11 May 2009 

Swine influenza in humans: Update 8

Current status of the outbreak

Cases of human swine influenza A (H1N1) have been identified in 30 countries [1], see Table listing affected countries.

While there has been human-to-human transmission in several countries, including the United Kingdom, 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 some have been hospitalised 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 had chronic medical conditions that have put them at risk for complications from influenza.  

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 [4]. Nevertheless, they emphasize continued vigilance by all countries as they deal with influenza.

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

The Foreign and Commonwealth Office advises against all non-essential travel to Mexico. There are no other travel restrictions.

Travellers should consider the necessity of going to swine influenza affected areas, the risk of acquiring swine influenza at the destination, and the level of medical care including access to anti-viral medications in the event of an influenza-like illness (ILI) (fever plus two or more of cough, sore throat, runny nose, muscle aches or headache).

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

• if you are ill with a respiratory illness you should delay travel
• follow public health guidance at your destination
• avoid crowding or mass gatherings
• avoid close contact (within 2 meters) 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 influenza is not passed through properly handled and prepared pork; the virus is killed by cooking to temperatures of 70°C [5]
• 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 [6]
• receive appropriate vaccines for your destination, including seasonal influenza vaccine if you come under the recommended risk groups (see NaTHNaC Health Information Sheet on Influenza)

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:

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. 9 May 2009. ]Accessed 11 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/

Centers for Disease Control and Prevention. Interim novel influenza A (H1N1) guidance for cruise ships. 4 May 2009. [Accessed 11 May 2009]. Available at: http://www.cdc.gov/h1n1flu/guidance/cruiseships.htm 

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

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

References

1. World Health Organization. Influenza A (H1N1) – update 25. 11 May 2009. [Accessed 11 May 2009]. Available at:

http://www.who.int/csr/don/2009_05_11/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/preview/mmwrhtml/mm5817a1.htm

4. World Health Organization. No rationale for travel restrictions. 1 May 2009 [Accessed 11 May 2009]. Available at: http://www.who.int/csr/disease/swineflu/guidance/public_health

/travel_advice/en/index.html

5. Organization for Animal Health. Joint FAO/WHO/OIE Statement on influenza A(H1N1) and the safety of pork. 7 May 2009 [Accessed 11 May 2009]. Available at: http://oie.int/eng/press/en_090507_bis.htm

6. World Health Organization. Advice on the use of masks in the community setting in influenza A (H1N1) outbreaks. Interim guidance. 3 May 2009. [Accessed 8 May 2009]. Available at: http://www.who.int/csr/resources/publications/swineflu/masks_c

ommunity/en/index.html