A series of COVID cases have demonstrated the effectiveness of zinc as a treatment for COVID 19. Four patients with laboratory confirmed COVID-19 were treated with high dose zinc salt oral lozenges in a case series. After a day of high-dose zinc therapy, it was suggested that zinc therapy played a role in clinical recovery. 

The suggested mechanism of zinc action is that it works by inhibiting SARS-CoV-2 virus replication. In an uncontrolled case series, initiation of high-dose zinc salt lozenges was followed by symptomatic and objective improvement in patients with clinical signs and symptoms. In earlier randomized controlled trials, it has been shown that in common colds caused by coronaviruses, zinc acetate and zinc gluconate effectively treat the common cold. 

Reference: Finzi E. Treatment of SARS-CoV-2 with high dose oral zinc salts: A report on four patients. Int J Infect Dis. 2020; 99: 307-309.