Matthew W, a 45-year-old ER nurse in San Diego tests positive for Covid-19. She has received the Pfizer vaccine on December 18.  

On December 24 she had a cold. She later went to the hospital and was confirmed to have a corona infection. 

Dr. Christian Ramers, a Santiago epidemiologist and a member of the Corona Vaccine Medical Advisory Board, told that this was not unpredictable. He said, "Nurse Matthew may have had a corona infection before she was vaccinated. 

In addition, a laboratory test indicated that the corona vaccine can take up to 10-14 days to develop protection from the vaccine.  That first dose we think gives you somewhere around 50%, and you need that second dose to get up to 95%,"