ABSTRACT
Immune correlates of protection can be used as surrogate endpoints for vaccine efficacy. Here, nonhuman primates (NHPs) received either no vaccine or doses ranging from 0.3 to 100 µg of the mRNA-1273 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. mRNA-1273 vaccination elicited circulating and mucosal antibody responses in a dose-dependent manner. Viral replication was significantly reduced in bronchoalveolar lavages and nasal swabs after SARS-CoV-2 challenge in vaccinated animals and most strongly correlated with levels of antiS antibody and neutralizing activity. Lower antibody levels were needed for reduction of viral replication in the lower airway than in the upper airway. Passive transfer of mRNA-1273induced immunoglobulin G to naïve hamsters was sufficient to mediate protection. Thus, mRNA-1273 vaccineinduced humoral immune responses are a mechanistic correlate of protection against SARS-CoV-2 in NHPs.
Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Immunogenicity, Vaccine , SARS-CoV-2/immunology , 2019-nCoV Vaccine mRNA-1273 , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antibody Affinity , Bronchoalveolar Lavage Fluid/immunology , Bronchoalveolar Lavage Fluid/virology , CD4-Positive T-Lymphocytes/immunology , COVID-19/immunology , COVID-19/virology , Female , Immunization Schedule , Immunization, Passive , Immunization, Secondary , Immunoglobulin G/immunology , Immunologic Memory , Lung/immunology , Lung/virology , Macaca mulatta , Male , Mesocricetus , Nasal Mucosa/immunology , Nasal Mucosa/virology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Vaccine Potency , Virus ReplicationABSTRACT
Immune correlates of protection can be used as surrogate endpoints for vaccine efficacy. The nonhuman primate (NHP) model of SARS-CoV-2 infection replicates key features of human infection and may be used to define immune correlates of protection following vaccination. Here, NHP received either no vaccine or doses ranging from 0.3 - 100 µg of mRNA-1273, a mRNA vaccine encoding the prefusion-stabilized SARS-CoV-2 spike (S-2P) protein encapsulated in a lipid nanoparticle. mRNA-1273 vaccination elicited robust circulating and mucosal antibody responses in a dose-dependent manner. Viral replication was significantly reduced in bronchoalveolar lavages and nasal swabs following SARS-CoV-2 challenge in vaccinated animals and was most strongly correlated with levels of anti-S antibody binding and neutralizing activity. Consistent with antibodies being a correlate of protection, passive transfer of vaccine-induced IgG to naïve hamsters was sufficient to mediate protection. Taken together, these data show that mRNA-1273 vaccine-induced humoral immune responses are a mechanistic correlate of protection against SARS-CoV-2 infection in NHP. ONE-SENTENCE SUMMARY: mRNA-1273 vaccine-induced antibody responses are a mechanistic correlate of protection against SARS-CoV-2 infection in NHP.