Determination of the cycle threshold value of the Xpert Xpress SARS-CoV-2/Flu/RSV test that corresponds to the presence of infectious SARS-CoV-2 in anterior nasal swabs.

Despite having high analytical sensitivities and specificities, qualitative SARS-CoV-2 nucleic acid amplification tests (NAATs) cannot distinguish infectious from non-infectious virus in clinical samples. In this study, we determined the highest cycle threshold (Ct) value of the SARS-CoV-2 targets in the Xpert Xpress SARS-CoV-2/Flu/RSV (Xpert 4plex) test that corresponded to the presence of detectable infectious SARS-CoV-2 in anterior nasal swab samples. A total of 111 individuals with nasopharyngeal swab specimens that were initially tested by the Xpert Xpress SARS-CoV-2 test were enrolled. A healthcare worker subsequently collected anterior nasal swabs from all SARS-CoV-2-positive individuals, and those specimens were tested by the Xpert 4plex test, viral culture, and laboratory-developed assays for SARS-CoV-2 replication intermediates. SARS-CoV-2 Ct values from the Xpert 4plex test were correlated with data from culture and replication intermediate testing to determine the Xpert 4plex assay Ct value that corresponded to the presence of infectious virus. Ninety-eight of the 111 (88.3%) individuals initially tested positive by the Xpert Xpress SARS-CoV-2 test. An anterior nasal swab specimen collected from positive individuals a median of 2 days later (range, 0-9 days) tested positive for SARS-CoV-2 by the Xpert 4plex test in 39.8% (39/98) of cases. Of these samples, 13 (33.3%) were considered to contain infectious virus based on the presence of cultivable virus and replication intermediates, and the highest Ct value observed for the Xpert 4plex test in these instances was 26.3. Specimens that yielded Ct values of ≤26.3 when tested by the Xpert 4plex test had a likelihood of containing infectious SARS-CoV-2; however, no infectious virus was detected in specimens with higher Ct values.IMPORTANCEUnderstanding the correlation between real-time PCR test results and the presence of infectious SARS-CoV-2 may be useful for informing patient management and workforce return-to-work or -duty. Further studies in different patient populations are needed to correlate Ct values or other biomarkers of viral replication along with the presence of infectious virus in clinical samples.

Response to a Serogroup B Meningococcal Disease Case Among Military Trainees.

We describe the public health response to a military trainee who developed serogroup B meningococcal disease while sharing underwater breathing equipment. Despite high transmission risk, with rapid isolation and postexposure prophylaxis administration, there were no secondary cases. This case supports carefully weighing serogroup B meningococcal vaccination in high-risk settings.

COVID-19 Contact Tracing in an Overseas U.S. Military Population.

The purpose of this study was to describe the early epidemiology and contact tracing challenges for Covid-19 infection in an overseas military and DoD population. From February 28, 2020 to April 27, 2020, patients who were diagnosed with Covid-19 infection completed a Centers for Disease Control Persons Under Investigation (PUI) form during their encounter with a medical provider. Positive results were forwarded to the Public Health Department. The results of the contact tracing and PUI form were entered into a database and analyzed. Eight Covid-19 cases were diagnosed in this overseas population. Based on beneficiary population, the cumulative incidence was ∼80/100,000 persons. The age distribution ranged from 25 to 60 years, median 36 years. Most patients were male (75%). More infection occurred in those living off base in the community (87.5%). With the capability of on-site testing at the hospital, the median duration from symptom onset to diagnosis improved from 5 days to 1 day. Disease contact tracing for DoD populations presents unique considerations in an overseas location. Public Health guidelines for the USA may have varying relevance in an overseas location. Rapid case identification with on-site testing is critical to disrupt disease transmission. Preventive measures for Covid-19 infection have decreased incidence of influenza-like illness.

Risk factors for medical disability in U.S. enlisted Marines: fiscal years 2001 to 2009.

OBJECTIVE: To assess factors associated with medical disability in the U.S. Marine Corps. METHODS: Case-control study enrolling 11,554 medical disability cases of U.S. enlisted Marines referred to the Physical Evaluation Board fiscal year 2001 to 2009 and 42,216 controls frequency matched to cases in a 4:1 ratio on year of accession into the service were analyzed utilizing bivariate and multivariate logistic regression analysis. RESULTS: Increased age and body mass index at accession were associated with higher odds of medical disability. Females (odds ratio adjusted [OR(adj)] = 1.3, 95% confidence interval [CI] = 1.2-1.3) have higher odds of disability than males. "Healthy Warrior Effect" was observed in that those who deployed (OR(adj) = 0.48, 95% CI = 0.46-0.50) had decreased odds of medical disability than those who did not deploy. Medical waivers at accession (OR(adj) = 1.12, 95% CI = 1.01-1.23) increased the odds of medical disability. CONCLUSIONS: Continued surveillance of the disability evaluation system is needed to help develop preventive measures and to help policy makers establish evidence-based policies on accession, deployment, and retention standards over the lifecycle of service members.