Defining the antibody response to SARS-CoV-2 will be essential for understanding disease progression, long-term immunity, and vaccine efficacy. Investigators designed a study investigating the neutralizing antibody response among post-infected and post-vaccinated individuals to determine how the spike protein neutralizing antibody correlates with natural infection and vaccination and how mutations of viral strains affect associated antibodies. New Taipei City Municipal TuCheng Hospital established a special infectious pneumonia ward in May 2021 to treat patients infected with symptomatic SARS-CoV-2 patients. During the period, 97 patients were admitted and enrolled. In light of the current timing of the pandemic, most published serological studies are predominantly cross-sectional or, at most, include a longitudinal follow-up. Cognitive function and PhenoAgeAccel will be examined for SARS-CoV-2 N and S titers decline trend analysis to correlate long-COVID brain fog or early decline of N and S antibodies.Therefore, investigators designed a three-year longitudinal study to detect patients' SARS-CoV-2 neutralizing and spike antibodies.