Sensitivity of Symptom-Based Screening for COVID-19 in Active Duty Basic Trainees.

Area of Science:

• Infectious Disease Epidemiology
• Public Health Surveillance
• Military Medicine

Background:

• Symptomatic Coronavirus Disease 2019 (COVID-19) screening is crucial for case identification.
• Traditional influenza-like illness (ILI) symptoms (fever, cough, dyspnea) may not effectively identify COVID-19 in young, healthy populations.
• Understanding symptom prevalence across different COVID-19 variants and vaccination statuses is essential for optimizing screening.

Purpose of the Study:

• To evaluate the utility of symptom-based screening for identifying COVID-19 in military trainees.
• To compare the sensitivity of ILI symptom screening across three distinct COVID-19 waves (pre-Delta, Delta, Omicron).
• To analyze symptom variations based on the predominant COVID-19 variant and vaccination status.

Main Methods:

• A descriptive cross-sectional study included 600 symptomatic military trainees tested for COVID-19.
• Trainees were sampled during three periods: pre-Delta, Delta, and Omicron variant predominance.
• Presenting symptoms were compared, and the sensitivity of ILI symptom screening was calculated for each period.

Main Results:

• The most common symptoms among positive COVID-19 cases were sore throat (64%), headache (56%), and cough (52%).
• Sore throat predominated during Delta and Omicron waves, while headache was most common pre-Delta.
• Overall ILI symptom screening sensitivity was 65%, ranging from 54% (pre-Delta) to 78% (Omicron). Ageusia was more frequent in unvaccinated individuals.

Conclusions:

• COVID-19 symptom prevalence in military trainees varied significantly by the predominant variant and vaccination status.
• Standard ILI symptom screening demonstrates fluctuating sensitivity, highlighting the need for adaptive strategies.
• Evolving screening protocols should consider changing symptom patterns throughout the pandemic.