Burden of Influenza-Associated Respiratory Hospitalizations, Vietnam, 2014-2016.

Influenza burden estimates are essential to informing prevention and control policies. To complement recent influenza vaccine production capacity in Vietnam, we used acute respiratory infection (ARI) hospitalization data, severe acute respiratory infection (SARI) surveillance data, and provincial population data from 4 provinces representing Vietnam's major regions during 2014-2016 to calculate provincial and national influenza-associated ARI and SARI hospitalization rates. We determined the proportion of ARI admissions meeting the World Health Organization SARI case definition through medical record review. The mean influenza-associated hospitalization rates per 100,000 population were 218 (95% uncertainty interval [UI] 197-238) for ARI and 134 (95% UI 119-149) for SARI. Influenza-associated SARI hospitalization rates per 100,000 population were highest among children <5 years of age (1,123; 95% UI 946-1,301) and adults >65 years of age (207; 95% UI 186-227), underscoring the need for prevention and control measures, such as vaccination, in these at-risk populations.

Costs and consequences: Hepatitis C seroprevalence in the military and its impact on potential screening strategies.

UNLABELLED: Knowledge of the contemporary epidemiology of hepatitis C viral (HCV) infection among military personnel can inform potential Department of Defense screening policy. HCV infection status at the time of accession and following deployment was determined by evaluating reposed serum from 10,000 service members recently deployed to combat operations in Iraq and Afghanistan in the period 2007-2010. A cost model was developed from the perspective of the Department of Defense for a military applicant screening program. Return on investment was based on comparison between screening program costs and potential treatment costs avoided. The prevalence of HCV antibody-positive and chronic HCV infection at accession among younger recently deployed military personnel born after 1965 was 0.98/1000 (95% confidence interval 0.45-1.85) and 0.43/1000 (95% confidence interval 0.12-1.11), respectively. Among these, service-related incidence was low; 64% of infections were present at the time of accession. With no screening, the cost to the Department of Defense of treating the estimated 93 cases of chronic HCV cases from a single year's accession cohort was $9.3 million. Screening with the HCV antibody test followed by the nucleic acid test for confirmation yielded a net annual savings and a $3.1 million dollar advantage over not screening. CONCLUSIONS: Applicant screening will reduce chronic HCV infection in the force, result in a small system costs savings, and decrease the threat of transfusion-transmitted HCV infection in the battlefield blood supply and may lead to earlier diagnosis and linkage to care; initiation of an applicant screening program will require ongoing evaluation that considers changes in the treatment cost and practice landscape, screening options, and the epidemiology of HCV in the applicant/accession and overall force populations.

Reported Global Avian Influenza Detections Among Humans and Animals During 2013-2022: Comprehensive Review and Analysis of Available Surveillance Data.

BACKGROUND: Avian influenza (AI) virus detections occurred frequently in 2022 and continue to pose a health, economic, and food security risk. The most recent global analysis of official reports of animal outbreaks and human infections with all reportable AI viruses was published almost a decade ago. Increased or renewed reports of AI viruses, especially high pathogenicity H5N8 and H5N1 in birds and H5N1, H5N8, and H5N6 in humans globally, have established the need for a comprehensive review of current global AI virus surveillance data to assess the pandemic risk of AI viruses. OBJECTIVE: This study aims to provide an analysis of global AI animal outbreak and human case surveillance information from the last decade by describing the circulating virus subtypes, regions and temporal trends in reporting, and country characteristics associated with AI virus outbreak reporting in animals; surveillance and reporting gaps for animals and humans are identified. METHODS: We analyzed AI virus infection reports among animals and humans submitted to animal and public health authorities from January 2013 to June 2022 and compared them with reports from January 2005 to December 2012. A multivariable regression analysis was used to evaluate associations between variables of interest and reported AI virus animal outbreaks. RESULTS: From 2013 to 2022, 52.2% (95/182) of World Organisation for Animal Health (WOAH) Member Countries identified 34 AI virus subtypes during 21,249 outbreaks. The most frequently reported subtypes were high pathogenicity AI H5N1 (10,079/21,249, 47.43%) and H5N8 (6722/21,249, 31.63%). A total of 10 high pathogenicity AI and 6 low pathogenicity AI virus subtypes were reported to the WOAH for the first time during 2013-2022. AI outbreaks in animals occurred in 26 more Member Countries than reported in the previous 8 years. Decreasing World Bank income classification was significantly associated with decreases in reported AI outbreaks (P<.001-.02). Between January 2013 and June 2022, 17/194 (8.8%) World Health Organization (WHO) Member States reported 2000 human AI virus infections of 10 virus subtypes. H7N9 (1568/2000, 78.40%) and H5N1 (254/2000, 12.70%) viruses accounted for the most human infections. As many as 8 of these 17 Member States did not report a human case prior to 2013. Of 1953 human cases with available information, 74.81% (n=1461) had a known animal exposure before onset of illness. The median time from illness onset to the notification posted on the WHO event information site was 15 days (IQR 9-30 days; mean 24 days). Seasonality patterns of animal outbreaks and human infections with AI viruses were very similar, occurred year-round, and peaked during November through May. CONCLUSIONS: Our analysis suggests that AI outbreaks are more frequently reported and geographically widespread than in the past. Global surveillance gaps include inconsistent reporting from all regions and human infection reporting delays. Continued monitoring for AI virus outbreaks in animals and human infections with AI viruses is crucial for pandemic preparedness.

Avian influenza A(H5) virus circulation in live bird markets in Vietnam, 2017-2022.

BACKGROUND: Highly pathogenic avian influenza A(H5) human infections are a global concern, with many A(H5) human cases detected in Vietnam, including a case in October 2022. Using avian influenza virus surveillance from March 2017-September 2022, we described the percent of pooled samples that were positive for avian influenza A, A(H5), A(H5N1), A(H5N6), and A(H5N8) viruses in live bird markets (LBMs) in Vietnam. METHODS: Monthly at each LBM, 30 poultry oropharyngeal swab specimens and five environmental samples were collected. Samples were pooled in groups of five and tested for influenza A, A(H5), A(H5N1), A(H5N6), and A(H5N8) viruses by real-time reverse-transcription polymerase chain reaction. Trends in the percent of pooled samples that were positive for avian influenza were summarized by LBM characteristics and time and compared with the number of passively detected avian influenza outbreaks using Spearman's rank correlation. RESULTS: A total of 25,774 pooled samples were collected through active surveillance at 167 LBMs in 24 provinces; 36.9% of pooled samples were positive for influenza A, 3.6% A(H5), 1.9% A(H5N1), 1.1% A(H5N6), and 0.2% A(H5N8). Influenza A(H5) viruses were identified January-December and at least once in 91.7% of sampled provinces. In 246 A(H5) outbreaks in poultry; 20.3% were influenza A(H5N1), 60.2% A(H5N6), and 19.5% A(H5N8); outbreaks did not correlate with active surveillance. CONCLUSIONS: In Vietnam, influenza A(H5) viruses were detected by active surveillance in LBMs year-round and in most provinces sampled. In addition to outbreak reporting, active surveillance for A(H5) viruses in settings with high potential for animal-to-human spillover can provide situational awareness.

Review of non-battle injuries in Air Force personnel deployed in support of Operation Enduring Freedom and Operation Iraqi Freedom.

This study examines non-battle injuries among U.S. Air Force members deployed during Operations Iraqi and Enduring Freedom. A cohort of 275,843 Active Duty, Guard, and Reserve members were identified for the period September 11, 2001 through October 31, 2006. Data on injuries were obtained from electronic medical records and deployment time was obtained from manpower records. Poisson regression was used to estimate adjusted incidence rate ratios (IRRs). The most common non-battle injuries were sprains and strains (53%) followed by open wounds (27%). Guard and Reserve members tended to have a lower rate of orthopedic non-battle injuries than Active Duty members in crude analyses and after adjustment for age, previous deployment, sex, race/ethnicity, and occupation (IRR = 0.95; 95% CI = 0.89-1.02 and IRR = 0.85; 95% CI = 0.77-0.93). Results from this study are intended to facilitate further research of potential differences between Air Force components to reduce non-battle injuries in a deployed environment.

Environmental sampling for SARS-CoV-2 at a reference laboratory and provincial hospital in central Viet Nam, 2020.

OBJECTIVE: To determine whether environmental surface contamination with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurred at a provincial hospital in Viet Nam that admitted patients with novel coronavirus disease 2019 (COVID-19) and at the regional reference laboratory responsible for confirmatory testing for SARS-CoV-2 in 2020. METHODS: Environmental samples were collected from patient and staff areas at the hospital and various operational and staff areas at the laboratory. Specimens from frequently touched surfaces in all rooms were collected using a moistened swab rubbed over a 25 cm2 area for each surface. The swabs were immediately transported to the laboratory for testing by real-time reverse transcription polymerase chain reaction (RT-PCR). Throat specimens were collected from staff at both locations and were also tested for SARS-CoV-2 using real-time RT-PCR. RESULTS: During the sampling period, the laboratory tested 6607 respiratory specimens for SARS-CoV-2 from patients within the region, and the hospital admitted 9 COVID-19 cases. Regular cleaning was conducted at both sites in accordance with infection prevention and control (IPC) practices. All 750 environmental samples (300 laboratory and 450 hospital) and 30 staff specimens were negative for SARS-CoV-2. DISCUSSION: IPC measures at the facilities may have contributed to the negative results from the environmental samples. Other possible explanations include sampling late in a patient's hospital stay when virus load was lower, having insufficient contact time with a surface or using insufficiently moist collection swabs. Further environmental sampling studies of SARS-CoV-2 should consider including testing for the environmental presence of viruses within laboratory settings, targeting the collection of samples to early in the course of a patient's illness and including sampling of confirmed positive control surfaces, while maintaining appropriate biosafety measures.

Health care transmission of a newly emergent adenovirus serotype in health care personnel at a military hospital in Texas, 2007.

BACKGROUND: Adenoviruses can cause outbreaks of febrile respiratory illness in military trainees, but until 2007, adenovirus serotype 14 (Ad14) was never associated with such outbreaks. From April through June 2007, 15 trainees at one base were hospitalized for pneumonia due to Ad14. Subsequent reports of febrile respiratory illness among health care personnel suggested nosocomial transmission. METHODS: Health care personnel participants completed a questionnaire and provided blood and nasal wash specimens for Ad14 diagnostic testing. We defined a confirmed case of Ad14 infection as one with titers > or = 1:80 or nasal wash specimens positive for Ad14 by polymerase chain reaction, whereas a possible case was defined by titers of 1:20 or 1:40. We also collected environmental samples. RESULTS: Among 218 tested health care personnel, 35 (16%) had titers > or = 1:20; of these, 7 had possible cases and 28 had confirmed cases of infection. Confirmed case patients were more likely to report febrile respiratory illness (57% vs 11%; P< .001) and to have had direct contact with patients with Ad14 infection (82% vs 62%; P.04 ). Of the 23 confirmed case patients with direct contact with Ad14-infected patients, 52% reported that patients were not in contact and droplet precautions at the time of exposure. Ad14 was recovered from several hospital surfaces. CONCLUSION: Our findings of possible nosocomial transmission of Ad14 highlight the need to reinforce infection control guidelines.

An outbreak of varicella in elementary school children with two-dose varicella vaccine recipients--Arkansas, 2006.

BACKGROUND: In June 2006, the Advisory Committee on Immunization Practices (ACIP) expanded its June 2005 recommendation for a second dose of varicella vaccine during outbreaks to a recommendation for routine school entry second dose varicella vaccination. In October 2006, the Arkansas Department of Health was notified of a varicella outbreak among students where some received a second dose during an outbreak-related vaccination campaign in February 2006. METHODS: The outbreak was investigated using a school-wide parental survey with a follow-up survey of identified case patients. Vaccination status was verified using state and local immunization records. Limited laboratory testing confirmed circulation of wild-type varicella, including varicella in 2-dose vaccine recipients. RESULTS: Vaccination information was available for 871 (99%) of the 880 children. Varicella vaccination coverage was 97% (2-dose, 39%; 1-dose, 58%). A review of the February vaccination clinic found no deficiencies; lot numbers did not differ between cases and noncases. Varicella was confirmed by PCR in 5 (42%) of 12 lesion specimens and by IgM in 1 (6%) of 16 serum specimens. Varicella was reported in 84 children, including 25 (30%) two-dose and 53 (63%) one-dose recipients. Attack rates among 2-dose recipients (10.4%) and 1-dose recipients (14.6%) were not significantly different (RR: 0.72, 95% CI: 0.44-1.15). All 2-dose recipients and 80% of 1-dose recipients reported having 50 or fewer skin lesions. CONCLUSION: This outbreak is the first to document varicella in both 1- and 2-dose vaccine recipients; both groups had mild disease. The vaccine effectiveness of 1 and 2 doses were similar.

Reproductive tract complications associated with Chlamydia trachomatis infection in US Air Force males within 4 years of testing.

BACKGROUND: Chlamydia trachomatis (CT) is a common sexually transmitted infection for which young, sexually active persons are at highest risk. Health consequences such as orchitis/epididymitis, prostatitis, infertility, and urethral stricture have been described among CT-infected males, although not all of these are indisputably linked to CT. Current literature lacks population-based studies needed to examine these associations on a larger scale, to evaluate the true risk of developing complications after a CT infection. The US Air Force contains a large population of young, sexually active males, making it suitable for conducting such a study. METHODS: We conducted a retrospective cohort study between 2001 and 2005 comparing the incidence of orchitis/epididymitis, prostatitis, infertility, and urethral stricture among male Air Force members with and without prior CT infections. Cumulative incidence rates were calculated and Cox proportional hazard models were generated to evaluate the risk of developing complications and to adjust for potential confounders. RESULTS: Among 17,764 men enrolled in the study, 913 (5.14%) experienced a reproductive tract outcome. Among CT-positive men, cumulative incidences of orchitis/epididymitis, prostatitis, infertility, and urethral stricture were 4.28%, 1.41%, 1.27%, and 0.13%, respectively. Orchitis/epididymitis [Hazard ratio (HR) = 1.38 (1.13-1.70)] and "any" outcome [HR = 1.37 (1.16-1.61)] were positively associated with CT; infertility was marginally associated [HR = 1.36 (0.93-2.00)]. CONCLUSIONS: Overall, the burden of reproductive health outcomes among Air Force males is small. Significant associations were observed between CT and both orchitis/epididymitis and any outcome; a larger cohort or longer follow-up may have detected a significant association between CT and infertility.

Epidemiology of HIV among US Air Force Military Personnel, 1996-2011.

OBJECTIVE: The objectives of this study were to describe the epidemiology of HIV in the United States Air Force (USAF) from 1996 through 2011 and to assess whether socio-demographic characteristics and service-related mobility, including military deployments, were associated with HIV infection. METHODS: We conducted a retrospective cohort analysis of USAF personnel who were HIV-infected during the study period January 1, 1996 through December 31, 2011 and a matched case-control study. Cases were USAF personnel newly-diagnosed with HIV during the study period. Five randomly-selected HIV-uninfected controls were matched to each case by age, length of service, sex, race, service, component, and HIV test collection date. Socio-demographic and service-related mobility factors and HIV diagnosis were assessed using conditional logistic regression. RESULTS: During the study period, the USAF had 541 newly diagnosed HIV-infected cases. HIV incidence rate (per 100,000 person-years) among 473 active duty members was highest in 2007 (16.78), among black/ African-American USAF members (26.60) and those aged 25 to 29 years (10.84). In unadjusted analysis restricted to personnel on active duty, 10 characteristics were identified and considered for final multivariate analysis. Of these single (adjusted odds ratio [aOR], 8.15, 95% confidence interval [CI] 5.71-11.6) or other marital status (aOR 4.60, 95% CI 2.72-7.75), communications/ intelligence (aOR 2.57, 95% CI 1.84-3.60) or healthcare (aOR 2.07, 95% CI 1.28-3.35) occupations, and having no deployment in the past 2 years before diagnosis (aOR 2.02, 95% CI 1.47-2.78) conferred higher odds of HIV infection in adjusted analysis. CONCLUSION: The highest risk of HIV infection in the USAF was among young unmarried deployment-naïve males, especially those in higher risk occupation groups. In an era when worldwide military operations have increased, these analyses identified potential areas where targeted HIV prevention efforts may be beneficial in reducing HIV incidence in the USAF military population.

Code-based syndromic surveillance for influenzalike illness by International Classification of Diseases, Ninth Revision.

With the spread of avian influenza, use of automated data streams to rapidly detect and track human influenza cases has increased. We performed correlation analyses to determine whether International Classification of Diseases, Ninth Revision (ICD-9), groupings used to detect influenzalike illness (ILI) within an automated syndromic system correlate with respiratory virus laboratory test results in the same population (r = 0.71 or 0.86, depending on group). We used temporal and signal-to-noise analysis to identify 2 subsets of ICD-9 codes that most accurately represent ILL trends, compared nationwide sentinel ILL surveillance data from the Centers for Disease Control and Prevention with the automated data (r = 0.97), and found the most sensitive set of ICD-9 codes for respiratory illness surveillance. Our results demonstrate a method for selecting the best group of ICD-9 codes to assist system developers and health officials who are interpreting similar data for daily public health activities.