COVID-19 has challenged the scientific community in the search for biological markers and information that can contribute to the early management of the severe disease. Given the global scale of COVID-19, including reports of reinfection even in the presence of effective vaccines, we have not yet been able to eradicate the disease. This factor implies the emergence of new waves and an increasing number of hospitalizations. This study aimed to characterize the neutralizing antibody (Nab) geometric mean titers (GMTs) in hospitalized patients with COVID-19 and to evaluate the association with length of stay, comorbidities, and patient outcome. Among the 103 participants, 84 (81.5%) had some previous condition associated with worsening health, and 31 (30%) died. We found that neutralization potency varied greatly across individuals and was significantly higher in patients discharged before 14 days than in patients who stayed longer in the hospital. During the study period, 15 people living with HIV (PLWH) were hospitalized, and no significant difference in clinical characteristics or anti-SARS-CoV-2 Nabs was observed. However, PLWH with severe COVID-19 were younger (41.7, IQR=17.5) than other hospitalized COVID-19 patients (59.3, IQR=22,P<0.01). A high anti-HIV-1 antibody GMT of 583.9 (95% CI: 344-990) was detected, demonstrating maintenance of anti-HIV-1 Nab production among PLWH coinfected with SARS-CoV-2. Therefore, these results indicate that neutralizing antibodies are not the only immunological response capable of controlling disease progression. Nevertheless, these data highlight the importance of more Nab screening studies to predict shorter hospital stays.