National Travel Health Network and Centre
Travel Health Information Sheets
November 2006
Poliomyelitis
Introduction
Poliomyelitis (polio) is a vaccine-preventable disease caused by the polio virus, a small RNA virus, of the genus Enterovirus within the picornavirus family. There are three serotypes of the human poliovirus (1, 2 & 3) [1]. Although great strides have been made in the global eradication of polio, four countries remain endemic for the disease (Afghanistan, India, Nigeria, Pakistan) with several others in Africa, Asia, and the Middle East reporting cases related to importation [2].
Epidemiology
Global Epidemiology [2]
In 1988, more than 125 countries in five continents were endemic for polio, with more than 1000 children paralysed every day. In that same year, the World Health Assembly voted to launch a global initiative to eradicate polio by 2000. The Global Polio Eradication Initiative was set up by national governments, the World Health Organization (WHO), Rotary International, the US Centers for Disease Control and Prevention (CDC) and UNICEF, and is the largest public health initiative ever known. The Initiative involved collaborative efforts to improve surveillance of polio and to organise immunisation campaigns. These activities have interrupted transmission of polio in over 100 countries.
The number of cases reported worldwide has declined from 350,000 in 1988 to 1486 in 2005. However, importation of polio from endemic countries continues to be a problem. As of October 2006 four countries remain endemic for polio: Afghanistan, India, Nigeria and Pakistan. Nigeria accounted for 61% (921 cases) of the 1,500 cases reported globally in 2006 (as of 24 October 2006) and India accounted for 28% (416 cases) of the total. In addition to endemic countries, Angola, the Democratic Republic of the Congo, Ethiopia, Kenya, Namibia, Niger, and Somalia in Africa, and Bangladesh and Nepal in Asia are considered to have active transmission of an imported polio virus [2]. Other countries outside of the regions that have eradicated polio (WHO regions of the Americas, Western Pacific and European) may also be a risk for travellers.
Polio in Travellers from England and Wales
Control of polio in the UK is excellent and there have been no confirmed cases of polio in over a decade. The last imported case reported was in a child who had travelled to India in 1993 [3].
Risks for travellers
Three regions of the world (the Americas, Western Pacific and European regions) have eradicated wild type poliovirus so travel to these regions presents a negligible risk. The risk of acquiring polio for those visiting countries outside of these regions will depend upon several factors including living conditions, length of stay and standards of food and water hygiene. The risk is highest for those intending to visit areas where there may be poor sanitation [4, 5].
Transmission
Polio is transmitted via the faecal-oral route by exposure to faecally contaminated food or water or by person to person contact. Pharyngeal secretions may contain virus and could play a limited role in transmission [6 7].
Signs and symptoms
These can be categorised according to the severity of symptoms [1]:
Asymptomatic
Accounts for up to 95% of all polio infections. Estimates of the ratio of asymptomatic to paralytic illness vary from 50:1 to 1000:1 (usually 200:1).
Minor, non-specific
Accounts for 4%-8% of infections. Three syndromes are seen and may be indistinguishable from other viral illnesses:
· upper respiratory tract infection (sore throat and fever)
· gastrointestinal disturbances ( nausea, vomiting, abdominal pain, constipation, or rarely diarrhoea)
· influenza-like illness
There is no central nervous system invasion and recovery is less than a week.
Non-paralytic aseptic meningitis
Occurs in 1%-2% of infections and is characterised by a non-specific prodrome followed by stiffness of the neck, back, and/or legs. Lasts from two to ten days with complete recovery.
Flaccid paralysis
Occurs in less than 1% of all polio infections. Prodromal symptoms last for one to ten days followed by paralytic symptoms which progress over two to three days and stabilise as the temperature returns to normal.
There may be two phases, especially in children. Minor symptoms may be followed by a one to seven day interval before the onset of flaccid paralysis with diminished deep tendon reflexes.
Death rates are generally 2%-5% of cases in children and up to 15%-30% of cases in adults (depending on age), increasing to 25%-75% of cases with bulbar involvement.
About 50% of people with paralytic polio recover without paralysis. Another 25% have mild permanent disability, and 25% have permanent severe paralysis. Rarely persons, who have made a complete recovery from polio, will develop a return or worsening of muscle weakness 15 or more years after this attack of polio. This is called Post Polio Syndrome.
Treatment
There are no antiviral drugs available, so treatment is supportive. This includes bed rest and respiratory support if there is respiratory muscle paralysis. Occupational therapy, physiotherapy and occasionally surgery have important roles in patient rehabilitation [1, 6].
Prevention
· Effective vaccination is available.
Travellers should also be advised to:
· Observe a high level of personal hygiene i.e. hand washing , especially after using the toilet and before eating.
· Only swim in chlorinated water or that which is unlikely to be contaminated with sewage.
· Eat food that has been thoroughly cooked and is served piping hot.
· Do not eat salads and fresh fruit.(5 7 8)
· See food & water hygiene advice
Poliomyelitis vaccine information
Indications for use of vaccine
Polio vaccine is recommended for:
· All infants from two months of age
· Travellers to areas or countries where poliomyelitis is epidemic or endemic and their last dose of polio vaccine has been 10 or more years ago [5, 9].
· Individuals not previously immunised
·
Availability of vaccine
In September, 2004, inactivated polio vaccines replaced oral polio vaccine in UK vaccine schedules. The change to an inactivated vaccine simplified paediatric vaccine schedules and eliminated the small risk of vaccine associate paralytic poliomyelitis from OPV. This change was also made recognising the decreased risk of imported wild type polio following the global efforts at polio eradication [10].
Vaccine schedules [11-14]
Interrupted courses
IPV®: [11]
Children: time intervals between doses longer than those recommended for routine primary immunization do not necessitate additional doses as long as a final total of three doses is reached.
Adults: those who have had 1 or 2 doses in the past should receive the remaining 1 or 2 doses. It does not matter how long the interval is from the earlier doses.
Pediacel®: [12]
There is no data regarding the administration of Pediacel® for one or two doses and use of different vaccines for other doses. Therefore it is recommended that infants who receive Pediacel® for the first dose should also receive this vaccine for the second and third doses of the primary immunisation series.
Repevax® [13] & Revaxis® [14]
Not applicable, single dose.
Contraindications
· History of hypersensitivity to the vaccine or its components
· Acute febrile illness / intercurrent infection
Contraindication to Pediacel® [12] & Repevax® [13]
· Neurological complications of unknown origin within 7 days of previous vaccination.
Adverse events
IPV® [11]
· A mild erythematous reaction at the site of injection and moderate fever occasionally occur.
·
Pediacel® [12]
· Clinical trials have shown that adverse reactions following polio vaccine tend to be mild and transient. They can include soreness, erythema and induration at the injection site.
· More serious reactions e.g. febrile convulsions, gastrointestinal problems and irritability have been rarely reported.
·
Repevax® [13]
· Clinical trials have shown that adverse reactions following polio vaccine tend to be mild and transient. They can include soreness, erythema and induration at the injection site.
· More serious reactions e.g. gastrointestinal problems, dermatitis and arthralgia have been rarely reported.
·
Revaxis® [14]
· Clinical trials have shown that adverse reactions following polio vaccine tend to be mild and transient. They can include soreness, erythema and induration at the injection site.
· More serious reactions e.g. gastrointestinal problems, vertigo and malaise have been rarely reported.
References
1. Centers for Disease Control. Chapter 8; Polio in National Immunization Program Pink Book 9th ed. Altanta: CDC; January 2006.
http://www.cdc.gov/nip/publications/pink/polio.pdf
2. World Health Organization. Global Polio Eradication Initiative website [online] [cited 18 October 2006]. Geneva: WHO; 2006. Available at http://www.polioeradication.org/
3. Health Protection Agency. Foreign travel-associated illness. England Wales and Northern Ireland - Annual Report 2005. Health Protection Agency Centre for Infections 2005.
http://www.hpa.org.uk/publications/2005/travel/travel.pdf
4. Department of Health Immunisation against Infectious Disease. The ‘Green Book’ chapters on Poliomyelitis. London: HMSO; 2006. http://www.dh.gov.uk/assetRoot/04/14/13/46/04141346.pdf
5. World Health Organization. International Travel & Health. Geneva: WHO; 2005. www.who.int/ith/index.html
6. Kumar P, Clark M. Clinical Medicine 6th ed. Edinburgh; WB Saunders 2005
7. Heymann D, editor. Control of Communicable Diseases Manual. 18th ed. Washington: American Public Health Association; 2004.
8. Lea G, Leese J, editors. Health Information for Overseas Travel. 2nd ed. London: The Stationery Office; 2001. www.archive.official-documents.co.uk/document/doh/hinfo/travel02.htm
9. NaTHNaC Clinical Update 19 August 2004. Poliomyelitis and Changes to Recommendations for Travellers. http://www.NaTHNaC.org/travel/news/polio_190804.htm
10. CMO Letter. 10 August 2004. http://www.dh.gov.uk/assetRoot/04/08/73/47/04087347.pdf
11. Summary of Product Characteristics: Polio Vaccine (Inactivated.) Maidenhead: Sanofi Pasteur; 2004
12. Sanofi Pasteur MSD Summary of Product Characteristics: Pediacel 3 February 2006
13. Sanofi Pasteur MSD Summary of Product Characteristics: Repevax 23 September 2005
14. Sanofi Pasteur MSD Summary of Product Characteristics: Revaxis 21 September 2005
15. Salisbury DM, Begg NT, editors. Immunisation against Infectious Disease. London: HMSO; 1996; Chapter 26; Polio; Updated August 2006. http://www.dh.gov.uk/assetRoot/04/13/79/26/04137926.pdf
16. Centers for Disease Control. Poliomyelitis Prevention in the United States; Updated Recommendations of the Advisory Committee on Immunization Practices (ACIP). Mortality and Morbidity Weekly Report; Atlanta: CDC; 19 May 2000 49 (RR05): 1-22 www.cdc.gov/mmwr/preview/mmwrhtml/rr4905a1.htm
Links
Centers for Disease Control (CDC) www.cdc.gov/travel/diseases/polio.htm
Committee to Advise on Tropical Medicine and Travel (CATMAT)
www.hc-sc.gc.ca/pphb-dgspsp/tmp-pmv/info/polio_e.html
WHO Global Polio Eradication Initiative http://www.polioeradication.org/
http://www.nathnac.org/pro/factsheets/polio.htm
|
