Considerations in boosting COVID-19 #vaccine immune responses - The Lancet
"If boosters (whether expressing original or variant antigens) are ultimately to be used, there will be a need to identify specific circumstances in which the direct and indirect benefits of doing so are, on balance, clearly beneficial."
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)02046-8/fulltext