Homologous protein domains in SARS-CoV-2 and measles, mumps and rubella viruses: preliminary evidence that MMR vaccine might provide protection against COVID-19

Robin Franklin; Adam Young; Bjoern Neumann; Rocio Fernandez; Alexis Joannides; Amir Reyahi; Yorgo Modis

Spike glycoproteins are class I viral membrane fusion proteins that share structural similarities with the Fusion proteins from both measles and mumps viruses. The Macro domains of SARS-CoV-2 and rubella virus share 29% amino acid sequence identity. Interestingly, the residues conserved in the SARS-CoV-2 and rubella Macro domains include surface-exposed residues and are present in the attenuated rubella virus used in the MMR vaccine. We identified at a population level that both older populations and males are both more likely to die from COVID-19, and less likely to be seropositive for rubella-specific immunity, based on historical vaccination programmes of all three countries considered in this report. Finally, the hypothesis that this macro domain could be recognised by antibodies raised against rubella was supported by data that demonstrated that patients who have SARS-CoV2 infection had raised levels of rubella IgG to a level in keeping with secondary rubella infection. Taken together, we suggest that MMR will not prevent COVID-19 infection but could potentially reduce poor outcome. To conclude whether MMR vaccination can improve the outcomes from Covid-19 infection, a study using individual based data to compare MMR immunity status in the affected population is warranted.