Benefits of integrated screening and vaccination for infection control

Abstract

Importance: Screening and vaccination are essential in the fight against infectious diseases, but need to be integrated and customized based on community and disease characteristics.

Objective: To develop effective screening and vaccination strategies, customized for a college campus, to reduce COVID-19 infections, hospitalizations, deaths, and peak hospitalizations.

Design, setting, and participants: We construct a compartmental model of disease spread under vaccination and routine screening, and study the efficacy of four mitigation strategies (routine screening only, vaccination only, vaccination with partial or full routine screening), and a no-intervention strategy. The study setting is a hypothetical college campus of 5,000 students and 455 faculty members during the Fall 2021 academic semester, when the Delta variant was the predominant strain. For sensitivity analysis, we vary the screening frequency, daily vaccination rate, initial vaccine coverage, and screening and vaccination compliance; and consider scenarios that represent low/medium/high transmission and test efficacy. Model parameters come from publicly available or published sources.

Results: With low initial vaccine coverage (30% in our study), even aggressive vaccination and screening result in a high number of infections: 1,020 to 2,040 (1,530 to 2,480) with routine daily (every other day) screening of the unvaccinated; 280 to 900 with daily screening extended to the newly vaccinated in base- and worst-case scenarios, which respectively consider reproduction numbers of 4.75 and 6.75 for the Delta variant.

Conclusion: Integrated vaccination and routine screening can allow for a safe opening of a college when both the vaccine effectiveness and the initial vaccine coverage are sufficiently high. The interventions need to be customized considering the initial vaccine coverage, estimated compliance, screening and vaccination capacity, disease transmission and adverse outcome rates, and the number of infections/peak hospitalizations the college is willing to tolerate.

Fig 1. Total number of infections versus screening frequency for three daily vaccination rates, indicated by color, for 60% initial campus-wide vaccine coverage (L_s = L_f = 60%) and 75% compliance (η = α = 75%) in the base-case scenario with full screening.

Each shaded region depicts the uncertainty region resulting from varying levels of screening and vaccination compliance (60%, 75%, 90%), test sensitivity (70%, 80%) and specificity (98%, 99.7%). N/A represents “no screening”.

Fig 2. Peak number of hospitalizations versus total number of infections for 60% initial campus-wide vaccine coverage (L_s = L_f = 60%) and 75% compliance (η = α = 75%) in the base-case scenario with full screening.

N/A represents “no screening”.

Fig 3. Total number of infections versus screening frequency for three levels of initial vaccine coverage, indicated by color, for a 60/day vaccination rate and 75% compliance (η = α = 75%) in the base-case scenario with full screening.

Each shaded region depicts the uncertainty region resulting from varying levels of screening and vaccination compliance (60%, 75%, 90%), test sensitivity (70%, 80%) and specificity (98%, 99.7%). N/A represents “no screening.” (Note: The shaded region of the blue line is extremely narrow for the scale used.).