With cases of Covid-19, seasonal flu, and other respiratory illnesses spiking across the US, hospitals in four states have brought back mask mandates for both patients and healthcare workers.

This move represents a return to stricter safety measures after mask mandates were lifted in many places following the decline of the Omicron wave in 2022.

New York, California, Illinois, and Massachusetts are among the states where hospitals are reinstating mask requirements.

New York City Health Commissioner Dr. Ashwin Vasan told WABC TV that all 11 public hospitals, 30 health centres, and five long-term care facilities are once again mandating masks.

"What we don't want is staffing shortages, right? When we saw the omicron wave in 2022, the biggest issues were not only people getting sick, but that we had a lot of frontline health workers; they were out with Covid-19," Vasan told WABC.

The renewed focus on masking comes as the winter months see a rise in respiratory illnesses. US Centres for Disease Control and Prevention data reveals a 16% increase in Covid-19 hospitalisations in the US between December 17-23 compared to the previous week, with over 29,000 individuals hospitalised with the virus. Additionally, over 14,700 flu hospitalisations were reported during the same period.

More than 1.1 million Americans have died from Covid-19, as per CDC data, which is a bigger number than most developed countries.

While mask mandates were a contentious issue during the pandemic, sparking debate and division, healthcare facilities are prioritising the health and safety of both patients and staff. The reinstitution of mask mandates underscores the ongoing threat of Covid-19 and other respiratory illnesses, particularly during the winter months.