From the Guidelines
Yes, you can get norovirus over and over again. After being infected with norovirus, you typically develop immunity, but this immunity is usually short-lived, lasting only a few months to a couple of years, as demonstrated in human challenge studies where infected volunteers were susceptible to reinfection with the same strain as well as to infection with heterologous strains 1. Additionally, there are many different strains of norovirus, and immunity to one strain doesn't necessarily protect you from others. This means you can become sick with norovirus multiple times, even within the same season.
The virus mutates frequently, creating new strains that can evade previously developed immunity, with evidence suggesting that new GII.4 variants evolve to escape the build-up of acquired immunity and innate resistance in the human population 1. To reduce your risk of repeated infections, practice thorough handwashing with soap and water for at least 20 seconds, especially after using the bathroom and before preparing food. Also, thoroughly clean contaminated surfaces with bleach-based cleaners, as norovirus is highly resistant to many standard disinfectants. Some people may be less susceptible to infection due to their genetic makeup, such as those with mutations in the 1,2-fucosyltransferase (FUT2) gene leading to a lack of expression of HBGAs on the surface of intestinal cells 1.
Key points to consider:
- Norovirus immunity is short-lived and strain-specific
- The virus mutates frequently, creating new strains that can evade previously developed immunity
- Practice thorough handwashing and surface cleaning to reduce the risk of infection
- Some people may be less susceptible to infection due to their genetic makeup
- Repeated infections with norovirus are possible and can occur throughout your life.
From the Research
Norovirus Infection and Re-Infection
- Norovirus is a highly contagious virus that can cause gastroenteritis in people of all ages, and it is possible to get infected with it multiple times 2, 3.
- The virus has a high mutational rate, which allows new variants to emerge and makes it difficult for the immune system to recognize and fight off repeat infections 2.
- Studies have shown that super-infections and relapses can occur in chronically infected patients, especially those who are immunocompromised 3.
- In fact, one study found that 17% of chronically infected patients experienced super-infections, and a third of patients with interrupted norovirus shedding continued to be infected with the same virus despite being PCR negative for up to 2 months 3.
Factors Contributing to Re-Infection
- The lack of a robust immune response to norovirus infection makes it possible for people to get re-infected with the same or different genotypes of the virus 4, 5.
- The virus can also survive in the environment for extended periods, making it easier for people to get re-infected 6.
- Additionally, the fact that norovirus can be transmitted through the fecal-oral route, and that people can shed the virus even after they have recovered, contributes to the high risk of re-infection 2, 6.
Implications for Infection Control
- The fact that people can get re-infected with norovirus highlights the importance of continued infection control measures, even in individuals who have previously been infected 3, 6.
- This includes practices such as hand washing, proper hygiene, and isolation of infected individuals to prevent the spread of the virus 2, 6.
- The development of effective vaccines and therapeutics is also crucial in preventing and treating norovirus infections, especially in high-risk populations such as immunocompromised individuals 4, 5.