Background: The article presents the results of a longitudinal study performed to assess the humoral immune response to the Johnson & Johnson (J&J) COVID-19 vaccine (Ad26.COV2.S) in a low-income, Hispanic patient population. In our work, we evaluate the COVID-19 health status of the patient population following vaccination. This work is a follow-up of a pilot study that analyses additional data to better understand the impact of the vaccine. Methods: Longitudinal cohort study testing the antibody responses of patients each visit within 120 days (initial, 1st follow-up, and 2nd follow-up). This study used the Clungene® SARS-CoV-2 IgG/IgM Rapid Test Cassette to determine the presence of binding antibodies resulting from the J&J COVID-19 vaccine. Results: Fifty-seven (57) patients were eligible for participation in this study after initial baseline antibodies were measured; seventy-four (74) patients were requested to participate, 17 were excluded because moderate to strong immunoglobulin G (IgG)/immunoglobulin M (IgM) responses. High loss to follow-up were multifactorial, but a predominant reason was travel out of state for work or return to country of origin.