Under the Microscope: Norovirus

  • 3 Minutes
Hyperrealistic Digital Rendering of Norovirus Under a Microscope with Luminous Spherical Particles Radiating Neon Light and Intricate Textures

Norovirus is one of the most persistent and contagious viruses in healthcare environments. It can survive for weeks on high‑touch surfaces, spread with ease, and cause sudden outbreaks of vomiting and diarrhoea. With a very low infectious dose and high environmental stability, Norovirus remains a serious microbial threat that requires strict hygiene and effective disinfection to control.

Norovirus is widespread in healthcare environments due to its incredible environmental resilience. It can remain infectious on high-touch surfaces in healthcare settings such as bed rails, doorknobs, bathroom fixtures, and medical equipment for up to two weeks, and even longer in cool, dry conditions. This persistence makes routine cleaning insufficient unless effective disinfectants and protocols are used1.

Norovirus causes acute viral gastroenteritis and results in hospitalisations and significant operational disruptions in healthcare facilities. It is sometimes called the “vomiting bug” or “stomach flu”. However, norovirus illness is not related to the flu. Symptoms, such as vomiting, diarrhoea, nausea, and cramps typically emerge 12-48 hours post-exposure and last 1-3 days in healthy individuals. Anyone can get infected with norovirus. Vulnerable populations (elderly, young children, immunocompromised) can experience severe dehydration and complications2.

  • Low infectious dose – Fewer than 20 viral particles can cause infection3.
  • High environmental stability – Resistant to many common disinfectants and capable of surviving freezing and heating to 145 °F (62.8 °C) while surviving for days on surfaces4.
  • High viral shedding – patients can shed billions of particles, including through vomit and faeces, with shedding continuing for at least two weeks after symptoms subside 3, 4.

Norovirus easily spreads by:

  • Person-to-person contact – Direct contact with infected individuals, often in healthcare settings where hygiene lapses are possible.
  • Eating food or drinking liquids contaminated with Norovirus.
  • Contact with contaminated objects or surfaces – In-direct transmission via surfaces contaminated with Norovirus particles and putting your unwashed fingers in your mouth.

Proper disinfection is critical in preventing Norovirus transmission in healthcare settings.

The most effective disinfectants should:

  • Eliminate bacterial spores, vegetative bacteria, mycobacteria, yeast, fungal spores, and viruses.

A disinfectant suitable for use against Norovirus should comply with EN 14476, demonstrating proven virucidal activity.

Other steps should also be taken to protect yourself and others:

  • Wash your hands well and often.
  • Cook shellfish thoroughly and wash fruits and vegetables.
  • Routine cleaning and disinfection of surfaces, targeting high-touch exposed surfaces.
  • Wash laundry in hot water.
  • Stay home when sick for 2 days (48 hours) after symptoms stop.

References:


1 Clinic, C. (2019). How Long Do Norovirus Germs Live on Household (and Office) Surfaces? [online] Cleveland Clinic. Available at: https://health.clevelandclinic.org/how-long-do-norovirus-germs-live-on-household-and-office-surfaces.

2 Centers for Disease Control and Prevention (2024). Norovirus. [online] Centers for Disease Control and Prevention. Available at: https://www.cdc.gov/norovirus/about/index.html.

3 Winder, N., Gohar, S. and Muthana, M. (2022). Norovirus: An Overview of Virology and Preventative Measures. Viruses, 14(12), p.2811. doi:https://doi.org/10.3390/v14122811.

4 www.nps.gov. (2023). Norovirus (U.S. National Park Service). [online] Available at: https://www.nps.gov/articles/norovirus.htm.

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