Impact of 2009 pandemic influenza among Vietnamese children based on a population‐based prospective surveillance from 2007 to 2011

Influenza and Other Respiratory Viruses

Minh Nhat Le²  Lay Myint Yoshida²  Motoi Suzuki²  Hien Anh Nguyen²  Huu Tho Le¹  Hiroyuki Moriuchi⁴  Duc Anh Dang³ 

[1] Khanh Hoa Health Service Department, Nha Trang, Vietnam;Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan;National Institutes of Hygiene and Epidemiology, Hanoi, Vietnam;Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan

关键词: Influenza;    pandemic;    pediatric;    Vietnam;   

DOI  :  10.1111/irv.12244

来源: Wiley

【 摘 要 】

Abstract

Background

Influenza virus is one of the major viral pathogens causing pediatric acute respiratory infection (ARI). The spread of pandemic influenza A (A(H1N1)pdm09) in 2009 around the globe had a huge impact on global health.

Objective

To investigate the impact of A(H1N1)pdm09 on pediatric ARI in Vietnam.

Study design

An ongoing population-based prospective surveillance in central Vietnam was used. All children aged <15 years residing in Nha Trang city, enrolled to the ARI surveillance in Khanh Hoa General Hospital, from February 2007 through March 2011 were studied. Clinical data and nasopharyngeal swab samples were collected. Influenza A was detected and genotyped by multiplex polymerase chain reaction assays and sequencing.

Results

Among enrolled 2736 hospitalized ARI cases, 354 (13%) were positive for influenza A. Genotyping results revealed that seasonal H3N2 and H1N1 (sea-H1N1) viruses were cocirculating before A(H1N1)pdm09 appeared in July 2009. The A(H1N1)pdm09 replaced the sea-H1N1 after the pandemic. The majority of influenza A cases (90%) were aged <5 years with incidence rate of 537 (387–775) per 100 000 population. Annual incidence rates of hospitalized influenza cases for pre-, initial and post-pandemic periods among children aged <5 year were 474, 452, and 387 per 100 000, respectively. Children with A(H1N1)pdm09 were elder, visited the hospital earlier, less frequently had severe signs, and were less frequently associated with viral coinfection compared with seasonal influenza cases.

Conclusions

The A(H1N1)pdm09 did not increase the influenza annual hospitalization incidence or disease severity compared with seasonal influenza among pediatric ARI cases in central Vietnam.

【 授权许可】

CC BY   
© 2014 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.