The discovery of two new receptors — neuropilin-1 and CD147 — explains why Covid-19 is a mix of respiratory, vascular, nervous, olfactory, and immunological diseases. — Abstract vector created by macrovector — www.freepik.com Ithas been odd right from the start. If SARS-CoV-2 (the novel coronavirus that causes Covid-19) uses the angiotensin-converting enzyme 2 (ACE2) as a receptor to infect cells, then why is it a lung disease when the lungs have low levels of ACE2?