Norovirus outbreaks have surged across the United States this month, according to the Centers for Disease Control and Prevention (CDC).

In the first week of December alone, 91 suspected or confirmed outbreaks were reported—the highest number recorded during this period in recent years. This figure surpasses outbreak levels recorded in early December in the years leading up to the COVID-19 pandemic.

Although norovirus outbreaks can occur year-round, they are most prevalent between November and April. The highly contagious virus affects an estimated 19 to 21 million Americans annually, causing sudden and severe gastrointestinal symptoms.

In one notable incident this month, at least 80 people fell ill after consuming raw oysters served at a restaurant event in Los Angeles. The oysters, traced to British Columbia, Canada, were sold in 14 states and the District of Columbia before being recalled. The Food and Drug Administration (FDA) has warned against consuming these oysters.

Recent norovirus-related recalls have also included fresh and frozen berries, according to the FDA database. Authorities are urging the public to remain vigilant about food safety, especially during the peak norovirus season.