Norovirus is a highly contagious virus that causes acute gastroenteritis, commonly known as the “stomach bug” or “winter vomiting bug.” This infection primarily causes sudden onset of vomiting and diarrhea. Reinfection with norovirus is indeed possible.
Understanding Norovirus Immunity
After a norovirus infection, the body develops some immunity; however, this protection is often short-lived. Immunity to a specific norovirus strain can last from approximately two months to several years, but it tends to be strain-specific.
There are many different strains of norovirus. An infection with one strain generally provides limited or no protection against other strains. This genetic variability is a significant reason why individuals can experience multiple infections throughout their lives. Therefore, even if you have recently recovered from norovirus, exposure to a different strain can lead to another illness.
How Re-infection Occurs
Re-infection with norovirus can happen through several pathways. One common way is exposure to a new strain of the virus, against which the body has no existing immunity. Even if it is the same strain, immunity from a previous infection can wane over time, making an individual susceptible again.
Environmental contamination also plays a role in re-infection. Norovirus is extremely contagious and can survive on surfaces for days to weeks. This persistence allows the virus to spread easily through contaminated objects and surfaces, increasing the risk of re-exposure.
Individuals can also shed the virus even without displaying symptoms, making them asymptomatic carriers. They can shed viral particles in their stool and vomit. This shedding can continue for two weeks or more after symptoms have resolved, posing an ongoing risk of transmission and potential re-infection.
Strategies for Preventing Re-exposure
Practicing thorough handwashing is one of the most effective strategies to prevent norovirus re-exposure. Hands should be washed frequently with soap and water for at least 20 seconds, particularly after using the restroom, changing diapers, and before preparing or handling food. While alcohol-based hand sanitizers can be used as an additional measure, they are not as effective against norovirus and should not replace proper handwashing with soap and water.
Disinfection of contaminated surfaces is also important. After an illness involving vomiting or diarrhea, surfaces should be immediately cleaned and disinfected. A bleach solution is recommended for effective disinfection against norovirus, which is resistant to many common cleaners. The bleach solution should remain on the surface for at least 5 minutes before rinsing.
Safe food handling practices also help minimize re-exposure risk. This includes washing fruits and vegetables and thoroughly cooking shellfish. Norovirus can survive high temperatures, so quick steaming processes may not be sufficient to eliminate it from food. Avoiding food prepared by individuals who are sick is also important.
To prevent further spread, sick individuals should stay home, especially those who handle food, and remain away for at least 48 hours after symptoms have stopped. Limiting close contact with infected people also reduces the chance of re-infection.