Estimating the burden of influenza-associated hospitalization and deaths in Oman (2012-2015)

Characteristics of influenza, SARS-CoV-2, and RSV surveillance systems that utilise ICD-coded data: a systematic review

Background

Some surveillance systems for influenza, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and respiratory syncytial virus (RSV) utilise International Classification of Diseases (ICD)-coded data and are useful for analysing trends and enhancing quick, evidence-based decisions against the epidemic potential that threatens global health security. With variations in the design of systems globally, the World Health Organization requested a systematic review to identify key characteristics of influenza, SARS-CoV-2, and RSV surveillance systems that utilise ICD-coded data, and to assess their performance.

Methods

We searched EMBASE, MEDLINE, and Global Health to identify relevant studies reporting on influenza, SARS-CoV-2, and RSV surveillance systems that use ICD-coded data. We independently assessed studies for the ICD codes used, their statistical estimates and limitations. We appraised included studies using Joana Briggs Institute's critical appraisal tools and synthesised using narrative synthesis.

Results

We identified 77 studies, reporting on 71 surveillance systems - 33 systems recorded surveillance data only, 15 systems recorded burden of disease data only, and 23 systems recorded both surveillance and burden of disease data. Surveillance systems utilised ICD-10 codes (75%), ICD-9 codes (22%), or both (3%). ICD-10 codes J09 and J10 were frequently used for influenza, U07.1 for COVID-19, and B97.4, J12.1, J20.5, and J21.0 for RSV. ICD-9 codes 487 and 488 were mostly used for influenza, and codes 466.11 and 480.1 for RSV. ICD-10 codes had low-to-moderate sensitivity (6.60-79.87%) and high specificity (97.40-99.72%) for influenza, low-to-high sensitivity (30.00-98.4%) and specificity (39.50-99.80%) for COVID-19, and low-to-high sensitivity (6.00-99.80%) and specificity (12.10-100.00%) for RSV. ICD-9 codes had low sensitivity (45.60%) and high specificity (97.90%) for influenza. Underestimation of infections or mortality attributable to influenza, SARS-CoV-2, or RSV is a major limitation to using ICD-coded data across surveillance systems.

Conclusions

The performance of ICD codes for syndromic- or disease-specific surveillance remains inconclusive, although using only ICD-coded data within these systems may underestimate influenza, SARS-CoV-2, or RSV-attributable morbidity and mortality. Future studies should assess the accuracy of ICD code combinations for surveillance of influenza, SARS-CoV-2, and RSV.

Uncovering the Burden of Influenza-Associated Illness across Levels of Severity in the Kingdom of Saudi Arabia Across Three Seasons

BACKGROUND

Influenza imposes a substantial global health burden, particularly among high-risk populations such as the elderly, young children, and individuals with chronic conditions. In Saudi Arabia, a national influenza sentinel surveillance program was established in 2017 to monitor respiratory virus trends, yet comprehensive estimates of the influenza-associated burden remain limited. This study aims to address this gap by quantifying influenza-associated severe acute respiratory infection (SARI) hospitalization rates and estimating the broader influenza burden across severity levels.

METHODS

Data from four sentinel hospitals in three regions of Saudi Arabia were analyzed across three influenza seasons: 2017-2018, 2018-2019, and 2022-2023. Weekly SARI case counts were combined with census population data to calculate SARI hospitalization rates per 100,000 population. Influenza positivity rates, derived from laboratory-confirmed cases, were used to estimate influenza-associated SARI hospitalization rates, stratified by age and season. The John Hopkins University/WHO Seasonal Influenza Burden Disease Estimator (Flutool) was employed to extrapolate national estimates of influenza-associated hospitalizations, deaths, and mild/moderate cases. Confidence intervals and age-specific stratifications were computed to enhance precision and comparability.

RESULTS

The average annual SARI hospitalization rate was 294 per 100,000 population (95% CI: 288-300). Influenza-associated SARI hospitalization rates averaged 48 per 100,000 population (95% CI: 45-50), with the highest burden observed in individuals aged 65 years and older (269 per 100,000, 95% CI: 240-301) and children aged 0-4 years (118 per 100,000, 95% CI: 107-131). Seasonal variation was noted, with the highest rates in the 2017-2018 season. National estimates suggested a substantial burden, with influenza-associated hospitalizations totaling 17,678 in 2017-2018, 7,683 in 2018-2019, and 13,982 in 2022-2023. The flutool analysis estimated annual influenza-associated deaths ranging from 30 to 4,441 and mild/moderate cases reaching up to 6.3 million in the most severe season.

CONCLUSIONS

This study demonstrates a significant burden of influenza-associated SARI hospitalizations in Saudi Arabia, with the highest rates observed in the elderly and young children. Seasonal variation was evident, highlighting the urgent need to enhance influenza vaccination coverage, particularly among high-risk groups such as the elderly and young children, to reduce severe outcomes. Expanding sentinel surveillance to more regions and incorporating detailed clinical and economic data are recommended to better inform public health policies. Strengthening pandemic preparedness and tailoring vaccination campaigns based on seasonality and age-specific risk will be critical for mitigating the influenza burden in Saudi Arabia.

The National Burden of Influenza-Associated Respiratory Illness Across Levels of Severity in Egypt, 2016-2019

INTRODUCTION

Influenza burden (IB) estimates are crucial for monitoring disease trends, allocating limited resources, and promoting influenza vaccination. However, IB in Egypt is poorly understood. This study estimates the mean-seasonal IB in Egypt, across levels of severity by age and regions using sentinel surveillance data between 2016 and 2019.

METHODS

Influenza surveillance was implemented among patients hospitalized with severe acute respiratory infection (SARI) at eight sentinel hospitals across Egypt. We estimated the influenza-associated SARI hospitalization in two governorates and then extrapolated nationally using the World Health Organization (WHO)-recommended methods. Thereafter, we estimated IB-associated mild/moderate illness and deaths using IB pyramid tool developed by WHO and the John Hopkins Center for Health Security. Rates were reported per 100,000 population.

RESULTS

The estimated mean seasonal number of influenza-associated mild/moderate illness, hospitalized noncritically and critically ill patients, and deaths was 16,425,938 (95% CI: 1,150,888-40,409,614), 30,335 (95% CI: 9971-670,288), 9110 (95% CI: 580-16,321), and 2660 (95% CI: 154-9908), respectively. The highest rate of influenza-associated mild/moderate illness was among aged 5-14 year (22,932; 95% CI: 825-25,546.3), whereas the highest rates of severe influenza were among aged > 65 years (hospitalizations: 159.4, 95% CI: 121.7-205.0; deaths: 56.0, 95% CI: 0.6-111.0). Children aged < 5 years also experience high rates of influenza-associated hospitalization (52.0, 95% CI: 43.0-62.0).

CONCLUSIONS

The WHO method estimated a high burden of severe influenza among aged ≥ 65 and aged < 5 years in Egypt. To reduce severe IB, increased influenza vaccine uptake together with enhanced immunization strategies implementations among the elderly and children are warranted.

A Call for Adopting High-Dose Influenza Vaccines for Adults Aged 65 and Above in Gulf Cooperation Council (GCC) Countries

Seasonal influenza poses significant health and economic challenges globally each year, particularly impacting the elderly population (aged ≥ 65 years) with increased rates of hospitalization, and mortality. The population of older adults is steadily increasing in the Gulf Cooperation Council (GCC) countries and is likely to increase even further. In addition, there is a high burden of chronic comorbidities in these countries like diabetes and obesity, which increases the likelihood of severe consequences of influenza infection. The GCC countries also host mass gathering events like Hajj, Umrah pilgrimage, Arba'een (nearby Iraq) pilgrimage, and international sports and business events, which further intensify the risk of outbreaks like influenza. These events facilitate the mixing of visitors from various countries. Thus, influenza activity in this North Hemisphere (NH) geography is usually present even before the availability of NH seasonal influenza vaccine. This is especially problematic for the elderly, whose protection from the previous year's immunization would have waned. Higher dosages of antigens or adjuvants have been used to improve immunogenicity in older people with superior vaccine effectiveness. Therefore, there is a compelling argument in favor of the implementation of high-dose seasonal influenza vaccines in the GCC countries to improve the protection of individuals aged 65 years and older against influenza infection and associated severe complications.

Incidence of influenza virus-associated Severe Acute Respiratory Infections in three districts in 2018 at Gharbia governorate, Egypt

AIMS

Influenza remains a contributor to substantial global morbidity and mortality. There is very limited data on disease burden in Egypt. The purpose of this study was to estimate the incidence of influenza-associated Severe Acute Respiratory Illness (SARI) in three districts in Gharbia governorate in 2018.

METHODS

This study Followed the World Health Organization (WHO) manual for estimating disease burden associated with seasonal influenza. The hospital admission database was screened for SARI patients in three districts at Gharbia governorate in 2018. A hospital admission survey (HAS) was used to define the catchment population. The incidence rate estimation was computed as the number of influenza-positive SARI cases per 100,000 population.

RESULTS

A total of 180 SARI cases were identified in the catchment area. The median age was 23 years [IQR: 2-53], and 45% were males. Out of the total SARI cases, 33.3% influenza was confirmed by the laboratory test of RP-PCR. Influenza A(H3N2) virus predominated representing 55.0% of patients, thanA(H1N1) 26.7% and Flu-B virus 18.3%. Influenza prevailed in winter and spring; no deaths from influenza were reported. The annual incidence of influenza-associated SARIs found higher in <2 years (282 /100,000) and ≥65 years patients (215/100,000) at significant level p<0.001.

CONCLUSION

The WHO Manual for estimating disease burden associated with seasonal influenza was successfully operationalized in the three districts of Gharbia governorate. It can be used in other districts. A considerable burden was associated with influenza viruses requiring hospitalization, especially among the older adult group.

Strengthening influenza surveillance capacity in the Eastern Mediterranean Region: Nearly two decades of direct support from the United States Centers for Disease Control and Prevention

Since 2004, the US Centers for Disease Control and Prevention (CDC) Influenza Division (ID) has supported seven countries in the Eastern Mediterranean region and the World Health Organization Regional Office for the Eastern Mediterranean to establish and strengthen influenza surveillance. The substantial growth of influenza surveillance capacities in the region demonstrates a commitment by governments to strengthen national programs and contribute to global surveillance. The full value of surveillance data is in its use to guide local public health decisions. CDC ID remains committed to supporting the region and supporting partners to translate surveillance data into policies and programs effectively.

Estimation of the influenza-associated respiratory hospitalization burden using sentinel surveillance data, Lebanon, 2015-2020

Introduction

Influenza epidemics cause around 3 to 5 million cases of severe illness worldwide every year. Estimates are needed for a better understanding of the burden of disease especially in low- and middle-income countries. The objective of this study is to estimate the number and rate of influenza-associated respiratory hospitalizations in Lebanon during five influenza seasons (2015-2016 to 2019-2020) by age and province of residence in addition to estimating the influenza burden by level of severity.

Methods

The severe acute respiratory infection sentinel surveillance system was used to compute influenza positivity from the influenza laboratory confirmed cases. The total of respiratory hospitalizations under the influenza and pneumonia diagnosis was retrieved from the Ministry of Public Health hospital billing database. Age-specific and province-specific frequencies and rates were estimated for each season. Rates per 100 000 population were calculated with 95% confidence levels.

Results

The estimated seasonal average of influenza-associated hospital admission was 2866 for a rate of 48.1 (95% CI: 46.4-49.9) per 100 000. As for the distribution by age group, the highest rates were seen in the two age groups ≥65 years and 0-4 years whereas the lowest rate was for the age group 15-49 years. For the distribution by province of residence, the highest influenza-associated hospitalization rates were reported from the Bekaa-Baalback/Hermel provinces.

Conclusion

This study shows the substantial burden of influenza in Lebanon mainly on high-risk groups (≥65 years and <5 years). It is crucial to translate these findings into policies and practices to reduce the burden and estimate the illness-related expenditure and indirect costs.

Estimation of seasonal influenza disease burden using sentinel site data in Pakistan 2017-2019: A cross-sectional study

Background

The influenza A(H1N1)pdm09 pandemic highlighted the need for reliable disease burden estimation from low- and middle-income countries like Pakistan. We designed retrospective age-stratified estimation of influenza-related severe acute respiratory infections (SARIs) incidence in Islamabad Pakistan 2017-2019.

Materials and Methods

The catchment area was mapped on SARI data from one designated influenza sentinel site and other healthcare facilities in the Islamabad region. The incidence rate was calculated as per 100,000 for each age group with 95% confidence interval.

Results

The catchment population for the sentinel site was 0.7 million against the total denominator of 1.015 million, and incidence rates were adjusted. During January 2017 to December 2019, among 13,905 hospitalizations, 6715 (48%) patients were enrolled; 1208 of these (18%) were positive for influenza. During 2017, influenza A/H3 dominated with 52% detections followed by A(H1N1)pdm09 (35%) and influenza B (13%). Furthermore, elderly 65+ years age group had highest hospitalizations and influenza positive. The incidence rates of all cause respiratory and influenza-related SARI were highest among children >5 years; highest incidence was found in 0 to 11 month/year group with 424/100,000 cases and lowest in 5-15 years 56/100,000. The estimated average annual influenza-associated hospitalization percentage was 29.3% during the study period.

Conclusion

Influenza accounts for a significant proportion of respiratory morbidity and hospitalization. These estimates would enable governments for evidence-based decisions and priority allocation of health resources. It is necessary to test for other respiratory pathogens for more clear disease burden estimation.

The burden of lower respiratory infections and their underlying etiologies in the Middle East and North Africa region, 1990-2019: results from the Global Burden of Disease Study 2019

BACKGROUND

Lower respiratory infections (LRIs) cause substantial mortality and morbidity. The present study reported and analysed the burden of LRIs in the Middle East and North Africa (MENA) region between 1990 and 2019, by age, sex, etiology, and socio-demographic index (SDI).

METHODS

The data used in this study were sourced from the Global Burden of Disease (GBD) study 2019. The annual incidence, deaths, and disability-adjusted life-years (DALYs) due to LRIs were presented as counts and age-standardised rates per 100,000 population, along with their 95% uncertainty intervals (UIs). The average annual percent changes (AAPC) in the age-standardised incidence, death and DALYs rates were calculated using Joinpoint software and correlations (Pearson's correlation coefficient) between the AAPCs and SDIs were calculated using Stata software.

RESULTS

In 2019, there were 34.1 million (95% UI 31.7-36.8) incident cases of LRIs in MENA, with an age-standardised rate of 6510.2 (95% UI 6063.6-6997.8) per 100,000 population. The number of regional DALYs was 4.7 million (95% UI 3.9-5.4), with an age-standardised rate of 888.5 (95% UI 761.1-1019.9) per 100,000 population, which has decreased since 1990. Furthermore, Egypt [8150.8 (95% UI 7535.8-8783.5)] and Afghanistan [61.9 (95% UI 52.1-72.6)] had the highest age-standardised incidence and death rates, respectively. In 2019, the regional incidence and DALY rates were highest in the 1-4 age group, in both females and males. In terms of deaths, pneumococcus and H. influenza type B were the most and least common types of LRIs, respectively. From 1990 to 2019, the burden of LRIs generally decreased with increasing SDI. There were significant positive correlations between SDI and the AAPCs for the age-standardised incidence, death and DALY rates (p < 0.05). Over the 1990-2019 period, the regional incidence, deaths and DALYs attributable to LRIs decreased with AAPCs of - 1.19% (- 1.25 to - 1.13), - 2.47% (- 2.65 to - 2.28) and - 4.21% (- 4.43 to - 3.99), respectively.

CONCLUSIONS

The LRI-associated burden in the MENA region decreased between 1990 and 2019. SDI had a significant positive correlation with the AAPC and pneumococcus was the most common underlying cause of LRIs. Afghanistan, Yemen and Egypt had the largest burdens in 2019. Further studies are needed to investigate the effectiveness of healthcare interventions and programs to control LRIs and their risk factors.

Estimated mortality due to seasonal influenza in southeast of Iran, 2006/2007 to 2011/2012 influenza seasons

BACKGROUND

Global estimates showed an estimate of up to 650,000 seasonal influenza-associated respiratory deaths annually. However, the mortality rate of seasonal influenza is unknown for most countries in the WHO Eastern Mediterranean Region, including Iran. We aimed to estimate the excess mortality attributable to seasonal influenza in Kerman province, southeast Iran for the influenza seasons 2006/2007-2011/2012.

METHODS

We applied a Serfling model to the weekly total pneumonia and influenza (PI) mortality rate during winter to define the epidemic periods and to the weekly age-specific PI, respiratory, circulatory, and all-cause deaths during non-epidemic periods to estimate baseline mortality. The excess mortality was calculated as the difference between observed and predicted mortality. Country estimates were obtained by multiplying the estimated annual excess death rates by the populations of Iran.

RESULTS

We estimated an annual average excess of 40 PI, 100 respiratory, 94 circulatory, and 306 all-cause deaths attributable to seasonal influenza in Kerman; corresponding to annual rates of 1.4 (95% confidence interval [CI] 1.1-1.8) PI, 3.6 (95% CI 2.6-4.8) respiratory, 3.4 (95% CI 2.1-5.2) circulatory, and 11.0 (95% CI 7.3-15.6) all-cause deaths per 100,000 population. Adults ≥75 years accounted for 56% and 53% of all excess respiratory and circulatory deaths, respectively. At country level, we would expect an annual of 1119 PI to 8792 all-cause deaths attributable to seasonal influenza.

CONCLUSIONS

Our findings help to define the mortality burden of seasonal influenza, most of which affects adults aged ≥75 years. This study supports influenza prevention and vaccination programs in older adults.

A Systematic Review of Influenza Epidemiology and Surveillance in the Eastern Mediterranean and North African Region

Seasonal influenza represents a huge health burden, resulting in significant mortality and morbidity. Following the 2009 H1N1 pandemic, focus has been directed on the burden of influenza globally. Country and regional disease burden estimates play important roles in helping inform decisions on national influenza intervention programmes. Despite improvements in influenza surveillance following the 2009 pandemic, many opportunities remain unexplored in the Eastern Mediterranean and North African (EMNA) region, which has a high prevalence of patients with chronic disease and thus a population at high risk of influenza complications. We conducted a systematic literature review of Embase, Medline, Scopus and the Cochrane Database of Systematic Reviews from 1 January 1998 to 31 January 2020 covering the EMNA region with the aim to describe the epidemiology of influenza in the region and assess the influenza epidemiological surveillance research landscape. Relevant data on study characteristics, population, clinical/virology characteristics and epidemiology were extracted and summarised descriptively. Of the 112 studies identified for inclusion, 90 were conducted in the Eastern Mediterranean region, 19 in North Africa and three across the EMNA region. Data were reported on 314,058 laboratory-confirmed influenza cases, 96 of which were derived from surveillance systems. Amongst the surveillance studies, the percentage of positive cases reported ranged from 1% to 100%. The predominantly identified influenza strain was strain A; H1N1 was the most prominent circulating subtype. Typing was performed in approximately 75% and subtyping in 50% of studies, respectively. Data on those considered most at risk for influenza complications were collected in 21% of studies, highlighting a regional gap for these data. Our review reveals existing gaps in regional estimates of influenza health and economic burden, hospitalisation rates and duration, and highlights the need for robust and high-quality epidemiology data to help inform public health interventions.

Burden of severe illness associated with laboratory confirmed influenza in adults aged 50-64 years: A rapid review

BACKGROUND

While the high burden of illness caused by seasonal influenza in children and the elderly is well recognize, less is known about the burden in adults 50-64 years of age. The lack of data for this age group is a key challenge in evaluating the cost-effectiveness of immunization programs. We aimed to assess influenza-associated hospitalization and mortality rates and case fatality rates for hospitalized cases among adults aged 50-64 years.

METHODS

This rapid review was conducted according to the PRISMA; we searched MEDLINE, EMBASE, Cochrane, Web of Science, and grey literature for articles and reports published since 2010. Studies reporting rates of hospitalization and/or mortality associated with laboratory-confirmed influenza among adults 50-64 or 45-64 years of age for the 2010-11 through 2019-20 seasons were included.

RESULTS

Twenty studies from 13 countries were reviewed. Reported rates of hospitalization associated with laboratory-confirmed influenza were 5.7 to 112.8 per 100,000. Rates tended to be higher in the 2015-2019 compared with the 2010-2014 seasons and were higher in studies reporting data from high-income versus low and middle-income countries. Mortality rates were reported in only one study, with rates ranging from 0.8 to 3.5 per 100,000 in four different seasons. The case fatality rate among those hospitalized with influenza, as reported by population-based studies, ranged from 1.3% to 5.6%.

CONCLUSIONS

Seasonal influenza imposes a significant burden of morbidity on adults 50-64 years of age but with high heterogeneity across seasons and geographic regions. Ongoing surveillance is required to improve estimates of burden to better inform influenza vaccination and other public health policies.

Variability in published rates of influenza-associated hospitalizations: A systematic review, 2007-2018

Background

Influenza burden estimates help provide evidence to support influenza prevention and control programs at local and international levels.

Methods

Through a systematic review, we aimed to identify all published articles estimating rates of influenza-associated hospitalizations, describe methods and data sources used, and identify regions of the world where estimates are still lacking. We evaluated study heterogeneity to determine if we could pool published rates to generate global estimates of influenza-associated hospitalization.

Results

We identified 98 published articles estimating influenza-associated hospitalization rates from 2007-2018. Most articles (65%) identified were from high-income countries, with 34 of those (53%) presenting estimates from the United States. While we identified fewer publications (18%) from low- and lower-middle-income countries, 50% of those were published from 2015-2018, suggesting an increase in publications from lower-income countries in recent years. Eighty percent (n = 78) used a multiplier approach. Regression modelling techniques were only used with data from upper-middle or high-income countries where hospital administrative data was available. We identified variability in the methods, case definitions, and data sources used, including 91 different age groups and 11 different categories of case definitions. Due to the high observed heterogeneity across articles (I²>99%), we were unable to pool published estimates.

Conclusions

The variety of methods, data sources, and case definitions adapted locally suggests that the current literature cannot be synthesized to generate global estimates of influenza-associated hospitalization burden.

Comparison of clinical characteristics and outcomes between respiratory syncytial virus and influenza-related pneumonia in China from 2013 to 2019

This study aims to compare clinical characteristics and severity between adults with respiratory syncytial virus (RSV-p) and influenza-related pneumonia (Flu-p). A total of 127 patients with RSV-p, 693 patients with influenza A-related pneumonia (FluA-p), and 386 patients with influenza B-related pneumonia (FluB-p) were retrospectively reviewed from 2013 through 2019 in five teaching hospitals in China. A multivariate logistic regression model indicated that age ≥ 50 years, cerebrovascular disease, chronic kidney disease, solid malignant tumor, nasal congestion, myalgia, sputum production, respiratory rates ≥ 30 beats/min, lymphocytes < 0.8×109/L, and blood albumin < 35 g/L were predictors that differentiated RSV-p from Flu-p. After adjusting for confounders, a multivariate logistic regression analysis confirmed that, relative to RSV-p, FluA-p (OR 2.313, 95% CI 1.377-3.885, p = 0.002) incurred an increased risk for severe outcomes, including invasive ventilation, ICU admission, and 30-day mortality; FluB-p (OR 1.630, 95% CI 0.958-2.741, p = 0.071) was not associated with increased risk. Some clinical variables were useful for discriminating RSV-p from Flu-p. The severity of RSV-p was less than that of FluA-p, but was comparable to FluB-p.

Epidemiology and outcome of influenza-associated infections among hospitalized patients with acute respiratory infections, Egypt national surveillance system, 2016-2019

Introduction

Egypt has established different types of surveillance systems to monitor influenza activities, early detect outbreaks, and tailor efficient prevention and control strategies. This is the first study to describe epidemiology and outcome of influenza‐associated infections among hospitalized patients using the National Electronic Disease Surveillance System (NEDSS) data, 2016‐2019.

Methods

Data reported from 284 hospitals all over Egypt were extracted from the NEDSS. Data of hospitalized patients with Acute Respiratory Infections (ARI), 2016‐2019, were included in the analysis. Laboratory testing for influenza by RT‐PCR according to US CDC testing protocol was used to confirm influenza type and subtype.

Results

Overall 46 417 patients hospitalized with ARI were identified, their mean age was 30.9 ± 26 and 52.9% were males. Among 41 512 (89.4%) laboratory‐tested patients, 7167 (17.3%) were positive for one or more types of influenza viruses. Influenza viruses circulated in all ages and throughout the year, with higher rates in winter, late childhood, and middle ages. Mortality from influenza was significantly higher than other causes of ARIs (5.0% vs 3.8%, P < .001), and it was associated with older ages, December‐May, delay in hospital admission, residence in urban and frontier governorates and infection with A/H1N1 virus. The distribution of influenza subtype by time shows alternate pattern between A/H1N1 and H3N2, each subtype peaks every other year with a high peak of A/H1N1 in 2016.

Conclusions

The national Egyptian surveillance succeeded to describe the epidemiology of hospitalized patients with ARIs and influenza in Egypt over time. Surveillance with strain‐specific laboratory testing and annual assessment of associated severity might be useful to guide influenza prevention and control strategies including vaccination and case management.

Clinical manifestations of adult patients requiring influenza-associated hospitalization: A prospective multicenter cohort study in Japan via internet surveillance

INTRODUCTION

Influenza remains a clinically heavy burden worldwide. The objective of this study was to clarify clinical manifestations of severely ill patients infected with influenza.

METHODS

The clinical data for patients who were severely ill with influenza, and required hospitalization were gathered and analyzed between November 2014 and August 2019 (5 influenza seasons) using an internet-surveillance system.

RESULTS

A total of 924 patients were enrolled and analyzed. The median age was 78 years (IQR, 67-84), and the patients in the 2015-2016 season were significantly younger than those in other seasons. Pneumonia was the most common disease indicated as a cause for hospitalization, followed by a poor general condition and exacerbation of underlying respiratory diseases. Antiviral drugs were administered in 97.0% of the patients with peramivir being the most-frequently use antiviral. In-hospital death was recorded for 44 patients (4.8%). Multivariate analysis indicated that nursing home resident (OR: 6.554) and obesity (OR: 24.343) were independent predictors of in-hospital mortality.

CONCLUSIONS

Complications of influenza infection remain a heavy burden especially among the elderly. Continuous nationwide surveillance will be required to grasp the actual situation of influenza epidemics. (UMIN000015989).

Influenza Vaccination Hesitancy among Healthcare Workers in South Al Batinah Governorate in Oman: A Cross-Sectional Study

Background: Seasonal influenza infections are a major cause of morbidity and mortality worldwide. Healthcare workers (HCWs) are an important target group for vaccination against influenza due to their increased risk of infection and their potential to transmit the infection to their patients, families and communities. The aim of this study was to assess the potential hesitancy and its associated factors towards influenza vaccination amongst HCWs in the South Al Batinah governorate in Oman. Methods: A cross-sectional survey of 390 HCWs with direct or indirect patient contact was conducted in May and June 2019 using a self-administered questionnaire. Associations between HCW characteristics and vaccination status were examined using bivariate and multivariate analyses to identify the likelihood of vaccination against seasonal influenza among HCWs. Results: Overall, 60% of HCWs were vaccinated in the 2018/2019 season; vaccine uptake among nurses was 52% and uptake was higher among women. Self-protection and protection of the community were the most cited reasons for vaccine acceptance, with side effects being the main reason for hesitancy. Vaccinated respondents had a higher mean knowledge score (7.18; standard deviation SD: 2.14) than unvaccinated respondents (6.30; SD: 2.2). Odds of vaccination were highest among respondents who believed influenza vaccine should be mandatory for HCWs (Odds ratio (OR): 2.04 [1.30–3.18]), those working in the general medicine, emergency medicine, or intensive care units (OR: 1.92 [1.20–3.10]), nurses and doctors (OR: 1.75 [1.09–2.79]) and those who believe that HCWs should receive an influenza vaccine (OR: 1.35 [1.07–2.77]). Conclusions: The study provides valuable insights into the enablers and barriers of influenza vaccination practices among HCWs and may inform interventions to increase acceptance of vaccination.

The burden of laboratory-confirmed influenza infection in Lebanon between 2008 and 2016: a single tertiary care center experience

BACKGROUND

Influenza is a major cause of morbidity and mortality worldwide. Following the 2009 pandemic, there was widened interest in studying influenza burden in all regions. However, since data from the World Health Organization (WHO) Middle East and North Africa (MENA) region remain limited, we aimed to contribute to the understanding of influenza burden in Lebanon.

METHODS

A retrospective chart review extending over a period of 8 seasons from Jan 1st, 2008 till June 30th, 2016 at a tertiary care center in Beirut was performed. All cases confirmed to have influenza based on rapid antigen detection or/and polymerase chain reaction on a respiratory sample were included for analysis. Data on epidemiology, clinical presentation, complications, antiviral use and mortality were collected for analysis.

RESULTS

A total of 1829 cases of laboratory-confirmed influenza were identified. Average annual positivity rate was 14% (positive tests over total requested). Both influenza A and B co-circulated in each season with predominance of influenza A. Influenza virus started circulating in December and peaked in January and February. The age group of 19-50 years accounted for the largest proportion of cases (22.5%) followed by the age group of 5-19 years (18%). Pneumonia was the most common complication reported in 33% of cases. Mortality reached 3.8%. The two extremes of age (< 2 years and ≥ 65 years) were associated with a more severe course of disease, hospitalization, intensive care unit (ICU) admission, complications, and mortality rate. Of all the identified cases, 26% were hospitalized. Moderate-to-severe disease was more likely in influenza B cases but no difference in mortality was reported between the two types. Antivirals were prescribed in 68.8% and antibiotics in 41% of cases. There seemed to be an increasing trend in the number of diagnosed and hospitalized cases over the years of the study.

CONCLUSION

Patients with laboratory-confirmed influenza at our center had a high rate of hospitalization and mortality. A population based prospective surveillance study is needed to better estimate the burden of Influenza in Lebanon that would help formulate a policy on influenza control.

Fourth meeting of the Eastern Mediterranean Acute Respiratory Infection Surveillance (EMARIS) network and first scientific conference on acute respiratory infections in the Eastern Mediterranean Region, 11-14 December, 2017, Amman, Jordan

Influenza causes significant morbidity and mortality worldwide. Owing to its ability to rapidly evolve and spread, the influenza virus is of global public health importance. Information on the burden, seasonality and risk factors of influenza in countries of the World Health Organization Eastern Mediterranean Region is emerging because of collaborative efforts between countries, WHO and its partners over the past 10 years. The fourth meeting of the Eastern Mediterranean Acute Respiratory Infection Surveillance network was held in Amman, Jordan on 11–14 December 2017. The meeting reviewed the progress and achievements reported by the countries in the areas of surveillance of and response to seasonal, zoonotic and pandemic influenza. The first scientific conference on acute respiratory infection in the Eastern Mediterranean Region was held at the same time and 38 abstracts from young researchers across the Region were presented on epidemiological and virological surveillance, outbreak detection and response, influenza at the animal-human interface, use and efficacy of new vaccines to control respiratory diseases and pandemic influenza threats. The meeting identified a number of challenges and ways to improve the quality of the surveillance system for influenza, sustain the system so as to address pandemic threats and use the data generated from the surveillance system to inform decision-making, policies and practices to reduce the burden of influenza-associated illnesses in the Region.

Pandemic influenza preparedness (PIP) framework: Progress challenges in improving influenza preparedness response capacities in the Eastern Mediterranean Region, 2014-2017

Influenza viruses with pandemic potential have been detected in humans in the Eastern Mediterranean Region. The Pandemic Influenza Preparedness (PIP) Framework aims to improve the sharing of influenza viruses with pandemic potential and increase access of developing countries to vaccines and other life-saving products during a pandemic. Under the Framework, countries have been supported to enhance their capacities to detect, prepare for and respond to pandemic influenza. In the Eastern Mediterranean Region, seven countries are priority countries for Laboratory and Surveillance (L&S) support: Afghanistan, Djibouti, Egypt, Jordan, Lebanon, Morocco and Yemen. During 2014-2017, US$ 2.7 million was invested in regional capacity-building and US$ 4.6 million directly in the priority countries. Countries were supported to strengthen influenza diagnostic capacities to improve detection, enhance influenza surveillance systems including sentinel surveillance for severe acute respiratory infection and influenza-like illness, and increase global sharing of surveillance data and influenza viruses. This paper highlights the progress made in improving influenza preparedness and response capacities in the Region from 2014 to 2017, and the challenges faced. By 2017, 18 of the 22 countries of the Region had laboratory-testing capacity, 19 had functioning sentinel influenza surveillance systems and 22 had trained national rapid response teams. The number of countries correctly identifying all influenza viruses in the WHO external quality assurance panel increased from 9 countries scoring 100% in 2014 to 15 countries in 2017, and the number sharing influenza viruses with WHO collaborating centres increased by 75% (from eight to 14 countries); more than half now share influenza data with regional or global surveillance platforms. Seven countries have estimated influenza disease burden and seven have introduced influenza vaccination for high-risk groups. Challenges included: protracted complex emergencies faced by nine countries which hindered implementation of influenza surveillance in areas with the most needs, high staff turnover, achieving timely virus sharing and limited utilization of influenza data where they are available to inform vaccine policies or establish threshold values to measure the start and severity of influenza seasons.

Estimates of influenza-associated hospitalisations in tropical Singapore, 2010-2017: Higher burden estimated in more recent years

BACKGROUND

We previously estimated Singapore's influenza-associated hospitalisation rate for pneumonia and influenza (P&I) in 2010-2012 to be 29.6 per 100 000 person-years, which corresponds to 11.2% of all P&I hospitalisations.

OBJECTIVES

This study aims to update Singapore's estimates of the influenza-associated pneumonia and influenza (P&I) hospitalisation burden using the latest data from 2010 to 2017.

METHODS

We estimated the number of P&I hospitalisations associated with influenza using generalised additive models. We specified the weekly number of admissions for P&I and the weekly influenza positivity in the models, along with potential confounders such as weekly respiratory syncytial virus (RSV) positivity and meteorological data.

RESULTS

In 2010-2017, 16.3% of all P&I hospitalisations in Singapore were estimated to be attributed to influenza, corresponding to an excess influenza-associated P&I hospitalisation rate of 50.1 per 100 000 person-years. Higher excess rates were estimated for children aged 0-4 years (186.8 per 100 000 person-years) and elderly aged ≥ 65 years (338.0 per 100 000 person-years). Higher influenza-associated hospitalisation rates were estimated for 2016 and 2017 (67.9 and 75.1 per 100 000 persons, respectively) years when the influenza A(H3N2) subtype was dominant.

CONCLUSION

Influenza burden in Singapore has increased since 2010. Influenza vaccination programmes should continue to be prioritised for the young and the elderly.

Improved capacity for influenza surveillance in the WHO Eastern Mediterranean Region: Progress in a challenging setting

BACKGROUND

The World Health Organization Regional Office for Eastern Mediterranean has partnered with the United States Centers for Disease Control and Prevention (CDC) to strengthen pandemic influenza preparedness and response in the Region since 2006. This partnership focuses on pandemic preparedness planning, establishing and enhancing influenza surveillance systems, improving laboratory capacity for detection of influenza viruses, estimating the influenza disease burden, and providing evidence to support policies for the introduction and increased use of seasonal influenza vaccines.

METHODS

Various published and unpublished data from public and WHO sources, programme indicators of the CDC cooperative agreement and Pandemic Influenza Preparedness Framework were reviewed and analysed. Analyses and review of the programme indicators and published articles enabled us to generate information that was unavailable from only WHO sources.

RESULTS

Most (19/22) countries of the Region have established influenza surveillance system; 16 countries in the Region have designated National Influenza Centres. The Region has seen considerable improvement in geographic coverage of influenza surveillance and influenza detection. Virus sharing has improved and almost all of the participating laboratories have achieved a 100% efficiency score in the WHO external quality assessment programme. At least seven countries have estimated their influenza disease burden using surveillance data and at least 17 are now using seasonal influenza vaccines as a control strategy for influenza illness.

CONCLUSION

The Region has achieved substantial progress in surveillance and response to seasonal influenza, despite the adverse effects to the health systems of many countries due to acute and protracted emergencies and other significant challenges.

Incidence and seasonality of respiratory viruses causing acute respiratory infections in the Northern United Arab Emirates

Background

The data on the seasonality of respiratory viruses helps to ensure the optimal vaccination period and to monitor the possible outbreaks of variant type.

Objectives

This study was designed to describe the molecular epidemiology and seasonality of acute respiratory infection (ARI)‐related respiratory viruses in the United Arab Emirates (UAE).

Methods

Both upper and lower respiratory specimens were collected for the analysis from all the patients who visited the Sheikh Khalifa Specialty Hospital (SKSH) with ARI for over 2 years. The multiplex real‐time reverse transcription polymerase chain reaction (rRT‐PCR) test was used to detect respiratory viruses, which include human adenovirus, influenza virus (FLU) A and B, respiratory syncytial virus, parainfluenza viruses, human rhinovirus (HRV), human metapneumovirus, human enterovirus, human coronavirus, and human bocavirus.

Results

A total of 1,362 respiratory samples were collected from 733 (53.8%) male and 629 (46.2%) female patients with ARI who visited the SKSH between November 2015 and February 2018. The rRT‐PCR test revealed an overall positivity rate of 37.2% (507/1362). The positive rate increased during winter; it was highest in December and lowest in September. FLU was the most frequently detected virus (273/1362 [20.0%]), followed by human rhinovirus (146/1362 [10.7%]). The FLU positivity rate showed two peaks, which occurred in August and December. The peak‐to‐low ratio for FLU was 2.26 (95% confidence interval: 1.52‐3.35).

Conclusions

The pattern of FLU in the UAE parallels to that of temperate countries. The trend of the small peak of FLU in the summer suggests a possibility of semi‐seasonal pattern in the UAE.

Fourth meeting of the Eastern Mediterranean Acute Respiratory Infection Surveillance (EMARIS) network and first scientific conference on acute respiratory infections in the Eastern Mediterranean Region, 11-14 December, 2017, Amman, Jordan

Influenza causes significant morbidity and mortality worldwide. Owing to its ability to rapidly evolve and spread, the influenza virus is of global public health importance. Information on the burden, seasonality and risk factors of influenza in countries of the World Health Organization Eastern Mediterranean Region is emerging because of collaborative efforts between countries, WHO and its partners over the past 10 years. The fourth meeting of the Eastern Mediterranean Acute Respiratory Infection Surveillance network was held in Amman, Jordan on 11–14 December 2017. The meeting reviewed the progress and achievements reported by the countries in the areas of surveillance of and response to seasonal, zoonotic and pandemic influenza. The first scientific conference on acute respiratory infection in the Eastern Mediterranean Region was held at the same time and 38 abstracts from young researchers across the Region were presented on epidemiological and virological surveillance, outbreak detection and response, influenza at the animal-human interface, use and efficacy of new vaccines to control respiratory diseases and pandemic influenza threats. The meeting identified a number of challenges and ways to improve the quality of the surveillance system for influenza, sustain the system so as to address pandemic threats and use the data generated from the surveillance system to inform decision-making, policies and practices to reduce the burden of influenza-associated illnesses in the Region.

Estimating the burden of influenza-associated hospitalization and deaths in Oman (2012-2015)

Background

Influenza is a serious vaccine‐preventable disease with high incidence, hospitalization, and mortality in high‐risk groups. The epidemiology, seasonality, and risk factors for influenza are well defined in most of the temperate countries, but estimating influenza burden in the World Health Organization (WHO) Region for the Eastern Mediterranean is scarce. In Oman, despite the advancements in influenza surveillance, the clinical burden and seasonality of influenza remain not fully understood.

Objectives

To estimate the incidence of influenza‐associated hospitalizations and in‐hospital death in Oman.

Patients and methods

Influenza‐associated hospitalizations and in‐hospital deaths were estimated using hospital discharge records based on ICD‐10 codes (J09‐J18), results of virological analysis and population census for the period between 2012 and 2015.

Results

During 2012 and 2015, we identified a total of 19 405 influenza‐associated hospitalization and 847 deaths. Influenza positivity percentage ranged from 6.4% in 2013 to 20.6% in 2015. Influenza‐associated hospitalization incidence rate was 7.3 (95% CI: 6.4‐8.1) per 100 000 in 2013 and 27.5 (95% CI: 25.9‐29.1) per 100 000 in 2015 with an overall rate of 20.6 (95% CI: 19.9‐21.3) per 100 000. The highest incidence of influenza‐associated death was among those aged ≥65 years and ranged between 39.5 (95% CI: 27.3‐51.8) per 100 000 in 2014 and 11.3 (95% CI: 7.5‐15.1) in 2015.

Conclusions

Influenza causes a substantial number of hospitalizations and deaths in Oman. Hospitalization rates were highest among children, and adults ≥65 years showed the highest death rate. The potential value of using seasonal influenza vaccine in these groups should be considered.