The flu vaccine is more effective at preventing serious disease than it is at preventing infection. Even a vaccine that only prevents you from getting seriously

The flu vaccine is more effective at preventing serious disease than it is at preventing infection. Even a vaccine that only prevents you from getting seriously ill can be incredibly useful. The inactivated polio vaccine, for example, does not prevent infection. It just prevents disease. That means that it cannot confer herd immunity (vaccinated people can act as asymptomatic carriers, leaving unvaccinated people at risk), but for most people who are vaccinated, it eliminates the most serious consequence of polio infection - paralysis. The SARS-CoV-2 vaccines might end up being the same, conferring protection from disease but not from infection, and even that would be important.