Frequency of Influenza, Influenza Types and Influenza Vaccine Use in Hospitalized Children with Influenza-Like Symptoms

Abstract

Influenza is an important cause of respiratory illness in children and is still an important cause of morbidity and mortality in children. The influenza virus subtypes determine the prevalence of the epidemic and pandemic influenza, the hospitalization and mortality rates in children each year. Surveillance of the circulation of different influenza virus strains is important in ensuring a good strain con-cordance for the composition of the annual influenza vaccine. The Global Influenza Hospital Surveillance Network® (GIHSN) is an international institution in which tertiary hospitals from many countries participate and where epidemiological surveillance of influenza disease is conducted. Six centers from Turkey participated in the study organized by GIHSN during the influenza season 2016 2017. The aim of this study was to demonstrate the frequency of influenza, virus types, clinical characteristics and vaccination rates in children admitted to our hospital with influenza-like symptoms in the influenza season 2016-2017. Informed consents were obtained from patients. 217 pediatric patients were screened with in the 24th and 48th hours of the hospitalization. Then a nasal/nasopharyngeal swab were collected from 184 patients who met the inclusion criteria. Real-time reverse-transcription polymerase chain reaction (rRT-PCR) was used to obtain laboratory results. Influenza virus, influenza virus subtypes were studied by rRT-PCR. The 83.3% of the patients with positive influenza was under 5 years of age. The rate of influenza positivity was 16.3% (n= 30 patients). Influenza A (H3N2) was the predominant strain in children. The 70% of isolates were influenza A (H3N2) and the 30% were influenza B (Yamagata). There were no case of influenza A (H1N1) or influenza B (Victoria). In 30% of cases with influenza positivity, there was an underlying disease. The most prevalent of them were neuromuscular disease followed by cardiovascular disease and asthma. Tobacco exposure was 86.6% in influenza positive cases. The empirical oseltamivir prescription rate was 28.2%. The vaccination rate of the influenza vaccine was very low (1.6%). The out of 3 patients with influenza positivity were admitted to pediatric intensive care unit, and 2 of them required mechanical ventilation. None of these patients required extracorpereal membrane oxygenation and did not die. Our results highlight the importance of surveillance for influenza and in particular, influenza vaccination rates of groups with risk for morbidity and mortality, such as children, need to be increased.