Having a more intense response to 2nd COVID-19 vaccine dose? Here’s why 

While a strong response is normal, the absence of a reaction doesn't necessarily signify a weak immune system or an ineffective vaccine.
                              While a strong response is normal, the absence of a reaction doesn't necessarily signify a weak immune system or an ineffective vaccine.

Source: Having a more intense response to 2nd COVID-19 vaccine dose? Here’s why