MA Among States Seeing Norovirus Stomach Bug Case Increases

MASSACHUSETTS — Cases of the common winter stomach bug called norovirus have been on the rise in New England and across the Northeast recently, according to recent data published by the Centers for Disease Control and Prevention.

Norovirus (also called Norwalk-like viruses, or NLV) is a highly contagious virus that causes vomiting and diarrhea. Often called the "stomach flu" or gastroenteritis, anyone can become infected or sick with norovirus, according to health officials.

"NLV are believed to be one of the most common causes of foodborne illness in the United States. Since it is difficult to test for NLV in the laboratory; it is hard to say how many people get infected by NLV in Massachusetts," the state Department of Public Health says.

Norovirus is often spread through direct contact with an infected person, eating food or drinking liquids contaminated with the virus, or touching contaminated surfaces, health officials said. It also spreads through the feces and vomit of an infected person. The virus can live on surfaces for long periods, and hand sanitizer doesn't typically kill the germs.

According to CDC data, the three-week average for positive norovirus tests in the Northeast region — which includes Massachusetts — reached nearly 14 percent over the week ending Feb. 3, and has only fallen slightly to 13.4 percent over the week ending Feb. 17.

Norovirus typically spikes in wintertime when people are indoors in close contact. The norovirus season peaked in 2023 over the end of February and first weeks of March, according to CDC data.

Norovirus typically infects between 19 and 21 million people per year, resulting in about 900 deaths and nearly 500,000 emergency room visits on average.

Massachusetts is one of 15 states that participates in the NoroSTAT program, reporting individual norovirus outbreaks to the CDC. According to NoroSTAT data, outbreaks typically peaked in December and January between 2012 and 2020. But peaks have been appearing later in recent years. Between 2021 and 2023, outbreaks peaked in February and early March.

The state Department of Public Health doesn't publish data on norovirus cases in Massachusetts, but does offer tips on how to avoid the bug.