Health Professionals

Clinical Updates

22 May 2009

Swine influenza in humans: Update 10

Current status of the outbreak

Cases of human swine influenza A (H1N1) have been identified in 44 countries [1], see Table listing affected countries. There has been human-to-human transmission in several countries, including the United Kingdom, however, there has been no sustained, community-wide transmission outside of North America.

Most confirmed cases have been characterised by an uncomplicated febrile respiratory illness [2, 3]. However, vomiting and diarrhoea have been seen in up to a quarter of patients, and in the United Sates about 4% have been hospitalized with more severe disease [2, 3]. Most deaths from this novel influenza virus have been recorded in Mexico, however, deaths have also occurred in the United States, Canada and Costa Rica. Outside of Mexico, those who have died have usually had chronic medical conditions that have put them at risk for complications from influenza.

The outbreak in Mexico appears to have peaked on 26 April 2009, with a steady decline of cases since that time [4]. In the United States the surveillance for swine influenza is now being done through their routine influenza surveillance systems [5].  

The WHO remains focused on mitigation of the consequences of the outbreak. They do not recommend closure of borders, nor do they recommend travel restrictions in an effort to prevent disruption to the global community [6]. Nevertheless, they emphasize continued vigilance by all countries as they deal with the potential social and economic disruptions caused by influenza [7].

The current pandemic influenza alert level remains at level 5, indicating that there is sustained, community level, human-to-human transmission of swine influenza occurring in at least two countries of a WHO region, in this case, Mexico and the United States in the Americas.

Advice for travellers

There currently are no travel restrictions to any country.

Before you travel

  • If you are ill with a respiratory illness you should delay travel
  • Check to see if your destination is reporting cases of swine flu. You can look on the NaTHNaC website for up-to-date case totals: http://www.nathnac.org/pro/swineflu.htm 
  • You should consider:
    • whether you need to go to a swine flu affected area
    • the risk of getting swine flu at your destination
    • the level of medical care at your destination including access to anti-viral medications in the event you need treatment for an influenza-like illness (ILI) (fever plus two or more of cough, sore throat, runny nose, muscle aches or headache).
  • You should receive appropriate vaccines and other preventive measures for your destination. This includes seasonal influenza vaccine if you come under the recommended risk groups (see NaTHNaC Health Information Sheet on Influenza)
  • You should obtain comprehensive travel health insurance, and clarify if there are any exclusions to coverage

During travel

Influenza is transmitted via the respiratory route and you should exercise sensible precautions:

  • follow public health guidance at your destination
  • avoid crowding or mass gatherings
  • avoid close contact (within 2 metres) with persons who are ill with an ILI
  • wash hands with soap and water; use waterless alcohol-based hand gels when soap and water is not available
  • avoid touching your nose, mouth or eyes, to prevent the spread of germs
  • cover your nose and mouth with a tissue when you cough or sneeze and dispose of the tissue promptly
  • keep hard surfaces (e.g. door handles, countertops) clean using a normal cleaning solution
  • assure that children follow similar advice
  • swine flu is not passed through properly handled and prepared pork; the virus is killed by cooking to temperatures of 70°C [8]
  • there is little evidence of the effectiveness of wearing masks at a mass level, however, properly fitted special grade masks can be worn in situations such as healthcare settings [9]

After you travel

Travellers who have visited affected areas should monitor their health for seven days after the visit. If you develop a febrile illness with cough, sore throat, runny nose, headache, or muscle aches within seven days, you should:

  • check your symptoms on NHS Direct (www.nhsdirect.nhs.uk) or NHS Choices (www.nhs.uk), and if you remain concerned, contact your GP or NHS Direct (0845 4647) and inform them of your travel history
  • limit contact with other people
  • cover your nose and mouth with a tissue when you cough or sneeze and dispose of the tissue promptly
  • wash hands with soap and water
  • keep hard surfaces (e.g. door handles, countertops) clean using a normal cleaning solution

There is guidance for health professionals who evaluate persons with suspected swine influenza on the Health Protection Agency website, listed below.

Further information is available at the following sources:

Foreign and Commonwealth Office. Swine flu outbreak: http://www.fco.gov.uk/en/travelling-and-living-overseas/swine-flu

Health Protection Agency, Swine Influenza: http://www.hpa.org.uk/webw/HPAweb&Page&HPAwebAutoListN

ame/Page/1240732817665?p=1240732817665

Health Protection Agency: Algorithm for the management of suspected cases (returning travellers and visitors from countries affected by swine influenza A/H1N1 or contacts). S5. 16 May 2009. [Accessed 21 May 2009]. Available at: http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/124073281

9361   

WHO, Influenza A (H1N1): http://www.who.int/csr/disease/swineflu/en/index.html

European Centre for Disease Prevention and Control: http://ecdc.europa.eu/

Centers for Disease Control and Prevention, H1N1 Flu (Swine flu): http://www.cdc.gov/h1n1flu/

NaTHNaC Country Information pages: http://www.nathnac.org/ds/map_world.aspx

NHS Choices: http://www.nhs.uk/Pages/HomePage.aspx 

The Lancet: H1N1 Flu Resource Centre: http://www.thelancet.com/H1N1-flu

References

1. World Health Organization. Influenza A (H1N1) – update 36. 22 May 2009. [Accessed 22 May 2009]. Available at: http://www.who.int/csr/don/2009_05_22/en/index.html

2. Novel swine-origin influenza A (H1N1) virus investigation team. Emergence of a novel swine-origin influenza A (H1N1) virus in humans. N Engl J Med. 361: 7 May 2009 (10.1056/NEJMoa0903810) Available at: http://content.nejm.org/cgi/content/full/NEJMoa0903810 

3. Centers for Disease Control and Prevention. Update: Novel influenza A (H1N1) virus infections – Worldwide, May 6, 2009. MMWR. 58:453-458, 2009. Available at: http://www.cdc.gov/mmwr/PDF/wk/mm5817.pdf  

4. Secretaría de salud, Mexico. Situación actual de la epidemia. 21 de Mayo 2009. [Accessed 22 May 2009]. Available at: http://portal.salud.gob.mx/descargas/pdf/influenza/situacion_ac

tual_epidemia_210509.pdf

5. Centers for Disease Control and Prevention. Flu Activity & Surveillance. Available at: http://www.cdc.gov/flu/weekly/fluactivity.htm

6. World Health Organization. No rationale for travel restrictions. 1 May 2009 [Accessed 15 May 2009]. Available at: http://www.who.int/csr/disease/swineflu/guidance/public_health

/travel_advice/en/index.html

7. World Health Organization. Assessing the severity of an influenza pandemic. 11 May 2009. [Accessed 15 May 2009]. Available at: http://www.who.int/csr/disease/swineflu/assess/disease_swin

eflu_assess_20090511/en/index.html 

8. World Organisation for Animal Health. Joint FAO/WHO/OIE Statement on influenza A (H1N1) and the safety of pork. 7 May 2009 [Accessed 15 May 2009]. Available at: http://oie.int/eng/press/en_090507_bis.htm

9. World Health Organization. Advice on the use of masks in the community setting in influenza A (H1N1) outbreaks. Interim guidance. 3 May 2009. [Accessed 15 May 2009]. Available at: http://www.who.int/csr/resources/publications/swineflu/masks

_community/en/index.html