Vaccination and non-pharmaceutical interventions for COVID-19: a mathematical modelling study
This study estimates vaccination alone is insufficient to contain the outbreak, highlighting risks associated with early/rapid relaxation of non-pharmaceutical interventions. In their absence, most optimistic assumption leads to estimated R of 1.58 (95% CI 1.36-1.84).
Source:
The Lancet Infectious Diseases
SPS commentary:
The authors show that only in a best-case scenario of high vaccine uptake (85% protection against infection and high efficacy against severe symptoms) could a gradual relaxation of NPIs be allowed without deaths surging over 500 per day.
The study found that the still unknown level of vaccine-induced protection against infection is crucial to the timing and effect of further waves on viral spread. Furthermore, the researchers quantify how low vaccine uptake, together with a lifting of NPIs, will induce further waves of hospitalisations and deaths, most of which could be prevented.
A related Comment notes how it is ‘intuitively clear’ that lifting restrictions too early will risk another pandemic wave, which will affect those who have not yet been vaccinated, and those who have only recently been vaccinated and remain partly susceptible. The authors say how compliance with NPIs has decreased because of behavioural fatigue, however despite this, governments and researchers now more than ever should stress the advantages of keeping case numbers low, the benefits of high vaccination uptake, and the responsibility that the vaccinated population has to those who are not yet protected, but who are largely expected to keep economies going.