Concurrent administration of COVID-19 vaccine and seasonal influenza vaccine: Expected rate of adverse effect

Abstract

Sir, The COVID-19 vaccine and influenza (flu) vaccination (dual immunization) may be administered simultaneously, per the clinical recommendation.[1] According to the results, dual immunization might be a good strategy to reduce the prevalence of infectious respiratory disorders.[1] In 63 of the investigations, a report by Xie et al. confirms the efficacy and safety of the combined COVID-19 and flu vaccination. There were no changes in adverse events or anti-spike antibody levels.[1] In this study, the authors go into greater detail about 42 occurrences of concurrent COVID-19 and seasonal flu vaccination delivery. The concurrent dual vaccines were given in every case in accordance with local norms. Based on monitoring of the reported adverse event,[2] there is no adverse effect. However, the mentioned reports are only very small observations studied and there is still no exact data on the incidence rate of adverse effects in the case of concurrent administration of COVID-19 vaccine and seasonal influenza vaccine is available. Essentially, each vaccine, COVID-19 vaccine, and seasonal influenza vaccine have its own incidence rate of adverse effects. When the two vaccines are used together, the combined chance of an adverse effect can be expected.[3] However, there is also the possibility of both vaccines having an adverse effect. Using a mathematical model-based approach, based on set theory, the final expected rate of adverse effect in case of concurrent administration of COVID-19 vaccine and seasonal influenza vaccine will be equal to “chance of adverse effect due to COVID-19 vaccine + Change of adverse effect due to influenza vaccine − Chance of jointed probability due to both vaccines.” This model is being used to predict the expected rate of adverse effects associated with the concurrent administration of the COVID-19 vaccine and seasonal influenza vaccine. According to previous data, the risk of adverse effects from the COVID-19 vaccine is 14.97/100,000 doses[4] and the risk of serious adverse effects from the influenza vaccine is 0.07 cases/100,000 distributed doses of the vaccine.[5] The combined chance resulting from both vaccines is projected to be per 0.0000001/100,000 doses, which is incredibly small. Calculated to be 15.04/100,000 doses, which is just nonsignificant for nondual COVID-19 vaccine administration, is the ultimate predicted rate of major side effects in the case of concurrent administration of COVID-19 vaccination and seasonal influenza vaccine. Therefore, it can attest to the safety and applicability of concurrent administration of the COVID-19 vaccine and the seasonal influenza vaccination in clinical settings. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.