The first reinfection in the world in Hong Kong, later in Europe (Holland, Belgium) and USA, was documented. In Mexico until November 2020 there are no medical articles that tell us about reinfection; in Celaya Guanajuato the case of a female patient presented with symptoms of COVID-19, 2 polymerase chain reaction in real time tests are performed, in the Laboratory of Public Health from Guanajuato State in an interval of time, less than 5 months; the first in June 2020, with a positive result, received symptomatic treatment and isolation at home for 14 days, negative IgG antibodies test 38 days later; the second time, she presented clinical data on COVID-19 in November From 2020. It was not find references about re-infections by SARS-CoV-2 in Mexico; in Celaya Guanajuato was presented the case of female patient who has symptoms of COVID-19, with new positive PCR, required hospitalization and high-flow oxygen therapy when presenting with pneumonia, was performed simple chest Computing tomography, IgG and IgM antibodies.The evolution was good with discharge from hospitalization 72 hours after admission, continuing his outpatient management until discharge.