Reply to Marakasova and Baranova, "MMR Vaccine and COVID-19: Measles Protein Homology May Contribute to Cross-Reactivity or to Complement Activation Protection"

Marakasova and Baranova make a good, incremental step trying to explain the results of our paper, "Analysis of Measles-Mumps-Rubella (MMR) Titers of Recovered COVID-19 Patients" (1). We believe the predictable waning of mumps IgG titers over time allows mumps titers to serve as a proxy measure of overall MMR II vaccine persistence. Even though we observed a significant inverse correlation only with mumps virus titers, any of the components of MMR II alone or in tandem, including measles as Marakasova and Baranova suggest, could be responsible for what we observed. They present a conventional approach to matching protein sequence and structure to structures recognized by antibodies generated during and after vaccination or disease.