How to manage a Norovirus outbreak

Health Protection Teams (HPTs) across England are responsible for the surveillance, prevention and control of communicable disease and non-infectious environmental hazards. Your local HPT helps to reduce the effect of diseases by managing reported cases and outbreaks of infectious diseases.  

HPTs also provide support to health professionals, including:

• local disease surveillance
• alert systems
• investigating and managing health protection incidents
• national and local action plans for infectious diseases.

Background and Epidemiological Information 

Outbreaks can occur in a variety of settings such as care homes, prisons, hospitals and schools, the North East & North Central London HPT received a call from a local school reporting 30 out of 630 pupils having symptoms of vomiting and diarrhoea. Our role is to carry out a risk assessment based on the symptoms and the timeline of cases to ascertain whether this was likely to be a point source outbreak (a single event that has caused the illness) or a continuous common source (illness that is being passed from person to person). After the initial risk assessment was carried out, given the pattern of the appearance of the cases, it was agreed that this outbreak was more likely to be caused by norovirus also known as the “winter vomiting bug” rather than illness caused by food poisoning.

What makes children so susceptible:

• immunity/age
• lack of prior exposure to virtual all infecting organisms
• degree of close contact
• hygiene practices.

Management of the Situation

Public Health England (PHE) have developed a norovirus toolkit and checklist which is used for the management of outbreaks. Upon completing the risk assessment with the school, we were informed that a school event was scheduled for the next day. Our role was to: 

Gather basic information such as: 

• name of the school, location and layout
• total number of children and staff. 

Gather information about the outbreak:

• number of children and/or staff affected
• their symptoms and dates of onset
• distribution of cases i.e. same class or spread across different classes.

Provide infection control advice:

• Use PHE Guidance on Norovirus to advise on effective hand hygiene and exclusion periods for symptomatic cases. 
• Provide verbal communications to the school and complete a Norovirus Checklist with the school to ensure all actions are being completed. 
• We advised the school to cancel any upcoming school events to ensure that there was no further spread of infection. 

Reflection and outcome 

Lessons for the future

When managing suspected Norovirus outbreaks, as a Health Protection Practitioner I’ve learned that it’s very important to ask the relevant questions and to always call the school back if I missed any important information that will determine our risk assessment.