Page 66 - JSOM Fall 2021

are a number of false negatives in our surveillance survey. An makes it difficult to draw conclusions on this subset of partic-
independent validation study of the Elecsys Anti-SARS-CoV-2 ipants, besides that significant work quality and time was lost.
test demonstrated a sensitivity of 99.5% at ≥ 14 days for 185
SARS-CoV-2 NAAT-positive confirmed samples. For 10,453 If antibody testing is deemed accurate and reliable, it has im-
samples from random blood donors, the test demonstrated portant impacts on the military to determine prevalence of
19
a 99.8% specificity. While the validation study contained COVID-19 and logistical planning. While hospitalization,
outpatient samples, the study did not report the number and morbidity, and mortality would likely be lower in the ac-
outcome of these outpatient samples. From the few outpatient tive-duty population than the general population, duty days
studies, it appears outpatient sensitivity is less than inpatient lost and hindered medical readiness degrades a ready fighting
samples with lower antibody titers. 20–22 Wellinghausen et al. force. The military could be considered at higher risk for con-
reported 45 / 51 (88% sensitivity) positivity for the Elecsys tracting COVID-19 given communal housing. Also, military
Anti-SARS-CoV-2 test after 10 days in five outpatient clin- training has the potential for “super-spreader” events given
23
ics. Last, the Elecsys Anti-SARS-CoV-2 test has excellent crowded, less sanitary operational environments. With the
concordance with other widely-used SARS-CoV-2 antibody advent of EUA of limited SARS-CoV-2 vaccinations, prior-
tests. 24,25 ity could be for those with negative antibody testing in con-
junction with mission-essential classification, age, and risk
Further SARS-CoV-2 antibody studies with large sample sizes factors. 26–27 In addition, antibody testing could easily be in-
in young, healthy populations are needed. This surveillance corporated into pre-deployment Soldier Readiness Processing
survey is not powered appropriately or compared to NAAT- (SRP) to determine if Soldiers are mission-ready. Serology is
confirmed participants to draw conclusions on its widespread drawn at SRP already, and with 18-minute turn-around times,
use in the healthy, active-duty population. With only 14 (5%) it may make it an easily accessible test. In the future, saliva
of the cohort being tested for SARS-CoV-2 NAAT testing, this testing may make antibody testing even more convenient. 28
may demonstrate a cohort who had symptoms prior to wide-
spread testing availability in June time frame. A future study More information will be needed as to antibody duration,
may be performed with correlation to those tested with SARS- COVID-19 symptom sensitivities and specificities to aid
CoV-2 NAAT testing to determine antibody duration and pre- in clinical decisions, and antibody response to COVID-19
vious COVID-19 infection prevalence. vaccinations.

This epidemiological survey is retrospective and therefore sub-
ject to recall bias of the participants during the questionnaire. Conclusion
This may lead to inaccurate reporting and timeline of symp- While there are limitations inherent to SARS-CoV-2 antibody
toms. While a convenience sample, selection bias of partici- testing and this epidemiological survey, prevalence of prior
pants is present and may distort its representation as a true SARS-CoV-2 infection is low. In this sample, symptoms for
prevalence of antibody positivity and potential COVID-19 COVID-19 were prevalent, with significant days of duty lost.
symptoms in the brigade. The sample had significantly greater The prevalence of prior SARS-CoV-2 infection found in this
proportions of females and medical MOSs as compared to the sample may be generalizable to the larger brigade. The prev-
brigade. This may be due to communication about the sur- alence of symptoms of possible COVID-19 are not generaliz-
veillance survey via medical logistical channels, which is more able to the larger brigade. There is utility to further studies of
likely to reach the medical subset of the brigade. Arguably SARS-CoV-2 antibody prevalence in military populations for
however, medical MOS participants are more likely than sup- purposes of vaccination triaging and deployment readiness.
port and combat arms participants to experience exposure to
COVID-19 given their duties of transporting quarantined Sol- Acknowledgments
diers, screening Soldiers, and performing medical assessments The authors acknowledge the following for their valuable
and treatment. Thus, we would expect the increased propor- contributions to this project: CPT Alicia Brown, PA-C; Jamie
tion of medical MOSs to increase the likelihood of antibody Turnbull, MLS, ASCP; CPT Chelsey Freland, RN; SPC Ramu
positivity, which was not the case. Chhetri; MAJ David Yun, MD; and MAJ Jeffrey Wittkopp,
DSc, PA-C for coordination of collection, testing, and data in-
Excluding participants with symptoms of COVID-19 in the put. The authors also acknowledge Madigan Army Medical
last 14 days may miss positive antibody tests. While the Elecsys Center Department of Clinical Investigation for their final re-
Anti-SARS-CoV-2 is 100% sensitive (95% CI: 88.1–100%) view and approval of submission.
≥ 14 days from positive NAAT confirmation, it still has 88.1%
(95% CI: 77.1–95.1%) and 65.5% (56.1–74.1%) sensitivity Disclaimer
at 7–13 days and 0–6 days post-PCR testing, respectively. The views expressed are those of the author(s) and do not re-
9
Additionally, the sample is subject to volunteer bias. As par- flect the official policy of the Department of the Army, the
ticipants with a history of symptoms and exposure are more Department of Defense, or the US Government.
likely to volunteer for the survey, there may have been over-
representation of symptoms and quarantine in the brigade. Disclosures
The authors have no financial or other conflicts of interest to
Another limitation is evolving definitions of respiratory quar- disclose.
ters and criteria for SARS-CoV-2 testing during the surveil-
lance period. Initial brigade medical procedures for respiratory References
quarters in March 2020 had been for cough and shortness 1. Shang J, Ye G, Shi K, et al. Structural basis of receptor recognition
by SARS-CoV-2. Nature. 2020;581(7807):221–224.
of breath for 72 hours. These procedures then changed with 2. Infectious Disease Society of America (IDSA). RT-PCR testing.
CDC guidance throughout the duration of the outbreak. This 18 November 2020. https://www.idsociety.org/covid-19-real-time

64 | JSOM Volume 21, Edition 3 / Fall 2021