The clinical and economic burden of community-onset complicated skin and skin structure infections in Korea

Background/Aims@#To investigate epidemiologic characteristics, clinical and economic burdens, and factors associated with mortality in complicated skin and skin structure infection (cSSSI) patients in Korea. @*Methods@#A retrospective, observational, nationwide study was conducted between April to July 2012 at 14 tertiary-hospitals in Korea. Eligible patients were hospitalized adults with community acquired cSSSI, who underwent surgical intervention and completed treatment between November 2009 and October 2011. Data on demography, clinical characteristics, outcomes and medical resource utilization were collected through medical record review. Direct medical costs were calculated by multiplying quantities of resources utilized by each unit price in Korea. @*Results@#Of 473 patients enrolled, 449 patients (except 24 patients with no record on surgical intervention) were eligible for analysis. Microbiological testing was performed on 66.1% of patients and 8.2% had multiple pathogens. Among culture confirmed pathogens (n = 297 patients, 340 episodes), 76.2% were gram-positive (Staphylococcus aureus; 41.2%) and 23.8% were gram-negative. The median duration of hospital stay was 16 days. Among treated patients, 3.3% experienced recurrence and 4.2% died in-hospital. The mean direct medical costs amounted to $4,195/ person, with the greatest expenses for hospitalization and antibiotics. The in-hospital mortality and total medical costs were higher in combined antibiotics therapy than monotherapy (p < 0.05). Charlson’s comorbidity index ≥ 3, standardized early warning scoring ≥ 4, sub-fascia infections and combined initial therapy, were all found to be associated with higher mortality. @*Conclusions@#Korean patients with community-onset cSSSI suffer from considerable clinical and economic burden. Efforts should be made to reduce this burden through appropriate initial treatment.

Hospital-based Influenza Morbidity and Mortality (HIMM) Surveillance for A/H7N9 Influenza Virus Infection in Returning Travelers

Since 2013, the Hospital-based Influenza Morbidity and Mortality (HIMM) surveillance system began a H7N9 influenza surveillance scheme for returning travelers in addition to pre-existing emergency room (ER)-based influenza-like illness (ILI) surveillance and severe acute respiratory infection (SARI) surveillance. Although limited to eastern China, avian A/H7N9 influenza virus is considered to have the highest pandemic potential among currently circulating influenza viruses. During the study period between October 1st, 2013 and April 30th, 2016, 11 cases presented with ILI within seven days of travel return. These patients visited China, Hong Kong, or neighboring Southeast Asian countries, but none of them visited a livestock market. Seasonal influenza virus (54.5%, 6 among 11) was the most common cause of ILI among returning travelers, and avian A/H7N9 influenza virus was not detected during the study period.

Immunogenicity and Safety of Trivalent Inactivated Influenza Vaccine: A Randomized, Double-Blind, Multi-Center, Phase 3 Clinical Trial in a Vaccine-Limited Country

Influenza vaccines are the primary method for controlling influenza and its complications. This study was conducted as a phase 3, randomized, double-blind, controlled, multi-center trial at seven university hospitals to evaluate the immunogenicity and safety of an inactivated, split, trivalent influenza vaccine (GC501, Green Cross Corporation, Yongin, Korea), which was newly manufactured in Korea in 2008. Between September 21 and 26, a total of 329 healthy subjects were recruited for the immunogenicity analysis, while 976 subjects were enrolled for the safety analysis. The GC501 vaccine met both FDA and EMEA criteria with > or = 80% of subjects achieving post-vaccination titers > or = 40 for all three subtypes, even in the elderly. The vaccine was well tolerated with only mild systemic and local adverse events. In summary, GC501 showed excellent immunogenicity and a good safety profile in both young adults and the elderly. The licensure of GC501 might be an important basis in preparation for the future influenza pandemic.

A 5-year review of clinical characteristics and mortality of burn patients with candidemia in a tertiary burn center / 대한내과학회지

BACKGROUND: Nosocomial candidemia is one of the most common blood-stream infection and associated with a high fatality rate in burn patients. To determine the clinical characteristics, strains of Candida species and to identify contributing factors to death, we analyzed severely burned patients with candidemia. METHODS: 60 cases with candidemia were reviewed retrospectively from January 1999 to December 2003 at a tertiary burn center in Korea. Candidemia was defined as at least one blood culture that grew Candida organisms. RESULTS: Burn size of all patients were 46+/-20.9% of total body surface area burn and overall mortality was 41.7%. 97 strains of Candida species from 60 cases were isolated. Candida albicans was the most frequently isolated species (53.6%), followed by C. tropicalis (20.6%), C. glabrata (15.5%) and C. parapsilosis (10.3%). Among various predisposing factors for candidemia, significant factors associated with death were endotracheal tube insertion or tracheostomy, mechanical ventilation, the use of vasoactive agents, arterial catheterization and nasogastric tube insertion in univariate analysis, but significant independent factors for mortality were mechanical ventilation (OR=26.63, 95% CI; 1.60, 444.18, p=0.022) and the use of vasoactive agents (OR=23.18, 95% CI; 2.80, 192.35, p=0.004) in multivariate analysis. Among 59 patients indwelling central venous catheters, only 24 patients (40.7%) received antifungal therapy with catheter removal while 19 patients (32.2%) had antifungal therapy without catheter removal. CONCLUSIONS: Clinical severity, such as mechanical ventilation or vasoactive agents dependencies, may contribute to high fatality in severely burned patients with candidemia.

Susceptibility of Clinical Isolates of Acinetobacter baumannii and Pseudomonas aeruginosa to Colistin and Polymyxin B in Korea / 감염과화학요법

BACKGROUND: The emergence of multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa has become a major problem. The use of nontraditional agents such as colistin and polymyxin B have been tried. The purpose of this study was to evaluate the colistin and polymyxin B susceptibility of A. baumannii and P. aeruginosa isolates in Korea. MATERIALS AND METHODS: According to susceptibility of ceftazidime and imipenem, selected 93 isolates of A. baumannii and 99 isolates of P. aeruginosa were collected from 5 university hospitals in Korea. Susceptibility to colistin and polymyxin B was tested using the reference broth microdilution method. RESULTS: The rates of other beta-lactams, aminoglycosides, and ciprofloxacin susceptibility were high (58-100%, 50-100%, and 75-100%, respectively) in ceftazidime- and imipenem-susceptible isolates but were low (< or =31%, < or =47%, and < or =18%, respectively) in ceftazidime- or imipenem-resistant isolates (P<0.05). Colistin and polymyxin B displayed a nearly identical spectrum of activity, exhibiting excellent potency against A. baumannii (MIC50/90, 1/2 microgram/mL) and P. aeruginosa (MIC50/90, 1/1 microgram/mL). Only one of the A. baumannii isolates was resistant to colistin (MIC, 4 microgram/mL), but the isolate was susceptible to polymyxin B (MIC, 2 microgram/mL). CONCLUSION: In Korea, no A. baumannii and P. aeruginosa isolates were resistant to both colistin and polymyxin B. These data suggested that polymyxins may be alternative drugs for multidrug-resistant A. baumannii and P. aeruginosa isolates.

Susceptibility of Clinical Isolates of Acinetobacter baumannii and Pseudomonas aeruginosa to Colistin and Polymyxin B in Korea / 감염과화학요법

BACKGROUND: The emergence of multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa has become a major problem. The use of nontraditional agents such as colistin and polymyxin B have been tried. The purpose of this study was to evaluate the colistin and polymyxin B susceptibility of A. baumannii and P. aeruginosa isolates in Korea. MATERIALS AND METHODS: According to susceptibility of ceftazidime and imipenem, selected 93 isolates of A. baumannii and 99 isolates of P. aeruginosa were collected from 5 university hospitals in Korea. Susceptibility to colistin and polymyxin B was tested using the reference broth microdilution method. RESULTS: The rates of other beta-lactams, aminoglycosides, and ciprofloxacin susceptibility were high (58-100%, 50-100%, and 75-100%, respectively) in ceftazidime- and imipenem-susceptible isolates but were low (< or =31%, < or =47%, and < or =18%, respectively) in ceftazidime- or imipenem-resistant isolates (P<0.05). Colistin and polymyxin B displayed a nearly identical spectrum of activity, exhibiting excellent potency against A. baumannii (MIC50/90, 1/2 microgram/mL) and P. aeruginosa (MIC50/90, 1/1 microgram/mL). Only one of the A. baumannii isolates was resistant to colistin (MIC, 4 microgram/mL), but the isolate was susceptible to polymyxin B (MIC, 2 microgram/mL). CONCLUSION: In Korea, no A. baumannii and P. aeruginosa isolates were resistant to both colistin and polymyxin B. These data suggested that polymyxins may be alternative drugs for multidrug-resistant A. baumannii and P. aeruginosa isolates.

Atypical Pathogens as Etiologic Agents in Hospitalized Patients with Community-Acquired Pneumonia in Korea: A Prospective Multi-Center Study

Local epidemiologic data on the etiologies of patients hospitalized with community-acquired pneumonia (CAP) is needed to develop guidelines for clinical practice. This study was conducted prospectively to determine the proportion of atypical bacterial pathogens in adults patients hospitalized with CAP in Korea between October 2001 and December 2002. Microbiological diagnosis was determined by serology for antibodies to Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneu-mophila. Nucleic acid of M. pneumoniae and C. pneumoniae in respiratory samples and Legionella antigen in urine samples were detected. The study population consisted of 126 patients (71 males, 55 females), averaging 54.6 yr (SD+/-17.8), whose paired sera were available. An etiologic diagnosis for atypical pathogens was made in 18 patients (14.3%): C. pneumoniae 9 (7.1%), M. pneumoniae 8 (6.3%), and L. pneumophila 3 patients (2.4%). Streptococcus preumoniae and other typical pathogens were isolated from 36 patients (28.6%). Of 126 patients, 16 (12.7%) were admitted to intensive care unit and atypical pathogens were identified in 5 patients (31.3%). Initial clinical features of patients with pneumonia due to atypical, typical or undetermined pathogens were indistinguishable. We conclude that atypical pathogens should be seriously considered in hospitalized patients with CAP, when initiating empiric treatment in Korea.

Clinical Characteristics in Patients with Vancomycin-Resistant Enterococci Colonization or Infection during 5 years in a Private General Hospital / 대한구급학회지

BACKGROUND: Vancomycin-resistant enterococci (VRE) is increasing rapidly through the world and is now a major cause of nosocomial infection. The transmission dynamics and factors contributing their dissemination are complex. We conducted a study to investigate clinical characteristics in patients with VRE colonization or infection during recent 5 years. METHODS: 154 cases that had the VRE infection or colonization from January 1, 2000 to April, 2004, were reviewed. We analyzed the risk factors of VRE infection and colonization and also compared various parameters contributing their dissemination between burn and non-burn patients with VRE. RESULTS: Total 212 strains of VRE were isolated from 154 patients. Of 212 strains of VRE, Enterococcus faecium (178 strains, 83.9%) were most common and followed by E. casseliflavus (28 strains, 13.2%), E. faecalis (5 strains, 2.4%) and E. gallinaum (1 strains, 0.5%). The most common place of VRE isolation was in burn intensive care unit (ICU), 95 cases (61.7%); 27 cases (17.5%) in general wards; 17 cases (11.0%) in surgical ICU; 15 cases (9.7%) in medical ICU. Compared with patients with VRE colonization, patients with VRE infection had older age, higher APACHE II scores and high death rate significantly. Then, VRE colonization were more common in burn patients while VRE infection were more common in non-burn patients. CONCLUSIONS: The findings from this study suggest that VRE infection are not uncommon among hospitalized patients. More strict infection control, close surveillance and judicious use of antibiotics may be warranted to prevent infection and transmission of VRE.

A Case of Disseminated Coccidioidomycosis Involving Lung and Skin in Patient with Diabetes Mellitus and Iatrogenic Cushings Syndrome / 결핵및호흡기질환

Coccidioidomycosis is caused by a dimorphous fungus, Coccidioides, which consists of two species, C. immitis and C. posadasii. Although these organisms are genetically distinct and do not exchange DNA, they appear identical phenotypically and the disease or immune response to the organisms is also identical. Coccidioides grows as a mycelium in the soil and is mainly found in Southwestern United States, northwestern Mexico, and Argentina. An infection usually results from inhaling the spores of the fungus in an endemic area. Patients with a localized infection and no risk factors for complications often require only a periodic reassessment to demonstrate the resolution of the self-limited process. However, patients with extensive spread of infection or high risk of complications as a result of immunosuppression or other preexisting factors require a variety of treatment strategies such as antifungal therapy, surgical debridement, or both. Korea is not endemic area of a coccidioidomycosis. We report a case of disseminated coccidioidomycosis involving the lung and skin, which was detected incidentally after sunburn in a 69 year-old Korean male with diabetes mellitus and iatrogenic Cushings syndrome, with a review of the relevant literature.

Efficacy of Influenza Vaccination among Chronic Ill Patients: Retrospective Case Control Study / 감염과화학요법

BACKGROUND: Influenza is one of the preventable respiratory disease by annual vaccination. Elderly people and patients with chronic medical disease are the primary target for influenza vaccination according to ACIP (Advisory Committee on Immunization). This study was done to determine whether influenza vaccination affects hospitalization due to influenza like illness or it's related complications among chronic ill patients. MATERIALS AND METHODS: Retrospective, case-control study was conducted for 5 months (Nov. 1999-Mar. 2000). Physicians from two-university hospitals in Korea were instructed to collect clinical data, sera from subjects presenting with a flu-like illness or flu-related exacerbation in patients with chronic underlying diseases. We compared the vaccination history of case patients with control. Logistic regression analysis was used to calculate the odd ratio and efficacy of influenza vaccination. RESULTS: Hospitalization due to ILI (influenza like illness) or it's related complications were observed more frequently in patients with chronic lung disease (25.3%) and chronic cardiac disease (31.3%) compared to others. Influenza vaccination resulted in fewer hospitalization with ILI or ILI-related acute exacerbation of underlying disease in chronic ill patients (adjusted odd ratio, 0.328 [CI, 0.14 to 0.73]) during influenza seasons. CONCLUSION: For patients with chronic disease, influenza vaccination is associated with substantial health benefit including fewer hospitalization. Health care providers should take advantage of all opportunities to immunize these high-risk patients.

Factors Influencing Decision Regarding Influenza Vaccination: A Survey of Healthcare Workers in One Hospital / 감염과화학요법

BACKGROUND: In spite of yearly recalls, influenza immunization rate among healthcare workers (HCWs) remained low in Korea University Guro Hospital. This study was conducted to identify the causes of non-compliance against influenza immunization and to analyze the barrier factors for the immunization. MATERIALS & METHODS: Questionnaires were distributed in March of 2000 at Korea University Guro Hospital. We evaluated factors associated with acceptance of influenza vaccination and opinions regarding influenza prevention (knowledge about influenza vaccination efficacy, que to action in vaccinee, perceptible benefit, barrier to vaccination). RESULTS: 309 completed questionnaires from HCWs were returned. Mean age and mean duration of work in hospital were higher and longer among vaccinee than non-vaccinee. Even though the necessity of influenza vaccination among HCWs were accepted well in vaccinee compared to non- vaccinee, the accurate reasons for vaccination were not quite understood among HCWs regardless of compliance. Vaccine campaign (30.8%) and advise from doctors (24.7%) were important for the promotion of vaccination among vaccinee. However, major reason for non-compliance among nursing staff and was mis-confidence that their bodies' self defense mechanisms would ward off infection (33.5%) and 'too busy to get injection' for doctors (65%). CONCLUSION: We conclude that regular education about perceptible benefits and wrong concerns about influenza vaccination among HCW's and easy accessibility to vaccination were important determinants to improve the influenza vaccination. On-site availability of a vaccination-nurse also proved to be important.

Efficacy of Influenza Vaccination among Chronic Ill Patients: Retrospective Case Control Study / 감염과화학요법

BACKGROUND: Influenza is one of the preventable respiratory disease by annual vaccination. Elderly people and patients with chronic medical disease are the primary target for influenza vaccination according to ACIP (Advisory Committee on Immunization). This study was done to determine whether influenza vaccination affects hospitalization due to influenza like illness or it's related complications among chronic ill patients. MATERIALS AND METHODS: Retrospective, case-control study was conducted for 5 months (Nov. 1999-Mar. 2000). Physicians from two-university hospitals in Korea were instructed to collect clinical data, sera from subjects presenting with a flu-like illness or flu-related exacerbation in patients with chronic underlying diseases. We compared the vaccination history of case patients with control. Logistic regression analysis was used to calculate the odd ratio and efficacy of influenza vaccination. RESULTS: Hospitalization due to ILI (influenza like illness) or it's related complications were observed more frequently in patients with chronic lung disease (25.3%) and chronic cardiac disease (31.3%) compared to others. Influenza vaccination resulted in fewer hospitalization with ILI or ILI-related acute exacerbation of underlying disease in chronic ill patients (adjusted odd ratio, 0.328 [CI, 0.14 to 0.73]) during influenza seasons. CONCLUSION: For patients with chronic disease, influenza vaccination is associated with substantial health benefit including fewer hospitalization. Health care providers should take advantage of all opportunities to immunize these high-risk patients.

Factors Influencing Decision Regarding Influenza Vaccination: A Survey of Healthcare Workers in One Hospital / 감염과화학요법

BACKGROUND: In spite of yearly recalls, influenza immunization rate among healthcare workers (HCWs) remained low in Korea University Guro Hospital. This study was conducted to identify the causes of non-compliance against influenza immunization and to analyze the barrier factors for the immunization. MATERIALS & METHODS: Questionnaires were distributed in March of 2000 at Korea University Guro Hospital. We evaluated factors associated with acceptance of influenza vaccination and opinions regarding influenza prevention (knowledge about influenza vaccination efficacy, que to action in vaccinee, perceptible benefit, barrier to vaccination). RESULTS: 309 completed questionnaires from HCWs were returned. Mean age and mean duration of work in hospital were higher and longer among vaccinee than non-vaccinee. Even though the necessity of influenza vaccination among HCWs were accepted well in vaccinee compared to non- vaccinee, the accurate reasons for vaccination were not quite understood among HCWs regardless of compliance. Vaccine campaign (30.8%) and advise from doctors (24.7%) were important for the promotion of vaccination among vaccinee. However, major reason for non-compliance among nursing staff and was mis-confidence that their bodies' self defense mechanisms would ward off infection (33.5%) and 'too busy to get injection' for doctors (65%). CONCLUSION: We conclude that regular education about perceptible benefits and wrong concerns about influenza vaccination among HCW's and easy accessibility to vaccination were important determinants to improve the influenza vaccination. On-site availability of a vaccination-nurse also proved to be important.

Two Cases of Infective Endocarditis in Burn Patients Requiring Surgical Intervention / 감염과화학요법

No abstract available.

Two Cases of Infective Endocarditis in Burn Patients Requiring Surgical Intervention / 감염과화학요법

No abstract available.

Colonization Rate, Risk Factor for Acquisition and Genetic Diversity of Vancomycin-Resistant Enterococci (VRE) Isolated from Rectal Culture of Patients in Intensvie Care Units from Ten Large Hospitals in Korea / 감염

BACKGROUND: VRE have become an emerging nosocomial pathogen in Korea, but there has not been nationwide study on the colonization of VRE among high risk groups of hospitalized patients. The purpose of this study was to determine the prevalence of rectal colonization of VRE among patients hospitalized in the intensive care unit (ICU), to study the risk factors for nosocomial acquisition of VRE among those patients, to define the genetic diversity of VRE strains in major hospitals in Korea. METHODS: Between January the 20th and 30th of 2000, a point surveillance study was conducted in the ICU of the ten large hospitals, which were located nationwide. Surveillance rectal swab cultures for detecting VRE were obtained among 214 patients admitted to the ICU during the study period. To isolate VRE, rectal swab cultures were performed on Enterococcosel(R) agar that containing 6 microgram/mL of vancomycin. Minimal inhibitory concentrations (MICs) of vancomycin and teicoplanin were determined by agar dilution method. For the genotyping of VRE isolates, the detection of vanA, vanB, vanC1 and vanC2 gene by polymerase chain reaction was done. Pulsed-field gel electrophoreis (PFGE) was used for elucidating the genetic relatedness of VRE isolates. To identify the risk factors for rectal VRE colonization, patients harboring VRE were compared to patients who were not colonized with this organism. RESULTS: The rectal colonization rate of VRE was variable from 9.7% to 51.9% according to hospital. 64 VRE strains which were isolated from 63 patients included 37 E. feacium. 26 E. gallinarum and 1 E. casseliflavus isolates. Therefore the colonization rate of clinically significant vanA type VRE was 17.3% (37/ 214). 37 E. feacium. 26 E. gallinarum and 1 E. casseliflavus isolates were presented as vanA, vanC1 and vanC2 genotypes, respectively. Risk factors for rectal VRE colonization included the presence of chronic illness, previous use of broad spectrum antibioitcs es-pecillay vancomycin, and prolonged stay in ICU. Various PFGE patterns are noted among vanA type VRE isolates, so individual acquisition of VRE during stay in the majority of ICUs were suggested. But there is some evidence of focal VRE spread within the ICU and between hospitals. CONCLUSION: This study demonstrated the high rectal colonization rate (17.3%) of clinically significant vanA type VRE among patients admitted to the ICUs of ten large hospitals located nation-widely. This study suggested that practicing HICPAC guidelines, restricted vancomycin usage and periodic surveillance cultures in patients with high risk factors are important in preventing the emergence and spread of VRE infection among ICU patients.

Infection Control Activity in Hallym University Medical Center / 병원감염관리

No Abstract available.

A case mycoplasma pneumoniae pneumonia with acute respiratory distress syndrome (ARDS) / 대한내과학회지

Pneumonia caused by Mycoplasma pneumoniae is manifested as a mild and self-limited. However, several overwhelming cases have been reported. Recently, we experienced a case of M. pneumoniae pneumonia that progressed into ARDS in a 68-year old man who was admitted because of fever and erythema multiforme on whole body. On admission, serum cold agglutinins and anti-mycoplasma Ab were negative. Lobar consolidation was visible at initial chest X-ray. But, bilateral infiltration was noted at follow-up chest X-ray and his condition was aggravated to ARDS. Anti-mycoplasma Ab was elevated up to 1:640. He was treated with roxithromycin, prednisolone and mechanical ventilator in ICU for 2 weeks. And after this, his clinical condition was recovered completely.

Epidemiologic study of nosocomial candidiasis by restriction fragment analysis (RFA) and southern hybridization / 대한내과학회지

BACKGROUND: Candida species are not only the leading cause of nosocomial fungal infections but also the important cause of infections in the immunocompromised hosts. Epidemiologic study of nosocomial candidiasis has been difficult because of the lack of a reliable typing system. We performed molecular epidemiologic study by using RFA and Southem hybridization for typing of candida isolates from patiients. METHODS: A total of 27 candida isolates from 19 immunocompromised patients were studied. Morphotyping and biotyping were done by germ tube test and API 20C system, respectively. Candidial chromosomal DNA was extracted, digested with EcoRI, HindalII and RFA was done. Southem hybridization of chromosomal DNA was also done with digoxigen-labelled Candial albicans-specific DNA probe. RESULTS: The time-period of development of oral candidiasis after admission was 5-14 days (mean: 8 days). C.albicans was the most common species (19), followed by C tropiadis (2), C glabn#zta (2), C.paratropicalis (2), and C parapsilosis (1). The subtypes of Candida species by RFA of chromosomal DNA were C. albieans, 12 types , C tropicalis, 2 types, C glabrata, 2 types ; C.parapsilasis, 1 type ; C. paratropicalis, 1 type. For 7 (87.5%) of 8 patients, RFA pattern of one isolate was identical to that of the other isolates. CONCLUSION: RFA of candidial chromosomal DNA results were obtainable within days. RFA showed high reproducibility, typeability and good discrimination power between isolates, provided a robust system that may be used rapidly to identify outbreaks of nosocomial candidiasis.

Diagnosis of acute Hantaan virus infection by IgG avidity assay / 대한내과학회지

OBJECTIVE: The golden standard of serodiagnosis of HFRS is IFA(indirect immunofluorescence antibody test). However, positive IFA for IgG antibody does not always correlate with current infection because IFA may be positive due to past exposure to Hantaan virus such as subclincal infection or due to vaccination in endemic area. So supplementary diagnostic method is needed to diagnosis of HFRS with more accuracy. METHODS: In this study, the usefulness of IgG avidity assay with 8 mole/l urea in diagnosis of HFRS was investigated. Serum samples from 45 patients with acute phase HFRS and 79 residents of endemic area, who had HFRS antibody were tested for IgG avidity. RESULTS: The distribution of IgG avidity index of HFRS antibody was different acute phase of HFRS patients from endemic area residents(p<0.001). Patients with acute phase HFRS exhibited lower avidity of Hantaan virus-specific IgG (mode of 64 of avidity index), in contrast endemic area resident had a higher avidity (mode of 4 of avidity index). CONCLUSION: The IgG avidity assay should assist in the diagnosis of acute phase HFRS and may be used to identify recent infection and past exposure to Hantaan virus.