interval infection 

COVID-19 infection coinciding with a patient's first vaccination and developing prior to receiving the second. The symptoms may easily be misinterpreted as side-effects from the vaccine.

He had felt strange since receiving his first dose of the vaccine - aching, fatigued, coughing, short of breath. Three weeks later, after receiving his second dose, he had a fever of 102, was fighting for breath and coughing badly. While it was logical to assume he was having a severe reaction to the vaccine, the stronger probability was that he had contracted an interval infection.

interval infection by Monkey's Dad February 28, 2021