Severe acute respiratory infection risk following glucocorticosteroid treatment in uncomplicated influenza-like illness resulting from pH1N1 influenza infection: a case control study.

BACKGROUND: Current studies regarding glucocorticosteroid treatment of influenza have only estimated risk of critical illness or death which can be easily confounded by timing of treatment administration. We used severe acute respiratory infection (sARI) as an endpoint and investigated risk associated with receiving glucocorticosteroids before sARI onset. METHODS: sARI cases were defined as influenza-like illness (ILI) with pH1N1 infection and respiratory distress. Controls were defined as pH1N1 cases other than sARI and randomly selected from the community. We compared glucocorticosteroids and other medications used before sARI onset using a matched case control study adjusted for age group as well as underlying disease. Time-dependent risk and dose responses at different time periods over the course of sARI cases were also examined. RESULTS: Of the sARI cases, 34% received glucocorticosteroids before sARI onset compared to 3.8% of controls during equivalent days (ORM-H = 17,95%CI = 2.1-135). Receiving glucocorticosteroids before sARI onset increased risk of developing subsequent critical illness or death (ORM-H = 5.7,95%CI = 1.6-20.2), and the ORM-H increased from 5.7 to 8.5 for continued glucocorticosteroid use after sARI onset. However, only receiving glucocorticosteroids after sARI onset did not increase risk of severe illness (ORM-H = 1.1,95%CI = 0.3-4.6). Each increase in glucocorticosteroids dose of 1 mg/kg/day before sARI onset resulted in an increase of 0.62 (R2 = 0.87) in the pMEWS score at the time of sARI onset. CONCLUSIONS: Early glucocorticosteroid treatment increased risk of sARI and subsequent critical illness or death; however, only receiving glucocorticosteroids after sARI onset did not increase risk of severe illness.

Epidemiology of avian influenza A H7N9 virus in human beings across five epidemics in mainland China, 2013-17: an epidemiological study of laboratory-confirmed case series.

BACKGROUND: The avian influenza A H7N9 virus has caused infections in human beings in China since 2013. A large epidemic in 2016-17 prompted concerns that the epidemiology of the virus might have changed, increasing the threat of a pandemic. We aimed to describe the epidemiological characteristics, clinical severity, and time-to-event distributions of patients infected with A H7N9 in the 2016-17 epidemic compared with previous epidemics. METHODS: In this epidemiological study, we obtained information about all laboratory-confirmed human cases of A H7N9 virus infection reported in mainland China as of Feb 23, 2017, from an integrated electronic database managed by the China Center for Disease Control and Prevention (CDC) and provincial CDCs. Every identified human case of A H7N9 virus infection was required to be reported to China CDC within 24 h via a national surveillance system for notifiable infectious diseases. We described the epidemiological characteristics across epidemics, and estimated the risk of death, mechanical ventilation, and admission to the intensive care unit for patients admitted to hospital for routine clinical practice rather than for isolation purpose. We estimated the incubation periods, and time delays from illness onset to hospital admission, illness onset to initiation of antiviral treatment, and hospital admission to death or discharge using survival analysis techniques. FINDINGS: Between Feb 19, 2013, and Feb 23, 2017, 1220 laboratory-confirmed human infections with A H7N9 virus were reported in mainland China, with 134 cases reported in the spring of 2013, 306 in 2013-14, 219 in 2014-15, 114 in 2015-16, and 447 in 2016-17. The 2016-17 A H7N9 epidemic began earlier, spread to more districts and counties in affected provinces, and had more confirmed cases than previous epidemics. The proportion of cases in middle-aged adults increased steadily from 41% (55 of 134) to 57% (254 of 447) from the first epidemic to the 2016-17 epidemic. Proportions of cases in semi-urban and rural residents in the 2015-16 and 2016-17 epidemics (63% [72 of 114] and 61% [274 of 447], respectively) were higher than those in the first three epidemics (39% [52 of 134], 55% [169 of 306], and 56% [122 of 219], respectively). The clinical severity of individuals admitted to hospital in the 2016-17 epidemic was similar to that in the previous epidemics. INTERPRETATION: Age distribution and case sources have changed gradually across epidemics since 2013, while clinical severity has not changed substantially. Continued vigilance and sustained intensive control efforts are needed to minimise the risk of human infection with A H7N9 virus. FUNDING: The National Science Fund for Distinguished Young Scholars.

Preliminary Epidemiology of Human Infections with Highly Pathogenic Avian Influenza A(H7N9) Virus, China, 2017.

We compared the characteristics of cases of highly pathogenic avian influenza (HPAI) and low pathogenic avian influenza (LPAI) A(H7N9) virus infections in China. HPAI A(H7N9) case-patients were more likely to have had exposure to sick and dead poultry in rural areas and were hospitalized earlier than were LPAI A(H7N9) case-patients.

Detection and Genetic Characteristics of H9N2 Avian Influenza Viruses from Live Poultry Markets in Hunan Province, China.

H9N2 avian influenza viruses (AIVs) are highly prevalent and of low pathogenicity in domestic poultry. These viruses show a high genetic compatibility with other subtypes of AIVs and have been involved in the genesis of H5N1, H7N9 and H10N8 viruses causing severe infection in humans. The first case of human infection with H9N2 viruses in Hunan province of China have been confirmed in November 2013 and identified that H9N2 viruses from live poultry markets (LPMs) near the patient's house could be the source of infection. However, the prevalence, distribution and genetic characteristics of H9N2 viruses in LPMs all over the province are not clear. We collected and tested 3943 environmental samples from 380 LPMs covering all 122 counties/districts of Hunan province from February to April, 2014. A total of 618 (15.7%) samples were H9 subtype positive and 200 (52.6%) markets in 98 (80.3%) counties/districts were contaminated with H9 subtype AIVs. We sequenced the entire coding sequences of the genomes of eleven H9N2 isolates from environmental samples. Phylogenetic analysis showed that the gene sequences of the H9N2 AIVs exhibited high homology (94.3%-100%). All eleven viruses were in a same branch in the phylogenetic trees and belonged to a same genotype. No gene reassortment had been found. Molecular analysis demonstrated that all the viruses had typical molecular characteristics of contemporary avian H9N2 influenza viruses. Continued surveillance of AIVs in LPMs is warranted for identification of further viral evolution and novel reassortants with pandemic potential.

[Clinical characteristics of adult influenza inpatients in ten provinces in China and analysis of severe risk factors].

OBJECTIVE: To identity the clinical characteristics and severe case risk factors for the adult inpatient cases confirmed of influenza monitored by the sentinel surveillance system for severe acute respiratory infection (SARI) inpatient cases in ten provinces in China. METHODS: Epidemiology and clinical information surveys were conducted for adult cases (≥ 15 year old) consistent with SARI case definition, who were monitored by SARI sentinel hospitals in ten cities in China from December 2009 to June 2014, with their respiratory tract specimens collected for influenza RNA detection. Adult SARI cases were classified into influenza inpatient group and outpatient group by the detection outcomes, analyzing their demographic information, clinical and epidemiology characteristics respectively, in addition to risk factors for severe inpatient cases. RESULTS: 3 071 adult SARI cases were recruited from ten hospitals, including 240 (7.8%) cases of laboratory-confirmed influenza, most of them being A (H1N1) pdm2009 and A (H3N2) sub-types. Age M of the included influenza cases was 63 year old, 47.1% of them being ≥ 65 seniors. 144 (60.0%) cases of the influenza inpatients suffered from at least one chronic underlying condition, and the proportion of emphysema (7.9%) was higher than non-influenza inpatient cases (3.8%), being statistically significant (χ(2) = 3.963, P = 0.047). 19.4% of the women of childbearing age infected of influenza were in pregnancy, and only 1.1% of the 240 influenza cases had been vaccinated against influenza. The proportion of sore throat and dyspnea found among influenza inpatients was higher than inpatients without influenza. 17.4% of the influenza cases were accepted into ICU for treatment, with no statistical significance with non-influenza inpatient cases (P = 0.160). 23.1% of the influenza inpatients received an antiviral drug therapy, a figure higher than the non-influenza inpatient cases (4.8%) (P < 0.001). 41.5% of the inpatients developed complications, with the proportion of viral pneumonia significantly higher than the non-influenza inpatient cases (P < 0.001). Asthma (RR = 15.200, 95% CI: 1.157-199.633), immunosuppressive diseases (RR = 5.250, 95% CI: 1.255-21.960), pregnancy (RR = 21.000, 95% CI: 1.734-254.275), time interval from onset to admission less 7 days (RR = 1.673, 95% CI: 1.071-2.614) were identified as risk factors of severely-ill influenza cases. CONCLUSION: It was found that adult influenza inpatients were mostly ≥ 65 year old seniors. The influenza vaccination rate among the influenza cases was very low, and antivirus drugs were used less than necessary. In this regard, influenza vaccination was recommended for high risk groups of pregnant women, seniors and chronic disease patients on annual basis, while influenza inpatients were advised to use antiviral drugs as early as possible.

[Analysis of genetic features of influenza B virus in Hunan province from 2007 to 2010].

OBJECTIVE: To investigate the gene variations of influenza B virus isolated in Hunan province from 2007 to 2010. METHODS: A total of 42 strains of influenza B virus,which were isolated in the Influenza Surveillance Network Laboratories in Hunan province between year 2007 and 2010, were selected for the study. The hemagglutinin 1 (HA1) and neuraminidase (NA) genes of the selected strains were amplified by RT-PCR, and the sequence of the purified product were detected and homologically compared with the sequence of influenza vaccine strains isolated from Northern Hemisphere by WHO during the same period. In addition, the phylogenetic trees were constructed to characterize the molecular features. RESULTS: In the Victoria branch of the HA1 gene phylogenetic tree, the strains isolated from year 2007 to 2009 were included in the V1 sub-branch, as well as the vaccine strain Malaysia/2506/2004; the strains isolated in year 2010 were involved in the V2 sub-branch, similar to the vaccine strains Brisbane/60/2008. In the Yamagata branch,the strains isolated in year 2007 were in the Y1 sub-branch,different from the strains isolated between year 2008 and 2010, which were in the Y2 sub-branch, instead. All virus in NA gene phylogenetic tree were included in the Yamagata branch, indicated their Yamagata origin. The genetic sequence analysis of the 7 strains isolated in year 2010 revealed that the viruses were classified as genotype 2 and genotype 15. The results of homological comparison between HA1 molecule and the influenza vaccine strains recommended by WHO were as below: Victoria lineage, 98.6% - 99.1% in 2007, 98.6% - 99.1% in 2008, 98.1% - 99.1% in 2009, and 97.6% - 99.1% in 2010; and Yamagata lineage, 97.9% - 98.5% in 2007, 97.9% - 98.5% in 2009 and 97.9% - 98.2% in 2010. The major mutations of the strains isolated in year 2007 were found in sites R48K, K88R, P108A, D197N and S230G. While the major mutations of the strains isolated between year 2009 and 2010 were sited in K88R, S150I, N166Y, D197N and S230G. CONCLUSION: The prevalent influenza B virus isolated in Hunan province from 2007 to 2010 has mutated and evolved continuously.

[Serological survey of pandemic influenza A (H1N1) virus infection among population in Hunan Province].

OBJECTIVE: To understand the infection condition and analytical methods of Influenza A (H1N1) virus in the population of Hunan Province during different periods. METHODS: Quick surveys on the positive rate of Influenza A (H1N1) virus hemagglutination inhibition (HI) test have been conducted for 5 times successively from November 2009 to March 2010 in 14 medical and health institutions of Changsha city, whose results were then compared with those from the sampling surveys of whole Hunan province. RESULTS: 2131 subjects were involved in this study; the total population standardized rates of antibody positive investigated for 5 times were 9.32% , 14.62%, 31.08%, 28.43% and 22.80% respectively; the population of 6-17-years-old has the highest rate of antibody positive; only 9.84% of the antibody positive subjects attributed to vaccine inoculation; there was no significant difference in the standardized positive rates between the quick serological surveys and the corresponding sampling survey of Hunan province (P > 0.05). CONCLUSION: The positive rate of A (H1N1) virus antibody reached the peak in late January 2010; quick investigations in small region could be used to evaluate the infection prevalence during pandemic of infectious diseases.