What role do immigrants play in the introduction of infectious diseases to Canada? Historically, immigration was a major factor in the introduction and spread of diseases such as smallpox and cholera. In the 18th and 19th centuries, immigrants arriving at coastal regions such as Halifax and Quebec brought diseases with them – for instance, among 98,000 immigrants that arrived at the port of Quebec in 1847, over 8,000 were hospitalized for infectious diseases and over 5,000 died of typhus fever.
The threat of imported immigrant diseases led to the establishment of the earliest infectious disease prevention and control measures, including quarantine, inspection, isolation, hospitalization and treatment of new immigrants.
Today, the importation of infectious diseases into Canada remains a significant public health threat. For instance, since 1997, outbreaks of measles – a highly contagious but vaccine-preventable viral disease, and one of the leading causes of death among young children globally – have either been imported into Canada or associated with imported cases.
Although new immigrants to Canada are generally healthier than settled immigrants and Canadian-born persons – a phenomenon termed the “healthy immigrant effect” – this advantage is lost when it comes to certain infectious diseases.
Similarly, between 1996 and 2011, cases of congenital rubella syndrome – an otherwise mild viral infection, which can cause miscarriages or fetal malformations in infected pregnant women – were linked to immigrant women who acquired the disease before arrival in Canada.
Although new immigrants to Canada are generally healthier than settled immigrants and Canadian-born persons – a phenomenon termed the “healthy immigrant effect” – this advantage is lost when it comes to certain infectious diseases, such as tuberculosis and HIV, which are endemic to the immigrants’ origin countries. Mortality from infectious diseases is also higher among immigrants compared to the Canadian-born population.
Immigrants Not Only Importers of Diseases
It is important to note, however, that immigrants are not solely to blame for disease importation, as the class of potential “disease importers” includes Canadian residents returning home from travel abroad and other types of migrants, such as refugees and temporary residents. Still, the fact remains that immigration does play a role in the introduction and transmission of infectious diseases to Canada.
Barriers to accessing health services upon arrival in Canada may prevent new immigrants from taking steps to protect themselves from infectious diseases.
The reasons why immigrants contribute to disease importation into Canada are not well established, but certain factors have been identified in academic literature. Many immigrants, for example, arrive in Canada from countries with high rates of certain infectious diseases, including countries, which have a high population exchange with Canada. Suboptimal immunization coverage in immigrants’ origin countries is also a factor.
While immigrants to Canada generally undergo pre-immigration health screening, including mandatory screening for HIV, tuberculosis and syphilis, they are not required to declare immunization status or to get immunized against infectious diseases prior to arriving in Canada.
Barriers to accessing health services upon arrival in Canada may prevent new immigrants from taking steps to protect themselves from infectious diseases, and the unprotected may become re-exposed when they travel back home to visit relatives and friends.
What Can New and Arriving Immigrants Do?
Many infectious diseases are vaccine-preventable, and the simple act of getting immunized can both provide immunity to and help eliminate or reduce the transmission and spread of common infectious diseases. In Canada (and many other countries), vaccines are offered without charge to the public and can be obtained from public health clinics and community health centres. New immigrants should ensure that they inquire about and obtain the required doses of available vaccines in their origin countries before arriving in Canada.
This ensures that arriving immigrants are protected and that they do not serve as disease transmitters in the period between arrival and eligibility for health care insurance coverage under provincial and territorial health plans.
Many infectious diseases affect young children more severely and disproportionately, so it is critical that parents inquire about getting their children immunized before, or upon, arrival in Canada.
It is also imperative to arrive in Canada with documentation showing vaccination status, as this will assist Canadian health authorities in determining whether updates or outstanding vaccines are needed. New immigrants should also seek out and obtain outstanding vaccines upon arrival in Canada. Many infectious diseases affect young children more severely and disproportionately, so it is critical that parents inquire about getting their children immunized before, or upon, arrival in Canada. Screening tests and health assessments prior to, and upon, arrival in Canada is also recommended.
Information about immunization and screening programs can be obtained from most health care institutions or by placing a call to a provincial or territorial health services helpline. Useful online resources include the Public Health Agency of Canada, Immunize Canada, the excellent ImmunizeCA app (available on iTunes, Google Play and BlackBerry World), the World Health Organization Immunization Portal and the Alberta Health Services Immunization Portal.
Taking preventative action against infectious diseases does not just protect immigrants and Canadians from dangerous and deadly infectious diseases, but also ensures that one of immigrants’ greatest gifts to their new country – the “healthy immigrant effect” – is maintained in an area that is of utmost importance to the health and well-being of their adopted country.
Dr. Ubaka Ogbogu is an assistant professor in the faculties of law and pharmacy and pharmaceutical sciences at the University of Alberta.