[ofTheFountain]

Only having 2 Pfizer/mRNA vaccines are'n enough to greatly reduce symptomatic covid infection. A booster (or previous covid infection) looks like it is needed.

Though this is only looking at the drop in vaccine efficacy with respect to symptomatic infections, two shots of an mRNA still might give decent protection against severe disease; don't know if there is a change with this.

[selectodude]

>two shots of an mRNA still might give decent protection against severe disease; don't know if there is a change with this.

There's not. Severe disease is caused by your body attacking your own lungs because the virus did so much damage between initial infection and your body recognizing the problem. Vaccines, any vaccine, dramatically shortens the time between initial infection and immune response. Shorter duration == less damage to your body in that time.