Containing Norovirus

Lisa RitchieNurse Consultant Infection Control

Norovirus:• Thought to be commonest cause of

acute gastroenteritis in humans• Usual incubation period is 12-48

hours• Usually manifests with acute onset

of vomiting and non-bloody diarrhoea with abdominal cramps and nausea

• Less frequent clinical manifestations include fever, headache and myalgia

• Symptoms usually last between 24-60 hours

• Infection is generally self-limiting• thought that up to 30% of infections

may be asymptomatic.

ICT alerted and ward closed

Exporting outbreak to multiple wards

Decontaminate Ward(s)

Cross transmission occurs

People with norovirussymptoms admitted to the ward

Immediate isolation &containment?

No cross transmission

Outbreak prevented

Early outbreak signsrecognised?

Able to apply and sustainNorovirus Control

Measures?

New cases cease

Ward(s) reopened

ICT (eventually) alerted

Yes

No

No

Yes

Yes

No

Inability to gain control

Continuous exporting of outbreak

Inability of systems to cope

No

No

Literature reviewLevels of Evidence and Category of Recommendation

SIGN levels of evidence3: Non-analytic studies, e.g. case reports, case series4: Expert opinion

SIGN grades of recommendationD Evidence level 3 or 4; or Extrapolated evidence fromStudies Rated as 2+

(SIGN. Key to evidence statements and grades of recommendations. SIGN50: a guideline developer’s handbook. Edinburgh: SIGN; 2008. Available at:http://www.sign.ac.uk/guidelines/fulltext/50/annexb.html (accessed:18/10/2010). Reproduced with permission)

Control measures for Norovirus:• Wards should be closed to new admissions • The ward should remain closed until it has been

terminally cleaned to the satisfaction of the ward manager and ICT and, – There have been no new cases of possible norovirus

for 48 hours and, – There has been no vomiting or diarrhoea for a full 48

hours which is considered to be caused by norovirus. • Patients should be cohorted • Staff should be cohorted• Non-essential staff should be excluded from affected

wards

Control measures for Norovirus:• Do not use alcohol based hand rub alone for routine

decontamination of hands when there is an outbreak of gastro-intestinal infection. Decontaminate hands by washing with liquid soap and warm water followed by alcohol based hand rub.

• A surgical face mask may be worn to minimise the risk of splash contamination and inhalation of norovirus and subsequent ingestion.

• 1000ppm available chlorine should be used for environmental cleaning to inactivate norovirus

• Carpets and soft furnishings should be steam cleaned or cleaned with water and detergent after an outbreak of norovirus

• Bed/window curtains should be removed and cleaned

Control measures for Norovirus:

Visitors should for their own safety be advised: • To reduce the number of visits whilst the

outbreak lasts. • To wash hands on entry and exit to the ward.• Not to visit if they themselves are suffering from

an infection and until they are 48 hours symptom free.

• That children should not visit the ward during an outbreak.

• That they should not visit other people in the ward or other wards.

Challenges:

• 4 hours on trolley in A&E• No designated ward / area available• Control measures• Change in symptom and behaviour of

Norovirus from season to season

Norovirus season has

begun – media

warnings

Early experiences

Lessons learned

Changing experiences?