However, asymptomatic patients (in particular never-symptomatic, as opposed to pre-symptomatic) are generally thought to be less infectious than symptomatic people.The 95% effectiveness of the Pfizer vaccine for symptomatic infection. However, there may be asymptomatic infection which also enables transmission. The vaccine provides about 85-95% protection against all infection (asymptomatic and symptomatic) for the original and the alpha variants. For the delta variant, the protection against all infection falls to about 79%. For the beta variant, the protection against all infection is about 75%.