The virus responsible for the ‘stomach flu’ or ‘winter vomiting disease‘ is causing more trouble than usual this winter in the US.
On December 5, just a month into the typical outbreak season, the US Centers for Disease Control and Prevention (CDC) reported no less than 91 cases of norovirus in just 7 days.
That same week in 2020, when many were isolating from the coronavirus, the CDC recorded only 2 cases of norovirus.
In the intervening years, the largest norovirus eruption this early in winter included just 56 cases.
What is driving the recent surge is unknown, but the sickness is emerging in pockets.
More than 40 norovirus cases in December hailed from Minnesota, where public health officials say they are experiencing almost twice the usual number.
A few days before Christmas, Jessica Hancock-Allen, the director of the infectious disease division at the Minnesota Department of Health, urged the public to take extra care at holiday gatherings.
“We want to make sure people are aware of this increase in norovirus outbreaks and taking steps to prevent spreading illness to family or friends,” said Hancock-Allen in a press release.
Typically, the US records about 2,500 cases of norovirus each year, with the majority of cases occurring between November and April.
Norovirus is not the same as influenza, despite the fact that it’s often called a ‘flu’. The pathogen causes gastrointestinal inflammation that can lead to symptoms like vomiting, diarrhea, stomach pain, and fever for around one to three days.
While spoiled food can transmit the highly contagious norovirus, direct contact with an infected person causes most outbreaks. Infections can occur at any time of year, but they are most common in winter, when people are cooped up inside. The virus also seems to cope quite well in the cold.
Part of the reason norovirus is so challenging to contain is because it can be contagious in a person’s poop hours before they start feeling sick, and can remain so for several weeks after they begin to feel better. This can lead to patients unknowingly spreading their sickness.
As such, health officials advise norovirus patients to stay home and isolate for two days after their symptoms cease, drinking lots of water to ensure they replace their lost fluids.
For those who have yet to get sick, hot water and soap are some of the best options to prevent infection, especially before preparing food or sitting down to eat. Most hand sanitizers do not kill norovirus, Hancock-Allen and her division warn.
Beyond infecting food or drink, norovirus can also survive on surfaces for weeks at a time. These should be disinfected immediately after they come into contact with bodily fluids, such as vomit or diarrhea, officials say.
To clean the area, the CDC suggests using a chlorine bleach solution with a concentration of 1,000 to 5,000 ppm, leaving the disinfectant solution on the affected area for at least 5 minutes.
The area should then be cleaned again with soap and hot water.
The cumulative tally of norovirus cases between August and December 5 reached almost 500. The CDC has yet to publish data from the rest of December, but after weeks of holiday gatherings, there was surely ample opportunity for further spread.
