Canadian Immunization Guide: Part 3 - Vaccination of Specific Populations

Immunization of Travellers

Updated: July 2013

Travel health information

Immunization to protect travellers can be life-saving and is a cornerstone of travel health protection. Other protective measures, such as sanitation and hygiene, food precautions, insect/animal bite prevention, and accident avoidance, are also essential for health protection while travelling and are complementary to immunization. An understanding of the personal protective measures recommended for travellers is an integral part of travel preparation, refer to the Committee to Advise on Tropical Medicine and Travel (CATMAT) website.

Travellers are exposed to different health risks than they are at home. Information about immunization requirements and recommendations related to travel is available from travel health clinics or public health agencies. Extensive information regarding travel-related diseases and immunization of travellers is available from the Travel Health program of the Public Health Agency of Canada (PHAC) and from CATMAT. Additional information is available from the United States Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO). Refer to the list of designated Yellow Fever vaccination centers in Canada.

Immunization of travellers

Travellers, in particular those undertaking travel to countries with health risks that are greater than in Canada, should solicit medical advice pre-departure. Pre-travel consultation affords an opportunity for health professionals to review the traveller's itinerary and develop appropriate health protection recommendations. It also allows for the review of preventive measures for travel-related illnesses and is an opportunity to assess the overall immunization status of clients. Unimmunized or incompletely immunized travellers should be offered vaccination as recommended in the routine immunization schedules (refer to Recommended Immunization Schedules in Part 1). A health care provider or travel health clinic should ideally be consulted as early as possible, ideally at least 4 to 6 weeks in advance of travel, to provide sufficient time for completion of optimal immunization schedules. In cases where there is insufficient time for the optimal immunization schedule, refer to the specific vaccine chapter for the suggested rapid or accelerated schedule. However, even if a traveller is departing at short notice, a pre-travel consultation is recommended.

The immunizations recommended for travellers vary according to the traveller's age; immunization history; existing medical conditions; destination(s); planned activities, duration and nature of travel (e.g., staying in urban hotels vs. visiting remote rural areas); legal requirements for entry into countries being visited; travellers' own preferences and values; and the amount of time available before departure. Immunizations related to travel can be categorized as those that are considered routine (part of the recommended primary series of immunizations or routine booster doses); those required by international law; and those recommended for maintenance of health while travelling.

Routine immunization

Unimmunized or incompletely immunized travellers should receive routine immunizations as appropriate for age and individual risk factors. Travellers may require additional doses or booster doses of routine immunizations, or a change in the routine immunization schedule. Refer to Recommended Immunization Schedules in Part 1 for a summary of the recommended immunization schedules for infants, children and adults. Recommendations for modification of the routine immunization schedule in relation to travel follow.

Accelerated primary vaccination schedule - infants

For infants embarking on travel, the primary vaccination series with diphtheria toxoid-tetanus toxoid-acellular pertussis-polio-Haemophilus influenzae type b-with or without hepatitis B vaccine (DTaP-IPV-Hib or DTaP-HB-IPV-Hib) and pneumococcal conjugate vaccine may be started at 6 weeks of age. Rotavirus vaccine may be given at 6 weeks of age concomitantly with these vaccines. The first dose of measles-mumps-rubella vaccine (MMR) should be given at an earlier age than usual for children travelling to countries outside of North America (refer to Measles below). Refer to vaccine-specific chapters in Part 4 for additional information including the minimum interval between vaccine doses in order to achieve maximum vaccination protection prior to travel.

Hepatitis B

Travel is a good opportunity to offer hepatitis B (HB) immunization to children and adults who have not been previously vaccinated. Hepatitis B vaccine should be particularly recommended to travellers who will be residing in areas with high levels of HB endemicity or working in health care facilities, and those likely to have contact with blood or to have sexual contact with residents of such areas. The age at which infants, children and adolescents are routinely offered HB vaccine varies from jurisdiction to jurisdiction in Canada. Since HB carrier rates are much higher in developing countries, complete HB immunization is recommended for children who will live in an area where HB is endemic. Hepatitis B is endemic in the Far East, the Middle East, Africa, South America, Eastern Europe and Central Asia. Refer to a map of countries and areas of risk for HB for additional information. Refer to Hepatitis B Vaccine in Part 4 and to the CATMAT Statement on hepatitis vaccines for travellers for additional information.

Concomitant immunization with HA and HB vaccines is recommended as HA vaccination is also indicated for travellers to developing countries. For those who are susceptible to both HA and HB virus, a combined HAHB vaccine can be used. For travellers presenting less than 21 days before departure, monovalent HA and HB vaccines should be administered separately, with the completion of both vaccine series after travel. Refer to Hepatitis A in the recommended vaccine section below.

Measles, mumps, rubella and varicella

Measles

Protection against measles is especially important for people planning travel to destinations outside of North America. Travellers born in 1970 or later who do not have documented evidence of receiving two doses of measles-containing vaccine on or after their first birthday, or laboratory evidence of immunity, or a history of laboratory confirmed measles disease should receive two doses of measles-containing vaccine.

Measles vaccine should be given at an earlier age than usual for children travelling to countries outside of North America. MMR vaccine may be given as early as 6 months of age; however, two additional doses of measles-containing vaccine must be administered after the child is 12 months old to ensure long lasting immunity to measles.

Travellers born before 1970 who do not have documented evidence of receiving measles-containing vaccine on or after their first birthday, or laboratory evidence of immunity, or a history of laboratory confirmed measles disease should receive one dose of MMR vaccine. Although immigrants originating from countries with high rates of circulating measles may already be immune to measles, they may still require MMR vaccine because they are susceptible to mumps or rubella as described below. Refer to Measles Vaccine in Part 4 for additional information.

Measles is endemic in many developing countries. Refer to measles incidence rates in WHO member countries for additional information.

Mumps

Protection against mumps is especially important for people planning travel to destinations outside of North America. Travellers born in 1970 or later who do not have documented evidence of receiving two doses of mumps-containing vaccine on or after their first birthday, or laboratory evidence of immunity, or a history of laboratory confirmed mumps disease should receive two doses of mumps-containing vaccine. Many immigrants originate from countries where mumps vaccine is not routinely given and may therefore have increased susceptibility to mumps. Travellers born before 1970 who do not have documented evidence of receiving mumps-containing vaccine on or after their first birthday, or laboratory evidence of immunity, or a history of laboratory confirmed mumps disease should receive one dose of MMR vaccine. Refer to Mumps Vaccine in Part 4 for additional information.

Mumps is endemic in many countries. Refer to mumps incidence rates in WHO member countries for additional information.

Rubella

Protection against rubella is important for people planning travel to rubella-endemic areas. Travellers who do not have documented evidence of receiving rubella-containing vaccine on or after their first birthday, or laboratory evidence of immunity, or a history of laboratory confirmed rubella infection should receive one dose of rubella-containing vaccine. In addition, many immigrants originate from countries where rubella vaccine is not routinely given resulting in increased susceptibility to rubella in this population. Refer to Rubella Vaccine in Part 4 for additional information.

Refer to rubella incidence rates in WHO member countries for additional information.

Varicella

People travelling or living abroad should be immune to varicella. In tropical climates varicella tends to occur at older ages (compared with temperate climates) and at any time of the year. Adolescent and adult immigrants born in tropical countries therefore are more likely to be susceptible to varicella as compared to the Canadian population. Two doses of univalent varicella or measles-mumps-rubella-varicella vaccine (MMRV) are recommended for immunization of healthy children aged 12 months to 12 years of age. Two doses of univalent varicella vaccine are recommended for susceptible adolescents (13 to 17 years of age) and susceptible adults (18 to 49 years of age). For adults 50 to 59 years of age, herpes zoster vaccine may be considered. Herpes zoster vaccine is recommended for adults without contraindications 60 years of age and older. Refer to Varicella (Chickenpox) Vaccine and Herpes Zoster (Shingles) Vaccine in Part 4 for additional general information.

Pertussis - adults

For pertussis prevention, acellular pertussis-containing vaccine (tetanus toxoid-reduced diphtheria toxoid-reduced acellular pertussis [Tdap]) is recommended for adults who have not previously received a dose in adulthood - regardless of the interval from the last tetanus-containing vaccine. The pre-travel consultation is an opportunity to give the adult booster to those who may not otherwise seek immunization from a vaccine provider. Refer to Pertussis Vaccine in Part 4 for additional information.

Poliomyelitis - adults

Polio vaccine for unimmunized adults is recommended to prevent the introduction and circulation of polio. If an adult has not been immunized against polio, catch-up vaccination can be done opportunistically. For example, IPV-containing vaccine is recommended for previously unimmunized adults when tetanus toxoid-containing vaccine is being given. A full primary series should be given to the unimmunized adult who is at increased risk of exposure to polio (e.g., travellers to areas where there are polio epidemics, military personnel or workers in refugee camps in endemic areas). For adults previously immunized against polio, a single lifetime booster of polio-containing vaccine is recommended for certain travellers at increased risk of exposure to polio (e.g., travellers to areas where there are polio epidemics, military personnel or workers in refugee camps in endemic areas). Refer to Poliomyelitis Vaccine in Part 4 for additional information.

Polio remains endemic in Afghanistan, Nigeria and Pakistan. Additional countries are known or suspected of having re-established transmission of poliovirus. Refer to the WHO polio eradication site for the most up-to-date information about the current status of polio around the world.

Tetanus and diphtheria - adults

Travel is a good opportunity to opportunistically provide tetanus and diphtheria immunization to adults who have not been previously vaccinated. A full primary series should be given to the unimmunized adult. All doses should contain polio vaccine as well and the first dose should contain acellular pertussis vaccine.

Previously immunized adult travellers should receive a booster dose of tetanus and diphtheria toxoid-containing vaccine every 10 years. For adults who have not previously received a dose of acellular pertussis vaccine in adulthood, it is recommended that the Tdap vaccine be given, regardless of the interval from the last tetanus-diphtheria booster. Refer to Tetanus Toxoid and Diphtheria Toxoid in Part 4 for additional information.

Tetanus occurs worldwide. A list of countries where diphtheria is endemic is available from the CDC.

Required immunization

The following immunizations may be a requirement of international law or proof of immunization may be considered a visa requirement:

Meningococcal

As a condition of entry, Saudi Arabia requires proof of meningococcal immunization for pilgrims to the Hajj or Umrah in Mecca. Quadrivalent conjugate meningococcal vaccine is recommended; monovalent serogroup C conjugate meningococcal vaccine is not appropriate for protection of travellers as it does not protect against serogroup A, which is endemic in selected regions of the world, or serogroup W-135 disease. Vaccination is needed between 10 days and 3 years prior to the date of entry into Saudi Arabia. Refer to the Saudi Ministry of Health requirements for additional information.

Yellow fever

Yellow fever (YF) vaccine is unique amongst travel vaccines in that its use is governed not only by patient requirements but also by international laws and agreements. YF immunization (documented by an International Certificate of Vaccination or Prophylaxis) is required to enter certain countries. Recent co-operation between WHO and CDC have defined areas of the globe by YF exposure risk and classify areas as either endemic, transitional, low risk or no risk. YF vaccine is recommended for healthy travellers (greater than 9 months of age) travelling through, visiting or living in areas where YF is considered endemic or transitional. There may also be nation specific immunization entry requirements in these regions.

YF vaccination is generally not recommended in areas where there is low potential for YF virus exposure; however, vaccination might be considered for a small subset of travellers to these areas, who are at increased risk of exposure to mosquitoes because of prolonged travel, heavy exposure to mosquitoes, or inability to avoid mosquito bites. Vaccination is not recommended for travellers whose itineraries are restricted to areas with no risk. Certain countries in Asia have both the primate hosts and insect vectors for YF but have had no documented cases. Some of these countries require proof of vaccination (or documentation of medical contraindication to vaccination) if a person is travelling from a YF risk area.

The decision to immunize a traveller against YF should take into account the traveller's itinerary and the associated risk for exposure to YF virus, the requirements of the country to be visited (including stopovers and airport transit) and individual risk factors for serious adverse events following vaccination. Although these serious adverse effects are very rare, certain groups such as older travellers (greater than 60 years of age) and persons with certain immune disorders are at higher risk and thus the decision to immunize must be carefully weighed with the risks. YF vaccine is contraindicated in infants less than 6 months of age, and is generally not recommended in infants less than 9 months of age. Refer to Yellow Fever Vaccine in Part 4 for additional information.

A recent update from WHO recommends that a transit time of less than 12 hours through an international airport would not put a traveller at risk for contraction of YF. Thus, this type of transit time through a region of transmission of YF should not be considered an actual exposure by subsequent destination countries. These recommendations have been published by WHO, but it is the right of each country to define its entry requirements. This should be confirmed prior to departure.

Some countries do not require YF vaccination of infants younger than a certain age (e.g., less than 1 year). Refer to a list of country-specific YF vaccination requirements and WHO recommendations and a WHO map of the areas in the Americas where YF vaccination is recommended.

The International Certificate of Vaccination or Prophylaxis is valid for 10 years, beginning 10 days after primary immunization and immediately after re-immunization, if re-immunized within the 10-year period. Travellers requiring the certificate but in whom the YF vaccine is medically contraindicated can be provided with an International Certificate of Medical Contraindication to Vaccination by a Yellow Fever Vaccination Centre following an individual risk assessment. Travellers without a valid International Certificate of Vaccination or Prophylaxis or a Certificate of Medical Contraindication to Vaccination may be denied entry into a country requiring such documentation, quarantined, or offered immunization at the point of entry (e.g., at the airport), potentially putting the health of the traveller at risk. If a booster is given beyond 10 years, there is a wait period of 10 days before the Certificate of Vaccination becomes valid. Although usually accepted, the International Health Regulations do not compel any country to accept an International Certificate of Medical Contraindication to Vaccination.

In Canada, Yellow Fever Vaccination Centre clinics are designated by PHAC (or in the case of the Canadian Forces, by the Directorate of Force Health Protection) to provide the International Certificate of Vaccination or Prophylaxis or International Certificate of Medical Contraindication to Vaccination. A list of YF vaccination centres available to the public can be obtained from PHAC.

Recommended immunization

Based on a risk assessment of the travel itinerary, the nature of travel, and the traveller's underlying health, the following vaccines should be considered (also refer to Yellow Fever):

Hepatitis A

Protection against hepatitis A (HA) is recommended for all travellers to developing countries, especially if travelling to rural areas or places with inadequate sanitary facilities. HA is one of the most common vaccine-preventable diseases in travellers. For travellers who are susceptible to both HA and HB virus, a combined HAHB vaccine can be used. Refer to Hepatitis A Vaccine and Hepatitis B Vaccine in Part 4 for additional information. Refer to the CATMAT Statement on hepatitis vaccines for travellers for additional information on rapid dosing schedules.

Refer to a WHOmap of countries and areas of risk for hepatitis A.

Influenza

All travellers are encouraged to receive influenza vaccine, especially those who are pregnant, children up to 5 years of age, those over 65 years of age, children and adults with a chronic health condition or other factors that would make them recommended recipients of influenza vaccine. Vaccines prepared specifically for use in the Southern Hemisphere are not available in Canada, and the extent to which recommended vaccine components for the Southern Hemisphere may overlap with those in available Canadian formulations will vary. It is not recommended to revaccinate a traveller vaccinated for the most recent influenza season if travelling in the Southern hemisphere between April and October. Refer to Influenza Vaccine in Part 4 for additional information.

Japanese encephalitis

Japanese encephalitis (JE) vaccine is recommended for adult travellers with a high exposure risk going to JE endemic/epidemic areas during the transmission season. The risk for acquiring JE is low for most travellers, particularly for short-term visitors to major urban areas. This is because the mosquito vector for JE and its animal reservoir(s) are primarily found in rural agricultural areas. JE occurs in many areas of Asia, especially in the south east and in parts of the western Pacific, and is the leading cause of viral encephalitis in Asia. Refer to Japanese Encephalitis Vaccine in Part 4 for additional information.

Refer to a CDC map of the areas at risk for JE transmission or the WHO map of the areas at risk for JE.

Meningococcal infection

Travellers to destinations where risk of meningococcal transmission is high should be vaccinated with a quadrivalent conjugate meningococcal vaccine. Refer to Meningococcal above for information about the requirement for meningococcal vaccination as a condition to entry for certain travellers to Saudi Arabia. Refer to Meningococcal Vaccine in Part 4 for additional information.

Invasive meningococcal disease occurs sporadically worldwide and in focal epidemics. The traditional endemic areas of the world include the savannah areas of sub-Saharan Africa extending from Gambia and Senegal in the west to Ethiopia and Western Eritrea in the east. Meningococcal disease is also associated with the Hajj, an Islamic pilgrimage to Mecca, Saudi Arabia. Refer to the CATMAT information on assessing a traveller's need for pre-travel vaccination for additional information. Refer to WHO meningococcal disease outbreak information.

Rabies

Travellers to rabies endemic areas where there is poor or unknown access to adequate and safe post-exposure management, as well as frequent and long-term travellers to high-risk areas should be considered for pre-exposure rabies immunization. Children (especially those who are too young to understand either the need to avoid animals or to report a traumatic animal contact) should receive pre-exposure immunization when travelling to endemic areas.

Pre-exposure rabies vaccination obviates the requirement for rabies immune globulin if rabies exposure occurs, which may be unsafe or unavailable in many countries with high rabies risk. Refer to Rabies Vaccine in Part 4 for additional information.

Public health officials should be consulted regarding travellers who have had an exposure to a potentially rabid animal, even if the traveller received a complete course of post-exposure prophylaxis in that country. The prevalence of rabies in developing countries is often much higher than in Canada and there may be concerns about the efficacy of available vaccines in these countries.

To identify high risk areas, see the WHO map of areas at risk for rabies transmission.

Tick-borne encephalitis

Tick-borne encephalitis (TBE) vaccine is available in Canada and may be indicated prior to travel in some countries. To identify travellers who are at risk of contracting the TBE virus, the season of travel, the travel itinerary, and planned activities should be considered. Ticks may bite on warm days throughout the year, but the majority of tick activity is from March to November. Risk activities include fieldwork, biking, hiking or camping outdoors. A map of endemic areas can be found on the site for the International Scientific Working Group on TBE which provides a map of endemic areas. Refer to the CATMAT Statement on Tick-borne Encephalitis.

Typhoid

Travellers to regions where typhoid fever is endemic or epidemic are at risk, with certain subpopulations at increased risk such as children and individuals visiting friends and relatives. Typhoid immunization is recommended for travellers to countries with a high incidence of typhoid disease who will have prolonged exposure to potentially contaminated food and water. Immunization is not routinely recommended for short-term holidays in resort hotels. Refer to Typhoid Vaccine in Part 4 for additional information.

Travellers to South Asia (i.e., the Indian subcontinent) are at highest risk of typhoid. But it is also found in Africa and the rest of Asia, and to some degree in all regions where sanitation and hygiene are suboptimal.

Bacille Calmette-Guérin (BCG)

Immunization with BCG vaccine may be considered for travellers planning extended stays in areas or countries of high tuberculosis prevalence in exceptional circumstances. Consultation with an infectious disease or travel medicine specialist is recommended. Refer to Bacille Calmette-Guérin Vaccine in Part 4 and the CATMAT statement Risk assessment and prevention of tuberculosis among travellers for additional information.

Cholera and travellers' diarrhea

Travellers to cholera-endemic countries who may be at significantly increased risk of exposure (e.g., humanitarian workers or health professionals working in endemic countries) may benefit from cholera vaccination. Most travellers following the usual tourist itineraries in countries affected by cholera are at extremely low risk of acquiring cholera infection. Travellers' diarrhea is usually a mild and self-limited illness. For protection against travellers' diarrhea, vaccination with cholera and travellers' diarrhea vaccine is of limited benefit and is not routinely recommended except for high-risk travellers (who are 2 years of age and older). Refer to Cholera and Travellers' Diarrhea Vaccine in Part 4 and the CATMAT Statement on new oral cholera and travellers' diarrhea vaccination for additional information. Refer to the WHO map of the areas reporting cholera outbreaks.

Immunocompromised travellers

An increasing number of Canadians are living with conditions that reduce immune competence, including organ transplantation, HIV infection and treatment with corticosteroids or immunosuppressive agents for a variety of indications. A growing number of these individuals are travelling to tropical and low-income countries. For information about immunization of travellers who are immunocompromised refer to Immunization of Immunocompromised Persons in Part 3, vaccine-specific chapters in Part 4, and the CATMAT statement The Immunocompromised Traveller.

Pregnant and breastfeeding travellers

The decision of whether to vaccinate pregnant or breastfeeding women travellers depends on many factors including the stage of pregnancy, the destination, the duration of travel, the risk of contracting the disease, the severity of the effect of the disease on the pregnant or breastfeeding woman and/or the fetus, the adverse effects of the vaccine on the pregnant woman and/or the fetus, and the values and preferences of the pregnant or breastfeeding woman and the vaccine provider. Live vaccines (such as MMR) should generally not be given to pregnant women. Probable transmission of vaccine strain of YF virus from a mother to her infant through breastfeeding has been reported; therefore, in general, breastfeeding mothers should not be vaccinated with YF vaccine. For information regarding immunization of pregnant or breastfeeding travellers refer to Immunization in Pregnancy and Breastfeeding in Part 3, vaccine-specific chapters in Part 4, and the CATMAT Statement on Pregnancy and Travel.

Older travellers

Older people travel to the full range of destinations, including high-risk destinations, and comprise a substantial proportion of travellers. Both vaccine efficacy and risk of adverse reactions may be affected by age. Declining cell-mediated and humoral immunity influence the response to immunization, potentially resulting in diminished, delayed, and less durable immune responses in the elderly with or without co-morbidities. The elderly may be more susceptible to adverse effects of some vaccines, especially yellow fever; however, they may also be more vulnerable to disease and complications for some vaccine-preventable illnesses, such as hepatitis A, typhoid fever, and yellow fever. For additional information regarding immunization of older travellers refer to the CATMAT Statement on older travellers.

Pediatric travellers

Travel immunization recommendations for children will vary with the individual risk of exposure and the severity of potential infection. Some travel-related infections, such as hepatitis A, typhoid, and rabies are more likely to occur in pediatric travellers than in adult travellers. Children are at higher risk for meningococcal infections. For additional information regarding immunization of pediatric travelers, refer to the CATMAT Statement on pediatric travellers.

Selected references

  • Centers for Disease Control and Prevention. Health Information for International Travel 2012(). The Yellow Book. Accessed May 2012 at: http://wwwnc.cdc.gov/travel/page/yellowbook-home-2012
  • Committee to Advise on Tropical Medicine and Travel. Statement on personal protective measures to prevent arthropod bites - update. Can Commun Dis Rep 2012;28(ACS-2):1-18. Accessed July 2013 at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/12vol38/acs-dcc-3/index-eng.php
  • Committee to Advise on Tropical Medicine and Travel. Statement on older travellers. Can Commun Dis Rep 2011;37(ACS-2):1-24. Accessed May 2012 at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/11vol37/acs-2/index-eng.php
  • Committee to Advise on Tropical Medicine and Travel. Statement on protection against Japanese encephalitis. Can Commun Dis Rep 2011;37(ACS-1):1-13. Accessed May 2012 at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/11vol37/acs-1/index-eng.php
  • Committee to Advise on Tropical Medicine and Travel. Statement on pediatric travellers. Can Commun Dis Rep 2010;36(ACS-3):1-31.Accessed May 2012 at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/10vol36/acs-3/june-juin-2010-eng.php
  • Committee to Advise on Tropical Medicine and Travel. Statement on pregnancy and travel. Can Commun:1-43. Accessed May 2012 at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/10vol36/acs-2/index-eng.php
  • Committee to Advise on Tropical Medicine and Travel. Statement for travellers and yellow fever. Can Comm Dis Rep 2010;36(ACS-11):1-23. Accessed July 2013 at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/13vol39/acs-dcc-2/index-eng.php
  • Committee to Advise on Tropical Medicine and Travel. Risk assessment and prevention of tuberculosis among travellers. Can Comm Dis Rep 2009;37(ACS-5):1-20. Accessed May 2012 at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/09vol35/acs-dcc-5/index-eng.php
  • Committee to Advise on Tropical Medicine and Travel. Statement on meningococcal vaccination for travellers. Can Commun Dis Rep 2009;35(ACS-4):1-22. Accessed May 2012 at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/09vol35/acs-dcc-4/index-eng.php
  • Committee to Advise on Tropical Medicine and Travel. Statement on hepatitis vaccines for travellers. Can Comm Dis Rep. 2008;34(ACS-2):1-24. Accessed May 2012 at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/08vol34/acs-2/index-eng.php
  • Committee to Advise on Tropical Medicine and Travel. The immunocompromised traveller. Can Commun Dis Rep 2007;33(ACS-4). Accessed May 2012 at: http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/07vol33/acs-04/index-eng.php
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