In addition to replicating in the lower respiratory tract, SARS-CoV-2 also replicates efficiently in the upper respiratory tract and causes no or few symptoms in the first phase of infection, like coronaviruses cause of common colds.
Pamoja na kuzalishwa katika njia ya chini ya kupumua, SARS-CoV-2 inaweza kuzalishwa katika sehemu ya juu ya njia ya kupumua kwa ufanisi na kusababisha dalili za wastani au kutoonyesha dalili zozote katika awamu ya awali ya maambukizi, sawa na virusi vingine vya CoV vinavyosababisha homa kali.