In a recent placebo-controlled trials of a Covid vaccine I heard of a report from one of the participants, who was a doctor.  He was delighted after receiving his first dose because he got a fever and body aches. He had definitely received the vaccine not the placebo.

Generating a fever, by cranking up the brain’s thermostat, is the body’s way of supercharging its immune system. The increased body temperature makes the cells that kill germs (neutrophil white cells), or make antibodies (B-cells), work much more efficiently and quickly.

In both animal and human studies of infected subjects if the temperature is […]