Weighted analysis of symptom profile by vaccination status in positive SARS-CoV-2 cases: observational study in São Gonçalo, Brazil

This study investigates symptom associations in SARS-CoV-2 positive individuals based on vaccination status. Unvaccinated individuals exhibited significantly higher odds of experiencing severe symptoms, including fever > 38.5□°C ( _log OR = 3.64, 95% CI: 1.52–5.77, p = 0.0008), rhinitis ( _log OR = 2.94, 95% CI: 0.82–5.05, p = 0.0065), headache ( _log OR = 2.17, 95% CI: 0.06–4.28, p = 0.0436), and myalgia ( _log OR = 3.25, 95% CI: 1.17–5.34, p = 0.0023). Conversely, unvaccinated individuals were less likely to report cough ( _log OR = -2.44, 95% CI: -4.53 to -0.34, p = 0.0226), potentially reflecting behavioral factors related to vaccine hesitancy. Among vaccinated participants, symptom profiles varied by vaccine type. Both Oxford-AstraZeneca and Pfizer-BNT162b2 vaccines were associated with increased odds of loss of smell ( _log OR = 0.81 and 1.47, respectively) and loss of taste ( _log OR = 0.75 for Oxford-AstraZeneca). Additionally, the Oxford-AstraZeneca vaccine was linked to dyspnea ( _log OR = 0.85, 95% CI: 0.02–1.69, p = 0.0449). These findings suggest that vaccination reduces the likelihood of severe systemic and respiratory symptoms while influencing specific symptom manifestations in breakthrough cases. Ongoing research is essential to understand vaccine-specific immune responses and their impact on clinical outcomes.