SARI, Influenza and Respiratory Pathogens

Transcription

1 ISSN Hospital Surveillance SARI, Influenza and Respiratory Pathogens Monthly Report, April 15 SUMMARY During weeks ( March 26 April 15), influenza activity remained low in hospital surveillance in Auckland and Counties Manukau District Health Boards. SARI surveillance SARI surveillance: There were 661 acute admissions to ADHB and CMDHB hospitals this month. Of the 377 patients with suspected respiratory infections, 119 (31.6%) patients met the SARI case definition. Seven SARI cases have been admitted to ICU and one SARI related death was reported. The monthly SARI incidence was 7.5 per population, lower than the incidence during the same period last year. The SARI related influenza incidence was.2 per population. Respiratory pathogen surveillance Influenza virus: During this month 8 SARI specimens were tested, 3 were positive for influenza viruses. For details, see Table 2 and Figure 2. Non-influenza respiratory viruses: For cumulative totals and temporal distribution, see Table 3 and Figure 3. The surveillance for 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 monthly 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 hospital SARI cases including ICU admissions and deaths for the past week as well as the cumulative period since 28 April 14. Note: Data in this report are provisional and may change as more cases are assessed and information is updated. Data were extracted on 12 May 15. 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.

2 SEVERE ACUTE RESPIRATORY INFECTION Severe acute respiratory infection (SARI) There were 661 acute admissions to ADHB and CMDHB hospitals during weeks 14-17, ending 26 April 15. A total of 377 patients with suspected respiratory infections were assessed in these hospitals. Of these, 119 (31.6%) patients met the SARI case definition. Seven SARI cases have been admitted to ICU and one SARI related death was reported during weeks Of the 119 SARI cases admitted last month, 68 were residents of ADHB and CMDHB. This gives a monthly SARI incidence of 7.5 per population. 64 SARI residents had specimens tested for influenza viruses, two were positive for influenza viruses. This gives a SARI related influenza incidence of.2 per patient population.

3 Incidence per residents Figure 1 Weekly resident SARI and influenza incidence since 28 April 14 and previous seasons SARI incidence SARI cases - all others SARI cases - influenza positive 12/3 SARI cases 13/4 SARI cases May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr Week (14/15) Since 28 April 14, a total of 15 SARI cases were identified. This gives a SARI proportion of 21.3 per acute hospitalisations (Table 2). 161 SARI cases have been admitted to ICU and 23 SARI related deaths were reported during this period. Of the 15 SARI cases, 1943 were ADHB and CMDHB residents, giving a SARI incidence of per population (Table 1). Among the 1839 tested SARI cases who were ADHB and CMDHB residents, 356 (19.4%) had positive influenza virus results. This gives a SARI related influenza incidence of 39.3 per population.

4 Table 1 Demographic characteristics of SARI cases and related influenza cases, since 28 April 14 Characteristics Admissions Assessed SARI & influenza cases among all hospital patients SARI Cases (%) Cases per hospitalisations Influenza positive 1 SARI cases (%) SARI & influenza cases among ADHB & CMDHB residents SARI incidence (per ) Influenza Cases Influenza incidence (per ) Overall (43.5) (19.9) Age group (years) < (9.8) to (12.1) to (18.2) to (37.5) to (34.1) to (.1) to (22.3) and over (11.7) Unknown (23.9) - - Ethnicity Maori (16.6) Pacific Peoples (18.) Asians (21.8) European and others (22.6) Unknown (23.9).. Hospitals ADHB (22.4) CMDHB (18.5) Sex Female (22.2) Male (16.7) Unknown (23.8) 1 - -

5 RESPIRATORY PATHOGEN SURVEILLANCE Influenza virus During weeks 14-17, 8 SARI specimens were tested; 3 were positive for influenza viruses. Since 28 April 14, a total of 2368 SARI specimens were tested, 473 (.%) were positive for influenza with the following viruses (see Table 2). Table 2 Influenza viruses among SARI cases since 28 April 14 Influenza viruses SARI Cases ICU Deaths No. of specimens tested No. of positive specimens (%) (.) 31 (18.7) 5 (.) Influenza A A (not subtyped) 86 4 A (H1N1)pdm A(H1N1)pdm9 by PCR A/California/7/9 (H1N1) - like 27 4 A(H3N2) 92 3 A(H3N2) by PCR 87 3 A/Texas//12 (H3N2) - like 5 Influenza B 46 1 B (lineage not determined) 42 1 B/Yamagata lineage 4 B/Yamagata lineage by PCR 1 B/Massachusetts/2/12 - like 3 B/Victoria lineage B/Victoria lineage by PCR B/Brisbane/6/8 - like Influenza and non-influenza co-detection (% +ve) 56 (11.8) 2 (6.5) 1 (.) 1 Number of specimens positive for at least one of the listed viruses; note a specimen may be positive for more than one virus

6 Non-influenza respiratory pathogens Since 28 April 14, a total of 1168 SARI specimens were tested for non-influenza viruses, 587 (.3%) were positive with the following viruses (see Table 3). Table 3 Non-influenza respiratory viruses among SARI cases, since 28 April 14 Non-influenza respiratory viruses SARI Cases ICU Deaths No. of specimens tested No. of positive specimens (%) (.3) 22 (47.8) 2 (.) Respiratory syncytial virus (RSV) Parainfluenza 1 (PIV1) 38 3 Parainfluenza 2 (PIV2) 3 Parainfluenza 3 (PIV3) Rhinovirus (RV) 6 5 Adenovirus (AdV) 93 8 Human metapneumovirus (hmpv) 98 2 Single virus detection (% of positives) 495 (84.3) 17 (77.3) 2 (.) Multiple virus detection (% of positives) 92 (15.7) 5 (22.7) (.) 1 Number of specimens positive for at least one of the listed viruses; note a specimen may be positive for more than one virus

7 Number of viruses Proportion positive Number of viruses Proportion positive Figure 2 Temporal distribution of the number and proportion of influenza viruses from SARI specimens by type and week A (Not subtyped) A(H3) A(H1N1)pdm9 B (Lineage not determined) B (Yamagata lineage) B (Victoria) Proportion positive for influenza Week (14/15) Figure 3 Temporal distribution of the number and proportion of non-influenza viruses from SARI specimens by type and week RSV parainfluenza 1 parainfluenza 2 parainfluenza 3 rhinovirus adenovirus hmpv Proportion positive for non-influenza pathogen Week (14/15) Figures for recent weeks will be underestimates due to time lag in receiving laboratory test results.

8 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 in Auckland Counties Manukau District Health Boards (ADHB and CMDHB), which together provide healthcare for 95,622 people. The aims of SARI surveillance are: 1) to measure the burden of severe disease caused by influenza and other respiratory pathogens; 2) to monitor trends in severe 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 disease; 5) to provide a study base to estimate the effectiveness of influenza vaccine. 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 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 Centers for Disease Control and Prevention and WHO Collaborating Centre at St Jude Children s Hospital in Memphis, USA.

9 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 days, AND requiring inpatient hospitalisation (defined as a patient who is admitted under a medical team and to a hospital ward or assessment unit). PCR method for influenza virus: ADHB Laboratory and ESR s National Influenza Centre (NIC) use CDC s real-time PCR protocol ( 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). This monthly report is compiled by ESR. For more information please contact: Thomas Metz T: ; E: Thomas.Metz@esr.cri.nz Tim Wood: T: ; E: Tim.Wood@esr.cri.nz Sue Huang: T: ; E: Sue.Huang@esr.cri.nz