Vaccine safety: Canada's system
Most parents know that vaccines are tested before they can be given to the general public. But they are probably less aware of the extensive monitoring, testing, information-sharing and decision-making that goes on behind the scenes.
Vaccines, like medicines, must go through a series of steps before they are approved for use. Before any vaccine is approved for use in Canada, it must be shown to be safe and effective in preventing the disease that it targets. Vaccines are among the most strictly regulated medical products in Canada.
The Public Health Agency of Canada’s National Advisory Committee on Immunization (NACI) makes recommendations on the use of vaccines in Canada. NACI members are non-governmental experts in infectious diseases, immunization, immunology, epidemiology and public health. The committee regularly reviews all the scientific information available on the safety and efficacy of vaccines—new vaccines as well as vaccines already in use.
Ensuring vaccine safety
Health authorities in Canada, including those in provincial and federal governments, take vaccine safety very seriously. Before a vaccine is licensed for use in Canada, the manufacturer must prove that their product is safe. This is done with studies to compare the immune and other reactions of people who are given the vaccine with those in people who are given an injection which does not contain the vaccine. People taking part in these studies (or “trials”) are volunteers. They understand that a vaccine is being studied and are informed about the possible side effects that may occur.
Monitoring vaccine safety is ongoing. Trials carried out before a vaccine is licensed can show that serious adverse effects after getting the vaccine being tested are uncommon. But because of the limited number of participants, such trials may not pick up the possibility of rare adverse effects. Monitoring for possible but rare serious adverse events must continue after any vaccine has been licensed for use.
The Biologics and Genetic Therapies Directorate (BGTD), which is part of Health Canada, regulates vaccines used in humans in Canada. They approve vaccines for use only if all acceptable standards of quality, safety and efficacy are met. The BGTD also supervises all aspects of production and quality control throughout the vaccine’s life cycle, ensuring that the batches used to immunize children today are as safe and effective as the ones tested during original clinical trials. The factory where a vaccine is manufactured is inspected by government authorities regularly to ensure that facilities and all stages of production and quality control conform to the highest standards.
Each individual batch of vaccine must also be authorized for sale in Canada. Manufacturers have to submit an official document providing results from all the tests for quality performed throughout the production process for that batch. Also, for most vaccines, the BGTD performs tests on samples from each batch in its own laboratory to monitor vaccine quality.
Monitoring vaccine safety
After BGTD has approved a vaccine, Canada has advanced systems in place to monitor safety and to make our medical experts aware of unusual post-vaccine events. In the very rare event that a batch of vaccine results in an unexpected side effect, these systems can ensure that the rest of the batch is not used. Canada is a world leader in post-marketing surveillance of vaccine adverse events.
An adverse event following immunization (AEFI) is any “untoward medical occurrence” after a vaccine has been given which may—or may not—have been caused by the vaccination. Some mild reactions are expected, such as fever and redness, swelling and soreness at an injection site. An unexpected AEFI is one that was not recognized previously and was not listed in information supplied by the manufacturer. A serious AEFI is one that is life-threatening and/or results in hospitalization, permanent disability, or death.
Voluntary reporting by health care professionals
In all provinces and territories, doctors and public health nurses are expected to report any serious or unexpected AEFI that occurs after vaccination to their local health department, especially if it is serious enough to require a visit to a doctor or hospitalization. Many less serious and expected events, such as fever or local reactions (e.g., redness, swelling) are also reported, especially if these occur in clusters or more frequently than usual.
- The local medical officer of health investigates all of these reports, and then forwards them to the provincial or territorial ministry of health.
- The reports then go to the Canadian Adverse Events Following Immunization Surveillance System (CAEFISS), a branch of the Public Health Agency of Canada. This federal agency keeps track of, and analyzes, all reports of adverse events after vaccination.
The system works!
- In the late 1980s, an increased rate of meningitis was noted after a new strain of mumps vaccine was introduced in Canada. The vaccine was withdrawn.
- In 2000-01, there were reports of a new oculo-respiratory syndrome (red eyes, cough and difficulty breathing) after influenza vaccine. Although these symptoms were mild and cleared within 48 hours in most cases, investigations were made to determine the cause. Changes to the vaccine manufacturing process have made this syndrome very rare.
Mandatory reporting by manufacturers
All vaccine manufacturers must quickly report any serious adverse events that they become aware of, in Canada or internationally, to Health Canada.
Canadian Immunization Research Network special immunization clinics (SICs)
Following an AEFI, not only must a cause be determined but an evaluation of the safety of further immunizations also has to be done. Not surprisingly, parents, patients and health care workers might be hesitant to continue administering a particular vaccine, especially if an AEFI required hospitalization.
To address this, the Canadian Immunization Research Network established 13 special immunization clinics (SICs) in 2013, staffed by paediatric and adult infectious disease specialists and allergists experienced in dealing with ‘challenging’ AEFIs. Patients with conditions that may put them at higher risk of an AEFI (eg, compromised immunity) are also seen in SICs. Referred patients are assessed and managed using a standardized approach. With consent, these cases are entered into a central registry to allow review of other immunization outcomes for people with similar AEFIs, and to better evaluate management procedures.
For SIC locations, please consult: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4173958/table/t1-pch-19-310/. Although access to clinics is only available by appointment in a dozen or so cities across Canada, you may contact them for advice.
Canada has a unique program called IMPACT—the Canadian Immunization Monitoring Program, ACTive — to detect adverse events related to vaccination and monitor vaccine-preventable diseases. The program is funded by the Public Health Agency of Canada and operated by the Canadian Paediatric Society.
IMPACT was designed over 20 years ago by researchers at paediatric health centres in Canada who were interested in vaccination. The program works as follows:
- A nurse at each of the 12 children’s hospitals across Canada reviews all admissions to the hospital for certain serious illnesses, including seizures, encephalitis, encephalopathy, loss of consciousness, meningitis, acute paralysis, bleeding or bruising, some types of rashes, and severe allergic reactions. Each year, these nurses screen more than 100,000 admissions at the 12 hospitals.
- If a child with any of these diagnoses had recently received a vaccine, a report is sent to the local health department and to CAEFISS for analysis.
Canadian Paediatric Surveillance Program
With the Canadian Paediatric Surveillance Program (CPSP), Canada has another valuable and unique surveillance tool for collecting active real-time data on rare diseases, including acute paralysis in children and some vaccine-preventable diseases.
The CPSP was established in 1996 through a partnership between the Public Health Agency of Canada and the Canadian Paediatric Society. The program involves more than 2,500 paediatricians and paediatric subspecialists from all provinces and territories who monitor their practices for rare conditions and report monthly to the CPSP.
CPSP surveillance of acute flaccid paralysis enabled Canada to fulfill its international obligations to the Pan American Health Organization and the World Health Organization by demonstrating the absence of paralytic polio and wild polioviruses in Canada.
Public Health Agency of Canada
Experts with this government body review all reported cases of serious adverse events following vaccination that result in hospitalization, permanent damage or death. Included for review are all cases of meningitis, encephalitis, encephalopathy, seizures without fever, death, or any event that required hospitalization following immunization.
Because such events are not necessarily caused by vaccination but may be linked in time by coincidence, careful review of the details of all cases, on a regular basis, is important to determine whether there are any concerns regarding vaccine safety.
The results of these reviews are reported to the doctor or nurse who reported the event. Summaries of results are posted on the Public Health Agency of Canada’s website.
Global Advisory Committee on Vaccine Safety
The World Health Organization established this committee in 1999 to advise on vaccine safety issues of potential global importance. The committee members are experts from around the world in the fields of epidemiology (the study of disease incidence, control and prevention), statistics, paediatrics, internal medicine, pharmacology and toxicology, infectious diseases, public health, immunology and autoimmunity, and drug regulation and safety. This committee has reviewed almost all issues relating to vaccine safety. Reports of the committee’s reviews are available at: www.who.int/vaccine_safety/committee/topics/en/.
Immunization Safety Review Committee
The National Academy of Medicine in the United States formed this committee to evaluate all available evidence on various immunization safety concerns. Specifically, the committee was asked to present its findings regarding possible causal associations between vaccines and certain adverse outcomes. Comprised of experts in infectious diseases, immunization, epidemiology, statistics and public health, the committee reviewed relevant published scientific and medical articles as well as unpublished data, personal communications and submissions by any interested parties. Their conclusions and recommendations are published by the National Academy of Sciences in eight reports.
More information from the CPS:
Reviewed by the following CPS committees:
- Infectious Diseases and Immunization Committee
Last Updated: November 2016