within 24 hrs) Consider renal function Dose adjustment = Pre-planning & preparedness Source: Communicable Diseases Network Australia. Guidelines for the prevention, control and public health management of influenza outbreaks in residential care facilities in Australia. CDNA 2017. Available from http://www.health.gov.au/internet/main/publishing.nsf/content/27be697a7fbf5ab5ca257bf0001d3ac8/$file/rcf_g uidelines.pdf
Antiviral prophylaxis For ALL asymptomatic residents For ALL un-vaccinated staff Incomplete coverage Effectiveness Should be organised within 24 hrs Considerations for decision to use Current epidemiology Outbreak characteristics (attack rate, morbidity ) Outbreak progress (eg. time since 1st case) Facility characteristics Clinical resources (GP No. & engagement, staff) Timeliness of oseltamivir supply Source: Communicable Diseases Network Australia. Guidelines for the prevention, control and public health management of influenza outbreaks in residential care facilities in Australia. CDNA 2017. Available from http://www.health.gov.au/internet/main/publishing.nsf/content/27be697a7fbf5ab5ca257bf0001d3ac8/$file/rcf_g uidelines.pdf
Conclusion Influenza is associated with seasonal outbreaks in the winter months. Elderly people are at risk of severe disease and complications. Elderly people may not have classical flu symptoms. Vaccination, infection control and antiviral medication have a role in preventing influenza.
Acknowledgements Metro South Public Health Unit Gayle Pollard Bonnie Macfarlane Kari Jarvinen Communicable Diseases Branch, Queensland Health
Contact email: Bhakti.Vasant@health.qld.gov.au Source of image: http://www.powerpointhintergrund.com/uploads/thank-you-background-powerpoint-22.jpeg