Influenza species and subtypes circulation among hospitalized patients in Laleh hospital during two influenza seasonal (2016-2017 and 2017-2018) using a multiplex Real Time-Polymerase Chain Reaction

Azhar, Iman Rezaee; Mohraz, Minoo; Mardani, Masoud; Tavakoli, Mohammad Ali; Afshar, Amin Ehteshami; Zamani, Mohammad; Sadeghpoor, Simin; Safari, Saeid; Dadashpoor, Roozbeh; Rezaee, Mahsa; Shirvani, Fariba; Azimi, Shohreh; Heydarifard, Zahra; Ranjbar, Hamidreza Hagh; Lotfi, Amir Hossain; Mosadegh, Farhad; Hashemnejad, Farhad; Jazayeri, Seyed Mohammad

Early and rapid detection of influenza viruses is crucial in controlling the severity and spread of the infection, due to the existence of neuraminidase inhibitors as therapeutic option. Nevertheless, differentiation between influenza subtypes is of clinical importance because flu A infection may be associated with higher morbidity and mortality especially among older adults and immunocompromised individuals. 3 In the present study, we clearly showed that 40.5% of hospitalized patients admitted to Laleh hospital due to acute respiratory symptoms were infected by different types of influenza virus. Similar to our finding, others reported influenza prevalence between 34.5% and 52.2% circulating in Iran. [10] [11] [12] [13] Contrary to our results that showed subtype fluA H1N1 has least common prevalence, previous studies performed in Iran including prevalence of 10.6% to 17.5%. [14] [15] [16] [17] The pattern of flu subtypes was different in two years period. 18, 19 although this relationship was not investigated in this study. Our data also indicated that the incidence of flu B in hospitalized patients was relatively high, in contrast with previous Iranian reports of 2.5% to 2.8% flu B prevalence among hospitalized patients. (4, 6) Other studies have evaluated distribution of types and subtypes of influenza viruses in patients. Horthongkham et al. reported 3.1% for flu B and they concluded that Victoria lineage was significantly associated with the duration of hospitalization. 7 However, in here, we did not analyze the lineage of flu B viruses in hospitalized patients. Cohen et al reported prevalence of 8% for influenza, A (H3N2) 37% and flu B (34%). 8 Garg et al. showed that fluA (H3N2) 62.8% and flu B (28.5%) had the highest rates for 2017-2018 influenza seasonality. 9 Among general and specific respiratory illness symptoms, we found that body pain and sore throat were the most significant symptoms among those who were flu positive compared to those who were flu negative. Other studies found similar findings, however with different frequencies. 10 Similar to other studies, cough was frequent in flu-positive patients, consistent with the fact that this is a common symptom in these patients.