Mask mandates return in multiple states as doctors warn of 'quad-demic' of four viral infections | 2 Jan 2025 | Four viruses are hitting the US as millions go back to work after the holidays, data show. Official figures reveal that infections cause by flu, Covid, RSV (a respiratory illness that causes the cold) and norovirus (sometimes called the stomach flu) all started to surge over the Christmas period, when families gathered to celebrate. The surge in infections is prompting a return of mask mandates in some states, with a hospital system in Wisconsin this week becoming the latest to reinstate them. Hospitals in parts of California, Illinois, Indiana and New Jersey have also brought back the rules for staff and visitors. Officials in New York City are urging people to consider wearing a face mask on public transport. [Do not comply.]