Fiona Havers

Outbreak of Variant Influenza A(H3N2) Virus in the United States

During an outbreak of H3N2v variant influenza, we identified 306 cases in ten states. Most cases reported agricultural fair attendance and/or contact with swine prior to illness. We found no evidence of efficient or sustained person-to-person transmission of H3N2v.

Monitoring Avian Influenza A(H7N9) Virus through National Influenza- like Illness Surveillance, China

In China during March 4–April 28, 2013, avian influenza A(H7N9) virus testing was performed on 20,739 specimens from patients with influenza-like illness in 10 provinces with confirmed human cases: 6 (0.03%) were positive, and increased numbers of unsubtypeable influenza-positive specimens were not seen. Careful monitoring and rapid characterization of influenza A(H7N9) and other influenza viruses remain critical.

Risk Factors for Influenza A(H7N9) Disease—China, 2013

BACKGROUND The majority of human cases of novel avian influenza A(H7N9), which emerged in China in spring 2013, include reported exposure to poultry. However, specific host and exposure risk factors for disease are unknown, yet critical to design prevention measures. METHODS In April-June 2013, we conducted a case-control study in 8 Chinese provinces. Patients with laboratory-confirmed A(H7N9) (n = 89) were matched by age, sex, and neighborhood to controls (n = 339). Subjects completed a questionnaire on medical history and potential exposures, including poultry markets and other poultry exposure. We used conditional logistic regression to calculate matched and adjusted odds ratios (ORs) for the association of A(H7N9) virus infection with potential risk factors. RESULTS Fifty-five percent of patients compared with 31% of controls reported any contact with poultry (matched OR [mOR], 7.8; 95% confidence interval [CI], 3.3-18.8). Sixty-seven percent of patients compared with 35% of controls visited a live poultry market (mOR, 5.4; CI, 3.0-9.7). Visiting live poultry markets increased risk of infection even after adjusting for poultry contact and other confounders (adjusted OR, 3.4; CI, 1.8-6.7). Backyard poultry were not associated with increased risk; 14% of cases did not report any poultry exposure or market visit. Obesity (mOR, 4.7; CI, 1.8-12.4), chronic obstructive pulmonary disease (mOR, 2.7; CI, 1.1-6.9), and immunosuppressive medications (mOR, 9.0; CI, 1.7-47.2) were associated with A(H7N9) disease. CONCLUSION Exposures to poultry in markets were associated with A(H7N9) virus infection, even without poultry contact. China should consider permanently closing live poultry markets or aggressively pursuing control measures to prevent spread of this emerging pathogen.

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.

Use of National Pneumonia Surveillance to Describe Influenza A(H7N9) Virus Epidemiology, China, 2004–2013

In mainland China, most avian influenza A(H7N9) cases in the spring of 2013 were reported through the pneumonia of unknown etiology (PUE) surveillance system. To understand the role of possible underreporting and surveillance bias in assessing the epidemiology of subtype H7N9 cases and the effect of live-poultry market closures, we examined all PUE cases reported from 2004 through May 3, 2013. Historically, the PUE system was underused, reporting was inconsistent, and PUE reporting was biased toward A(H7N9)-affected provinces, with sparse data from unaffected provinces; however, we found no evidence that the older ages of persons with A(H7N9) resulted from surveillance bias. The absolute number and the proportion of PUE cases confirmed to be A(H7N9) declined after live-poultry market closures (p<0.001), indicating that market closures might have positively affected outbreak control. In China, PUE surveillance needs to be improved.

Human Influenza A(H7N9) Virus Infection Associated with Poultry Farm, Northeastern China

We report on a case of human infection with influenza A(H7N9) virus in Jilin Province in northeastern China. This case was associated with a poultry farm rather than a live bird market, which may point to a new focus for public health surveillance and interventions in this evolving outbreak.

Use of Influenza Antiviral Medications Among Outpatients at High Risk for Influenza-Associated Complications During the 2013–2014 Influenza Season

During the 2013-2014 influenza season, we analyzed data from 6004 outpatients aged ≥6 months with acute respiratory illness (ARI). Among the 2786 ARI patients at higher risk for influenza complications, 835 (30%) presented to care ≤2 days from symptom onset; among those, 126 (15%) were prescribed an antiviral medication.

Statin Use and Hospital Length of Stay Among Adults Hospitalized With Community-acquired Pneumonia

BACKGROUND Prior retrospective studies suggest that statins may benefit patients with community-acquired pneumonia (CAP) due to antiinflammatory and immunomodulatory effects. However, prospective studies of the impact of statins on CAP outcomes are needed. We determined whether statin use was associated with improved outcomes in adults hospitalized with CAP. METHODS Adults aged ≥18 years hospitalized with CAP were prospectively enrolled at 3 hospitals in Chicago, Illinois, and 2 hospitals in Nashville, Tennessee, from January 2010-June 2012. Adults receiving statins before and throughout hospitalization (statin users) were compared with those who did not receive statins (nonusers). Proportional subdistribution hazards models were used to examine the association between statin use and hospital length of stay (LOS). In-hospital mortality was a secondary outcome. We also compared groups matched on propensity score. RESULTS Of 2016 adults enrolled, 483 (24%) were statin users; 1533 (76%) were nonusers. Statin users were significantly older, had more comorbidities, had more years of education, and were more likely to have health insurance than nonusers. Multivariable regression demonstrated that statin users and nonusers had similar LOS (adjusted hazard ratio [HR], 0.99; 95% confidence interval [CI], .88-1.12), as did those in the propensity-matched groups (HR, 1.03; 95% CI, .88-1.21). No significant associations were found between statin use and LOS or in-hospital mortality, even when stratified by pneumonia severity. CONCLUSIONS In a large prospective study of adults hospitalized with CAP, we found no evidence to suggest that statin use before and during hospitalization improved LOS or in-hospital mortality.

Risk Factors for Influenza A(H7N9) Disease in China, a Matched Case Control Study, October 2014 to April 2015

Background. Human infections with avian influenza A(H7N9) virus have been associated with exposure to poultry and live poultry markets (LPMs). We conducted a case-control study to identify additional and more specific risk factors. Methods. Cases were laboratory-confirmed A(H7N9) infections in persons in China reported from October 1, 2014 to April 30, 2015. Poultry workers, those with insufficient data, and those refusing participation were excluded. We matched up to 4 controls per case by sex, age, and residential community. Using conditional logistic regression, we examined associations between A(H7N9) infection and potential risk factors. Results. Eighty-five cases and 334 controls were enrolled with similar demographic characteristics. Increased risk of A(H7N9) infection was associated with the following: visiting LPMs (adjusted odds ratio [aOR], 6.3; 95% confidence interval [CI], 2.6–15.3), direct contact with live poultry in LPMs (aOR, 4.1; 95% CI, 1.1–15.6), stopping at a live poultry stall when visiting LPMs (aOR, 2.7; 95% CI, 1.1–6.9), raising backyard poultry at home (aOR, 7.7; 95% CI, 2.0–30.5), direct contact with backyard poultry (aOR, 4.9; 95% CI, 1.1–22.1), and having ≥1 chronic disease (aOR, 3.1; 95% CI, 1.5–6.5). Conclusions. Our study identified raising backyard poultry at home as a risk factor for illness with A(H7N9), suggesting the need for enhanced avian influenza surveillance in rural areas.

Detecting Spread of Avian Influenza A(H7N9) Virus Beyond China

This virus is unlikely to have spread substantially among humans in Vietnam, Thailand, Cambodia, and Laos.