Part of the issue with fast-acting viral respiratory diseases seems to be that vaccines don't induce mucosal immunity: "Currently approved SARS-CoV-2 vaccines i

Part of the issue with fast-acting viral respiratory diseases seems to be that vaccines don't induce mucosal immunity: "Currently approved SARS-CoV-2 vaccines induce robust systemic immunity but poor immunity at the respiratory mucosa, meaning that they are highly effective against symptomatic disease but do not prevent viral transmission." https://www.nature.com/articles/s41590-022-01405-w https://www.nature.com/articles/s41590-022-01405-w