"Stomach flu" isn’t actually flu—it’s a highly transmissible infectious virus called Norwalk virus, or norovirus. Ninety percent of epidemics of gastroenteritis, a stomach disease characterized by abdominal pain, nausea and vomiting, diarrhea, and often fever and lethargy, that aren’t due to bacteria are caused by norovirus. The virus is also extremely transmissible: it’s passed directly from person to person, it gets in the air when a stricken person vomits or when vomit or diarrhea is flushed, and it can be passed in contaminated food.
Scary as that sounds, the good news is that the spread can be stopped by hygiene measures. Chlorine bleach kills the virus on surfaces, and proper cooking renders it inert in food—that means at least 140 degrees Fahrenheit for at least five minutes, particularly with sauces and shellfish. What’s more, copper and copper alloys seem to kill Norwalk virus on contact, according to research published in September. Surfaces and cookware that is at least 60 percent copper destroys the virus even at room temperature, though doctors caution that it’s still important to keep the surfaces clean.
On the other side of prevention, researchers announced a step forward in the development of the first-ever norovirus vaccine. Because of the protean nature of the virus and the brief duration of immunity after infection—someone who has had a norovirus infection starts to become susceptible to the same strain after just six months, and immunity is entirely gone after two years—it has been difficult to create a vaccine to effectively protect people who are exposed to the virus. However, in trials, volunteers who received the test vaccine got sick after deliberate exposure to norovirus half as often as those who did not.
This could be important to very old or very young patients, who are particularly prone to have adverse outcomes from infection. Most people who are infected eventually recover, but there are around 800 deaths annually. There’s no treatment for the disease, but people who get sick are advised to stay hydrated to counteract fluid loss and wait it out at home.