ISSN 2324-497 Community and Hospital Surveillance ILI, SARI, Influenza and Respiratory Pathogens 15 Influenza Season, Week 27, ending 5 July 15 SUMMARY During week 27 (29 June 5 July 15), influenza activity increased in community and hospital surveillance in Auckland and Counties Manukau District Health Boards. ILI and SARI surveillance ILI surveillance: The weekly ILI incidence was 49.3 per 1 patient population (see Figure 1 of the report), above the seasonal threshold of ILI consultations. The ILI related influenza incidence was 23.6 per 1 patient population. SARI surveillance: There were 2835 acute admissions to ADHB and CMDHB hospitals this week. Of the 223 patients with suspected respiratory infections, 14 (46.6%) patients met the SARI case definition. Five SARI cases have been admitted to ICU and no SARI related deaths were reported. The weekly SARI incidence was 8.7 per 1 population. The SARI related influenza incidence was 1.2 per 1 population. Respiratory pathogen surveillance Influenza virus: During this week, 47 ILI specimens were tested, 24 were positive for influenza viruses. In addition, 55 SARI specimens were tested, 11 were positive for influenza viruses. For details, see Table 3 and Figures 3&4. Non-influenza respiratory viruses: For cumulative totals and temporal distribution, see Table 4 and Figures 5&6. The surveillance for community-based influenza-like illness (ILI) and hospital-based severe acute respiratory infections (SARI) provides evidence to inform public health and clinical practice to reduce the impact of influenza virus infection and other important respiratory pathogens. As part of the Southern Hemisphere Influenza and Vaccine Effectiveness Research & Surveillance (SHIVERS) project, this weekly report summarises data obtained from the Auckland and Counties Manukau District Health Boards (ADHB and CMDHB) of New Zealand with a population of 95,622 people. The report includes incidence, demographic characteristics, clinical outcomes and aetiologies for community ILI cases as well as hospital SARI cases including ICU admissions and deaths for the past week as well as the cumulative period since 27 April 15. Note: Data in this report are provisional and may change as more cases are assessed and information is updated. Data were extracted on 1 July 15.
18 19 21 22 23 24 25 26 27 28 29 31 32 33 34 35 36 37 38 39 Incidence per 1 residents INFLUENZA-LIKE ILLNESS and SEVERE ACUTE RESPIRATORY INFECTION Influenza-like illness (ILI) During week 27, ending 5 July 15, 52 patients with influenza-like illness consulted sentinel general practices. Of these, 48 were enrolled patients residing in ADHB and CMDHB. The weekly ILI incidence was 49.3 per 1 patient population. Of the 45 tested ILI cases who were enrolled ADHB and CMDHB residents, 23 were positive for influenza viruses. This gives an ILI related influenza incidence of 23.6 per 1 patient population. Figure 1 Weekly resident ILI and influenza incidence since 27 April 15 14 1 1 8 6 4 ILI cases - all others ILI cases - influenza positive 13 ILI cases 14 ILI cases May Jun Jul Aug Sep Week (15) Since 27 April 15, a total of 248 ILI cases were identified. Of them, 224 were enrolled patients residing in ADHB and CMDHB. This gives a cumulative ILI incidence of 2.2 per 1 patient population (Table 1). Among the 216 tested ILI cases who were enrolled ADHB and CMDHB residents, 53 (24.5%) were positive for influenza viruses. This gives an ILI related influenza incidence of 54.5 per 1 patient population.
Table 1 Demographic characteristics of ILI and influenza cases, since 27 April 15 ILI cases Influenza cases Prop Influenza positive 1 (%) ILI cases ILI incidence (per 1 ) Influenza cases Influenza incidence (per 1 ) Overall 248 57 24.1 224 2.2 53 54.5 Age group (years) <1 3. 2 173.6. 1 to 4 36 3 8.3 35 517.8 3 44.4 5 to 19 77 25 32.5 71 3.5 24 18.3 to 34 33 6 18.2 27 132.1 4 19.6 35 to 49 46 11 23.9 41 189. 1 46.1 5 to 64 35 7. 31 1.8 7 45.6 65 to 79 13 5 38.5 12 162. 5 67.5 8 and over 5. 5 215.. Unknown - - - Ethnicity Maori 4. 18 262.9 4 58.4 Pacific Peoples 31 5 16.1 28 121.9 4 17.4 Asians 41 11 26.8 35 228.3 1 65.2 European and others 156 37 23.7 143 274.4 35 67.2 Unknown -.. DHB Auckland 184 44 23.9 181 294.7 43 7. Counties Manukau 8 26.7 83.6 8 22.3 Sex Characteristics ILI & influenza cases among sentinel practices ILI & influenza cases among ADHB & CMDHB residents Female 145 31 21.4 1 252.6 29 56.4 Male 13 26 25.2 94 5.1 24 52.4 Unknown - - - 1 Proportion of cases tested which were positive for influenza viruses Severe acute respiratory infection (SARI) There were 2835 acute admissions to ADHB and CMDHB hospitals during week 27, ending 5 July 15. A total of 223 patients with suspected respiratory infections were assessed in these hospitals. Of these, 14 (46.6%) patients met the SARI case definition. Five SARI cases have been admitted to ICU and no SARI related deaths were reported this week. Of the 14 SARI cases this week, 79 were residents of ADHB and CMDHB. This gives a weekly SARI incidence of 8.7 per 1 population. 5 SARI residents had specimens tested for influenza viruses, 1 were positive for influenza viruses. This gives a SARI related influenza incidence of 1.2 per 1 patient population.
18 22 24 26 28 32 34 36 38 4 42 44 46 48 5 52 2 4 6 8 1 12 14 16 Incidence per 1 residents Figure 2 Weekly resident SARI and influenza incidence since 27 April 15 and previous seasons SARI incidence 18 16 14 12 1 8 6 4 2 SARI cases - all others SARI cases - influenza positive 12/3 SARI cases 13/4 SARI cases 14/5 SARI cases May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr Week (15/16) Since 27 April 15, a total of 649 SARI cases were identified. This gives a SARI proportion of 24.1 per 1 acute hospitalisations (Table 2). 52 SARI cases have been admitted to ICU and seven SARI related deaths were reported during this period. Of the 649 SARI cases, 51 were ADHB and CMDHB residents, giving a SARI incidence of 55.3 per 1 population (Table 2). Among the 387 tested SARI cases who were ADHB and CMDHB residents, 23 (5.9%) had positive influenza virus results. This gives a SARI related influenza incidence of 2.5 per 1 population.
Table 2 Demographic characteristics of SARI cases and related influenza cases, since 27 April 15 SARI Cases (%) Cases per 1 hospitalisations Influenza positive 1 SARI cases (%) SARI incidence (per 1 ) Influenza Cases Influenza incidence (per 1 ) Overall 26898 1554 649 (41.8) 24.1 26 (6.1) 51 55.3 23 2.5 Age group (years) <1 964 139 144.2 1 (.9) 131 969.9 1 7.4 1 to 4 211 154 73.3 3 (2.7) 138 261. 2 3.8 5 to 19 3225 43 13.3 4 (13.8) 37 19.2 3 1.6 to 34 4917 35 7.1 5 (16.7) 34 16.3 5 2.4 35 to 49 4127 39 9.4 3 (8.3) 38 19.9 2 1. 5 to 64 45 47 1.4 7 (18.4) 46.6 7 4.7 65 to 79 431 54 12.5 2 (4.7) 52 71.1 2 2.7 8 and over 2724 26 9.5 1 (4.5) 25 16.7 1 4.3 Unknown 112 (.) - - Ethnicity Maori 3595 134 37.3 5 (5.) 122 122.6 4 4. Pacific Peoples 5574 4 36.6 7 (4.4) 196 142. 6 4.3 Asians 495 47 11.5 2 (4.9) 45 21.4 2 1. European and others 13438 152 11.3 12 (1.3) 138 34.4 11 2.7 Unknown 191 112 (.).. Hospitals ADHB 1523 788 238 15.8 16 (1.5) 15 34.4 14 3.2 CMDHB 11875 766 411 34.6 1 (3.6) 351 74.8 9 1.9 Sex Characteristics Admissions Assessed SARI & influenza cases among all hospital patients SARI & influenza cases among ADHB & CMDHB residents Female 1414 26 18.4 12 (5.9) 244 52.5 1 2.1 Male 12793 276 21.6 14 (6.5) 256 58.1 13 3. Unknown 1 113 (.) 1 - - 1 Proportion of cases tested which were positive for influenza viruses
RESPIRATORY PATHOGEN SURVEILLANCE Influenza virus During week 27, 47 ILI specimens were tested; 24 were positive for influenza viruses. In addition, 55 SARI specimens were tested; 11 were positive for influenza viruses. Since 27 April 15, a total of 239 ILI specimens were tested for influenza viruses and 57 (23.8%) were positive for influenza with the following viruses (see Table 3). Of the 464 SARI specimens tested, (6.5%) were positive for influenza with the following viruses (see Table 3). Table 3 Influenza viruses among ILI and SARI cases since 27 April 15 Influenza viruses ILI SARI Cases Cases ICU Deaths No. of specimens tested 239 464 45 3 No. of positive specimens (%) 1 57 (23.8) (6.5) 3 (6.7) (.) Influenza A 34 19 1 A (not subtyped) 21 1 1 A (H1N1)pdm9 A(H1N1)pdm9 by PCR A/California/7/9 (H1N1) - like A(H3N2) 13 9 A(H3N2) by PCR 11 8 A/Switzerland/9715293/13 (H3N2) - like 2 1 Influenza B 23 11 2 B (lineage not determined) 17 9 2 B/Yamagata lineage 6 2 B/Yamagata lineage by PCR B/Phuket/73/13 - like 6 2 B/Victoria lineage B/Victoria lineage by PCR B/Brisbane/6/8 - like Influenza and non-influenza co-detection (% +ve) 2 (3.5) (.) (.) (-) 1 Number of specimens positive for at least one of the listed viruses; note a specimen may be positive for more than one virus The recommended influenza vaccine formulation for New Zealand in 15 is: A(H1N1) - an A/California/7/9 (H1N1)pdm9-like strain* A(H3N2) - an A/Switzerland/9715293/13 (H3N2)-like strain B - a B/Phuket/73/13-like strain * Note: A/California/7/9 (H1N1)-like strain is an influenza A(H1N1)pdm9 strain.
Non-influenza respiratory pathogens Since 27 April 15, a total of 174 ILI specimens were tested for non-influenza viruses and 67 (38.5%) were positive with the following viruses (see Table 4). Of the 185 SARI specimens tested for non-influenza viruses, 117 (63.2%) were positive with the following viruses (see Table 4). Table 4 Non-influenza respiratory viruses among SARI cases, since 27 April 15 Non-influenza respiratory viruses ILI SARI Cases Cases ICU Deaths No. of specimens tested 174 185 5 1 No. of positive specimens (%) 1 67 (38.5) 117 (63.2) 2 (4.) (.) Respiratory syncytial virus (RSV) 53 1 Parainfluenza 1 (PIV1) Parainfluenza 2 (PIV2) 7 1 Parainfluenza 3 (PIV3) 8 2 Rhinovirus (RV) 21 38 Adenovirus (AdV) 8 26 1 Human metapneumovirus (hmpv) 2 5 1 Enterovirus 9 5 Single virus detection (% of positives) 61 (91.) 14 (88.9) 1 (5.) (-) Multiple virus detection (% of positives) 6 (9.) 13 (11.1) 1 (5.) (-) 1 Number of specimens positive for at least one of the listed viruses; note a specimen may be positive for more than one virus
Number of viruses Proportion positive Number of viruses Proportion positive Figure 3 Temporal distribution of the number and proportion of influenza viruses from ILI specimens by type and week 1 8 75 7 65 6 55 5 45 4 35 25 15 1 5 A (Not subtyped) A(H3N2) A(H1N1)pdm9 B (Lineage not determined) B (Yamagata lineage) B (Victoria) Proportion positive for influenza 18 19 21 22 23 24 25 26 27 28 29 31 32 33 34 35 36 37 38 39 Week (15) 1 9 8 7 6 5 4 1 Figure 4 Temporal distribution of the number and proportion of influenza viruses from SARI specimens by type and week 1 5 45 4 35 25 15 1 5 A (Not subtyped) A(H3N2) A(H1N1)pdm9 B (Lineage not determined) B (Yamagata lineage) B (Victoria) Proportion positive for influenza 18 22 24 26 28 32 34 36 38 4 42 44 46 48 5 52 2 4 6 8 1 12 14 16 Week (15/16) 1 9 8 7 6 5 4 1
Number of viruses Proportion positive Number of viruses Proportion positive Figure 5 Temporal distribution of the number and proportion of non-influenza viruses from ILI specimens by type and week 1 7 65 6 55 5 45 4 35 25 15 1 5 18 19 21 22 23 24 25 26 27 28 29 31 32 33 34 35 36 37 38 39 Week (15) RSV parainfluenza 1 parainfluenza 2 parainfluenza 3 rhinovirus adenovirus hmpv enterovirus Proportion positive for non-influenza pathogen 1 9 8 7 6 5 4 1 Figure 6 Temporal distribution of the number and proportion of non-influenza viruses from SARI specimens by type and week 1 6 55 5 45 4 35 25 15 1 5 18 22 24 26 28 32 34 36 38 4 42 44 46 48 5 52 2 4 6 8 1 12 14 16 Week (15/16) RSV parainfluenza 1 parainfluenza 2 parainfluenza 3 rhinovirus adenovirus hmpv enterovirus Proportion positive for non-influenza pathogen 1 9 8 7 6 5 4 1 1 Figures for recent weeks will be underestimates due to time lag in receiving laboratory test results.
APPENDIX Recent global experience with pandemic influenza A(H1N1)pdm9 highlights the importance of monitoring severe and mild respiratory disease to support pandemic preparedness as well as seasonal influenza prevention and control. An enhanced, active, population-based surveillance has been established for hospital-based severe acute respiratory infection (SARI) cases as well as for community-based influenza-like illness cases in Auckland Counties Manukau District Health Boards (ADHB and CMDHB), which together provide healthcare for 838, people. The aims of ILI and SARI surveillance are: 1) to measure the burden of severe and mild disease caused by influenza and other respiratory pathogens; 2) to monitor trends in severe and mild disease caused by influenza and other respiratory pathogens; 3) to identify high risk groups that should be prioritized for prevention and treatment; 4) to monitor antigenic, genetic and antiviral characteristics of influenza viruses associated with severe and mild disease. 5) to provide a study base to estimate the effectiveness of influenza vaccine. ACKNOWLEDGEMENT We acknowledge the support of the US Department of Health and Human Services, Centers for Disease Control and Prevention (CDC) and the New Zealand Ministry of Health. The SHIVERS project is a five year research cooperative agreement between the Institute of Environmental Science and Research (ESR) in New Zealand and US CDC s National Center for Immunization and Respiratory Diseases (NCIRD) Influenza Division. The SHIVERS project is funded by the CDC under award number 5U1IP48-4. SARI surveillance is a key component of the SHIVERS project and is augmented during the summer season through funding from the New Zealand Ministry of Health The SHIVERS project is a multi-centre and multi-disciplinary collaboration between ESR, Auckland District Health Board, Counties Manukau District Health Board, University of Otago, University of Auckland, participating sentinel general practices, Primary Health Organisations (Procare, Auckland and East Tamaki Healthcare), Auckland Regional Public Health Service, the US Centres for Disease Control and Prevention and WHO Collaborating Centre at St Jude Children s Hospital in Memphis, USA. The SARI surveillance protocol was developed by: Sue Huang, Sally Roberts, Colin McArthur, Michael Baker, Cameron Grant, Deborah Williamson, Adrian Trenholme, Conroy Wong, Susan Taylor, Lyndsay LeComte, Graham Mackereth, Don Bandaranayake, Tim Wood, Ange Bissielo, Ruth Seeds, Nikki Turner, Nevil Pierse, Paul Thomas, Richard Webby, Diane Gross, Jazmin Duque, Mark Thompson and Marc-Alain Widdowson. The ILI surveillance protocol was developed by: Sue Huang, Nikki Turner, John Cameron, Michael Baker, Bruce Adlam, Graham Mackereth, Don Bandaranayake, Ange Bissielo, Tim Wood, Ruth Seeds, Barbara McArdle, Tracey Poole, Rosemary Gordon, Sam Wong, Leane Els, Marion Howie, Gillian Davies, Paul Thomas, Richard Webby, Diane Gross, Jazmin Duque and Marc-Alain Widdowson.
NOTES ON INTERPRETATION SARI case definition: An acute respiratory illness with a history of fever or measured fever of 38 C, AND cough, AND onset within the past 1 days, AND requiring inpatient hospitalisation (defined as a patient who is admitted under a medical team and to a hospital ward or assessment unit). ILI case definition: An acute respiratory illness with a history of fever or measured fever of 38 C, AND cough, AND onset within the past 1 days, AND requiring GP consultation. ILI sentinel general practices: a total of 16 sentinel general practices have agreed to participate in community ILI surveillance. These practices have 15,269 enrolled patients, covering roughly 12% of the ADHB and CMDHB population. PCR method for influenza virus: ADHB Laboratory and ESR s National Influenza Centre (NIC) use CDC s real-time PCR protocol (http://www.accessdata.fda.gov/cdrh_docs/pdf8/k857.pdf.); CMDHB laboratory uses commercially available multiplex real-time PCR assay from AusDiagnostics. Ongoing validation between the AusDiagnostic assays and CDC s influenza assay will be conducted on a weekly basis. The real-time PCR assay for non-influenza respiratory viruses (respiratory syncytial virus, parainfluenza virus types 1-3, human metapneumovirus, rhinovirus and adenovirus) was obtained from the U.S. Centers for Disease Control and Prevention and are available on request. Note: The rhinovirus PCR detects mostly rhinovirus with slight cross-reactivity against enterovirus. The surveillance week is Monday to Sunday inclusive, and data are extracted on the subsequent Tuesday. Results from previous weeks will be revised as data are updated (laboratory test results in particular may be delayed). A seasonal threshold of 36 ILI consultations per 1, patient population was based on New Zealand s ILI data during -13 (excluding 9). It is the level of influenza activity that signals the start and end of the annual influenza season. This weekly report is compiled by ESR. For more information please contact: Thomas Metz: T:+64 4 529 625; E: Thomas.Metz@esr.cri.nz Tim Wood: T:+64 4 529 611; E: Tim.Wood@esr.cri.nz Sue Huang: T:+64 4 529 66; E: Sue.Huang@esr.cri.nz