As students return to school, are face shields really effective against COVID-19? By: MarketWatch September 02, 2020 at 11:01 AM EDT Face shields and masks with valves perform differently at preventing COVID-19 transmission, studies show. Read More >> Related Stocks: Astrazeneca Plc ADR Banco Santander ADR Biontech Se ADR Gsk Plc ADR Johnson & Johnson Moderna Inc Nasdaq Composite Pfizer