Norovirus cases are on the rise across America. Here's how to protect yourself

As winter comes to an end, COVID-19 cases are waning. But that doesn’t mean that the country is in the clear in regards to illness. Another contagious virus, norovirus, is on the rise, according to data from the Centers for Disease Control and Prevention.

Local reports show that cases are especially surging in Texas, Florida, the Northeast and California. Sewage analysis data from Wastewater Scan, which can give a rough estimate of cases, also shows a steep rise over the past 180 days.

According to the CDC, there are between 19 million to 21 million cases of norovirus a year, and an estimated 900 people die from it while 109,000 are hospitalized. In fact, it’s estimated that one in every 15 people per year get infected. The COVID-19 pandemic ushered in a new era of public health in the United States where masking became both more common and politicized. Is wearing a mask something people can do as norovirus surges this spring? 

“Norovirus is highly contagious,” Dr. Linda Yancey, infectious disease specialist at Memorial Hermann Health System in Houston, told Salon via email. “It only takes a few viral particles to cause an infection.”

Specifically, it takes less than 100 particles to make a person sick. It’s not hard for an infected person to infect another when they shed billions of virus particles in their stool and vomit. Unwashed or less than thoroughly washed hands can easily lead to another person’s illness.

Norovirus is primarily spread through contact with an infected person. It can also be spread from infected food and water, or by touching surfaces that have the virus on them. Infected people are contagious the moment they start to feel sick and for a few days after. But infected surfaces can linger and still have the power to infect people days later. For these reasons, masking is unfortunately not going to help very much, experts say.

“No, norovirus is not spread through the air,” Yancey said when asked about masking. “It is spread by direct contact with an infected person, surface, or food and water.”

Katelyn Jetelina, an epidemiologist and author of Your Local Epidemiologist, told Salon via email a parent of a sick child who has norovirus can opt to wear a surgical mask if they have one laying around and their child is actively throwing up. 

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“This will help with droplets,” she said, adding that while some research has shown that norovirus can be airborne, “what is possible is not always probable.” That said, “The best thing to do is to wash hands and use bleach-based products to wipe down surfaces; this is a stubborn little virus and it takes a lot to kill.”

Public health officials recommend bleach because norovirus is known to survive some disinfectants, including hand sanitizer.

“Norovirus is not killed by hand sanitizer,” Yancey said. “It is controlled by handwashing with soap and water; you can protect yourself by paying close attention to handwashing with soap and water, by making sure that you are drinking clean water, and by paying attention to food safety regulations.”

Unfortunately, there is no vaccine or way to treat norovirus. When someone is infected, it can cause diarrhea and vomiting multiple times a day, leading people to become severely dehydrated. Symptoms can be managed, like drinking fluids to make up for dehydration and fluid loss, but antibiotics won’t help as those drugs target bacteria.

The good news is that norovirus cases are usually highest between November to April in the United States. While we are seeing a surge now, it will hopefully wane by early summer. Most infected people get better within one to three days.While we are hearing a lot about norovirus in the news, experts say it’s not any worse this year than previous years — at least not yet. 

“It’s about the same as previous years,” Jetelina said. “Our surveillance is pretty poor (compared to COVID-19 for example), but we can track how many people test positive [and] that rate is about the same as last year.”