Seasonal influenza activity based on laboratory surveillance in Malaysia, 2011‐2016

Abstract

Influenza seasonality in equatorial countries is little understood. Seasonal and alert influenza thresholds were determined for Malaysia, using laboratory-based data obtained from the Malaysia Influenza Surveillance System and a major teaching hospital, from 2011 to 2016. Influenza was present year-round, with no clear annual seasons. Variable periods of higher transmission occurred inconsistently, in November to December, January to March, July to September, or a combination of these. These coincide with seasons in the nearby southeast Asian countries or winter seasons of the northern and southern hemispheres. Changes in the predominant circulating influenza type were only sometimes associated with increased transmission. The data can provide public health interventions such as vaccines.

Influenza in Malaysian adult patients hospitalized with community-acquired pneumonia, acute exacerbation of chronic obstructive pulmonary disease or asthma: a multicenter, active surveillance study

“…Influenza positivity peaked in June and July 2019, coinciding with increased enrolment of participants from May through July, possibly due to increased circulating influenza during this time. The two periods of increased influenza activity observed in our study broadly correspond to the seasons occurring in the Northern and Southern hemispheres, respectively, in-line with previous observations [ 23 ]. Similar trends were also observed among the numbers of Malaysian isolates sent to the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne in 2018–2019 [ 24 ].…”

“…Accordingly, reports of the presence or absence of seasonal peaks in Malaysia have been inconsistent [ 8 , 19 , 21 ]. Observations based on laboratory surveillance between 2011 and 2016 demonstrated variable periods of higher transmission coinciding with winter seasons of northern (November–February) and/or southern (July–September) hemisphere regions [ 23 ].…”

Evaluation of rapid influenza diagnostic tests for influenza A and B in the tropics

“…The sensitivity rates reported here may overstate actual rates seen in a more mixed age population, as influenza viral loads and sensitivity rates of RIDTs are known to be higher in children compared with that in adults . In addition, only seven influenza B samples were collected in this study, and as influenza B may predominate over influenza A in certain years, overall sensitivity of RIDTs will fluctuate, as the sensitivity for influenza A is higher than for influenza B.…”

“…Influenza viruses are important causes of acute respiratory illness resulting in high morbidity and mortality, and have a strong seasonal pattern in temperate countries. However, Malaysia has year‐round, low‐level influenza, with no clear seasonality, although some years show periods of increased transmission in November‐March and July‐September, coinciding with winter seasons in temperate countries or seasons in other Asian countries . It is difficult to clinically distinguish influenza from other causes of respiratory viral infection, as symptoms and signs are non‐specific .…”

Comparative global epidemiology of influenza, respiratory syncytial and parainfluenza viruses, 2010–2015

“…Despite multiple single-site or national surveillance data for influenza and/or RSV being available either via publication or online, e.g. from Argentina, 9 Brazil, 10 Canada, 11 UK, 12 The Netherlands, 13 Finland, 14 Bulgaria, 15 Russia, 16 South Africa, 17 Rwanda, 18 Madagascar, 19 Cambodia, 20 Thailand, 21 Malaysia, 22 Singapore, 23 The Philippines, 24 Indonesia, 25 Hong Kong, 26 Mongolia, 27 Japan, 28 Australia, 29 and New Zealand, 30 there are still relatively few global-scale studies that compare the contemporaneous (i.e. over the same time period) incidence patterns of common respiratory viruses across different countries -and nearly all of these used mostly publicly available surveillance data extracted from national surveillance websites, or published studies.…”