Severe acute respiratory infections associated with influenza and non-influenza viruses - Yemen, 2011-2014

Abstract

Background: In 2010, influenza surveillance started in Yemen after H1N1 influenza outbreak. Ministry of Health (MoH) established two sentinel sites for Severe Acute Respiratory Infection (SARI) at the two main public hospitals in Sana’a and Aden with the support of NAMRU3, where SARI samples tested for influenza and non-influenza viruses by the Real-Time-PCR assay. The aim is to describe the SARI severity as indicated by admission to intensive care unit (ICU) and fatality as well as associated influenza and non-influenza viruses among hospitalized patients of the two sentinel sites in order to provide recommendations for improving influenza surveillance Methods & Materials: Data of hospitalized patients of the two sites who meet WHO SARI case definition during 2011 to 2014 was obtained from MoH. Data was cleaned and analyzed using SPSS program where P value < 0.05 was the cut point for significance Results: 1,665 met SARI cases definition during 2011 to 2014, of which 64% from Aden, two thirds were below the age of two years, 48% were males, 24% has chronic diseases and 33% was admitted to the ICU. Overall fatality rate was 10% which significantly higher among patients from Aden than Sana’a (14% vs. 3%, P <0.001). 1299 (78%) samples were tested where influenza viruses were confirmed in 67 (5%); of which 41 (61%) was type A and 27 (39%) was type B. Non-influenza viruses were detected in 39% (509) of samples including 246 (48%) Respiratory Syncytial Virus and 99 (19%) was Adenovirus. The influenza viruses was significantly higher in Sana’a than Aden (63% vs 37% P value < 0.01) while the Non-influenza virus was significantly higher in Aden than Sana’a (54% vs. 46%, P value < 0.01). The case fatality rate among non-influenza was 11% compared to 6% among influenza cases but the difference was not statistically significant. Conclusion: Our findings showed that most SARI cases was of non-influenza type with high mortality that necessitate prompt diagnosis and treatment of suspected cases. Expanding SARI surveillance to include more public and private hospitals in different governorates is recommended to give more comprehensive picture. Further studies to better understand the geographical differences are needed