Prevalence of Influenza Virus Type and Subtype at Siriraj Hospital, Bangkok, Thailand During 2013 - 2017

Abstract

Background: Influenza A (pandemic and seasonal H1/H3) and influenza B viruses were the predominant circulating seasonal influenza strains. Following its massive outbreak in 2009 globally, including Thailand, influenza A (H1N1) pdm09 viruses have replaced the previous seasonal H1 strain and become one of the circulating strains ever since. Both influenza A and B viruses are highly contagious and potentially cause respiratory illness ranging from mild to severe.
 Objective: To determine the prevalence of types and subtypes of circulating influenza virus strains in Bangkok, Thailand during 2013 - 2017.
 Methods: The 4385 nasopharyngeal wash specimens were collected from patients presented with influenza-like illness from January 2013 to December 2017 at Siriraj Hospital, Bangkok, Thailand. Influenza virus types and subtypes were determined using real-time RT-PCR technique. Clinical characteristics of patients infected with influenza A viruses and influenza B virus were compared and analyzed.
 Results: Of 4385 nasopharyngeal wash specimens, the prevalence of influenza virus infection during 2013 - 2017 was 18.22% (n = 799). Of 799 influenza-positive samples, 608 (76.09%) and 191 (23.90%) samples were positive for influenza A and influenza B viruses, respectively. Most patients were presented with fever, cough, and runny nose; however, patients infected with influenza A virus generally had higher severity than those with influenza B virus infection (P < .05).
 Conclusions: The findings provided the characteristics of influenza virus types and subtypes at Siriraj Hospital, Bangkok, Thailand during 2013 - 2017. Sporadic cases of influenza occurred all year round, but the incidence peaked in March 2014 and August 2017. The outcomes of this study are potentially useful for prevention, treatment, and disease monitoring.

Predicting acute respiratory distress syndrome in influenza pneumonia patients using delta mean platelet volume

“…Pneumonia occurred in approximately 32.8% of patients with a positive influenza test, and 26.4% of pneumonia patients developed ARDS. We found that influenza A was more common than influenza B, which is comparable to a previous study performed at the largest hospital in Thailand [ 21 ]. Influenza A causes more severe disease than influenza B [ 21 , 22 ].…”

“…We found that influenza A was more common than influenza B, which is comparable to a previous study performed at the largest hospital in Thailand [ 21 ]. Influenza A causes more severe disease than influenza B [ 21 , 22 ]. White blood cell counts in the ARDS group were significantly higher than in the non-ARDS group.…”

Outcomes of early oseltamivir treatment for hospitalized adult patients with community-acquired influenza pneumonia

“…Secondly, the circulating influenza in our studied population was equally proportionate between influenza A and B. Although in Thailand, influenza A is the prevalent type accounting for 76% in the tertiary care hospital system [ 31 ]. In a recent systematic review the epidemic strain was influenza A [ 32 ].…”