It will if closures are lifted but vaccination is made a requirement (either privately or by government mandate) for on-site work, schooling, etc. The flu vaccine is treated as primarily a personal preventive medical treatment; while it is encouraged for public as well as personal health reasons, there is no force put behind it. But it is quite possible, and there is plenty of precedent for, public health measures to be mandated (especially a conditional mandate, like for schools, work in particular conditions--including any public content or even on-premises work) and enforced.