Epidemiological charsteristics of severe acute respiratory illness cases at national influenza central laboratory Pakistan (NICLP) centre of sentinel surveillence. September 17 to February 2018

Abstract

Purpose: To describe the epidemiology of SARI, identify influenza positivity and circulating influenza subtypes among SARI patients. Background: Severe acute respiratory illness (SARI) is recognized as a leading cause of morbidity and mortality globally. SARI is a rapidly progressive illness caused by pathogens like influenza having pandemic potential. In 2008 a sentinel lab-based influenza surveillance network was established in Pakistan in collaboration with CDC having objectives to assess trends of Influenza-like-Illness (ILI) and Severe Acute Respiratory Illness (SARI). Methods & Materials: A descriptive epidemiological study was conducted based on influenza surveillance data obtained from NICLP from September 2017 to February 2018. Study was done from data records and samples of suspected SARI patients received at NICLP. Patients who met standard WHO-SARI case definition (fever = 38+cough with or without any other cause in the last 10 days in a hospitalized case) Samples were tested at NICLP for confirmation by RT-PCR. Frequencies were calculated and data analyzed as per time, place and person. Results: A total of 1500 suspected samples were received out of which 471 met SARI case defination. Most effected age group was 30–39 years with n = 94 (20.0%) Median hospital stay was 5 days. During hospitalization 124 (26.3%) were ICU admissions, out of them 2 (0.42%) were on ventilator, 83 (17.6%) were mechanically ventilated. Of all SARI admissions 50.1% (236) were positive for influenza viruses, among positive 95.0% were Influenza A.61% were A/H1N1, 33.9% were A/H3N1, 5.0% were influenza B. travel history was positive in 8.9% contact history with flu patient was 11.5% (54). Males were 50.1% (263). Among females 1.25% females were pregnant. Among positive cases 176 (74.6%) were reported from Rawalpindi. Majority of cases were reported in January (277) followed by February (112). Conclusion: Influenza viruses are frequent cause of SARI admissions, so developing strategies to control influenza is a key stone to reduce SARI burden. Based on the results, policy for inclusion of flu vaccination on annual basis for improved vaccination coverage is recommended for general community especially high risk groups.