An interesting study published in the New England Journal of Medicine, October 15 2020 by Anderson and others evaluated the Moderna mRNA-1273 vaccine.
Non-human primates received 10 or 100 mcg of the mRNA-1273 vaccine encoding the profusion stabilised spike protein of SARS-CoV-2 or no vaccine. Antibody and T-cell responses were assessed before upper and lower airways challenge with SARS-CoV-2.
Acute viral application and viral genomes in bronchoalveolar lavage fluid and nasal swab specimens were assessed by PCR and histopathological analysis and viral quantification were performed on lung tissue specimens.
The mRNA-1273 vaccine candidate induced antibody levels exceeding those in human convalescent phase serum.
Viral replication was not detected in bronchoalveolar lavage fluid by day two after challenge in seven of eight animals in both vaccinated groups.
No viral replication was detectable in the nose of any of the eight animals in the 100 mcg dose group by day two after challenge and limited inflammation or detectable viral genome or antigen was noted in lungs of animals in either vaccine group.
Vaccination of non-human primates with the Moderna mRNA-1273 vaccine induced a robust SARS-CoV-2 neutralising activity, rapid protection in the upper and lower airways and no pathological changes in the lungs.
Dr Paul Ettlinger
The London General Practice