Do you have any estimate of immunization rates among people living on the street or in shelters? That's such a good place to communicate disease among already weakened people.

In short, there is no one single estimate. The literature on this subject finds those who are homeless are less likely to be immunized against a variety of diseases, including influenza. One Toronto influenza study found that out of 75 participants, only 6.7% had documentation indicating they had received vaccination the year before the study. In Buchner et. al’s study in New York, only 25% of people experiencing homelessness had received an influenza vaccine. (The authors also highlight the fact that influenza or influenza-like illness was the suspected cause of death for 3.4% of deaths among the homeless in the city.)

Immunization rates can also be lower for certain groups, such as youth, whose early departure from school and non-participation in public health programs makes them more vulnerable to vaccine-preventable diseases. 


Doctor preparing vaccines
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But immunization is complicated, and even housed people sometimes have difficulty keeping track of their vaccinations. Even healthcare providers have been found to be lacking knowledge about immunization schedules. 

With cases of measles popping up in Canada, immunization has become quite a hot topic. The immunization rate for measles, tuberculosis and DPT3 has been declining over the past decade—so much so that a 2013 UNICEF report card ranked Canada 28 of 29 developed countries in that category. According to an article in The Globe and Mail, Canada has an approximate measles vaccination rate of 95%, but there are areas where it’s as low as 50%. Religious and philosophical beliefs often play roles in parents deciding whether or not to vaccinate their children. 

While early vaccination is important, according to Immunize Canada, even adults need booster shots to maintain immunity. Due to inconsistent record keeping, many people are not aware of vaccination schedules or what they’ve been immunized for. 

These issues are even more complicated for people experiencing homelessness. As we’ve covered before, health, poverty and homelessness are interrelated and introduce some key challenges. People experiencing homelessness often have poorer health and are susceptible to a number of communicable diseases. Many have difficulty accessing healthcare, even from public programs, due to a number of barriers, including: missing identification, lack of permanent address, fear of stigma or discrimination, and limited or no funds for prescription medication. 

Solutions: Education, incentives and tracking

The unpredictability of homeless people’s lives makes it difficult to adhere to vaccination schedules, as explored in Stein and Nyamathi’s research on hepatitis B vaccination. With case management, incentives and tracking, however, researchers found that 68% of the participants completed their schedules. 

One Vancouver study found that immunization in non-traditional settings is very successful in reducing reported diseases. Vaccines were offered in blitz formats and combined, achieving vaccination rates among participants between 58% and 79%. In a Halifax study with homeless youth, participants recommended better advertising of free vaccination programs, and generally more youth- and homeless-friendly approaches to care. 

When it comes to avoiding pandemics, communities can greatly reduce transmission and impact through comprehensive planning. For people working in the social services, the Influenza Planning Guide for Alberta’s Vulnerable Populations and Shelter Serving Agencies is a great resource. 

As some experts have argued, it’s important to go beyond calculating medical risks to keep the social determinants of health in mind when discussing pandemics, disease and immunization. Social factors—like poverty and other sites of oppression—are key to helping us understand how risk and vulnerability vary from person to person.

This post is part of our Friday "Ask the Hub" blog series. Have a homeless-related question you want answered? E-mail us at thehub@edu.yorku.ca and we will provide a research-based answer.

Photo: PATH Global Health

Emma WoolleyResearch AssistantCanadian Observatory on Homelessness/Homeless Hub: York University