Vaccination status, favipiravir, and micronutrient supplementation roles in post-COVID symptoms: A longitudinal study

Introduction Post-COVID symptoms are the new concern in the COVID-19 pandemic, where recovered patients experience residual symptoms affecting their quality of life. Therefore, it is imperative to evaluate the role of complete vaccination, prescribed medication, and micronutrients during COVID episodes in the occurrence of post-COVID symptoms. Method A longitudinal evaluation of Indonesia's recovered COVID-19 patients was performed using the data collected from July 2021 and extracted in mid-February 2022. All participants were confirmed with a Real-Time Polymerase Chain Reaction test (PCR) and/or antigen test. This study collected demography and comorbidities information, symptoms and treatment of COVID-19, and collection of self-reported post-COVID symptoms every 30 days within 90 days after diagnosis/onset. Exposures of interest include vaccination status, Favipiravir administration, Vitamin C, Vitamin D, and Zinc. A Generalized Estimating Equation (GEE) was used to evaluate the longitudinal effect of exposures, presented with adjusted odds ratios and its 95% confidence interval. Results A total of 923 participants (18.2% fully-vaccinated) were involved in the study, with 79.7% being non-hospitalized. Only 25.7% did not develop any residual symptoms within 90 days. Fatigue was the most reported post-COVID symptom in each measurement time (39.5%, 16.3%, and 7.3%). Full-vaccination was effective against chronic cough (aOR 0.527, 95% CI 0.286-0.971), chronic headache (aOR 0.317, 95% CI 0.163-0.616), and chronic arthritis (aOR 0.285, 95% CI 0.116-0.703). The combination of micronutrient supplementations and Favipiravir gave no significant effect on all post-COVID symptoms. However, early initiation of Favipiravir and delaying vitamin D administration were associated with arthritis. Conclusion Full vaccination of COVID-19 prevents the disease and the development of residual symptoms when infected with SARS-COV-2. Hence, it is crucial to reconsider the prescription of micronutrient supplementation or adjust the dose of Favipiravir in the current guideline.