Differences in Influenza Seasonality by Latitude, Northern India

Koul, Parvaiz A; Broor, Shobha; Saha, Siddhartha Sankar; Barnes, John; Smith, Catherine M.; Shaw, Michael; Chadha, Mandeep S.; Lal, Renu B.

doi:10.3201/eid2010.140431

Cited by 56 publications

(55 citation statements)

References 14 publications

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“…Seasonality has been associated not only with climatological but also latitudinal variations [5, 24–26]. Influenza virus infection was found throughout the year in these countries, but more than 60% of influenza positivity rates were observed during the months of June to November [5].…”

Section: Discussionmentioning

confidence: 99%

“…Thus, April to May is the most appropriate month for influenza vaccination for the Philippines and countries with similar seasonality [5]. In areas in India north of 30° N however, there was also increased influenza activity during winter, so that a separate vaccination timing has been recommended [5, 24, 25] for this country. In contrast, tropical countries in Asia below 11° N like Indonesia (Jakarta, 6.2° N), Malaysia (Kuala Lumpur, 3.2° N), and Singapore (1.3° N), influenza was found all throughout the year with no distinct influenza season [5].…”

Section: Discussionmentioning

confidence: 99%

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National Influenza Surveillance in the Philippines from 2006 to 2012: seasonality and circulating strains

et al. 2016

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BackgroundThe results of routine influenza surveillance in 13 regions in the Philippines from 2006 to 2012 are presented, describing the annual seasonal epidemics of confirmed influenza virus infection, seasonal and alert thresholds, epidemic curve, and circulating influenza strains.MethodsRetrospective analysis of Philippine influenza surveillance data from 2006 to 2012 was conducted to determine seasonality with the use of weekly influenza positivity rates and calculating epidemic curves and seasonal and alert thresholds using the World Health Organization (WHO) global epidemiological surveillance standards for influenza.ResultsIncreased weekly influenza positive rates were observed from June to November, coinciding with the rainy season and school opening. Two or more peaks of influenza activity were observed with different dominant influenza types associated with each peak. A-H1N1, A-H3N2, and two types of B viruses circulated during the influenza season in varying proportions every year. Increased influenza activity for 2012 occurred 8 weeks late in week 29, rather than the expected week of rise of cases in week 21 as depicted in the established average epidemic curve and seasonal threshold. The intensity was severe going above the alert threshold but of short duration. Southern Hemisphere vaccine strains matched circulating influenza virus for more surveillance years than Northern Hemisphere vaccine strains.ConclusionsInfluenza seasonality in the Philippines is from June to November. The ideal time to administer Southern Hemisphere influenza vaccine should be from April to May. With two lineages of influenza B circulating annually, quadrivalent vaccine might have more impact on influenza control than trivalent vaccine. Establishment of thresholds and average epidemic curve provide a tool for policy-makers to assess the intensity or severity of the current influenza epidemic even early in its course, to help plan more precisely resources necessary to control the outbreak. Influenza surveillance activities should be continued in the Philippines and funding for such activities should already be incorporated into the Philippine health budget.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-016-2087-9) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

National Influenza Surveillance in the Philippines from 2006 to 2012: seasonality and circulating strains

et al. 2016

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“…1 , 2 We have earlier reported a recrudescence of A/H1N1pdm09 in 2012-13 in Kashmir region of the northern Indian state of Jammu and Kashmir where influenza is an important cause of acute respiratory infections during the winter months. 3 , 4…”

Section: Introductionmentioning

confidence: 99%

The 2015 Outbreak of Severe Influenza in Kashmir, North India: Emergence of a New Clade of A/H1n1 Influenza Virus

et al. 2018

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Introduction: Following the initial outbreak of A/H1N1pdm09, periodic resurgences of the virus, with variable morbidity and mortality, have been reported from various parts of India including the temperate Kashmir region of northern India. An outbreak of A/H1N1 was reported in early 2015 across India with a high morbidity and mortality. We studied patients during the outbreak in Kashmir.Methods: Patients (n=1780, age 1 month to 90 years, median 35 years) presenting with acute respiratory illness to a tertiary care hospital in Srinagar, Kashmir from October 2014 to April 2015 were recruited. After clinical data recording, combined throat and nasal swabs were collected in viral transport medium and tested by real-time RT-PCR for influenza viruses. All influenza A positive samples were further subtyped using primers and probes for A/H1N1pdm09 and A/H3 whereas influenza B samples were further subtyped into B/Yamagata and B/Victoria lineages. Virus isolation, hemagglutination inhibition testing, sequencing and phylogenetic analysis was carried out using standard procedures. Testing for H275Y mutation was done to determine sensitivity to oseltamivir. All patients received symptomatic therapy and influenza positive patients were administered oseltamivir.Results: Of the 1780 patients, 540 (30%) required hospitalization and 533 tested positive for influenza [influenza A=517(A/H1N1pdm09=437, A/H3N2=78 with co-infection of both in 2 cases); influenza B=16 (B/Yamgata=15)]. About 14% (n=254) had been vaccinated against influenza, having received the NH 2014-15 vaccine, 27 (11.3%) of these testing positive for influenza. Sixteen patients, including 4 pregnant females, died due to multi-organ failure. HA sequencing depicted that 2015 isolates belonged to Clade 6B.1. No H275Y mutation was reported from A/H1N1 positives.Conclusion: Resurgent outbreak of A/H1N1pdm09, with emergence of clade 6B.1, in 2014-15 resulted in high rate of hospitalizations, morbidity and mortality. Periodic resurgences and appearance of mutants emphasize continued surveillance so as to identify newer mutations with potential for outbreaks and severe outcomes.

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“…The relationship to the influenza virus with low temperature reported from the states of India Jain et al, 2009;Koul et al, 2014;Chadha et al, 2015) The case fatality rate (CFR) was less than 1.9% compared to other states of India and equal to previous studies from Tamilnadu (Puvanalingam et al, 2011). The CFR was found to be 12.…”

Section: Methodsmentioning

confidence: 74%

An Experience of Pandemic Influenza A (H1N1) 2009 Virus Outbreak in 2017 at Tertiary Care Hospital, Chennai, Tamilnadu, India

Thilakavathi¹,

Rosyvennila²

2018

Int.J.Curr.Microbiol.App.Sci

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Differences in Influenza Seasonality by Latitude, Northern India

Cited by 56 publications

References 14 publications

National Influenza Surveillance in the Philippines from 2006 to 2012: seasonality and circulating strains

National Influenza Surveillance in the Philippines from 2006 to 2012: seasonality and circulating strains

The 2015 Outbreak of Severe Influenza in Kashmir, North India: Emergence of a New Clade of A/H1n1 Influenza Virus

An Experience of Pandemic Influenza A (H1N1) 2009 Virus Outbreak in 2017 at Tertiary Care Hospital, Chennai, Tamilnadu, India

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