Traveller vaccination poliomyelitis

Template:Traveller vaccination poliomyelitis Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Usama Talib, BSc, MD [2]

Disease cause

Poliovirus types 1, 2 and 3.

Transmission

Polioviruses are spread predominantly by the faecal–oral route although the oral–oral route may also be common.

Nature of the disease

Poliomyelitis, also known as polio or infantile paralysis, is a disease of the central nervous system. Following primary asymptomatic infection of the alimentary tract by poliovirus, paralytic disease develops in less than 1% of cases. In developing countries, 65% to 75% of cases occur in children under 3 years of age and 95% in children under 5 years of age. The resulting paralysis is permanent, although some recovery of function is possible. There is no cure.

Geographical distribution

Significant progress has been made towards the global eradication of polio. Only 359 cases of polio due to wild poliovirus type 1 (WPV1) were reported in 2014, largely from the three countries that remain endemic for polio - Afghanistan, Nigeria and Pakistan. As of end-November 2015, only 56 cases were reported globally, from Pakistan and Afghanistan . Nigeria has not reported a polio case since July 2014. However, the risk of new outbreaks following virus importation into polio-free countries with low population immunity persists as long as transmission continues in the remaining endemic countries.

Risk for travellers

Until the disease has been certified as eradicated globally, the risks of acquiring polio (for travellers to infected areas) and of reinfection of polio-free areas (by travellers from infected areas) remain. All travellers to and from countries and areas infected by wild poliovirus or circulating vaccine-derived polioviruses (cVDPV) should be adequately vaccinated.

Vaccine

• Both orally-administered, live attenuated polio vaccines (OPV) and inactivated poliovirus vaccines (IPV) for intramuscular (or subcutaneous) injection are widely used internationally. IPV is considered very safe. A rare adverse event associated with OPV is vaccine-associated paralytic poliomyelitis (VAPP), which occurs once in about 2.4 million doses. Outbreaks of polio due to circulating vaccine-derived polioviruses continue to be detected occasionally, mainly in areas of low immunization coverage.

• WHO no longer recommends an OPV-only vaccination schedule. For all countries currently using OPV only, at least 1 dose of IPV should be added to the schedule. In polio-endemic countries and in countries at high risk for importation and subsequent spread, WHO also recommends an OPV dose at birth (“zero dose”), followed by the primary series of three OPV doses and at least one IPV dose.
• The primary series consisting of three OPV doses plus one IPV dose can be initiated from the age of 6 weeks with a minimum interval of 4 weeks between the OPV doses. Routine vaccination with a sequential schedule using IPV followed by OPV can also be used in countries with low risk of importation of poliovirus and high vaccination coverage rate. Routine vaccination with IPV alone should be used only in countries with high vaccination coverage (>90%) and at low risk of importation and spread of wild poliovirus.
• Before travelling to areas with active poliovirus transmission, travellers from polio-free countries should ensure that they have completed the age-appropriate polio vaccination series, according to their respective national immunization schedule. Travellers to polio-infected areas who completed an OPV or IPV vaccine series >12 months previously should be given another one-time booster dose of polio vaccine. Travellers to polio-infected areas who have not received any polio vaccine previously should complete a primary schedule of polio vaccination before departure.
• Before travelling abroad, persons of all ages residing in polioinfected countries (i.e. those with active transmission of a wild or vaccine-derived poliovirus) and long-term visitors to such countries (i.e. persons who spend more than 4 weeks in the country), should have completed a full course of vaccination against polio in compliance with the national schedule. Travellers from infected areas should receive an additional dose of OPV or IPV within 4 weeks to 12 months of travel, in order to boost intestinal mucosal immunity and reduce the risk of poliovirus shedding, which could lead to reintroduction of poliovirus into a polio-free area. For persons who previously received only IPV, OPV should be the choice for the booster dose, if available and feasible. In case of unavoidable last-minute travel, travellers should still receive one dose of OPV or IPV before departure, if they have not received a documented dose of polio vaccine within the previous 12 months.
• Some polio-free countries require resident travellers and long-term visitors from polio-infected countries to provide documentation of recent vaccination against polio in order to obtain an entry visa, or they may require travellers to receive an additional dose of polio vaccine on arrival, or both.
• All travellers are advised to carry their written vaccination record (patient-retained record) in the event that evidence of polio vaccination is requested for entry into countries being visited. They should preferably use the International Certificate of Vaccination or Prophylaxis, which is available from the WHO website.

Summary of vaccine data

	Considerations for travellers for Hepatitis E vaccination
Type of vaccine	Recombinant vaccine based on genotype 1 capsid protein which cross-protects against all 4 genotypes of hepatitis E virus of human relevance.
Number of doses	3 (administered intramuscularly at 0, 1 and 6 months). The possible need for booster doses after >2 years is not yet defined.
Contraindications	Not described, except for serious allergy to vaccine components.nsitivity to previous dose.
Adverse reactions	Rare local reactions.
Before departure	4 weeks.
Indication	Travellers, health-care and humanitarian relief workers travelling to areas during outbreaks of hepatitis E.
Special precautions	So far, no safety data are available on its use in children, the elderly, pregnant women, or patients with chronic liver disease or immunodeficiencies.