Issue 512 – Battling Norovirus? Here’s How to Stay Protected

What is Norovirus?

Norovirus, previously known as Norwalk-like virus (NLVs), is a group of viruses that infect humans and cause gastroenteritis (inflammation of the stomach and intestines).

Symptoms of Norovirus

Common symptoms include nausea, vomiting, diarrhea, and abdominal cramps. Some may also experience fever, chills, fatigue, headache, and muscle aches. Young children are more likely to present with vomiting. Symptoms typically last between 1 to 10 days and resolve on their own.

Incubation Period

Symptoms usually appear 24 to 48 hours after exposure.

How Norovirus Spreads

1. Consuming food or water contaminated with the virus.
2. Touching contaminated surfaces and then touching your mouth, nose, or eyes.
3. Inhaling aerosolized particles from vomit or feces during close contact with infected individuals. Even a very small viral load can cause infection.

Who Is at Risk?

People of all ages can be infected. Outbreaks are common in crowded places like schools, hospitals, care homes, and shelters. While most people recover without complications, dehydration caused by vomiting and diarrhea can be dangerous, especially for infants, the elderly, immunocompromised individuals, and those requiring long-term care.

How Contagious Is Norovirus?

Norovirus is highly contagious and spreads easily through vomit and feces. Even after symptoms improve, infected individuals may continue shedding the virus in their stool for up to two weeks.

Is There a Cure for Norovirus?

There is no specific antiviral treatment. The key is to stay hydrated and replenish electrolytes. Oral rehydration solutions are recommended, especially for infants and children.

What to Do If You’re Infected

Stay hydrated and maintain adequate nutrition. Eat small, frequent meals of bland foods, and avoid oily or sugary items that may worsen diarrhea. Maintain good hygiene—wash hands frequently and thoroughly—and avoid contact with others to prevent transmission.

Can You Get Norovirus More Than Once? Is There a Vaccine?

Due to the virus’s high genetic variability, a previous infection does not guarantee immunity against other strains. There is currently no vaccine available for norovirus.

Daily Tips to Prevent Norovirus Infection

1. Practice proper hand hygiene, especially before preparing or eating food, after using the restroom, and after caring for someone who is sick or handling diapers.
2. Wash fruits and vegetables thoroughly. Avoid raw or undercooked seafood, especially shellfish. Use serving utensils like communal chopsticks and spoons when dining with others.
3. Disinfect surfaces and contaminated linens with bleach. Infected individuals should avoid preparing food or close contact with others for at least two days after symptoms stop.
4. Breastfeeding helps strengthen infants’ immunity.
5. Wear a mask when in public or when cleaning up vomit/feces to prevent airborne transmission.

How to Disinfect Using Bleach Solutions

Alcohol-based disinfectants are not effective against norovirus. Use a high-concentration bleach solution. Always wear gloves, a mask, apron, and eye protection. Prepare fresh solutions daily, label them clearly, and discard unused portions after 24 hours.

For general environmental disinfection (1,000 ppm):

• Large volume: Mix 200 mL bleach with 10 L water (10 tablespoons bleach + 8 large PET bottles of water).
• Small volume: Mix 20 mL bleach with 1 L water.

For vomit and feces disinfection (5,000 ppm):

• Large volume: Mix 1,000 mL bleach with 10 L water (50 tablespoons bleach + 8 large PET bottles of water).
• Small volume: Mix 100 mL bleach with 1 L water.

Source: Taiwan Centers for Disease Control (TCDC), Ministry of Health and Welfare