Incidence Rate Of Influenza Research Articles

Unintended beneficial effects of COVID-19 on influenza-associated emergency department use in Korea

BackgroundNon-pharmaceutical interventions, including hand hygiene, wearing masks, and cough etiquette, and public health measures such as social distancing, used to prevent the spread of coronavirus disease 2019 (COVID-19), could reduce the incidence rate of respiratory viral infections such as influenza. We evaluated the effect of COVID-19 on the incidence of influenza in Korea. MethodsThis retrospective study included all patients who visited five urban emergency departments (EDs) during the influenza epidemic seasons of 2017–18, 2018–19, and 2019–20. Influenza was defined as ICD-10 codes J09, J10, and J11, determined from ED discharge records. The weekly incidence rates of influenza per 1000 ED visits during the 2019–20 season, when COVID-19 became a pandemic, were compared with those of 2017–18 and 2018–19. The actual incidence rate of the 2019–20 season was compared with the predicted value using a generalized estimation equation model based on 2017–18 and 2018–19 data. ResultsThe weekly influenza incidence rate decreased from 101.6 to 56.6 between week 4 and week 5 in 2020 when the first COVID-19 patient was diagnosed and public health measures were implemented. The weekly incidence rate during week 10 and week 22 of the 2019–20 season decreased most steeply compared to 2017–18 and 2018–19. The actual influenza incidence rate observed in the 2019–20 season was lower than the rate predicted in the 2017–18 and 2018–19 seasons starting from week 7 when a COVID-19 outbreak occurred in Korea. ConclusionsThe implementation of non-pharmaceutical interventions and public health measures for the COVID-19 epidemic effectively reduced the transmission of influenza and associated ED use in Korea. Implementing appropriate public health measures could reduce outbreaks and lessen the burden of influenza during future influenza epidemics.

Efficacy and safety of a universal influenza A vaccine (MVA-NP+M1) in adults when given after seasonal quadrivalent influenza vaccine immunisation (FLU009): a phase 2b, randomised, double-blind trial

In animal, epidemiological, and human challenge studies, a pre-existing T-cell response to internal proteins of influenza A has been associated with improved virological and disease outcomes. The aim of this study was to assess whether inducing additional responses to conserved CD4 and CD8 T-cell antigens provides added benefit to standard influenza vaccination. We designed a phase 2b, randomised, placebo-controlled, double-blind trial of a recombinant viral-vectored vaccine (modified vaccinia Ankara expressing virus nucleoprotein and matrix protein 1; MVA-NP+M1), which has been shown to induce both CD4 and CD8 T cells, at eight outpatient clinical trial sites in Australia over two consecutive influenza seasons. We recruited non-immunosuppressed adults (≥18 years) who had received the 2019 quadrivalent influenza vaccine (QIV) vaccine within 28 days before study enrolment and randomisation (day 0). Participants were randomly assigned (1:1) according to a computer-generated random sequence to receive one dose of 1·5 × 108 plaque-forming units of MVA-NP+M1 or saline (placebo) intramuscularly. Randomisation was stratified by age (<65 years or ≥65 years). The patients and trial assessors were masked to treatment assignment. During the subsequent influenza seasons, participants with symptoms related to respiratory illness or influenza-like illness were to attend the clinic within 72 h of symptom onset for two nasal swabs for influenza testing by quantitative RT-PCR. The primary endpoint was the incidence rate of laboratory-confirmed influenza in the intention-to-treat (ITT) population. Safety (solicited adverse events within 7 days and unsolicited adverse events within 28 days after study vaccination, and serious adverse events for the study duration) was assessed in all randomly assigned participants who received at least one vaccination (according to the treatment received). The trial is registered with ClinicalTrials.gov, NCT03880474. Between April 2 and June 14, 2019, 2152 adults were randomly allocated and received MVA-NP+M1 (n=1077) or placebo (n=1075), comprising the efficacy (ITT) analysis set. Participants were followed up throughout the 2019 Australia influenza season (May 1 to Oct 15, 2019). 419 (19·5%) of 2152 participants were aged 65 years or older. The incidence of laboratory-confirmed influenza did not differ between the MVA-NP+M1 group (35 of 1077 participants; 3·25% [95% CI 2·31-4·44]) and the placebo group (23 of 1075; 2·14% [1·39-3·14]; Fisher's exact p=0·14). 23 severe solicited local injection site reactions were reported in 13 (0·6%) of 2152 participants, 22 of which were reported in the MVA-NP + M1 group (in 12 [1·1%] participants). 100 severe systemic events were reported in 45 (4·2%) MVA-NP + M1 recipients, and 20 were reported in 14 (1·3%) placebo recipients. Three unsolicited grade 3 events in three participants (two headache and one nausea, all in the MVA-NP+M1 group) were deemed vaccine related. 21 serious adverse events were reported in 18 (1·7%) of 1077 participants in the MVA-NP+M1 group and 25 serious adverse events were reported in 22 (2·0%) of 1075 participants in the placebo group; none were considered vaccine related. The trial was stopped after one season for futility on the recommendation of the data monitoring committee. MVA-NP+M1 was well tolerated with no vaccine-associated serious adverse events. A vaccine designed to induce moderate T-cell responses to the cross-reactive internal proteins of influenza A did not lead to improved incidence when given within 28 days after standard QIV immunisation. A greater magnitude of T-cell response with a different vaccine or regimen, or localisation in the lungs via alternative delivery, such as intranasal or aerosol, might be successful and require further investigation. Vaccitech.

Incidence and length of outbreak period of COVID-19 and population density in comparison with seasonal influenza in Japan

ObjectivesThere is no consensus regarding the impact of population density on the transmission of respiratory viral infections such as COVID-19 and seasonal influenza. Our study aimed to determine the correlation between population density and the incidence and duration of COVID-19 transmission. MethodsPublicly available data for confirmed COVID-19 cases in Japan, from January 2020 through November 2021, were retrospectively collected. The average numbers of seasonal influenza cases reported in the national database from 2013–2014 through 2019–2020 were identified. Using data for COVID-19 and seasonal influenza population density and incidence rates (age-adjusted), the Pearson's correlation coefficient was determined. ResultsA significant positive correlation between log population density and length of outbreak period was observed for COVID-19 (r = 0.734; p < 0.001) but not for seasonal influenza. Additionally, a significant linear correlation was observed between population density and age-adjusted incidence rate for COVID-19 (r = 0.692; p < 0.001) but not for seasonal influenza. ConclusionsIn Japan, areas with high population density experienced a prolonged and more intense COVID-19 outbreak compared with areas with low population density. This was not observed with seasonal influenza, suggesting that public health measures against COVID-19 should be tailored according to population density.

No evidence of SARS-CoV-2 in hospitalized patients with severe acute respiratory syndrome in five Italian hospitals from 1st November 2019 to 29th February 2020.

On 9th January 2020, China CDC reported a novel coronavirus (later named SARS-CoV-2) as the causative agent of the coronavirus disease 2019 (COVID-19). Identifying the first appearance of virus is of epidemiological importance to tracking and mapping the spread of SARS-CoV-2 in a country. We therefore conducted a retrospective observational study to detect SARS-CoV-2 in oropharyngeal samples collected from hospitalized patients with a Severe Acute Respiratory Infection (SARI) enrolled in the DRIVE (Development of Robust and Innovative Vaccine Effectiveness) study in five Italian hospitals (CIRI-IT BIVE hospitals network) (1st November 2019 - 29th February 2020). To acquire new information on the real trend in SARS-CoV-2 infection during pandemic phase I and to determine the possible early appearance of the virus in Italy. Samples were tested for influenza [RT-PCR assay (A/H1N1, A/H3N2, B/Yam, B/Vic)] in accordance with the DRIVE study protocol. Subsequently, swabs underwent molecular testing for SARS-COV-2. [one-step real-time multiplex retro-transcription (RT) PCR]. In the 1683 samples collected, no evidence of SARS-CoV-2 was found. Moreover, 28.3% (477/1683) of swabs were positive for influenza viruses, the majority being type A (358 vs 119 type B). A/H3N2 was predominant among influenza A viruses (55%); among influenza B viruses, B/Victoria was prevalent. The highest influenza incidence rate was reported in patients aged 0-17 years (40.3%) followed by those aged 18-64 years (24.4%) and ≥65 years (14.8%). In Italy, some studies have shown the early circulation of SARS-CoV-2 in northern regions, those most severely affected during phase I of the pandemic. In central and southern regions, by contrast no early circulation of the virus was registered. These results are in line with ours. These findings highlight the need to continue to carry out retrospective studies, in order to understand the epidemiology of the novel coronavirus, to better identify the clinical characteristics of COVID-19 in comparison with other acute respiratory illnesses (ARI), and to evaluate the real burden of COVID-19 on the healthcare system.

Reduction of influenza in Osaka, Japan during the COVID-19 outbreak: a population-based ORION registry study

ObjectivesThe spread of COVID-19 has affected the incidence of other infectious diseases, but there are no reports of studies using comprehensive regional population-based data to evaluate the impact of COVID-19 on influenza incidence. We attempted to evaluate the impact of COVID-19 on influenza using the population-based ORION (Osaka Emergency Information Research Intelligent Operation Network) registry. MethodsThe ORION registry of emergency patients treated by emergency medical service (EMS) personnel was developed by the Osaka Prefecture government. From ORION, we included emergency patients with influenza using the ICD (International Statistical Classification of Diseases and Related Health Problems) 10 codes. Influenza incidence rate ratio (IRR) and associated 95% CI were calculated. ResultsThe number of influenza patients transported by EMS decreased during the COVID-19 pandemic. The IRR showed a substantial decrease in influenza patients in 2020 (IRR 2020/2018 0.39, 95% CI 0.37–0.41). ConclusionsA comprehensive regional analysis using the population-based ORION registry confirmed that from January 2020, when the first confirmed cases of COVID-19 infection were reported in Osaka, Japan, the number of influenza patients transported by EMS decreased dramatically.

Trends, patterns, and incidence rate of seasonal influenza among Dubai population and some associated factors, 2017-2-19

Background: WHO estimates that seasonal influenza may result in 290 000-650 000 deaths each year due to respiratory diseases alone. In addition, affected more than 10% of total population annually worldwide, Seasonal influenza is highly contagious disease; spreads easily, with rapid transmission in crowded areas including schools and nursing homes. Objectives: To Study incidence rate, trends and patterns of seasonal influenza among Dubai population for the period 2017-2019, to Study some of the associated factors. Materials &amp; Subjects: A retrospective records review study was carried out of convenience sample of 29158 confirmed seasonal influenza case reported in Emirate of Dubai for the period 2017-2019. All age groups, genders, nationalities, occupations, education and seasons were considered. Findings: The study showed that 53.42% of total seasonal influenza cases were among male groups in Dubai, almost 50% % of the cases were among age group less than 15 years old, and almost one quarter of cases were among the age group between 30-40 years old, the present study showed that 54.37% were among Asian groups, 14.59% of the seasonal influenza incidence in Dubai during 2017-2019 were among Emirati population and 18.79% were among Arabs groups .As per occupation, the study showed that 30.74% of total seasonal influenza cases were among students in Dubai, on the other hand the study revealed that 84.53% of the total seasonal influenza cases during 2017-2019 were handled at outpatient level, yet 15.47% were sever enough cases to be admitted and treated at inpatient facilities. Incidence rate per 100000 population were increased respectively from 2017 through out 2019 (168, 297,466). The study revealed as well that the rate as per nationality the seasonal influenza incidence rate in Dubai from 2017=2019 650/100000 among Jordanian living in Dubai,, almost 50% % of the cases were among age group less than 15 years old, and almost one quarter of cases were among the age group between 30-40 years old, the present study showed that 54.37% were among Asian groups, 14.59% of the seasonal influenza incidence in Dubai during 2017-2019 were among Emirati population and 19.71% were among Arabs groups . The study showed that 30.74% of total seasonal influenza were students in Dubai, 84.53% of the total seasonal influenza cases during 2017-2019 were managed at outpatient. yet 15.47% were sever enough cases to be admitted and treated at inpatient level of different health care facilities in Dubai. Incidence among Egyptian was 557/100000, while among Emirates, 325 /100000, Incidence rate of seasonal influenza 2017-2019 according to age distributions showed that 30.7%among students, and 7.8%among children preschool age, and 5.22%among housewives. The present study showed that the incidence rate of seasonal influenza in Dubai in 2017-2019 as per moth distributions was the highest, 21.4%in November followed by 18.2%in December, and the least was 2%in July. Conclusions: incidence rate of seasonal influenza in Dubai keep increasing during the last three years, the highest rates significantly come from children segment of population specially students and elderly group as well, the period from October to end of February of each years.

Trends, Patterns, and Incidence Rate of Season al Influenza among Dubai Population and Some Associated Factors, 2017-2-19

Trends, Patterns, and Incidence Rate of Season al Influenza among Dubai Population and Some Associated Factors, 2017-2-19

Estimation of influenza-attributable burden in primary care from season 2014/2015 to 2018/2019, France.

Influenza viruses cause seasonal epidemics whose intensity varies according to the circulating virus type and subtype. We aim to estimate influenza-like illness (ILI) incidence attributable to influenza viruses in France from October 2014 to May 2019. Physicians participating in the French Sentinelles network reported the number of patients with ILI seen in consultation and performed nasopharyngeal swabs in a sample of these patients. The swabs were tested by RT-PCR for the presence of influenza viruses. These clinical and virological data were combined to estimate ILI incidence attributable to influenza viruses by subtypes and age groups. Influenza incidence rates over seasons ranged from 1.9 (95% CI, 1.9; 2.0) to 3.4% (95% CI, 3.2; 3.6) of the population. Each season, more than half of ILI cases were attributable to influenza. Children under 15 years were the most affected, with influenza incidence rates ranging from 3.0 (95% CI, 2.8;3.3) to 5.7% (95% CI, 5.3;6.1). Co-circulation of several (sub)types of influenza viruses was observed each year, except in 2016/2017 where A(H3N2) viruses accounted for 98.0% of the influenza cases. Weekly ILI incidences attributable to each influenza virus (sub)type were mostly synchronized with ILI incidence, except in 2014/2015 and 2017/2018, where incidence attributable to type B viruses peaked few weeks later. The burden of medically attended influenza among patients with ILI is significant in France, varying considerably across years and age groups. These results show the importance of influenza surveillance in primary care combining clinical and virological data.

Cost-Effectiveness of Quadrivalent Versus Trivalent Influenza Vaccination in the Dutch National Influenza Prevention Program

ObjectivesAs of 2019, quadrivalent influenza vaccine (QIV) has replaced trivalent influenza vaccine (TIV) in the national immunization program in The Netherlands. Target groups are individuals of 60+ years of age and those with chronic diseases. The objective was to estimate the incremental break-even price of QIV over TIV at a threshold of €20 000 per quality-adjusted life-year (QALY). MethodsAn age-structured compartmental dynamic model was adapted for The Netherlands to assess health outcomes and associated costs of vaccinating all individuals at higher risk for influenza with QIV instead of TIV over the seasons 2010 to 2018. Influenza incidence rates were derived from a global database. Other parameters (probabilities, QALYs and costs) were extracted from the literature and applied according to Dutch guidelines. A threshold of €20 000 per QALY was applied to estimate the incremental break-even prices of QIV versus TIV. Sensitivity analyses were performed to test the robustness of the model outcomes. ResultsRetrospectively, vaccination with QIV instead of TIV could have prevented on average 9500 symptomatic influenza cases, 2130 outpatient visits, 84 hospitalizations, and 38 deaths per year over the seasons 2010 to 2018. This translates into 385 QALYs and 398 life-years potentially gained. On average, totals of €431 527 direct and €2 388 810 indirect costs could have been saved each year. ConclusionUsing QIV over TIV during the influenza seasons 2010 to 2018 would have been cost-effective at an incremental price of maximally €3.81 (95% confidence interval, €3.26-4.31). Sensitivity analysis showed consistent findings on the incremental break-even price in the same range.

Features of Long-Term Incidence Rates of Acute Viral Upper Respiratory Tract Infections and Influenza in the Population of the Rostov Region

Summary. Introduction: As of today, acute viral upper respiratory tract infections (URTIs) remain the most common diseases in the world and the Russian Federation and one of the most important problems of national health care. The objective of our work was to study the dynamics and intensity of the epidemic process of influenza and other URTIs in the Russian Federation and Rostov Region over a thirty-year period and to establish the main features of the disease incidence in the Rostov Region. Materials and methods: We analyzed data of annual State Reports on Sanitary and Epidemiological Wellbeing of the Population in the Russian Federation and Statistical Form No. 2 on information about infectious and parasitic diseases for the period 1990–2019 and data on the size of population using StatSoft STATISTICA 6.1.478 Russian, Microsoft Excel, and NextGIS QGIS software. Results: We found that in 1990–1999, 2000–2009, and 2010–2019, regional URTI rates tended to decrease in each subsequent decade compared to the previous one. The long-term incidence rate of URTIs in the Rostov Region was 16,099.2 ± (2.045 × 384.2) ‰оо, lower than the Russian average rate of 19,710.3 ± (2.045 × 326.4) (p = 0.05). The amplitude of fluctuations in the incidence was 8,015.4 ‰оо and 7,619.6 ‰оо in the Rostov Region and the Russian Federation, respectively. Until 1997, regional incidence rates were comparable to the national averages but demonstrated an upward trend since the year 2000. We revealed unevenness of the course of the epidemic process related to cyclicity, with an increase in the duration of cycles since 1998. It was determined that the regional incidence of influenza was significantly lower than the national average and had a tendency to decrease. The long-term influenza rate in the Rostov Region was 412.4 ± (2.045 × 131.3) (p = 0.05) or almost three times lower than that in the country 1,553.0 ± (2.045 × 301.2) (p = 0.05). The dynamics of influenza incidence in the Rostov Region also had a cyclical course with a smaller amplitude of fluctuations (3,215.1 ‰оо) than in the Russian Federation (5,164.8 ‰оо). The duration of epidemic cycles in 1990–1998 and 2002–2012 was two years but we noted a three-year cycle in 1999–2001. We established a correlation between influenza and URTI rates and population density in regional cities and various age groups: the highest URTI rates (74.9 %) were registered in children between two to 17 years of age while 52.5 % of influenza cases were adults (aged 18+). Conclusion: The established characteristics of the development of the epidemic process of influenza and URTIs in the Rostov Region prove the necessity of a differentiated approach to organizing and implementing comprehensive preventive measures within optimization of epidemiological surveillance of these diseases, and can also serve as basic criteria for disease prediction.

Incidence of hospital-acquired influenza in adults: A prospective surveillance study from 2004 to 2017 in a French tertiary care hospital

Hospital-acquired influenza potentially leads to significant morbidity and mortality in already vulnerable patients, but its overall burden is not fully understood. We undertook this study to estimate the incidence and trends of hospital-acquired laboratory-confirmed influenza among adults, and to compare clinical characteristics between hospital-acquired and community-acquired influenza cases. This was a prospective surveillance study over 11 years of adults with influenza-like-illness (ILI) hospitalized in surgery, medicine and geriatric wards in a tertiary acute-care hospital in Lyon, France. Nasal swabs were systematically collected from those with ILI and tested for influenza by reverse transcriptase-polymerase chain reaction at the national influenza reference laboratory (Lyon, France). Influenza was laboratory confirmed at a rate of 1 in 13 patients who developed ILI during their hospitalization. Having an underlying disease was an important characteristic of hospital-acquired ILI cases. Cardiovascular disease was the most frequent underlying condition in both influenza-positive and influenza-negative patients. Complications were more frequent for influenza-positive than influenza-negative patients. The influenza incidence rate was highest in the geriatric ward and increased over the study period. Hospital-acquired influenza poses a significant risk to already vulnerable patients. Longitudinal surveillance data are essential to support better recognition and monitoring of viral infections in hospitals.

Public health needs and challenges in influenza and dengue vaccines–Implications from epidemiological findings

Background: The incidence and mortality rates of influenza and dengue have been high in most Asian countries. Vaccination is the one of the most important and successful public health measures in controlling many infectious diseases such as poliomyelitis, measles, and Japanese encephalitis. However, the etiological agents of these two diseases are RNA viruses involving different subtypes/serotypes with dynamic changes each year, posing greater challenges in future years. Methods and materials: Field epidemiology during outbreak periods provides the best chance in fully understanding dynamic changes of the studied virus and evaluating the impact of mismatched human influenza viruses. On the other hand, incidence and hospitalization rates, case fatality rates and seroepidemiological study of dengue are important in assessing public health needs and community effectiveness of vaccine as well as in finding target population to receive dengue vaccine. Results: We found that the higher isolation rate of seasonal influenza A (H3N2) and the circulating vaccine-mismatched human influenza viruses, the greater monthly P&I mortality in elderly, using a negative binomial model. Moreover, those years with high excess P&I mortality had the circulating virus strains with a lower amino acid identity percentages of HA1 protein with the vaccine strains. During 2009 pandemic influenza, one unique adaptive mutant at E374K of HA2 in A (H1N1/09) viruses evolved through the epidemic, emerged as a dominant strain at post-peak period, extended in areas with high population densities before mass immunization, persisted till ten months post-nationwide vaccination, and were finally fixed as herd immunity developed. Recently, different tetravalent dengue vaccines providing immunity against all four serotypes of dengue virus (DENV) have been developed to avoid antibody-dependent enhancement (ADE) from secondary DENV infection. The initial clinical trials in many cities of dengue-endemic countries did reduce the incidence and hospitalization rates of dengue. Conclusion: Weekly monitoring excess P&I mortality and evaluating laboratory-confirmed human influenza cases with/without receiving flu vaccines plus serological tests on antigenic variation can assure public health effectiveness of influenza vaccines. Once novel influenza virus emerges with worldwide spread, virological surveillance in high population-density areas can assess the virus with high epidemic potential. Furthermore, more immuno-epidemiological studies are needed for dengue in different settings.

Comparative Analysis of the Morbidity of Respiratory Infections in the Arctic Zone and other Territories of Russia

Relevance. The Arctic Zone is a territory with very specific characteristics among the following: extreme climatic conditions, low population density, remoteness from industrial centers, and dependence even on insignificant anthropogenic impact. The concentration of natural resources and the focal development of territories leads to an increase of migratory flows. All of these factors influence the morbidity of the population. Aims. The aim of this study was to reveal the difference in the intensity of morbidity in the Arctic zone in comparison with other territories. Materials & Methods. We conducted a comparative retrospective analysis of the incidence of influenza, ARVI, community-acquired pneumonia, pertussis, and meningococcal infection in adults in the Arctic zone of Russia for the period of 2007–2018. Also, we conducted a correlation analysis using the Pearson method. We performed data processing in Microsoft Excel 2019. Results: In the retrospective analysis, the incidence rates ARVI and influenza are significantly higher in the Arctic zone in comparison with other territories. The incidence rate of influenza in the Arctic is comparable with other regions but complications arise more frequently. As much as influenza, ARVI may be more severe. The incidence rates of pertussis and meningococcal infection do not show any significant deviations from the rates in other regions. Conclusion: Thus, higher incidence rates ARVI and influenza were registered in the Arctic. Influenza and ARVI may be more severe.

Nonpharmaceutical Interventions Used to Control COVID-19 Reduced Seasonal Influenza Transmission in China.

To suppress the ongoing COVID-19 pandemic, the Chinese government has implemented a set of non-pharmaceutical interventions (NPIs). Because COVID-19 and influenza have similar means of transmission, it is hypothesized that NPIs targeting COVID-19 may also affect influenza transmission. In this study, the extent to which NPIs targeting COVID-19 have affected seasonal influenza transmission was explored. Indicators of seasonal influenza activity in the epidemiological year 2019/20 were compared with those in 2017/18 and 2018/19. Results show that the incidence rate of seasonal influenza reduced by 64% in 2019/20 (p&0.001). These findings suggest that NPIs aimed at controlling COVID-19 significantly reduced the seasonal influenza transmission in China. (105 words)

The impact of healthcare worker influenza vaccination on nosocomial influenza in a tertiary hospital: an ecological study

BackgroundTo protect hospitalized patients, who are more susceptible to complications of influenza, seasonal influenza vaccination of healthcare workers (HCW) has been recommended internationally. However, its effectiveness is still being debated. To assess the effectiveness of HCW influenza vaccination, we performed an ecological study to evaluate the association between healthcare worker influenza vaccination and the incidence of nosocomial influenza in a tertiary hospital within Singapore between 2013 and 2018.MethodsNosocomial influenza was defined as influenza among inpatients diagnosed 7 days or more after admission by laboratory testing, while healthcare worker influenza vaccination rate was defined as the proportion of healthcare workers that was vaccinated at the end of each annual seasonal vaccination exercise. A modified Poisson regression was performed to assess the association between the HCW vaccination rates and monthly nosocomial influenza incidence rates.ResultsNosocomial influenza incidence rates followed the trend of non-nosocomial influenza, showing a predominant mid-year peak. Across 2,480,010 patient-days, there were 256 nosocomial influenza cases (1.03 per 10,000 patient-days). Controlling for background influenza activity and the number of influenza tests performed, no statistically significant association was observed between vaccination coverage and nosocomial influenza incidence rate although a protective effect was suggested (IRR 0.89, 95%CI:0.69–1.15, p = 0.37).ConclusionNo significant association was observed between influenza vaccination rates and nosocomial influenza incidence rates, although a protective effect was suggested. Aligning local HCW vaccine timing and formulation to that of the Southern Hemisphere may improve effectiveness. HCW vaccination remains important but demonstrating its effectiveness in preventing nosocomial influenza is challenging.

Burden and seasonality of medically attended influenza like illness (ILI) in Ethiopia, 2012 to 2017

BackgroundThe influenza virus spreads rapidly around the world in seasonal epidemics, resulting in significant morbidity and mortality. Influenza-related incidence data are limited in many countries in Africa despite established sentinel surveillance. This study aimed to address the information gap by estimating the burden and seasonality of medically attended influenza like illness in Ethiopia.MethodInfluenza sentinel surveillance data collected from 3 influenza like illness (ILI) and 5 Severe Acute Respiratory Illness (SARI) sites from 2012 to 2017 was used for analysis. Descriptive statistics were applied for simple analysis. The proportion of medically attended influenza positive cases and incidence rate of ILI was determined using total admitted patients and catchment area population. Seasonality was estimated based on weekly trend of ILI and predicted threshold was done by applying the “Moving Epidemic Method (MEM)”.ResultA total of 5715 medically attended influenza suspected patients who fulfills ILI and SARI case definition (77% ILI and 23% SARI) was enrolled. Laboratory confirmed influenza virus (influenza positive case) among ILI and SARI suspected case was 25% (1130/4426) and 3% (36/1289). Of which, 65% were influenza type A. The predominantly circulating influenza subtype were seasonal influenza A(H3N2) (n = 455, 60%) and Influenza A(H1N1)pdm09 (n = 293, 38.81%). The estimated mean annual influenza positive case proportion and ILI incidence rate was 160.04 and 52.48 per 100,000 population. The Incidence rate of ILI was higher in the age group of 15–44 years of age [‘Incidence rate (R) = 254.6 per 100,000 population’, 95% CI; 173.65, 335.55] and 5–14 years of age [R = 49.5, CI 95%; 31.47, 130.43]. The seasonality of influenza has two peak seasons; in a period from October–December and from April–June.ConclusionSignificant morbidity of influenza like illness was observed with two peak seasons of the year and seasonal influenza A (H3N2) remains the predominantly circulating influenza subtype. Further study need to be considered to identify potential risks and improving the surveillance system to continue early detection and monitoring of circulating influenza virus in the country has paramount importance.

Economic Burden of Influenza in Thailand: A Systematic Review.

Thailand has a high incidence and high mortality rates of influenza. This study summarizes the evidence on economic burden or costs of influenza subsequent to the occurrence of influenza illness in the Thai population by specific characteristics such as population demographics, health conditions, healthcare facilities, and/or cost types from published literature. A systematic search was conducted in six electronic databases. All costs were extracted and adjusted to 2018 US dollar value. Out of 581 records, 11 articles (1 with macroeconomic analysis and 10 with microeconomic analyses) were included. Direct medical costs per episode for outpatients and inpatients ranged from US$4.21 to US$212.17 and from US$163.62 to US$4577.83, respectively, across distinct influenza illnesses. The overall burden of influenza was between US$31.1 and US$83.6 million per year and 50-53% of these estimates referred to lost productivity. Costs of screening for an outbreak of influenza at an 8-bed-intensive-care-unit hospital was US$38242.75 per year. Labor-sensitive sectors such as services were the most affected part of the Thai economy. High economic burden tended to occur among children and older adults with co-morbidities and to be related to complications, non-vaccinated status, and severe influenza illness. Strategies involving prevention, limit of transmission, and treatment focusing on aforementioned patients’ factors, containment of hospitalization expenses and quarantine process, and assistance on labor-sensitive economy sectors are likely to reduce the economic burden of influenza. However, a research gap exists regarding knowledge about the economic burden of influenza in Thailand.

Spatiotemporal Analysis of Influenza in China, 2005\u20132018

Influenza is a major cause of morbidity and mortality worldwide, as well as in China. Knowledge of the spatial and temporal characteristics of influenza is important in evaluating and developing disease control programs. This study aims to describe an accurate spatiotemporal pattern of influenza at the prefecture level and explore the risk factors associated with influenza incidence risk in mainland China from 2005 to 2018. The incidence data of influenza were obtained from the Chinese Notifiable Infectious Disease Reporting System (CNIDRS). The Besag York Mollié (BYM) model was extended to include temporal and space-time interaction terms. The parameters for this extended Bayesian spatiotemporal model were estimated through integrated nested Laplace approximations (INLA) using the package R-INLA in R. A total of 702,226 influenza cases were reported in mainland China in CNIDRS from 2005–2018. The yearly reported incidence rate of influenza increased 15.6 times over the study period, from 3.51 in 2005 to 55.09 in 2008 per 100,000 populations. The temporal term in the spatiotemporal model showed that much of the increase occurred during the last 3 years of the study period. The risk factor analysis showed that the decreased number of influenza vaccines for sale, the new update of the influenza surveillance protocol, the increase in the rate of influenza A (H1N1)pdm09 among all processed specimens from influenza-like illness (ILI) patients, and the increase in the latitude and longitude of geographic location were associated with an increase in the influenza incidence risk. After the adjusting for fixed covariate effects and time random effects, the map of the spatial structured term shows that high-risk areas clustered in the central part of China and the lowest-risk areas in the east and west. Large space-time variations in influenza have been found since 2009. In conclusion, an increasing trend of influenza was observed from 2005 to 2018. The insufficient flu vaccine supplements, the newly emerging influenza A (H1N1)pdm09 and expansion of influenza surveillance efforts might be the major causes of the dramatic changes in outbreak and spatio-temporal epidemic patterns. Clusters of prefectures with high relative risks of influenza were identified in the central part of China. Future research with more risk factors at both national and local levels is necessary to explain the changing spatiotemporal patterns of influenza in China.

Incidence of acute respiratory tract infections (2006–2015) and influenza (2006–2013) among French armed forces

ObjectivesWe aimed to assess the incidence of respiratory tract infections in military settings between 2006 and 2015. Patients and methodsWe performed a retrospective epidemiological study of the entire military population from 2006 to 2015. Comprehensive data was collected from all medical centers, operational medical units, naval services, and army training hospitals and provided by the epidemiological surveillance of the armies. ResultsThe annual average population of the study was 331,394 soldiers. For acute respiratory tract infections (2006–2015), 22,818 cases were reported in metropolitan France, 3,211 cases in French overseas territories, 1,595 cases in the French Navy, and 1,318 cases in external military operations for a total of 28,942 cases. For influenza (2006–2013), 934 cases were reported in metropolitan France, 101 cases in French overseas territories, and 23 cases in external operations, for a total of 1,058 cases. The mean incidence rate of acute respiratory tract infections expressed as case number per 1,000 person-years (PY) was 8.7 PY (95% CI [8.6–8.8]) with an exceptional increased incidence rate in 2009 (25.9 PY, 95% CI [25.4–26.4]). The mean incidence rate of influenza was 0.35 PY (95% CI [0.33–0.37]) with a peak incidence rate of 1.9 PY in 2009. ConclusionAcute respiratory tract infections are at the forefront of infectious episodes in the French armies. Although not necessarily severe, current prevention measures are not enough to reduce the incidence threshold of these infections and need to be improved.

SIR+A mathematical model for evaluating and predicting 2016–2017 ARVI-influenza incidence by using on the Moscow territory

Influenza is a major challenge to global healthcare due to its high transmissivity and ability to cause major epidemics. Influenza epidemics and pandemics are associated with changes in the society structure that contribute to the spread of new viral strains in certain environmental and social settings. Currently, influenza is one of the most common global diseases that results in annual epidemics or even pandemics, often leading to lethal outcome. Influenza viruses are uniquely prone to variability via point mutations, recombination and gene reassortment accompanied with changes in their biological properties considered as the main cause of uncontrolled infection spread. Hence, examining cohorts of predisposed individuals by using probability models provides not only additional information about viral outbreaks, but also allows monitoring dynamics of viral epidemics in controlled areas. Understanding influenza epidemiology is crucial for restructuring healthcare resources. Public healthcare service mainly relies on influenza vaccination. However, there are vulnerable cohorts such as elderly and immunocompromised individuals, which usually contain no protective antiinfluenza virus antibody level. Despite advances in the developing vaccines and chemotherapy, large-scale influenza epidemics still continue to emerge. Upon that, no reliable methods for disease prognosis based on rate of ongoing epidemic situation are currently available. Monitoring and predicting emerging epidemics is complicated due to discrepancy between dynamics of influenza epidemics that might be evaluated by using surveillance data as well as platform for tracking influenza incidence rate. However, it may be profoundly exacerbated by mutations found in the influenza virus genome by altering genuine morbidity dynamics. Use of probabilistic models for assessing parameters of stochastic epidemics would contribute to more accurately predicted changes in morbidity rate. Here, an SIR+A probabilistic model considering a relationship between infected, susceptible and protected individuals as well as the aggressiveness of external risks for predicting changes in influenza morbidity rate that allowed to evaluate and predict the 2016 ARVI influenza incidence rate in Moscow area. Moreover, introducing an intensity of infection parameter allows to conduct a reliable analysis of incidence rate and predict its changes.