A population-based study on incidence and economic burden of influenza-like illness in south China, 2007

Incidence, circulation, and spatiotemporal analysis of seasonal influenza in Shandong, China, 2008-2019: A retrospective study

BACKGROUND

Understanding the influenza-like illness (ILI) incidence, circulation pattern of virus strains and spatiotemporal pattern of influenza transmission are important for designing control interventions. Based on the 10 years' surveillance data, we aimed to provide a baseline characterization and the epidemiology and dynamics of influenza virus in Shandong.

METHODS

We extracted surveillance and laboratory testing data. We estimated the ILI incidence and analyzed the predominant virus. A wavelet power analysis was used to illustrate the periodicity. In addition, we applied a linear regression model to characterize the correlation of influenza seasonality with longitude.

RESULTS

The average ILI incidence was estimated to be 3744.79 per 1 million (95% confidence interval [CI]: 2558.09-4931.45) during 2009-2018. Influenza A/H1N1 and A/H3N2 strains predominated in the most influenza seasons in Shandong. The annual amplitude of influenza epidemics decreased with longitude (P < 0.05). In contrast, the epidemic peak of influenza emerged earlier in the western region and increased with longitude in influenza A (P < 0.05). The annual peak of the influenza B epidemic lagged a median of 4.2 weeks compared with that of influenza A.

CONCLUSIONS

The development or modification of seasonal influenza vaccination strategies requires the recognition that the incidence is higher in preschool- and school-aged children. Although seasonal influenza circulates annually in Shandong, the predominant virus strain circulation pattern is extremely unpredictable and strengthening surveillance for the predominant virus strain is necessary. Lower longitude inland regions need to take nonpharmaceutical or pharmaceutical interventions in advance during influenza high-occurrence seasons.

The Economic Burden of Influenza-Like Illness among Children, Chronic Disease Patients, and the Elderly in China: A National Cross-Sectional Survey

Background: The disease burden of seasonal influenza is substantial in China, while there is still a lack of nationwide economic burden estimates. This study aims to examine influenza-like illness (ILI) prevalence, healthcare-seeking behaviors, economic impact of ILI, and its influencing factors among three priority groups during the 2018–19 influenza season. Methods: From August to October 2019, 6668 children’s caregivers, 1735 chronic disease patients, and 3849 elderly people were recruited from 10 provinces in China to participate in an on-site survey. The economic burden of ILI consisted of direct (medical or non-medical) and indirect burdens, and a two-part model was adopted to predict the influencing factors of total economic burden. Results: There were 45.73% children, 16.77% chronic disease patients, and 12.70% elderly people reporting ILI, and most participants chose outpatient service or over-the-counter (OTC) medication after ILI. The average economic burden was CNY 1647 (USD 237.2) for children, CNY 951 (USD 136.9) for chronic disease patients, and CNY 1796 (USD 258.6) for the elderly. Two-part regression showed that age, gender, whether the only child in the family, region, and household income were important predictors of ILI economic burden among children, while age, region, place of residence, basic health insurance, and household income were significant predictors of ILI economic burden among chronic disease patients and the elderly. Conclusions: A large economic burden of ILI was highlighted, especially among the elderly with less income and larger medical burdens, as well as children, with higher prevalence and higher self-payment ratio. It is important to adopt targeted interventions for high-risk groups, and this study can help national-level decision-making on the introduction of influenza vaccination as a public health project.

Economic burden of influenza illness among children under 5 years in Suzhou, China: Report from the cost surveys during 2011/12 to 2016/17 influenza seasons

BACKGROUND

Data are limited on the economic burden of seasonal influenza in China. We estimated the cost due to influenza illness among children < 5-year-old in Suzhou, China.

METHODS

This study adopted a societal perspective to estimate direct medical cost, direct non-medical cost, and indirect cost related to lost productivity. Data to calculate costs and rates of three influenza illness outcomes (non-medically attended, outpatient and hospitalization) were collected from prospective community-based cohort studies and hospital-based enhanced laboratory-confirmed influenza surveillance in Suzhou during the 2011/12 to 2016/17 influenza seasons. We used mean cost-per-episode, annual incidence rates of episodes of each outcome, and annual population size to estimate the total annual economic burden of influenza illnesses among children < 5-year-old for Suzhou. All costs were reported in 2017 U.S. dollars.

RESULTS

The mean cost-per-episode (standard deviation) was $9.92 (13.26) for non-medically attended influenza, $161.05 (176.98) for influenza outpatient illnesses, and $1425.95 (603.59) for influenza hospitalizations. By applying the annual incidence rates to the population size, we estimated an annual total of 4,919 episodes of non-medically attended influenza, 21,994 influenza outpatient, and 2,633 influenza hospitalization. Total annual economic burden of influenza to society among children < 5-year-old in Suzhou was $7.37 (95% confidence interval, 6.9-7.8) million, with estimated costs for non-medically attended influenza of $49,000 (46,000-52,000), influenza outpatients $3.5 (3.3-3.8) million, and influenza hospitalizations $3.8 (3.6-3.9) million. Among outpatients, the indirect cost was 36.3% ($1.3 million) of total economic burden, accounting for 21,994 days of lost productivity annually. Among inpatients, the indirect cost was 22.1% ($829,000), accounting for 18,431 days of lost productivity annually.

CONCLUSIONS

Our findings show that influenza in children < 5-year-oldcauses substantial societal economic burden in Suzhou, China. Assessing the potential economic benefit of increasing influenza vaccination coverage in this population is warranted.

Treatment of coronavirus disease 2019 in Shandong, China: a cost and affordability analysis

Background

Coronavirus disease 2019 (COVID-19) is now a global public threat. Given the pandemic of COVID-19, the economic impact of COVID-19 is essential to add value to the policy-making process. We retrospectively conducted a cost and affordability analysis to determine the medical costs of COVID-19 patients in China, and also assess the factors affecting their costs.

Methods

This analysis was retrospectively conducted in Shandong Provincial Chest Hospital between 24 January and 16 March 2020. The total direct medical expenditures were analyzed by cost factors. We also assessed affordability by comparing the simulated out-of-pocket expenditure of COVID-19 cases relative to the per capita disposable income. Differences between groups were tested by student t test and Mann-Whitney test when appropriate. A multiple logistic regression model was built to determine the risk factors associated with high cost.

Results

A total of 70 COVID-19 patients were included in the analysis. The overall mean cost was USD 6827 per treated episode. The highest mean cost was observed in drug acquisition, accounting for 45.1% of the overall cost. Total mean cost was significantly higher in patients with pre-existing diseases compared to those without pre-existing diseases. Pre-existing diseases and the advanced disease severity were strongly associated with higher cost. Around USD 0.49 billion were expected for clinical manage of COVID-19 in China. Among rural households, the proportions of health insurance coverage should be increased to 70% for severe cases, and 80% for critically ill cases to avoid catastrophic health expenditure.

Conclusions

Our data demonstrate that clinical management of COVID-19 patients incurs a great financial burden to national health insurance. The cost for drug acquisition is the major contributor to the medical cost, whereas the risk factors for higher cost are pre-existing diseases and severity of COVID-19. Improvement of insurance coverage will need to address the barriers of rural patients to avoid the occurrence of catastrophic health expenditure.

Environmental complex exposure and the risk of influenza-like illness among housewives: A case study in Shanxi Province, China

The association between environmental pollution and risk of influenza-like illness (ILI) among general population has been reported. However, the relationships between the individual pollutants and ILI risk are still under discussion. Our study aimed to explore the associations of the typical environmental polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s with ILI risk among women population. We carried out a cross-sectional study and included a total of 396 housewives in Shanxi Province, China. The information on their general characteristics and ILI frequency was collected by questionnaire. We collected their hair samples and analyzed the concentrations of PAHs and various metal(loid)s. The results indicated that only acenaphthylene concentration of the nine detected PAH congeners in the hair was significantly associated with ILI risk with adjusted odds ratio (AOR) and 95% confidence interval (95% CI) of 0.58 (0.38 - 0.91). Among the concerned 4 toxic metal(loid)s and 15 rare earth elements, only the hair concentration of arsenic had a positive dose-response relationship with ILI risk. In addition, we found that there were negative dose-response associations of the three essential trace elements (i.e. chromium, cobalt, and nickel), and four essential alkaline earth elements (i.e. magnesium, calcium, strontium, barium) with ILI risk. It was concluded that the environmental exposure to certain compounds of housewives may contribute to their ILI development.

Effectiveness and Parental Acceptability of Social Networking Interventions for Promoting Seasonal Influenza Vaccination Among Young Children: Randomized Controlled Trial

BACKGROUND

Seasonal influenza vaccination (SIV) coverage among young children remains low worldwide. Mobile social networking apps such as WhatsApp Messenger are promising tools for health interventions.

OBJECTIVE

This was a preliminary study to test the effectiveness and parental acceptability of a social networking intervention that sends weekly vaccination reminders and encourages exchange of SIV-related views and experiences among mothers via WhatsApp discussion groups for promoting childhood SIV. The second objective was to examine the effect of introducing time pressure on mothers' decision making for childhood SIV for vaccination decision making. This was done using countdowns of the recommended vaccination timing.

METHODS

Mothers of child(ren) aged 6 to 72 months were randomly allocated to control or to one of two social networking intervention groups receiving vaccination reminders with (SNI+TP) or without (SNI-TP) a time pressure component via WhatsApp discussion groups at a ratio of 5:2:2. All participants first completed a baseline assessment. Both the SNI-TP and SNI+TP groups subsequently received weekly vaccination reminders from October to December 2017 and participated in WhatsApp discussions about SIV moderated by a health professional. All participants completed a follow-up assessment from April to May 2018.

RESULTS

A total of 84.9% (174/205), 71% (57/80), and 75% (60/80) who were allocated to the control, SNI-TP, and SNI+TP groups, respectively, completed the outcome assessment. The social networking intervention significantly promoted mothers' self-efficacy for taking children for SIV (SNI-TP: odds ratio [OR] 2.69 [1.07-6.79]; SNI+TP: OR 2.50 [1.13-5.55]), but did not result in significantly improved children's SIV uptake. Moreover, after adjusting for mothers' working status, introducing additional time pressure reduced the overall SIV uptake in children of working mothers (OR 0.27 [0.10-0.77]) but significantly increased the SIV uptake among children of mothers without a full-time job (OR 6.53 [1.87-22.82]). Most participants' WhatsApp posts were about sharing experience or views (226/434, 52.1%) of which 44.7% (101/226) were categorized as negative, such as their concerns over vaccine safety, side effects and effectiveness. Although participants shared predominantly negative experience or views about SIV at the beginning of the discussion, the moderator was able to encourage the discussion of more positive experience or views and more knowledge and information. Most intervention group participants indicated willingness to receive the same interventions (110/117, 94.0%) and recommend the interventions to other mothers (102/117, 87.2%) in future.

CONCLUSIONS

Online information support can effectively promote mothers' self-efficacy for taking children for SIV but alone it may not sufficient to address maternal concerns over SIV to achieve a positive vaccination decision. However, the active involvement of health professionals in online discussions can shape positive discussions about vaccination. Time pressure on decision making interacts with maternal work status, facilitating vaccination uptake among mothers who may have more free time, but having the opposite effect among busier working mothers.

TRIAL REGISTRATION

Hong Kong University Clinical Trials Registry HKUCTR-2250; https://tinyurl.com/vejv276.

Possible interference between seasonal epidemics of influenza and other respiratory viruses in Hong Kong, 2014-2017

Background

Unlike influenza viruses, little is known about the prevalence and seasonality of other respiratory viruses because laboratory surveillance for non-influenza respiratory viruses is not well developed or supported in China and other resource-limited countries. We studied the interference between seasonal epidemics of influenza viruses and five other common viruses that cause respiratory illnesses in Hong Kong from 2014 to 2017.

Methods

The weekly laboratory-confirmed positive rates of each virus were analyzed from 2014 to 2017 in Hong Kong to describe the epidemiological trends and interference between influenza viruses, respiratory syncytial virus (RSV), parainfluenza virus (PIV), adenovirus, enterovirus and rhinovirus. A sinusoidal model was established to estimate the peak timing of each virus by phase angle parameters.

Results

Seasonal features of the influenza viruses, PIV, enterovirus and adenovirus were obvious, whereas annual peaks of RSV and rhinovirus were not observed. The incidence of the influenza viruses usually peaked in February and July, and the summer peaks in July were generally caused by the H3 subtype of influenza A alone. When influenza viruses were active, other viruses tended to have a low level of activity. The peaks of the influenza viruses were not synchronized. An epidemic of rhinovirus tended to shift the subsequent epidemics of the other viruses.

Conclusion

The evidence from recent surveillance data in Hong Kong suggests that viral interference during the epidemics of influenza viruses and other common respiratory viruses might affect the timing and duration of subsequent epidemics of a certain or several viruses.

Social and economic burden of patients with influenza-like illness and clinically diagnosed flu treated at various health facilities in Vietnam

Influenza is a malady related to the human respiratory system, and its influenza-like illness (ILI) can cause an economic and social burden, especially among children and the elderly. This study was conducted to estimate the cost of illness based on a social perspective of ILI cases. A prospective study was conducted between February and March of 2016 in pharmacies, private clinics at Khanh Hoa, Lam Dong, Tay Ninh, Dong Nai Province, and Ho Chi Minh City, and Hospital of Tropical Diseases. Demographic and clinical information were collected by face-to-face interview. Direct costs (e.g., diagnosis and therapeutics) and indirect costs (e.g., cost of day loss) are included as treatment costs. The average cost of treatment associated with ILI was US$ 88.09 per case for all age groups; direct non-medical cost was higher compared to direct medical cost: 39.5% in pharmacies, 71.1% in clinics, and 64.2% in hospital. The indirect cost was US$27.49 per episode. The average total cost for children below 14 years old was much higher than that for the other age groups. The cost of illness of ILI was, therefore, the reason for the economic burden of influenza patients and their families. This study provides a database for future research and programs, and policies that can be adopted for influenza or ILI in Vietnam.

VP34 Economic Impact Of Influenza-Like-Illness In Vietnam

INTRODUCTION:

Influenza is a disease related to the human respiratory system, with economic and social burden a common cause of Influenza-Like-Illness (ILI) among children and the elderly. This study was conducted to estimate cost of illness based on social perspectives of ILI cases.

METHODS:

A prospective study was conducted between February and March 2016 in pharmacies and private clinics at Khanh Hoa, Lam Dong, Tay Ninh, Dong Nai province, Ho Chi Minh City and Hospital of Tropical Diseases. Demographic and clinical information was collected by face-to-face interview. Treatment costs included direct costs (for example, diagnosis, therapeutics) and indirect cost (cost of days lost).

RESULTS:

Average costs associated with the ILI were USD88.09 per case among all age groups, direct non-medical costs were more dominant than direct medical costs accounting for 39.5 percent in pharmacies, 71.1 percent in clinics and 64.2 percent in hospitals. Total average cost was estimated to be EUR105 in children, and EUR514 in adults in Germany (1); and in South China, direct medical cost of ILI would be USD22.69 (2).

CONCLUSIONS:

The cost of ILI was the reason for the economic burden of patients and their families. This study provides the data for the future research, programs and policies which can be applied for influenza or ILI in Vietnam.

Influenza-like illness in an urban community of Salvador, Brazil: incidence, seasonality and risk factors

BACKGROUND

Our understanding of the epidemiology of influenza is limited in tropical regions, which in turn has hampered identifying optimal region-specific policy to diminish disease burden. Influenza-like illness (ILI) is a clinical diagnosis that can be used as a surrogate for influenza. This study aimed to define the incidence and seasonality of ILI and to assess its association with climatic variables and school calendar in an urban community in the tropical region of Salvador, Brazil.

METHODS

Between 2009 and 2013, we conducted enhanced community-based surveillance for acute febrile illnesses (AFI) among patients ≥ 5 years of age in a slum community emergency unit in Salvador, Brazil. ILI was defined as a measured temperature of ≥ 37.8 °C or reported fever in a patient with cough or sore throat for ≤ 7 days, and negative test results for dengue and leptospirosis. Seasonality was analyzed with a harmonic regression model. Negative binomial regression models were used to correlate ILI incidence with rainfall, temperature, relative humidity and the number of days per month that schools were in session while controlling for seasonality.

RESULTS

There were 2,651 (45.6% of 5,817 AFI patients) ILI cases with a mean annual incidence of 60 cases/1,000 population (95% CI 58-62). Risk of ILI was highest among 5-9 year olds with an annual incidence of 105 cases/1,000 population in 2009. ILI had a clear seasonal pattern with peaks between the 35-40th week of the year. ILI peaks were higher and earlier in 5-9 year olds compared with > 19 year olds. No association was seen between ILI and precipitation, relative humidity or temperature. There was a significant association between the incidence of ILI in children 5-9 years of age and number of scheduled school days per month.

CONCLUSIONS

We identified a significant burden of ILI with distinct seasonality in the Brazilian tropics and highest rates among young school-age children. Seasonal peaks of ILI in children 5-9 years of age were positively associated with the number of school days, indicating that children may play a role in the timing of seasonal influenza transmission.

Impact of Influenza on Outpatient Visits, Hospitalizations, and Deaths by Using a Time Series Poisson Generalized Additive Model

BACKGROUND

The disease burden associated with influenza in developing tropical and subtropical countries is poorly understood owing to the lack of a comprehensive disease surveillance system and information-exchange mechanisms. The impact of influenza on outpatient visits, hospital admissions, and deaths has not been fully demonstrated to date in south China.

METHODS

A time series Poisson generalized additive model was used to quantitatively assess influenza-like illness (ILI) and influenza disease burden by using influenza surveillance data in Zhuhai City from 2007 to 2009, combined with the outpatient, inpatient, and respiratory disease mortality data of the same period.

RESULTS

The influenza activity in Zhuhai City demonstrated a typical subtropical seasonal pattern; however, each influenza virus subtype showed a specific transmission variation. The weekly ILI case number and virus isolation rate had a very close positive correlation (r = 0.774, P < 0.0001). The impact of ILI and influenza on weekly outpatient visits was statistically significant (P < 0.05). We determined that 10.7% of outpatient visits were associated with ILI and 1.88% were associated with influenza. ILI also had a significant influence on the hospitalization rates (P < 0.05), but mainly in populations <25 years of age. No statistically significant effect of influenza on hospital admissions was found (P > 0.05). The impact of ILI on chronic obstructive pulmonary disease (COPD) was most significant (P < 0.05), with 33.1% of COPD-related deaths being attributable to ILI. The impact of influenza on the mortality rate requires further evaluation.

CONCLUSIONS

ILI is a feasible indicator of influenza activity. Both ILI and influenza have a large impact on outpatient visits. Although ILI affects the number of hospital admissions and deaths, we found no consistent influence of influenza, which requires further assessment.

A systematic review of the social and economic burden of influenza in low- and middle-income countries

OBJECTIVES

The economic burden of seasonal influenza outbreaks as well as influenza pandemics in lower- and middle-income countries (LMIC) has yet to be specifically systematically reviewed. The aim of this systematic review is to assess the evidence of influenza economic burden assessment methods in LMIC and to quantify the economic consequences of influenza disease in these countries, including broader opportunity costs in terms of impaired social progress and economic development.

METHODS

We conducted an all language literature search across 5 key databases using an extensive list of key words for the time period 1950-2013. We included studies which explored direct costs (medical and non-medical), indirect costs (productivity losses), and broader economic impact in LMIC associated with different influenza outcomes such as confirmed seasonal influenza infection, influenza-like illnesses, and pandemic influenza.

RESULTS

We included 62 full-text studies in English, Spanish, Russian, Chinese languages, mostly from the countries of Latin American and the Caribbean and East Asia and Pacific with pertinent cost data found in 39 papers. Estimates for direct and indirect costs were the highest in Latin American and the Caribbean. Compared to high-income economies, direct costs in LMIC were lower and productivity losses higher. Evidence on broader impact of influenza included impact on the wider national economy, security dimension, medical insurance policy, legal frameworks, distributional impact, and investment flows.

CONCLUSION

The economic burden of influenza in LMIC encompasses multiple dimensions such as direct costs to the health service and households, indirect costs due to productivity losses as well as broader detriments to the wider economy. Evidence from sub-Saharan Africa and in pregnant women remains very limited. Heterogeneity of methods used to estimate cost components makes data synthesis challenging. There is a strong need for standardizing research, data collection and evaluation methods for both direct and indirect cost components.

Viral etiology of influenza-like illnesses in Huizhou, China, from 2011 to 2013

Little information is available on the etiology and prevalence of viruses other than influenza viruses causing influenza-like illnesses (ILIs) in China. This study was conducted for simultaneous detection and identification of 14 respiratory viruses in Huizhou using real-time PCR. In total, viruses were detected in 48.66 % of ILI patient samples, in which influenza virus (19.98 %) was the most commonly detected, followed by rhinovirus (7.46 %), human coronaviruses (3.63 %), human metapneumovirus (3.06 %), parainfluenza virus (3.06 %), respiratory syncytial virus (2.39 %), adenovirus (2.29 %), and human bocavirus (1.43 %). Co-infections occurred in 5.35 % of all tested specimens and 11.00 % (56/509) of infected patients. Children under 5 years and adults older than 60 years were more likely to have one or more detectable viruses associated with their ILI (OR=1.75, 95 % CI: 1.37; 2.23). Influenza virus was detected during each month of each year, and increased viral activity was observed in 2013. Infections with adenovirus and human metapneumovirus had characteristic seasonal patterns. No significant differences were found in positive the rate between the gender groups, while significantly differences in positive rate were found among the different age groups (P-value<0.001). This study confirmed that multiple respiratory viruses may circulate concurrently in the population and play an important role in the etiology of ILI. The most frequent symptoms associated with respiratory viruses were sore throat, rhinorrhea and headache. This information needs to be considered by clinicians when treating patients presenting with ILI, and it could serve as a reference for government officers when designing and implementing effective intervention plans.

National surveillance for influenza and influenza-like illness in Vietnam, 2006-2010

Influenza virus infections result in considerable morbidity and mortality both in the temperate and tropical world. Influenza surveillance over multiple years is important to determine the impact and epidemiology of influenza and to develop a national vaccine policy, especially in countries developing influenza vaccine manufacturing capacity, such as Vietnam. We conducted surveillance of influenza and influenza-like illness in Vietnam through the National Influenza Surveillance System during 2006-2010. At 15 sentinel sites, the first two patients presenting each weekday with influenza-like illness (ILI), defined as fever and cough and/or sore throat with illness onset within 3 days, were enrolled and throat specimens were collected and tested for influenza virus type and influenza A subtype by RT-PCR. De-identified demographic and provider reported subsequent hospitalization information was collected on each patient. Each site also collected information on the total number of patients with influenza-like illness evaluated per week. Of 29,804 enrolled patients presenting with influenza-like illness, 6516 (22%) were influenza positive. Of enrolled patients, 2737 (9.3%) were reported as subsequently hospitalized; of the 2737, 527 (19%) were influenza positive. Across all age groups with ILI, school-aged children had the highest percent of influenza infection (29%) and the highest percent of subsequent hospitalizations associated with influenza infection (28%). Influenza viruses co-circulated throughout most years in Vietnam during 2006-2010 and often reached peak levels multiple times during a year, when >20% of tests were influenza positive. Influenza is an important cause of all influenza-like illness and provider reported subsequent hospitalization among outpatients in Vietnam, especially among school-aged children. These findings may have important implications for influenza vaccine policy in Vietnam.

Incidence of symptomatic A(H1N1)pdm09 influenza during the pandemic and post-pandemic periods in a rural Indian community

BACKGROUND

Data on influenza illness rates with population denominators are needed to quantify overall morbidity and to prioritize public health intervention strategies.

METHODS

The rates of influenza A(H1N1)pdm09 infection during pandemic phases were determined in a longitudinal community cohort study as part of an influenza vaccine study in a rural community of North India.

RESULTS

During the 711,731 person-weeks of surveillance, a total of 1410/7571 (19%) febrile acute respiratory illness cases were positive for influenza. Of these, 749 (53%) were influenza A(H1N1)pdm09, 643 (46%) influenza B, and 18 (1%) influenza A (H3N2). The overall incidence rate of influenza-associated febrile acute respiratory illness was 128/1000 person-years. The incidence rates of influenza A(H1N1)pdm09 were high during both the pandemic phase (179/1000 person-years; November 2009 to January 2010) and post-pandemic phase (156/1000 person-years; August to October 2010), with children<18 years of age being at the greatest risk of influenza infection in the community.

CONCLUSIONS

These findings provide important information for planning clinical and public health intervention strategies to mitigate the impact of influenza epidemics.

Direct medical cost of influenza-related hospitalizations among severe acute respiratory infections cases in three provinces in China

Background

Influenza-related hospitalizations impose a considerable economic and social burden. This study aimed to better understand the economic burden of influenza-related hospitalizations among patients in China in different age and risk categories.

Methods

Laboratory-confirmed influenza-related hospitalizations between December 2009 and June 2011 from three hospitals participating in the Chinese Severe Acute Respiratory Infections (SARI) sentinel surveillance system were included in this study. Hospital billing data were collected from each hospital’s Hospital Information System (HIS) and divided into five cost categories. Demographic and clinical information was collected from medical records. Mean (range) and median (interquartile range [IQR]) costs were calculated and compared among children (≤15 years), adults (16–64 years) and elderly (≥65 years) groups. Factors influencing cost were analyzed.

Results

A total of 106 laboratory-confirmed influenza-related hospitalizations were identified, 60% of which were children. The mean (range) direct medical cost was $1,797 ($80–$27,545) for all hospitalizations, and the median (IQR) direct medical cost was $231 ($164), $854 ($890), and $2,263 ($7,803) for children, adults, and elderly, respectively. Therapeutics and diagnostics were the two largest components of direct medical cost, comprising 57% and 23%, respectively. Cost of physician services was the lowest at less than 1%.

Conclusion

Direct medical cost of influenza-related hospitalizations imposes a heavy burden on patients and their families in China. Further study is needed to provide more comprehensive evidence on the economic burden of influenza. Our study highlights the need to increase vaccination rate and develop targeted national preventive strategies.

Surveillance of 16 respiratory viruses in patients with influenza-like illness in Nanjing, China

Much less is known about the etiology of influenza‐like illness in China. A continuous surveillance of 16 respiratory viruses was conducted from November 2010 to October 2011 of outpatients with influenza‐like illness in Nanjing, China. The two largest general hospitals and a provincial virus laboratory in Nanjing participated in this study. Throat swabs were collected from outpatients during medical visits for influenza‐like illness and were tested for 16 respiratory viruses using PCR. Three hundred seventeen viruses were detected in samples from 246 (50.6%) patients with influenza‐like illness. The viruses found mostly commonly were influenza, rhinovirus, hCoV HKU1, and adenovirus. The identification rates of respiratory viruses differed significantly among different sampling seasons (P = 0.0002). The rates of influenza A and hCoV HKU1 were much higher during the influenza‐like illness winter peak than during the influenza‐like illness summer peak and other months. Co‐infections were detected in 57 (11.7%) patients and were found most commonly in adults older than 60 years. RSV was detected in 5.9% and 2.6% of patients who were 0–5 and 6–15 years old, respectively, but was not detected in other age groups. This study confirmed that multiple respiratory viruses may circulate concurrently in the population and account for a large proportion of influenza‐like illness. In addition to influenza virus, hCoV HKU1 may be associated with the influenza‐like illness winter peak in Nanjing, China. J. Med. Virol. 84:1980–1984, 2012. © 2012 Wiley Periodicals, Inc.

Epidemiologic and economic burden of influenza in the outpatient setting: a prospective study in a subtropical area of China

Objectives

To understand the incidence of outpatient influenza cases in a subtropical area of China and the associated economic burden on patients' families.

Methods

A hospital-based prospective study was conducted in Zhuhai City during 2008–2009. All outpatient influenza-like illness (ILI) cases were identified in 28 sentinel hospitals. A representative sample of throat swabs from ILI cases were collected for virus isolation using Madin-Darby canine kidney cells. The incidence of outpatient influenza cases in Zhuhai was estimated on the basis of the number of influenza patients detected by the sentinel sites. A telephone survey on the direct costs associated with illness was conducted as a follow-up.

Results

The incidence of influenza was estimated to be 4.1 per 1,000 population in 2008 and 19.2 per 1,000 population in 2009. Children aged <5 years were the most-affected population, suffering from influenza at the highest rates (34.3 per 1,000 population in 2008 and 95.3 per 1,000 population in 2009). A high incidence of 29.2–40.9 per 1000 population was also seen in young people aged 5–24 years in 2009. ILI activity and influenza virus isolations adopted a consistent seasonal pattern, with a summer peak in July 2008 and the longest epidemic period lasting from July–December 2009. The medical costs per episode of influenza among urban patients were higher than those for rural patients. A total of $1.1 million in direct economic losses were estimated to be associated with outpatient influenza during 2008–2009 in Zhuhai community.

Conclusions

Influenza attacks children aged <5 years in greater proportions than children in other age groups. Seasonal influenza 2008 and Pandemic influenza A (H1N1) 2009 had different epidemiological and etiological characteristics. Direct costs (mostly medical costs) impose an enormous burden on the patient family. Vaccination strategies for high-risk groups need to be further strengthened.