Canadian Immunization Guide: Part 1 - Key Immunization Information

Benefits of Immunization

Updated: August 2016

Benefits of immunization

Immunization is one of the most important accomplishments in public health that has, over the past 50 years, led to the elimination, containment and control of  diseases that were once very common in Canada.  Before vaccines became available, many Canadian children were hospitalized or died from diseases such as diphtheria, pertussis, measles and polio. Today, although these disease causing bacteria and viruses still exist, such diseases are rarely seen in Canada. However, if the current vaccination programs were reduced or stopped, diseases controlled through immunization would re-appear in Canada. This phenomenon has been observed in other countries where large epidemics occurred following a decline in immunization rates, resulting in many preventable hospitalizations and deaths.
Immunization is important in all stages of life. Infants and young children are particularly susceptible to vaccine preventable diseases because their immune systems are less mature and therefore less able to fight infection; as a result, they require timely immunization. Older children and adults also require immunization to restore waning immunity and to build new immunity against diseases that are more common in adults.
Immunization directly protects individuals who receive vaccines. Through community (or herd)immunity, immunization against many diseases also prevents the spread of infection in the community and indirectly protects:

  • newborns who have not yet received all of their vaccines
  • people who cannot be vaccinated for medical reasons, such as people who had an organ transplant or are undergoing treatment for cancer or other illnesses
  • people who may not adequately respond to immunization such as the elderly.

Impact of vaccines on vaccine preventable diseases

Table 1, Figure 1, Figure 2, and Figure 3 illustrate the impact of vaccines on infectious diseases in Canada. Refer to the vaccine-specific chapters in Part 4 for additional information about the success of immunization programs against specific vaccine preventable diseases.

Table 1: incidence of select vaccine preventable diseases in Canada - pre-vaccine era compared with 2007-2011
Disease and impact Vaccine introduction and disease reporting Pre-vaccine era 2007-2011Table 1 - Footnote 1
Pre-vaccine period 5-year average annual incidence per 100,000 Peak annual number of casesTable 1 - Footnote 2 5-year average annual incidence per 100,000 Peak annual number of cases

Abbreviations:
CRS = congenital rubella syndrome
HB = hepatitis B
Hib = Haemophilus influenzae type b
IPV = inactivated poliomyelitis vaccine

Diphtheria

Infection of the throat causes severe breathing difficulty which may result in asphyxia. Infection also results in the dissemination of diphtheria toxin, which damages the heart and central nervous system. In the pre-vaccine era case fatality was about 5% to 10%, with the highest death rates occurring in the very young and the elderly.

  • Diphtheria toxoid introduced in 1926

  • Routine infant immunization since 1930

  • National notifiable diseases reporting began in 1924

1925-1929 84.2 9,010 0.006 4

Haemophilus influenzae type b (Hib) invasive disease (in children less than 5 years of age,this infection can cause otitis media, meningitis, epiglottitis, bacteremia, cellulitis, pneumonia or septic arthritis in young children. The case fatality rate of meningitis is about 5%. Severe neurologic sequelae occur in 10% to 15% of survivors and deafness in 15% to 20%

  • Vaccines first introduced in 1986

  • Conjugate vaccine introduced in 1988

  • Routine infant immunization since 1988-1989

  • National notifiable disease reporting of all invasive Hib disease began in 1986

1986-1990 30.1Table 1 - Footnote 3 671 0.49Table 1 - Footnote 3 18

Hepatitis B (HB)

Infection in approximately 3 to 10% of adults results in chronic infection leading to a chronic carrier state that may result in cirrhosis, liver cancer, and death.

  • Universal HB immunization for adolescents implemented in the early- to mid-1990s

  • National notifiable disease reporting of HB infection began in 1969

1989-1993 9.1Table 1 - Footnote 4 3,378Table 1 - Footnote 5 5.3Table 1 - Footnote 6 2,011Table 1 - Footnote 7

Measles

Bronchopneumonia and otitis media occur in about 1/10 cases and encephalitis occurs in 1/1,000 cases (the infection is fatal in 15% and neurologic sequelae in 25%). Case fatality rate is 1 to 2 per 1,000. Subacute sclerosing panencephalitis is a rare but fatal complication.

  • Live vaccine authorized in 1963

  • Universal immunization program implemented in 1983

  • 2-dose measles-containing vaccine schedule introduced 1996/1997

  • National notifiable diseases reporting began in 1924 (no reporting from 1959 to 1968)

1950-1954 372.7 61,370 0.60Table 1 - Footnote 8 752Table 1 - Footnote 8

Meningococcal serogroup C invasive disease

Invasive meningococcal disease most often results in meningitis or septicemia. Severe cases can result in delirium and coma and, if untreated, shock and death. The case fatality rate is 10%, and 10% to 20% of survivors have long term sequelae such as digit or limb amputations, neurologic disabilities, and deafness.

  • Polysaccharide vaccines first introduced in Canada in 1981

  • Routine infant or toddler immunization programs using conjugate vaccine introduced across Canada between 2002 and 2006

  • National notifiable disease reporting began in 1924

1997-2001 0.30 186 0.06 30

Mumps

Acute parotitis develops in 40%, of which 25% are unilateral. Complications include orchitis (20% to 30% of post-pubertal males), oophoritis (5% of post-pubertal females), meningitis (less than 10% of cases), deafness (0.5 to 5/100,000 cases) and encephalitis (less than 1/50,000 cases). Rarely, mumps can cause permanent infertility.

  • Vaccine authorized in 1969

  • Universal immunization program implemented in 1983

  • National notifiable disease reporting began in 1924 (no reporting from 1960 to 1985)

1950-1954 251.2 43,671 1.84 1,110

Pertussis

Young infantsare most affected by complications, such as vomiting after a coughing spell, weight loss, breathing problems, choking spells, pneumonia, convulsions, encephalopathy, and, death. Older children and adults may develop persistent cough.

  • Whole cell pertussis vaccine authorized in 1943

  • Acellular pertussis vaccine replaced whole cell pertussis vaccine in 1997-1998
  • Adolescent and adult acellular vaccine formulation authorized in 1999

  • National notifiable disease reporting began in 1924

1938-1942 156.0 19,878 3.88 1,961

Poliomyelitis

Paralysis occurs in less than 1% of infections but among those paralyzed, about 2% to 5% of children and 15% to 30% of adults die.

  • Inactivated polio (IPV) vaccine authorized in 1955
  • Oral polio vaccine authorized in 1962 and in use in Canada until 1996
  • IPV vaccine used primarily from 1996-present
1950-1954 17.5 5,384 0 0

Rubella and congenital rubella syndrome (CRS)

Although rubella is generally a mild disease, encephalitis occurs in 1/6,000 cases. However, rubella infection in pregnancy can cause (CRS). Infection in the first 10 weeks of pregnancy has an 85% risk of leading to CRS. CRS can result in miscarriage, stillbirth and fetal malformations (congenital heart disease, cataracts, deafness and mental retardation).

  • Rubella vaccine introduced 1969

  • Universal immunization program implemented in 1983

  • National notifiable disease reporting began in 1924

  • National notifiable diseases reporting of CRS began in 1979

  • Rubella: 1950-1954

  • CRS: 1979-1983

  • Rubella: 37,917

  • CRS: 29

  • Rubella:10

  • CRS: 1

Tetanus

Infection leads to general rigidity, and convulsive spasms, with death in about 10% of cases. Higher rates of death occur among infants.

  • Tetanus toxoid introduced in 1940

  • National notifiable diseases reporting began in 1957

1935-1939 0.13 25 0.01 6
 

Figure 1: Haemophilus influenzae type b disease - reported number of casesFootnote 1 and incidence rates, Canada, 1979-2010Footnote 2

Figure 1: Haemophilus influenzae type b disease

Abbreviations:
Hib = Haemophilus influenzae type b
PRP-D = Hib conjugate vaccine containing purified polyribosylribitol phosphate capsular polysaccharide of Hib covalently bound to diphtheria protein.

Haemophilus influenzae type b disease - reported number of casesFootnote 1 and incidence rates, Canada, 1979-2010Footnote 2 - Text Equivalent

This image is a histogram showing the reported number of cases of Haemophilus influenzae type b (Hib) in Canada over time. A superimposed graph shows the incidence rates of Haemophilus influenzae type b (Hib) in Canada over time. The x axis represents the time between 1979 and 2010. The y axis on the left represents the reported number of cases starting from 0 at the bottom to 1200 at the top. The y axis on the right represents incidence rates per 100,000 starting with 0 at the bottom to 4 at the top. The bars represent the reported number of cases and the blue line shows the Hib incidence rate. In 1979, the reported number of Hib meningitis cases was 220. The Hib meningitis cases steadily escalated to about 510 by 1985. The reported number of invasive Hib cases hit a peak of almost 900 by 1989. The PRP-D was introduced in 1988Footnote 3. According to a note at the bottom of the histogram, PRP-D is the Hib conjugate vaccine containing purified polyribosylribitol phosphate capsular polysaccharide of Hib covalently bound to diphtheria protein. The reported number of cases sharply declined to about 530 in the year 1990, and steadily to a low of about 30 in 1999. The number remained stable around that level until 2010.

The incidence rate of Hib was close to 1 per 100,000 in 1979, rising steadily to 2 per 100,000 population in 1985. All invasive disease caused by Hib reached an incidence rate of 2.7 by 1986. By the time the Hib conjugate vaccine PRP-D was introduced in 1988, the incidence rate was 3 per 100,000. The peak incidence rate of all invasive disease caused by Hib in Canada was about 3.7 in the year 1989. Since then, the incidence declined sharply and steadily over the years. The rate was about 1 in 1992 and dropped below 0.5 per 100,000 by 1993. The rate fell close to 0.1 in 1999, and remained around 0.2 during the years 2000 to 2008. By 2010, the incidence was no more than 0.1 per 100,000.

A note at the bottom of the table indicates that case data have been "obtained from the Canadian Notifiable Disease Surveillance System" and "population data obtained from Statistics Canada July 1st annual estimates." It also mentions that "data for 2009 and 2010 are preliminary."

Another note clarifies that "only Hib meningitis was reportable from 1979 to 1985. After this, all invasive disease caused by Hib became reportable."

 

Figure 2: Diphtheria - reported number of cases and incidence rates, Canada, 1924-2008

Figure 2: Diphtheria
Figure 2: Diphtheria - reported number of cases and incidence rates, Canada, 1924-2008 - Text Equivalent

This image includes two graphs showing the reported cases and incidence of diphtheria in Canada. The bigger graph shows the trends in diphtheria incidence over the years, with x axis representing time in years between 1924 and 2004. The y axis represents rate per 100,000 population starting with 0 at the bottom and ending in 120 at the top. The graph showing the incidence rates has an orange line inside representing the trends since 1924, when the rate was close to 98 per 100,000. Although it declined to about 75 by 1926, it quickly climbed to a peak of 90 by 1927. It is apparent that the introduction of diphtheria toxoid in 1926 resulted in a drastic decline in incidence starting from around 1929. The rate fell to less than 20 by 1936. Another peak of about 32 occurred around 1938, which fell to 20 by 1941. Although the rate continued to fluctuate around 25 until 1944, the rate of incidence started to decline thereafter, reaching 10 per 100,000 by 1947 and close to 0 by 1969. The rate of incidence continues to remain around 0 until 1984. No reports of incidence rates are available since 1984.

The smaller graph illustrating the reported cases of diphtheria has a dark orange line showing the trends since 1955 until 2008. The x axis of this graph represents time in years between 1955 and 2008. The y axis of this graph represents the number of reported cases starting from 0 at the bottom to 200 at the top. Starting at around 137 in 1955, the initial peak appears to have occurred around 1957, followed by a steep decline to about 37 by the year 1960. The number of cases increased to almost 90 by 1962. Another transient decline can be noticed at around 1965 when the number of cases fell to 25. The cases steadily increased over the next decade, reaching an all-time high peak of almost 175 by 1974. Diphtheria cases then declined to 100 by 1975. Except for another increase to 125 cases by 1977, the number declined sharply to single digits by 1982. The number of diphtheria cases continued its downward trend reaching 0 by 1990 and close to 0 ever since.

The notes at the bottom acknowledge the population data sources including "Statistics Canada, Population by Sex and Age, 1921-1971, revised annual estimates of population, Canada and the provinces, (Catalogue 91-512); and Statistics Canada, Population estimates 0-90+ July Canada - Provinces 1971-2008.xls

 

Figure 3: Rubella - reported number of cases and incidence rates, Canada, 1979 to 2010

Figure 3: Rubella

Abbreviation:
MMR = measles-mumps-rubella vaccine

Figure 3: Reported number of cases and incidence rates of rubella in Canada, 1979 to 2010 - Text Equivalent

This image includes a graph showing the reported number of cases and incidence rates of rubella in Canada over time. On the graph, the x axis represents the time between 1979 and 2010. The y axis on the left represents rubella cases, starting with 0 at the bottom to 9000 at the top. The y axis on the right represents incidence rates per 1,000,000 starting with 0 at the bottom to 400 at the top. The rectangular bars on the graph represent rubella cases while the single black line shows rubella incidence rate. In 1979, the reported number was at its peak at nearly 8200 cases, at a rate of approximately 337 cases per 1,000,000. Since then, the number of cases and rates of incidence show a steady decline except for a few spikes. While the number of cases declined to almost 3000 in 1980 and below 2000 in 1981, they steady climbed to another peak of about 7500 in 1983, in which year the routine 1-dose MMR vaccine was introduced. The cases declined drastically as a result to less than 2000 before rising to more than 3000 in the following two years, and declining once again to below 1000 by 1988. After a few fluctuations over the next few years, the number of cases declined to nearly 100 by 1994-96 before once again peaking at 4000 by 1997. The introduction of the routine 2-dose MMR vaccine in 1996-1997 appears to have made a difference, with fewer and fewer cases, and the bar approaching unity by 1998. Except for a small increase to about 200 cases in 2005 the bar continued to remain close to zero.

The black line representing the reported incidence rate of rubella shows a decline from a peak of almost 337 per 1,000,000 in 1979 to 80 by 1981, only to hit another peak of 300 by 1983, when the routine single-dose MMR vaccine was introduced. The reported incidence rate declined to less than 100 by 1984. After a few fluctuations, the rate declined to about a dozen cases by 1994. After another sharp rise in 1997 at 140, the line approached unity by mid-1998 following the introduction of the routine 2-dose MMR vaccine in 1996-1997. In 2005, the incidence rate of rubella in Canada increased to about 10 per 1,000,000, before declining to 0 the next year. There were no reports of cases or incidence rates between 2003 and middle of 2004 as well as after mid-2006.

Cost benefit of vaccines

Vaccine preventable diseases result in significant costs to individuals, the health care system, and society, including costs associated with absenteeism from work or school, visits to health care providers, hospitalizations, and premature deaths. In addition to being one of the most beneficial, immunization is also one of the most cost effective public health interventions.

Many vaccines provide savings in health care costs (refer to Table 2). This means that the cost of implementing the immunization program is less than the cost of treating the illness that would occur if the program was not implemented. Because immunization with these vaccines maintains health and results in cost savings, the decision to include these vaccines in publicly funded immunization programs is straightforward. Other vaccines, particularly those administered through routine immunization programs, are highly cost effective. This means that these vaccines are less costly than the health care or societal cost savings they produce.

Table 2: Cost savings achieved through selected immunization programs
Immunization program Cost saving per $1 spent
Influenza for adults 65 years of age and older $45
Measles, mumps, rubella for children $16
Pneumococcal polysaccharide for adults 65 years of age and older $8
Diphtheria, pertussis, tetanus for children $6

While newer vaccines tend to be costlier and may not be cost saving, they compare very favorably to other public health interventions in terms of cost per life year saved (refer to Table 3). In Canada, evaluation of the benefits and costs of new immunization programs is done by Provinces and Territories. Refer to Immunization in Canada in Part 1 for additional information about immunization policy and program development.

Table 3: Cost per life year saved for selected immunization programs and other public health interventions (adapted from references)
Public health intervention Cost per life year savedTable 3 - Footnote 1
Vaccines
Hepatitis B screening in pregnancy and immunization of children of carriers $164
Human papillomavirus vaccine for 12 year old girls in a school-based immunization program $12,921
Varicella vaccine for children $16,000
Pneumococcal conjugate vaccine for children $125,000
Other interventions
Mandatory seat belt law $69
Chlorination of drinking water $3,100
Smoking cessation counseling $1,000 to $10,000
Annual screening for cervical cancer $40,000
Driver and passenger air bags/manual lap belts (vs. airbag for driver only and belts) $61,000
Smoke detectors in homes $210,000
Crossing control arm for school buses $410,000
Radiation emission standard for nuclear power plants $100,000,000

Selected references

  • Centers for Disease Control and Prevention. An ounce of prevention - what are the returns? Second edition, 1999. Accessed July 2015 at: http://www.cdc.gov/mmwr/PDF/other/ozprev.pdf
  • Centers for Disease Control and Prevention. Basics and Common Questions: How Vaccines Prevent Disease. Accessed July 2015 at: ttp://www.cdc.gov/vaccines/parents/vaccine-decision/prevent-diseases.html
  • Centers for Disease Control and Prevention. Basics and Common Questions: What Would Happen If We Stopped Vaccinations? Accessed July 2015 at: http://www.cdc.gov/vaccines/vac-gen/whatifstop.htm
  • Centers for Disease Control and Prevention. Basics and Common Questions: Why Immunize? Accessed July 2015 at: http://www.cdc.gov/vaccines/vac-gen/why.htm
  • Centers for Disease Control and Prevention. Vaccine Contraindications and Precautions: Recommendations and Guidelines. Accessed July 2015 at: http://www.cdc.gov/vaccines/recs/vac-admin/contraindications.htm
  • Coyle D, Coyle K, Bettinger JA et al. Cost effectiveness of infant vaccination for rotavirus in Canada. Can J Infect Dis Med Microbiol 2012;23(2):71-77.
  • Ess SM, Szucs TD. Economic evaluation of immunization strategies. Clin Infect Dis 2002;35:294-7.
  • Schiefele, David W. The Impact of Vaccines in Canada: More Than a Century of Success. Accessed July 2015 at: http://www.onehealth.ca/r_alberta_nwt/video_conferences/R080312B-HOa.pdf
  • Tengs, TO, Adams ME, Pliskin JS et al. Five hundred live-saving interventions and their cost-effectiveness. Risk Anal 1995;15:369-90.
  • Tully S, Anonychuk A, Sanchez D et al. Time for change? An economic evaluation of integrated cervical screening and HPV immunization programs in Canada. Vaccine 2012;30:425-35.
  • World Health Organization, United Nations Children's Fund, World Bank. State of the World's Vaccines and Immunization. Geneva, Switzerland: World Health Organization; 2009;3rd edition. Accessed July 2015 at http://whqlibdoc.who.int/publications/2009/9789241563864_eng.pdf
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