Abstract There are many doubts about the SARS-CoV-2 immune response's length, and it is unknown whether those patients may exhibit different kinetics in the secretion of IgG anti-SARS-CoV2 according to the severity of their infection. This research aimed to evaluate IgG antibodies' kinetics and persistence against the SARS-CoV-2 Spike protein in a group of COVID-19 patients with different clinical disease presentations in the Colombian Caribbean region. Two blood samples were taken. The first one was at the first surge in August 2020; the second was six months later, February 2021. The study showed a decrease of 61.1% in their median of IgG antibodies after six months (P > 0.0001). According to the clinical form of COVD-19, the patients that required hospitalization (moderate or severe) COVD-19 showed a lower secretion of IgG against SARS-CoV2 and a higher negative seroconversion for IgG 69.2% in the second serological evaluation (P < 0.05). Thus, the drop of antibodies-SARS-CoV-2 is typical in all the clinical forms of COVID-19. It is worrisome in patients with moderate or severe clinical forms. The evaluation of natural immunity is mandatory to define the vaccination strategy mainly in patients that suffered complicated forms of COVID-19.