Evaluation of late disorders as possible long-COVID and/or vaccination consequences

Abstract

Abstract Background:Following SARS-CoV-2 outbreak, another crisis has been established by progress or persistence of COVID-19 symptoms, as post or long COVID, which is critical to be recognized according to increasing number of late symptoms reports. In this study, we investigated long-term disorders in vaccinated individuals who developed late adverse events/side effects post-vaccination and/or COVID-19 episode owing to the challenging differentiation between them. Methods: The vaccinated individuals of four vaccine regimens including inactivated virus-based/prime-boost group, inactivated virus-based prime/subunit protein-based boost, adenovirus-based prime/boost and adenovirus-based prime/subunit protein-based boost were followed from the first dose of vaccination up to 6-month post the booster shot. All the vaccine adverse events were documented through in-depth interview using a researcher-made questionnaire as well as the COVID-19 history and demographics. The medical history of all the cases were also collected and the late disorders post-vaccination were investigated by Adverse Events Committee of Pasteur Institute of Iran. Results: Totally 329 individuals who got 3 doses of vaccination were followed 6 months after the booster shots among whom 41 (12.4%) of investigated cases (including 31 females) with the mean age of 40.9±10.48 years had a type of disorder following vaccination. The late adverse events/side effects were captured in various forms among which gynecological and osteoarticular involvements were the most common ones. After evaluation of the medical background, age, vaccination and the date of disorder initiation, 39% of the documented complains have been found to be linked with long-COVID-19 as a trigger. Interestingly, the average time of symptoms persistence was 155±10.4 days and mostly continued up to the end of the study. Conclusion: In this era in which the vast majority of the global population have developed COVID-19 and/or got vaccinated against it, identification of the late disorders as the vaccine side effect or long-COVID manifestation is difficult. Therefore, some complications though late ones, might be a possible consequence of any SARS-CoV-2 infection or vaccination. This study takes the advantage of long-term follow-up which presents various forms of late events in each episode of COVID-19 infection and vaccination. The rate of late-disorders in the present study also highlights the importance of long-term follow-up studies among population worldwide.