Compromised Immune System and Viruses
Question: Weren't polio survivors’ immune systems compromised when we got the poliovirus? Why else would it take hold rather than being fought off, as would be the flu?
Dr. Bruno’s Response: Being infected with and having neurons damaged by the poliovirus does not mean that your immune system was compromised. Unlike the flu viruses, to which people are exposed at least yearly, you were a "poliovirus virgin" having never before been exposed to any of the three polioviruses.
Your immune system (as with COVID today) had no antibodies or B cells or T cells to fight them. But your immune system learned quickly to attack the poliovirus. Had you been immune compromised during the acute polio infection you quite likely would have died. The purpose of the polio vaccines was to expose the immune system to the polioviruses without causing neuronal damage, to teach it to attack the polioviruses before they could cause neuron damage and death.