mRNA-1273 protects against SARS-CoV-2 beta infection in nonhuman primates

Nat Immunol. 2021 Oct;22(10):1306-1315. doi: 10.1038/s41590-021-01021-0. Epub 2021 Aug 20.


B.1.351 is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant most resistant to antibody neutralization. We demonstrate how the dose and number of immunizations influence protection. Nonhuman primates received two doses of 30 or 100 µg of Moderna's mRNA-1273 vaccine, a single immunization of 30 µg, or no vaccine. Two doses of 100 µg of mRNA-1273 induced 50% inhibitory reciprocal serum dilution neutralizing antibody titers against live SARS-CoV-2 p.Asp614Gly and B.1.351 of 3,300 and 240, respectively. Higher neutralizing responses against B.1.617.2 were also observed after two doses compared to a single dose. After challenge with B.1.351, there was ~4- to 5-log10 reduction of viral subgenomic RNA and low to undetectable replication in bronchoalveolar lavages in the two-dose vaccine groups, with a 1-log10 reduction in nasal swabs in the 100-µg group. These data establish that a two-dose regimen of mRNA-1273 will be critical for providing upper and lower airway protection against major variants of concern.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies, Neutralizing / immunology
  • Antibodies, Viral / immunology
  • COVID-19 / immunology*
  • COVID-19 / virology
  • COVID-19 Vaccines / immunology*
  • Cell Line
  • Chlorocebus aethiops
  • Female
  • Humans
  • Macaca mulatta
  • Male
  • Mesocricetus
  • Primates / immunology*
  • Primates / virology
  • RNA, Viral / immunology
  • SARS-CoV-2 / immunology*
  • Spike Glycoprotein, Coronavirus / immunology
  • Vaccination / methods
  • Vero Cells
  • Viral Load / methods


  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19 Vaccines
  • RNA, Viral
  • Spike Glycoprotein, Coronavirus
  • mRNA-1273 vaccine

Supplementary concepts

  • SARS-CoV-2 variants