Are painless vaccinations effective?

Painless vaccines refer to DTP vaccine with acellular Pertussis component (DTaP). DTaP fails to prevent transmission and spread of Pertussis among  people as it does not prevent Pertussis from entering and living inside the airways of vaccinated persons. So, the vaccinated persons are themselves immune but can still spread the disease to non vaccinated people or people with weak immunity.  Pertussis outbreak reports from USA where painless DTaP vaccine is commonly used further proves this point. Also DTaP provides lesser immunity than DTwP vaccine according to recent reports. For more info see DTP (DTwP / DTaP) Vaccine

Are painless vaccinations effective?