Evaluation of COVID-19 Intuitively Appealing Vaccine Protocols and R0 Increase Fears, Strategic Lessons

Abstract

Background: Late phase COVID-19 strategic decisions are being made for vaccine protocols such as selective vs. fast. Quantitative trade studies have not appeared. A new faster spreading strain has developed. Quantitative analysis of how it will affect vaccination schedules and final unlock protocol are needed. Lessons learned papers so far deal with prevention of spreading and practice of care issues, leaving major strategy questions about vaccination approach and final unlock open. Methods: We use an SIR-based model tuned for COVID-19 and accounting for seasonality, immunity decline, and vaccination. We add the capability to handle a changing fundamental replication rate (R0) and declining ratio of total to known cases (determined by data fitting). Results: For the present R0 and vaccination schedule a full internal U.S. unlock in April or May 2021 is supportable, however infections reintroduced would propagate in the fall if immunity wears off in 240 days. If the increased R0 becomes established then the infection is never completely extinguished and recurs. If immunity lasts 240 days, re-vaccination is not needed until 2022 even with increased R0 making doses available for use in other countries. Likely 77,000 lives were lost by not meeting the initially planned vaccination targets. Conclusions: The usefulness of trade studies in saving lives is established. Intuitively appealing strategies are not necessarily optimal. Lack of inexpensive random sample testing hampers ability to do trade studies. Phase 3 vaccine trial protocols for epidemics with heavy loss of life should be revisited.