Vincent Munster - January 20, 2021

Vincent Munster, PhD, Chief Virus Ecology Section, Rocky Mountain Laboratories NIAID/NIH, "Medical countermeasure development against COVID19 in the rhesus macaque model"

This study introduced a nasal spray as a better vaccination strategy in the protection of the upper respiratory system. The SARS-CoV-2 challenging study indicated that Rhesus macaques show similar clinical and histopathological signs as expressed in humans. The viral RNA was shed from upper respiratory tracts (nose and throat) up to 12-15 days of post-infection. The human also spread a high dose of the viral RNA from the nose. Adenovirus-based spike protein vaccine (ChAdOx1 nCoV-19) was developed and this induced good humoral and cellular responses in mice and rhesus macaques models. The vaccine protects the lower respiratory tract against SARS-CoV-2 infection but not effective in the upper respiratory tract because Intramuscular (IM) injection provides systemic protection but did not prevent well the viral replication in upper respiratory tracts. The intranasal vaccine protected both the upper and lower respiratory tract in hamster and rhesus macaques models. The nasal vaccination induces antibodies (IgG and IgA) against the virus and reduced infectious transmission. Additionally, serum binding assay showed this AstraZeneca vaccine would have a protective effect on current UK variants.