Comparing influenza vaccine effectiveness between cell-derived and egg-derived vaccines, 2017-2018 influenza season.

The Department of Defense Global Respiratory Pathogen Surveillance Program conducted a study to compare the differences in vaccine effectiveness (VE) of the cell-derived and egg-derived vaccines. DoD healthcare beneficiaries, excluding service members, that presented with influenza-like illness for the period of 1 October 2017 through 28 April 2018 were included in a test-negative case-control study examining laboratory confirmed influenza infections. Three VE analyses were performed (1) influenza infection among those vaccinated with cell-derived vaccines (2) influenza infection among those vaccinated with egg-derived vaccines and a (3) relative VE which directly compared the odds of influenza infection with cell-derived vaccine against those with egg-derived vaccines. The cell-derived and egg-derived vaccines were moderately protective against all influenza types with significant VE estimates for all dependents at 46% (95% confidence interval, 33, 56) and 53% (45, 60), respectively. Of the subtype analyses, influenza A(H1N1)pdm09 performed the best. In the cell-derived vaccine, the adult age group was moderate to high at 71% (44, 85) and children moderate at 56% (15, 75). In the egg-derived vaccine, the children age group was at a high 88% (80, 93) effectiveness and adults at 81% (56, 92). When comparing cell-derived vaccine directly to the egg-derived vaccine, the relative VE found significant results only for influenza A(H1N1)pdm09 which favored the egg-derived vaccine with odds ratios of 2.0 (1.1, 3.6) for all dependents and 2.9 (1.3, 6.3) for children. In the influenza A(H3N2) analysis, statistical significance was not gained; however, the odds favored the cell-derived vaccine.

Department of Defense end-of-season influenza vaccine effectiveness estimates for the 2017-2018 season.

The Department of Defense (DoD) generates influenza vaccine effectiveness (VE) estimates each season. The Armed Forces Health Surveillance Branch Air Force (AFHSB-AF) satellite, Naval Health Research Center Operational Infectious Disease Directorate at the Naval Health Research Center (NHRCOID), and the Armed Forces Health Surveillance Branch (AFHSB) all conduct influenza surveillance and perform test-negative case-control analyses to estimate seasonal influenza VE for DoD populations. The mid-season estimates contribute to the aggregate data utilized by the Food and Drug Administration's Vaccine and Related Biological Products Advisory Committee to select the composition of the influenza vaccine for the next influenza season. The full season data provide DoD with direct estimates for force health protection decisions. The 2017-2018 DoD influenza season was predominated by influenza A(H3N2) with varying levels of adjusted overall VE estimates. AFHSB-AF satellite's VE for dependents was moderate at 49% (95% confidence interval [CI]: 42%-55%) for all strains. NHRC-OID's VE among dependents was moderate-high at 63% (95% CI: 50%-73%) for all strains. AFHSB service member VE was low at 18% (95% CI: 4%-30%). These estimates highlight the need for continued influenza surveillance and VE estimate calculations each season among the different DoD populations as circulating strains and VE may change annually.

The effects of prenatal vitamin supplementation on operationally significant health outcomes in female air force trainees.

OBJECTIVES: A prenatal vitamin supplementation program for female basic military trainees at Joint Base San Antonio-Lackland was initiated in June 2012 with the goals of decreasing attrition and improving performance. This project examined whether supplementation influences attrition rates, incidence of stress fractures and iron deficiency anemia, and physical performance. METHODS: This was a cohort-based pilot study with an historical control group. Primary outcome measures included all-cause attrition, medical attrition, stress fractures, and iron deficiency anemia. RESULTS: Incidence rates of all-cause attrition, medical attrition, stress fractures, and anemia were similar in both groups, although the lower medical attrition in the supplementation group approached statistical significance (risk ratio, 0.74; 95% confidence interval, 0.54-1.01). CONCLUSION: Although this study found no statistical benefit, the operationally significant reduction in medical attrition of 26% suggests that providing prenatal vitamin supplementation to female basic trainees in the Air Force may be worthwhile.

Concurrent bilateral femoral neck stress fractures in a military recruit: a case report.

BACKGROUND: Stress fractures are overuse injuries that historically afflict a large number of military recruits, likely because of the sudden increase of high-intensity activity, such as running and marching. CASE: A 23-year-old male U.S. Air Force recruit presented with hip pain during his second week of basic training and was diagnosed with bilateral femoral neck stress fractures, grade 4 on the right and grade 3 on the left. This is the first known case of concurrent bilateral femoral neck stress fractures in a U.S. military recruit reported in the medical literature. CONCLUSION: This report describes a severe case of stress fracture in an individual with no readily identifiable risk factors.

Bilateral lower extremity inflammatory lymphedema in Air Force basic trainees: clinical and epidemiologic study of a new disease entity.

IMPORTANCE: This observational study characterizes a new clinical condition identified in 55 military trainees. OBJECTIVE: To determine the incidence and underlying cause of bilateral lower extremity inflammatory lymphedema in Air Force basic trainees. DESIGN, SETTING, AND PARTICIPANTS: An observational study was conducted at Lackland Air Force Base in San Antonio, Texas. Participants included 14 243 Air Force basic trainees who entered training between September 2011 and January 2012 and the 55 trainees (0.4%) who developed bilateral lower extremity inflammatory lymphedema that occurred during the 8½-week basic training course. Two modifiable risk factors were evaluated: vaccine reaction and newly issued military footwear (combat boots and boot socks). INTERVENTIONS: During November 2011, all new trainees wore only white socks and running shoes rather than the issued military footwear. During December 2011 and January 2012, the scheduled administration of tetanus/diphtheria/acellular pertussis and meningococcal vaccines, respectively, was delayed by 1 week for all new trainees. A full medical record review was conducted for every confirmed case of bilateral lower extremity inflammatory lymphedema. MAIN OUTCOMES AND MEASURES: Identification of incident cases, symptom onset, antimicrobial treatment, immunization reaction, laboratory studies, specialty referral, and biopsy. RESULTS: Fifty-four of the 55 incident cases (98%) of bilateral lower extremity inflammatory lymphedema occurred during the first 120 hours of training. Alterations in the timing of the military footwear used and selected vaccine administration had no effect on the incidence of new cases. Two participants (4%) experienced symptom onset before receipt of the vaccines. Oral antimicrobial medications were not found to speed symptom resolution compared with conservative treatment measures (P = .34). One incident case was diagnosed as leukocytoclastic vasculitis by tissue examination. CONCLUSIONS AND RELEVANCE: Multiple training-related risk factors were ruled out as sources of bilateral lower extremity inflammatory lymphedema. Cases are likely secondary to prolonged standing with resultant gravity-dependent venous congestion and inflammatory vasculitis. The potential roles of undiagnosed venous reflux disease and the military physical training environment in these cases remain to be elucidated.

Prevalence and Impact of Anemia on Basic Trainees in the US Air Force.

BACKGROUND: Anemia has been implicated in adverse health outcomes of athletes and military trainees, ranging from overuse injuries to degraded physical and cognitive performance. The purpose of this study was to investigate prevalence of anemia among US Air Force (USAF) basic trainees, to compare physical performance and discharge rates between anemic and non-anemic trainees, and to determine the risks and relative risks of being discharged for anemic versus non-anemic women and men. METHODS: All USAF basic trainees were screened for anemia between July 2013 and January 2014, during an 8-week basic training course at Joint Base San Antonio-Lackland, TX. Age, sex, screening hemoglobin, anthropometric measurements, initial/final physical fitness assessment scores, and discharge data were collected from trainees. Those identified as anemic (hemoglobin <13.5 g/dL for males and <12.0 g/dL for females) received additional labwork, nutritional counseling, and oral iron-replacement, if indicated. Mean percent improvement was calculated for all performance parameters from beginning to end of training. Anemic trainees were compared to non-anemic trainees by t test with Welch modification. Results were stratified by sex and anemia severity with post-hoc Bonferroni correction. RESULTS: Prevalence of anemia was 12.6 % (N = 18,827). Respective prevalence of borderline, moderate, and severe anemia was 12.6, 10.9, and 1.9 % for females and 4.8, 3.8, and 0.3 % for males. Mean 1.5-mile run-time, push-up and sit-up counts improved from beginning to end of training for both anemic and non-anemic trainees (p < 0.001 both). Non-anemic trainees had slightly greater run-time improvements than borderline and moderate anemics (female: 17.7 vs. 15.2, and 15.1 % improvement, p < 0.05 both; male: 14.9 vs. 13.2, and 13.5 % improvement, p < 0.05 both). One-way ANOVA demonstrated statistically significant differences between initial and final fitness data for all measures and both genders (p < 0.001) with the exception of final sit-up counts for male trainees (p = 0.082). Discharge rate for anemic trainees was 9.0 % (20 % for severely anemic trainees) as compared to 5.7 % for non-anemics. CONCLUSIONS: Anemia was prevalent among USAF basic trainees. Identification and treatment of anemia may optimize physical performance and decrease the rate of medical discharge.

Deployment-related depression screening, 2001-2008: comparing clinical versus research surveys.

BACKGROUND: Potential adverse mental health effects of deployment, including depression, are an ongoing concern. Although a previous study assessed under-reporting of depression on post-deployment health assessments compared to anonymous surveys, those results were not examined at the individual level to identify demographic or military factors that may be associated with unwillingness to report depression symptoms. PURPOSE: To compare self-reported depression symptoms on post-deployment health assessments with responses to the same depression questions on a research survey. METHODS: This cross-sectional study analyzed depression screening responses from 2001 to 2008 from participants of the Millennium Cohort Study, a longitudinal military cohort study, who completed a post-deployment health assessment within 30 days of a research survey. Kappa statistics and percent positive and negative agreement were calculated. Demographic and military characteristics associated with discordant screening results were examined. Initial analyses were performed in 2011, with additional analyses in 2013. RESULTS: Moderate agreement (κ=0.464) was observed between paired survey responses. A higher proportion of active duty members, the unmarried, and new accessions into military service endorsed depression symptoms on the research survey but not the military-linked survey. In stratified analyses, agreement was higher in Reserve/National Guard members than active duty (κ=0.561 vs 0.409). New active duty accessions showed lower agreement (κ=0.388), as did unmarried active duty participants (κ=0.304). CONCLUSIONS: Deployment health surveys are important tools for identifying returning service members experiencing depression symptoms. However, these findings suggest that ongoing stigma and barriers to appropriate follow-up mental health care remain to be addressed in the military setting.

Syncope among U.S. Air Force basic military trainees, August 2012-July 2013.

Syncope is a common event with many possible etiologies, ranging from benign to severe. Syncopal episodes of any origin, however, may result in traumatic injury due to postural collapse. Based on the prevalence of internal and external stressors during training, basic military trainees may be at increased risk for syncope. Between 1 August 2012 and 31 July 2013, there were 112 unique individuals who experienced syncopal or pre-syncopal events among basic military trainees at Joint Base San Antonio-Lackland, Texas, the only basic training site in the U.S. Air Force. The overall rate was 19.6 cases per 1,000 person-years (18.4 and 36.1 per 1,000 person-years in males and females, respectively). Based upon the findings of electronic chart review of the 112 cases, a majority of events occurred either during or immediately after exercise (n=38) or during a blood draw, immunization, or laceration repair (n=22). The most common etiologies were judged to be neurocardiogenic (n=54) and orthostatic hypotension (n=40), and two cases were attributed to cardiovascular disease. These findings support current preventive measures, including anemia screening during medical in-processing, an emphasis on hydration throughout training, and a padded floor in the trainee vaccination bay.

Staphylococcus aureus and other skin and soft tissue infections among basic military trainees, Lackland Air Force Base, Texas, 2008-2012.

Military training environments have been identified as high-risk settings for acquisition of skin and soft tissue infections (SSTIs), including those caused by methicillin-resistant Staphylococcus aureus (MRSA). Among the 148,355 basic military trainees at Lackland Air Force Base, Texas, between 1 October 2008 and 30 September 2012, there were 289 SSTIs, including 48 cases of culture-confirmed MRSA and 48 cases of possible MRSA-defined as SSTIs treated with both incision and drainage and MRSA drug coverage (i.e., trimethoprim-sulfamethoxazole, clindamycin, a tetracycline, or linezolid). The period prevalence rates of all SSTIs and MRSA SSTIs increased annually since fiscal year 2010. Of the 87 SSTIs cultured during the surveillance period, 74 were positive: MRSA (n=48); methicillin-sensitive Staphylococcus aureus (n=24); Haemophilus parainfluenzae (n=1); and viridans Streptococcus (n=1). Among MRSA positive cultures, three were resistant to clindamycin, one to tetracycline, and one to both clindamycin and tetracycline; none was resistant to trimethoprim-sulfamethoxazole. An algorithmic clinical approach and heightened public health measures may reduce rates of future SSTIs among basic trainees at Lackland Air Force Base.