Assessing COVID-19 Prevention Strategies to Permit the Safe Opening of Residential Colleges in Fall 2021

Ann Intern Med. 2021 Nov;174(11):1563-1571. doi: 10.7326/M21-2965. Epub 2021 Aug 31.


Background: Effective vaccines, improved testing technologies, and decreases in COVID-19 incidence prompt an examination of the choices available to residential college administrators seeking to safely resume in-person campus activities in fall 2021.

Objective: To help college administrators design and evaluate customized COVID-19 safety plans.

Design: Decision analysis using a compartmental epidemic model to optimize vaccination, testing, and other nonpharmaceutical interventions depending on decision makers' preferences, choices, and assumptions about epidemic severity and vaccine effectiveness against infection, transmission, and disease progression.

Setting: U.S. residential colleges.

Participants: Hypothetical cohort of 5000 persons (students, faculty, and staff) living and working in close proximity on campus.

Measurements: Cumulative infections over a 120-day semester.

Results: Under base-case assumptions, if 90% coverage can be attained with a vaccine that is 85% protective against infection and 25% protective against asymptomatic transmission, the model finds that campus activities can be resumed while holding cumulative cases below 5% of the population without the need for routine, asymptomatic testing. With 50% population coverage using such a vaccine, a similar cap on cumulative cases would require either daily asymptomatic testing of unvaccinated persons or a combination of less frequent testing and resumption of aggressive distancing and other nonpharmaceutical prevention policies. Colleges returning to pre-COVID-19 campus activities without either broad vaccination coverage or high-frequency testing put their campus population at risk for widespread viral transmission.

Limitation: Uncertainty in data, particularly vaccine effectiveness (preventive and transmission); no distinguishing between students and employees; and assumes limited community intermixing.

Conclusion: Vaccination coverage is the most powerful tool available to residential college administrators seeking to achieve a safe return to prepandemic operations this fall. Given the breadth of potential outcomes in the face of uncontrollable and uncertain factors, even colleges with high vaccination rates should be prepared to reinstitute or expand testing and distancing policies on short notice.

Primary funding source: National Institute on Drug Abuse.

MeSH terms

  • COVID-19 / epidemiology
  • COVID-19 / prevention & control*
  • COVID-19 Vaccines / administration & dosage*
  • Decision Support Techniques
  • Disease Transmission, Infectious / prevention & control*
  • Humans
  • Incidence
  • Mass Screening
  • Pandemics
  • Risk Assessment
  • SARS-CoV-2
  • United States / epidemiology
  • Universities / organization & administration*


  • COVID-19 Vaccines