Significant revisions since the last chapter update are highlighted in the CIG Table of Updates which is available on the PHAC website.
For additional information, refer to previously published the National Advisory Committee on Immunization (NACI) Statements and Statement Updates.
Pertussis (whooping cough) is caused by the bacterium Bordetella pertussis.
Humans. Adolescents and adults are often the source of infection in infants.
Pertussis is highly communicable, with studies showing 80% secondary attack rates among susceptible household contacts. Transmission is less likely from vaccinated cases and to vaccinated contacts. Pertussis is usually transmitted by the respiratory route through contact with respiratory droplets; indirect spread through contaminated objects occurs rarely, if at all. The incubation period is 9 to 10 days (range, 6 to 20 days), and may rarely be as long as 42 days. Infectiousness is greatest during the catarrhal period and during the first 2 weeks after cough onset. Patients are no longer contagious after 5 days of appropriate antibiotic treatment.
Pertussis can affect individuals of any age; however, severity is greatest among infants who are too young to be protected by a complete vaccine series. Young infants are also at highest risk of pertussis-associated complications. Immunity to pertussis from childhood vaccination and natural disease wanes with time; therefore, adolescents and adults who have not received a booster vaccination are at risk of infection and its consequent transmission to others.
Seasonal and temporal patterns
Pertussis is an endemic disease common to children (especially young children) everywhere, regardless of ethnicity, climate or geographic location.
Spectrum of clinical illness
The clinical course of pertussis is divided into three stages. The initial catarrhal stage is characterized by runny nose, sneezing, low-grade fever, and a mild cough, similar to a cold. After 1 to 2 weeks of gradually worsening cough, the paroxysmal stage begins. The paroxysmal stage is characterized by bursts of rapid coughing, ending with an inspiratory whoop and sometimes post-tussive vomiting. This stage lasts from 1 to 6 weeks but may persist for up to 10 weeks. In the convalescent stage, recovery is gradual and may take weeks to months.
The clinical course varies with age. In young infants, who are at the highest risk, clinical symptoms are frequently atypical. Whoop and post-tussive vomiting may be absent. The presentation may be characterized solely by episodes of apnea. Serious complications occur mainly in infants and may include pneumonia, atelectasis, seizures, encephalopathy, hernias and death.
Pertussis may be milder in adolescents and adults, but symptoms can range from asymptomatic infection to a very prolonged, debilitating cough. Pertussis is a common and often unrecognized cause of cough persisting for over 2 weeks in adolescents and adults. Complications in adolescents and adults include sleep disturbance, rib fractures, subconjuctival hemorrhages, rectal prolapse, and urinary incontinence, all from intense and persistent coughing. Adolescents and adults with a cough, and less so in those who are asymptomatic, are a source of infection for those most at risk, namely infants.
Mortality is rare in industrialized countries. Pneumonia is the most common cause of death, typically in infants less than 6 months of age. One to three deaths related to pertussis occur each year in Canada, particularly in infants who are too young to be immunized, or unimmunized or partially immunized children.
Pertussis is endemic worldwide, even in regions with high vaccination coverage. In Canada, pertussis incidence is highest in infants and children, and decreases sharply in those older than 14 years of age, with peaks in activity occurring in two to five year cycles. For more information about pertussis distribution in Canada refer to the Public Health Agency of Canada pertussis web page. Comprehensive updates on the epidemiology of pertussis in Canada are published periodically in the Canada Communicable Disease Report (CCDR).
In Canada, pertussis vaccine is only available as an acellular preparation in a combination vaccine. The amount of acellular pertussis antigen present varies by product. Preparations containing higher concentrations of acellular pertussis antigen (designated as "aP") are administered for primary immunization of infants and young children less than 7 years of age (pediatric formulation) and may be administered as a booster for children 4 years to less than 7 years of age. Preparations containing a lower concentration (designated as "ap" and referred to as "reduced") may also be administered as a booster dose to children 4 years to less than 7 years of age and are the recommended product for older children, adolescents and adults (adolescent/adult formulation).
For complete prescribing information, consult the product leaflet or information contained within Health Canada's authorized product monographs available through the Drug Product Database. Refer to Table 1 Contents of Immunizing Agents Available in Canada in Part 1 for a list of all vaccines available for use in Canada and their contents.
The vaccine efficacy following the primary series with acellular pertussis vaccines is estimated to be about 85%, and approximately 90% following booster immunization. Although the duration of protection afforded by acellular pertussis vaccine is unknown, available data suggests that protection does not significantly decline between the first booster (18 months) and second booster (4-6 years) with an acellular pertussis vaccine. However, a progressive decline in protection has been observed following the second booster dose. NACI will be assessing the implications of this finding.
Immunologic correlates of protection against pertussis are not well-defined, but higher levels of anti-pertussis antibodies seem to be associated with greater protection. In general, acellular pertussis-containing combination vaccines have demonstrated good immunogenicity of their component antigens. Consistently high response to pertussis vaccine has been observed after booster vaccination.
Acellular pertussis vaccine is recommended for routine infant immunization beginning at 2 months of age. DTaP-IPV (with or without Hib) vaccine is authorized for use in children less than 7 years of age. DTaP-HB-IPV-Hib vaccine is authorized for use in children 6 weeks to 23 months of age and may be given to children aged 24 months to less than 7 years, if necessary. DTaP-IPV or Tdap-IPV vaccine should be used as the booster dose for children at 4 to 6 years of age. Children 7 years of age and older should receive the adolescent/adult formulation of diphtheria-tetanus-pertussis-containing vaccine with or without polio (Tdap or Tdap-IPV) for primary immunization or booster doses, as it contains less diphtheria toxoid than preparations given to younger children and is less likely to cause reactions in older children. Tdap vaccine should be administered to adolescents at 14 to 16 years of age as the first 10-year booster dose; Tdap-IPV vaccine should be used if IPV vaccine is also indicated.
All adults should receive one dose of Tdap vaccine if they have not previously received pertussis-containing vaccines in adulthood. In particular, adults who have not previously received pertussis-containing vaccines in adulthood, and who anticipate having regular contact with an infant, should receive a dose of Tdap vaccine, ideally administered at least 2 weeks before contact with the infant.
Persons who have had pertussis infection should receive pertussis-containing vaccines as recommended because infection does not confer long term immunity.
Refer to Schedule and Booster doses and re-immunization. Refer to Diphtheria Toxoid, Tetanus Toxoid, Poliomyelitis Vaccine, Haemophilus influenzae type b Vaccine, and Hepatitis B Vaccine in Part 4 for additional information.
Children and adults lacking adequate documentation of immunization should be considered unimmunized and started on an immunization schedule appropriate for their age and risk factors. There are no established serologic correlates for protection against pertussis. Refer to Immunization of Persons with Inadequate Immunization Records in Part 3 for additional general information.
Immunization with Tdap to date has been shown to be safe in pregnant women and allows high levels of antibody to be transferred to newborns during the first two months of life when the morbidity and mortality from pertussis infection is the highest. All pregnant women at or after 26 weeks of pregnancy who have not received a dose of a pertussis-containing vaccine in adulthood should be encouraged to receive Tdap vaccination. Immunization should not be delayed until close to delivery since this may provide insufficient time for optimal transfer of antibodies and direct protection of the infant against pertussis. In special circumstances, such as an outbreak situation, all pregnant women who are 26 weeks gestation or greater may be offered Tdap vaccination irrespective of their immunization history based on recommendations from local public health officials. Refer to Immunization in Pregnancy and Breastfeeding in Part 3 for additional general information.
Premature infants in stable clinical condition should be immunized with pertussis-containing vaccine at the same chronological age and according to the same schedule as full-term infants. Infants born prematurely (especially those weighing less than 1,500 grams at birth) are at higher risk of apnea and bradycardia following vaccination. Hospitalized premature infants should have continuous cardiac and respiratory monitoring for 48 hours after their first immunization. Refer to Immunization of Infants Born Prematurely in Part 3 for additional general information.
Residents of long-term care facilities should receive all routine immunizations appropriate for their age and risk factors, including acellular pertussis-containing vaccine. Refer to Immunization of Persons/Residents in Health Care Institutions in Part 3 for additional general information.
Diphtheria-tetanus-pertussis-polio-Hib-containing vaccines may be administered to immunocompromised persons. When considering immunization of an immunocompromised person, consultation with the individual's attending physician may be of assistance in addition to the guidance provided in Immunocompromised persons in Diphtheria Toxoid and Haemophilus influenza type b Vaccine in Part 4. For complex cases, referral to a physician with expertise in immunization or immunodeficiency is advised.
People with neurological disorders are at risk of added morbidity and mortality from pertussis disease. Persons with neurological disorders with onset preceding immunization should receive all routinely recommended immunizations, including pertussis-containing vaccine.
Cases of Guillain Barré Syndrome (GBS) have been reported very rarely following administration of a tetanus toxoid-containing vaccine. Refer to Contraindications and Precautions for additional information. Refer to Tetanus Toxoid in Part 4 for additional information.
Refer to Immunization of Persons with Chronic Diseases in Part 3 for additional general information.
Unimmunized or incompletely immunized travellers should receive diphtheria-tetanus-pertussis-polio-Hib-containing vaccine as appropriate for age. Refer to Diphtheria Toxoid and Poliomyelitis Vaccine in Part 4 for information regarding other components in acellular pertussis-containing combination vaccines. Refer to Immunization of Travellers in Part 3 for additional general information.
Health care providers who see people newly arrived in Canada should review the immunization status and update immunization for these individuals. Children who have received one or more doses of diphtheria-tetanus-whole cell pertussis (DPT) vaccine before arriving in Canada should have their vaccine series completed with acellular pertussis- containing vaccine (DTaP or Tdap) as appropriate for age. Refer to Immunization of Persons New to Canada in Part 3 for additional general information.
All health care and child care workers, regardless of age, should receive a single dose of Tdap vaccine for pertussis protection if this vaccine was not previously administered in adulthood, even if the person is not due for a tetanus and diphtheria booster. Refer to Immunization of Workers in Part 3 for additional general information.
Acellular pertussis vaccine has been used for the control of pertussis outbreaks in defined populations, such as in schools or hospitals, although data supporting its effectiveness are lacking. Children exposed to a case of pertussis should have their immunization status reviewed and updated as required. In an outbreak, public health officials may recommend that pregnant women be offered Tdap vaccination after 26 weeks of gestation, irrespective of their immunization history.
Each dose of pertussis-containing vaccine is 0.5 mL
Route of administration
Pertussis-containing vaccines must be administered intramuscularly. Refer to Vaccine Administration Practices in Part 1 for additional information.
Infants and children (2 months to 6 years of age)
Routine pertussis immunization of infants: DTaP-IPV-Hib vaccine should be given at 2, 4, 6 and 12 to 23 months of age (generally given at 18 months of age).
If infant immunization for hepatitis B is undertaken, DTaP-HB-IPV-Hib vaccine may be used as an alternative to separately administered hepatitis B and DTaP-IPV-Hib vaccines. DTaP-HB-IPV-Hib vaccine is authorized for use in children 6 weeks to 23 months of age and may be given to children aged 24 months to less than 7 years, if necessary. DTaP-HB-IPV-Hib vaccine may be given at 2, 4, 6 and 12 to 23 months of age, but the fourth dose is unlikely to provide significant additional hepatitis B protection and will increase cost. Alternative schedules may be used as follow:
If rapid protection is required for an infant, the first dose of DTaP-IPV-Hib or DTaP-HB-IPV-Hib vaccine can be given at 6 weeks of age. The first three doses may be administered at intervals of 4 weeks and, optimally, the fourth dose given 12 months after the third dose. The fourth dose may be given at a minimum interval of 6 months after the third dose in certain situations (e.g., travel) but must be administered on or after 12 months of age for sustained immunity.
Children less than 7 years of age, not immunized in infancy: should receive three doses of DTaP-IPV (with or without Hib) vaccine with an interval of 8 weeks between doses, followed by a dose of DTaP-IPV vaccine 6 to 12 months after the third dose. A booster dose of either DTaP-IPV or Tdap-IPV vaccine should be administered at 4 to 6 years of age (school entry). The booster dose at 4 to 6 years of age is not required if the fourth dose of tetanus-toxoid containing vaccine was administered after the fourth birthday.
If rapid protection is required for a child less than 7 years of age not immunized in infancy, the first three doses of vaccine may be administered at intervals of 4 weeks and, optimally the fourth dose given 12 months after the third dose. The fourth dose may be given at a minimum interval of 6 months after the third dose in certain situations (e.g., travel).
Children who received a primary series of acellular pertussis-containing vaccine and a booster dose 6-12 months later as outlined above should receive a booster dose of either DTaP-IPV or Tdap-IPV vaccine at 4 to 6 years of age (school entry); and, 10 years later, a booster dose of Tdap vaccine at 14 to 16 years of age. The booster dose at 4 to 6 years of age is not required if the fourth dose of acellular pertussis-containing vaccine was administered after the fourth birthday.
Children and adolescents (7 years to 17 years of age)
Children 7 years of age and older, not previously immunized, should receive three doses of Tdap-IPV vaccine, with an interval of 8 weeks between the first two doses, followed by a third dose administered 6 to 12 months after the second dose. A booster dose of Tdap vaccine should be administered 10 years after the last dose.
Adults (18 years of age and older)
Adults who have not previously received Tdap vaccine in adulthood should receive one dose of Tdap vaccine, which can be administered regardless of the interval since the last dose of tetanus and diphtheria toxoid-containing vaccine.
The preschool booster dose of either DTaP-IPV or Tdap-IPV vaccine should be administered at 4 to 6 years of age. Adolescents should routinely receive a booster dose of Tdap vaccine at 14 to 16 years of age. Adults who have not previously received Tdap vaccine in adulthood, should receive one dose of Tdap vaccine, regardless of the interval since the last dose of tetanus or diphtheria toxoid-containing vaccine.
Serologic testing is not recommended before or after receiving pertussis vaccine.
Pertussis-containing vaccines should be stored in a refrigerator at +2°C to +8°C and should not be frozen.
Refer to Storage and Handling of Immunizing Agents in Part 1 for additional general information.
Pertussis-containing vaccines may be administered concomitantly with routine vaccines at different injection sites, using separate needles and syringes. Refer to Timing of Vaccine Administration in Part 1 for additional general information.
Refer to Vaccine Safety in Part 2 for additional general information. Refer to Diphtheria Toxoid, Tetanus Toxoid, Poliomyelitis Vaccine, Haemophilus influenzae type b Vaccine and Hepatitis B Vaccine in Part 4 for additional information regarding other components in pertussis-containing combination vaccines.
Redness, swelling and pain at the injection site are the most common adverse reactions to childhood pertussis-containing combination vaccines. A nodule may be palpable at the injection site and may persist for several weeks. Abscess at the injection site has been reported, especially if care is not taken to ensure IM injection, and inadvertent SC administration occurs.
In clinical trials, injection site adverse reactions, including tenderness, erythema, swelling, or any combination thereof, were reported in 10% to 40% of children after each of the first 3 doses of pertussis-containing vaccine. Mild systemic reactions such as fever, irritability and/or fussiness were commonly reported (8% to 29%), as well as drowsiness (40% to 52%).
In two clinical studies, swelling, greater than 5 cm, and erythema were reported in 15% to 20% of vaccinees after the fourth or fifth doses of DTaP vaccines. Extensive limb swelling, greater than 10 cm in diameter, and possibly involving the entire proximal limb, may occur in 2% to 6% of children. While these injection site reactions produce significant swelling, pain is generally limited. There is some evidence that children with extensive limb swelling following the fourth dose of a DTaP vaccine are at increased risk of such an event following the fifth dose. The presence of a large injection site reaction to a previous dose is not a contraindication to continuing the recommended schedule.
Among adults given a booster dose of Tdap vaccine, very common reactions include pain, redness and swelling at the injection site, headache, and fatigue. Fever and chills are common reactions. Overall, adverse reactions are less common in adults than adolescents. The interval between the childhood DTaP vaccine series or a dose of Td vaccine, and a dose of Tdap vaccine does not affect the rate of injection site or systemic adverse events.
Serious adverse events are rare following immunization and, in most cases, data are insufficient to determine a causal association. Anaphylaxis following vaccination with pertussis-containing vaccine may occur, but is very rare.
Hypotonic hyporesponsive episodes (HHE) and seizures may occur following immunization with pertussis-containing vaccine. The WHO case definition of HHE includes sudden onset of hypotonia (muscle limpness), hyporesponsiveness (reduced responsiveness or unresponsiveness), and pallor or cyanosis. However, there is evidence that there are no adverse consequences to these events and the adverse consequences of being incompletely immunized have been well documented. HHE occur less frequently following receipt of acellular pertussis-containing vaccine than following whole cell pertussis-containing vaccines, which are no longer in use in Canada. High fever and convulsions, both febrile and afebrile, are rarely reported and are not contraindications to further immunization with acellular pertussis-containing vaccine. Encephalopathy with onset temporally related to pertussis immunization is very rare and an alternative etiology is usually established. Encephalopathy itself, from whatever cause, is not a contraindication to pertussis immunization. Refer to Immunization of Persons with Chronic Diseases in Part 3 for additional information.
Epidemiological studies do not support allegations of a causal relationship between pertussis-containing vaccines and permanent neurological injury.
Vaccine providers are asked to report, through local public health officials, any serious or unexpected adverse event felt to be temporally related to vaccination. An unexpected AEFI is an event that is not listed in available product information but may be due to the immunization, or a change in the frequency of a known AEFI. Refer to Reporting Adverse Events Following Immunization (AEFI) in Canada in Vaccine Safety Part 2 for additional information about AEFI reporting.
Pertussis-containing vaccines are contraindicated in persons with a history of anaphylaxis after previous administration of the vaccine and in persons with proven immediate or anaphylactic hypersensitivity to any component of the vaccine or its container. Refer to Table 1 in Contents of Immunizing Agents Available for Use in Canada in Part 1 for a list of all vaccines available for use in Canada and their contents. For pertussis-containing vaccines, potential allergens include:
There are no currently known potential allergens in ADACEL® vaccine.
With respect to Infanrix hexa™, hypersensitivity to yeast is very rare and a personal history of yeast allergy is not generally reliable. In situations of suspected hypersensitivity or non-anaphylactic allergy to vaccine components, investigation is indicated, which may involve immunization in a controlled setting. Consultation with an allergist is advised.
It is prudent to not administer further doses of tetanus-toxoid containing vaccine to persons who develop Guillain-Barre Syndrome (GBS) within 6 weeks of receiving such vaccine. Those who develop GBS outside the 6 week interval may receive subsequent doses of tetanus toxoid-containing vaccine. If there is a history of both Campylobacter infection (which has been associated with GBS) and receipt of a tetanus and diphtheria toxoid-containing vaccine within the 6 weeks before the onset of GBS, consultation with an infectious disease specialist is advised. Refer to Tetanus Toxoid in Part 4 for additional information.
Administration of pertussis-containing vaccine should be postponed in persons suffering from severe acute illness. Immunization should not be delayed because of minor acute illness, with or without fever. Refer to General Contraindications and Precautions in Part 2 for additional general information.
The primary series of three doses of pertussis-containing vaccine should be completed with an appropriate vaccine from the same manufacturer whenever possible. However, if the original vaccine is unknown or unavailable, an alternative combination vaccine from a different manufacturer may be used to complete the primary series. On the basis of expert opinion, an appropriate product from any manufacturer can be used for all booster doses. Refer to Principles of Vaccine Interchangeability in Part 1 for additional general information.