A highly immunogenic and effective measles virus-based Th1-biased COVID-19 vaccine

Proc Natl Acad Sci U S A. 2020 Dec 22;117(51):32657-32666. doi: 10.1073/pnas.2014468117. Epub 2020 Nov 30.


The COVID-19 pandemic is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and has spread worldwide, with millions of cases and more than 1 million deaths to date. The gravity of the situation mandates accelerated efforts to identify safe and effective vaccines. Here, we generated measles virus (MeV)-based vaccine candidates expressing the SARS-CoV-2 spike glycoprotein (S). Insertion of the full-length S protein gene in two different MeV genomic positions resulted in modulated S protein expression. The variant with lower S protein expression levels was genetically stable and induced high levels of effective Th1-biased antibody and T cell responses in mice after two immunizations. In addition to neutralizing IgG antibody responses in a protective range, multifunctional CD8+ and CD4+ T cell responses with S protein-specific killing activity were detected. Upon challenge using a mouse-adapted SARS-CoV-2, virus loads in vaccinated mice were significantly lower, while vaccinated Syrian hamsters revealed protection in a harsh challenge setup using an early-passage human patient isolate. These results are highly encouraging and support further development of MeV-based COVID-19 vaccines.

Keywords: COVID-19; SARS-CoV-2; Th1 immune bias; effective immunity; measles vaccine platform.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Viral / immunology
  • COVID-19 / epidemiology
  • COVID-19 / immunology
  • COVID-19 / prevention & control*
  • COVID-19 / virology
  • COVID-19 Vaccines / administration & dosage
  • COVID-19 Vaccines / genetics
  • COVID-19 Vaccines / immunology*
  • Humans
  • Measles Vaccine / genetics
  • Measles Vaccine / immunology
  • Measles virus / genetics
  • Measles virus / immunology*
  • Mice
  • Pandemics
  • SARS-CoV-2 / genetics
  • SARS-CoV-2 / immunology*
  • Spike Glycoprotein, Coronavirus / administration & dosage
  • Spike Glycoprotein, Coronavirus / genetics
  • Spike Glycoprotein, Coronavirus / immunology
  • T-Lymphocytes / immunology
  • Th1 Cells / immunology*


  • Antibodies, Viral
  • COVID-19 Vaccines
  • Measles Vaccine
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2