Is there a norovirus vaccine? Here's how the highly-contagious stomach bug spreads

LOS ANGELES - Cases of norovirus are spiking in parts of the U.S. this winter, according to the latest government data from the U.S. Centers for Disease Control and Prevention.

The most recent numbers show there were 91 outbreaks of norovirus reported during the week of Dec. 5, up from 69 outbreaks the last week of November.

Numbers from the past few years show a maximum of 65 outbreaks reported during that first week of December.

Here's what you need to know about the highly-contagious stomach bug.

What is norovirus?

Norovirus is the leading cause of foodborne illness in the United States, responsible for 58% of such infections acquired in the country each year, according to the CDC.

Noroviruses have been called "the perfect human pathogens." They’re a type of highly contagious stomach bug that causes severe vomiting and diarrhea, along with headache, fever and body aches. It spreads fast and far on surfaces and through the air in tiny droplets of vomit. Most people fully recover.

How does it spread?

Most norovirus outbreaks occur when people who are already infected spread the virus to others by direct means, such as through sharing food or eating utensils. Outbreaks can also be spread through food, water or contaminated surfaces.

Shellfish, especially oysters and clams, are also known to spread the bug, because they are filter feeders and can accumulate the virus from untreated sewage flowing into their habitats.

Cruises are often associated with norovirus, due to the close quarters and shared facilities. Nursing homes, hospitals, jails, and preschools can all be sites of an outbreak as well.

Avoiding raw or undercooked shellfish can also reduce the risk of infection. Since norovirus can survive temperatures up to 145°F, quick steaming will not kill the virus.

What are the symptoms?

A person usually develops symptoms 12 to 48 hours after being exposed to norovirus.

Most common symptoms include diarrhea, vomiting, nausea, and stomach pain. Other symptoms include fever, headache, and body aches,

Dehydration

If you have norovirus illness, you can feel extremely ill, and vomit or have diarrhea many times a day. This can lead to dehydration (loss of body fluids), especially in young children, older adults, and people with other illnesses. Symptoms of dehydration include:

• Decreased urination
• Dry mouth and throat
• Feeling dizzy when standing up
• Crying with few or no tears

Who's at risk?

People of all ages can get infected from norovirus. Young children, older people and those with weakened immune systems are most at risk, with dehydration from vomiting and diarrhea the top concern.

There is no medication to treat norovirus. Rehydration is recommended by drinking water and other liquids, with the exception of coffee, tea and alcohol.

Anyone suffering from dehydration should seek medical help. Symptoms of dehydration include a decrease in urination, dry mouth and throat, and feeling dizzy when standing. Dehydrated children may be unusually sleepy or fussy and cry with few or no tears.

Is there a vaccine?

There’s currently no approved vaccine for norovirus, although Moderna has begun a phase three trial in the U.S. for a vaccine using mRNA technology and aims to test it in 25,000 adults worldwide. Norovirus causes about 200,000 deaths worldwide each year. 

How can I protect myself?

Wash your hands 

Wash your hands often with soap and water for at least 20 seconds, especially:

• After using the toilet or changing diapers.
• Before eating, preparing, or handling food.
• Before giving yourself or someone else medicine.

Be aware that:

• Hand sanitizer does not work well against norovirus.
• You can use hand sanitizers in addition to hand washing, but hand sanitizer is not a substitute for handwashing, which is best.

Handle and prepare food safely

Before preparing and eating your food:

• Carefully wash fruits and vegetables well.
• Cook oysters and other shellfish thoroughly to an internal temperature of at least 145°F.
• Routinely clean and sanitize kitchen utensils, cutting boards, counters, and surfaces, especially after handling shellfish.
• Keep raw oysters away from ready-to-eat food in the grocery cart, refrigerator, and on cutting boards.
• Throw away food that might contain norovirus.

Be aware that:

• Noroviruses are relatively resistant to heat and can survive temperatures as high as 145°F.
• Quick steaming processes will not heat foods enough to kill noroviruses.
• Food contaminated with norovirus may look, smell, or taste normal.

Clean and disinfect surfaces

After someone vomits or has diarrhea:

• Wear rubber or disposable gloves and wipe the entire area with paper towels and throw them in a plastic trash bag.
• Disinfect the area as directed on the product label.To disinfect, use a chlorine bleach solution with a concentration of 1,000 to 5,000 ppm (5 to 25 tablespoons of household bleach [5% to 8%] per gallon of water) or use an EPA-registered disinfecting product against norovirus.
• To disinfect, use a chlorine bleach solution with a concentration of 1,000 to 5,000 ppm (5 to 25 tablespoons of household bleach [5% to 8%] per gallon of water) or use an EPA-registered disinfecting product against norovirus.
• Leave bleach disinfectant on the affected area for at least 5 minutes.
• Clean the entire area again with soap and hot water.
• Wash laundry, take out the trash, and wash your hands.

Wash laundry well

Immediately remove and wash clothes or linens that may have vomit or poop on them.

• Wear rubber or disposable gloves.
• Handle items carefully without shaking them.
• Wash the items with detergent and hot water at the maximum available cycle length and then machine dry them at the highest heat setting.
• Wash your hands after with soap and water.

Health