SARS-CoV2 infects respiratory epithelial cells via its cellular
receptor angiotensin-converting
enzyme 2, causing a
viral pneumonia with pronounced
inflammation resulting in significant damage to the lungs and other organ systems, including the kidneys, though symptoms and disease severity are quite variable depending on the intensity of exposure and presence of underlying conditions that may affect the immune response. The resulting disease,
coronavirus disease 2019 (COVID-19), can cause multi-organ system dysfunction in patients requiring hospitalisation and
intensive care treatment. Serious
infections like
COVID-19 often negatively affect nutritional status, and the resulting
nutritional deficiencies may increase disease severity and impair recovery. One example is the
viral infection measles, where associated
vitamin A (VA) deficiency increases disease severity and appropriately timed supplementation during recovery reduces mortality and hastens recovery. VA may play a similar role in
COVID-19. First, VA is important in maintaining innate and adaptive immunity to promote clearance of a primary
infection as well as minimise risks from
secondary infections. Second, VA plays a unique role in the respiratory tract, minimising damaging
inflammation, supporting repair of respiratory epithelium and preventing
fibrosis. Third, VA deficiency may develop during
COVID-19 due to specific effects on lung and liver stores caused by
inflammation and impaired kidney function, suggesting that supplements may be needed to restore adequate status. Fourth, VA supplementation may counteract adverse effects of SARS-CoV2 on the
angiotensin system as well as minimises adverse effects of some
COVID-19 therapies. Evaluating interactions of SARS-CoV2
infection with VA metabolism may thus provide improved
COVID-19 therapy.