Background: Incidence and severity of SARS-CoV2 infection are significantly lower in children and teenagers proposing that certain vaccines, routinely administered to neonates and children may provide cross-protection against this emerging infection. Objective: To assess the cross-protection induced by prior measles, mumps and rubella (MMR) vaccinations against COVID-19. Methods: The antibody responses to MMR and tetanus vaccines were determined in 53 patients affected with SARS-CoV2 infection and 52 age-matched healthy subjects. Serum levels of antibodies specific for NP and RBD of SARS-CoV2 were also determined in both groups of subjects with ELISA. Results: Our results revealed significant differences in anti-NP (p <0.0001) and anti-RBD (p <0.0001) IgG levels between patients and healthy controls. While the levels of rubella- and mumps specific IgG were not different in the two groups of subjects, measles-specific IgG was significantly higher in patients (p <0.01). The serum titer of anti-tetanus antibody, however, was significantly lower in patients compared to healthy individuals (p <0.01). Conclusion: Our findings suggest that measles vaccination triggers those B cells cross-reactive with SARS-CoV2 antigens leading to the production of increased levels of measles-specific antibody.