Cross-protection to new drifted influenza A(H3) viruses and prevalence of protective antibodies to seasonal influenza, during 2014 in Portugal

Pandit

et al. 2020

Heliyon

Background: Influenza is a highly contagious viral respiratory infection caused by influenza viruses whose epidemic and pandemic have resulted in significant morbidity and mortality. The annual epidemic of influenza results in an estimated 3-5 million cases of severe illness and about 290000-650000 deaths globally. The vaccination program has been successful to control the epidemic however, it further needs improvement. This study was aimed to investigate the types of influenza viruses prevailing in Nepal during 2016 and, to match the recommended vaccine for use during the same season. Methods: A descriptive cross sectional study was carried out at National Public Health Laboratory, Kathmandu, Nepal for the period of one year (Jan-Dec 2016). A total of 1683 throat swab specimen was collected from patients of different age group referred to NPHL for influenza testing. The specimen was primarily stored at 4 C and processed using ABI 7500 RT PCR system for the identification of influenza viruses. Results: Of the total 1683 patients suspected of having influenza infection, influenza viruses were isolated from 614 (36.5%) patients with male predominance. The highest number of infection was caused by influenza A/H3 strain (51.0%) followed by influenza B (40.4%) and influenza A (H1N1) pdm09 (8.6%). Two peaks of infection were observed during the year 2016. The widely available trivalent vaccine during the season did not match the prevailing strain because of the dominance of B/Yamagata lineage over B/Victoria lineage. Conclusion:We concluded that Nepal experiences semiannual cycle of influenza infection, firstly during the month of January-February and secondly during the month of July-August. The vaccine to be introduced in Nepal need to be decided by national authority based on prevailing influenza types to confer effective immunization.

Section: Introductionmentioning

confidence: 99%

Overview of seasonal influenza and recommended vaccine during the 2016/2017 season in Nepal

Pandit

et al. 2020

Heliyon

Clin Med Insights Pediatr

“…Despite higher rates (64%-65%) of vaccination in both cohorts going into the second season, controls had a greater attack rate than cases in season 2, possibly due to natural immunity in cases, having had recent influenza. Cross protection against drifted A strains has been demonstrated, 20 and a previous study of back-to-back H3N2 epidemics showed some cross protection and very high levels of seroprevalence after each epidemic. 21 Having had influenza B may not have been as protective against the new strain as having had influenza A in season 1, although the difference did not reach statistical significance.…”

Section: Discussionmentioning

confidence: 75%

Factors Influencing Frequency of Pediatric Clinically Distinguishable Influenza: A 2 Season Case-Control Study

Salazar

Field

2022

Background: Little is known about the individual differences in susceptibility to, or lifetime frequency of clinically distinguishable influenza in children. Methods: Rapid enzyme linked immunoassay-confirmed influenza pediatric cases (n = 96) in season 1 (2017-2018) were compared to age-matched (mean 7.7 years) controls (n = 171) with no evidence of influenza in season 1. The 2 cohorts were again studied in season 2 (2018-2019) for influenza outcomes and influences. Medical records, questionnaires, and interviews were used to determine past influenza disease and vaccine histories. Results: After season 2, known lifetime influenza illnesses per year of age averaged 22.6% in cases and 5.6% in controls, with 62% of controls still having never experienced known influenza. Having had prior influenza was marginally significant as a risk for season 1 influenza in cases versus controls ( P = .055), yet a significant risk factor in controls for season 2 ( P = .018). Influenza vaccine rates were significantly higher in controls than in cases for season 1, with a greater female vaccine benefit. Lack of previous influenza had greater calculated effectiveness (52%) than vaccination (17%-26%) in escaping season 2 influenza. Lifetime rates of vaccination did not correlate with lifetime rates of known influenza in either cohort. Conclusions: Lifetime clinically distinguishable influenza rates varied among children, with many escaping it for years even without being immunized against it. Findings of less than expected clinical influenza, no correlation between vaccination frequency and disease frequency, sex differences, and an association between past clinical influenza and current risk, point to innate differences in individual influenza experiences.

“…Identi cation of in uenza virus infection by rapid tests can facilitate prompt implementation of control measures before con rmatory test results are available from shell vial culture, tissue cell viral culture, or RT-PCR. In particular, a wide range of sensitivities of the rapid in uenza tests have been reported, where as speci cities have been reported to be high, compared with reference tests [1,[8][9][10][11][12]. In the context of enrolling participants in studies to knowledge of transmission of in uenza virus,a rapid in uenza diagnostic test was used to screen persons with in uenza-like illness in the Nepal during the 2016 in uenza seasons.…”

Section: Introductionmentioning

confidence: 99%

Investigate the diagnostic accuracy of rapid influenza diagnostic kit method in comparison to the real time reverse transcription polymerase chain reaction

lav²,

Manandhar

2022

Preprint

Background: This study is cross-sectional and consecutive study carried out to find out the sensitivity and specificity of QuickVue rapid influenza diagnostic kit test with reference to real time RT-PCR.This study was conducted at National Influenza Center, Reference Laboratory, National Public Health Laboratory, Teku, Kathmandu. This study was undertaken in individuals having Influenza like illness visiting National Public Health Laboratory. Material & Methods: A total of 1683 throat swab specimens, obtained from patients with Influenza like Illness (ILI) at National Influenza Surveillance Network (NISN) sentinel hospitals, were transported to National Influenza Center, maintaining reverse cold chain, within 48 hours. Viral RNA was extracted using QIAmp viral RNA kit. Polymerase Chain Reaction assay (PCR) was performed following CDC Real-time rRTPCR protocol for detection and characterization of the influenza viruses including pandemic influenza virus A (H1N1) pdm 09. Samples were tested with quick view rapid test.Results: A total 1683 samples were processed for influenza testing by RDTQuickVue Influenza A+Band PCR simultaneously. Among 1683 samples 491 were positive by rapid testing and PCR as well. Whereas 122 were positive only by PCR. And out of 1520 negative samples, 1508 were negative by rapid testing & PCR as well and 12 were negative only by the PCR. Conclusion: In our study it shows overallgood positivepredictive and negative predictive value help to provide about influenza in quickly as point of care testing that help in the clinical management of the patient in the outbreak with less trained manpower and cost-effective kits. However more data and test need to be done to evaluate the clinical performance of RDT for influenza diagnosis on extrapolated to other age group & clinical information for specific symptoms and severity is require.