With the 3-year pandemic of COVID-19 arrived to the end, it is time to seriously reevaluate some unanswered questions. For example, although vaccinations reduced severe symptoms and mortality rate of COVID-19, it remains vague whether vaccinations are necessary to prevent the disease caused by mild viral variants like Omicron and, if yes, between the new mRNA vaccines (RV) and the conventional inactivated viral vaccines (IV), which should be prioritized. This short study, presented as a Research Letter, is attempted to help address these questions. We hope that it fits the scope of your prestigious journal and look forward to hearing from you.