PREAMBLE

The National Advisory Committee on Immunization (NACI) provides Health Canada with ongoing and timely medical, scientific, and public-health advice relating to immunization. Health Canada acknowledges that the advice and recommendations set out in this statement are based upon the best current available scientific knowledge, and is disseminating this document for information purposes. Persons administering or using the vaccine(s) should also be aware of the contents of the relevant product monograph(s). Recommendations for use and other information set out herein may differ from that set out in the product monograph(s) of the Canadian licensed manufacturer(s) of the vaccine(s). Manufacturer(s) have only sought approval of the vaccine(s) and provided evidence as to its safety and efficacy when used in accordance with the product monographs.

INTRODUCTION

A combined acellular pertussis, tetanus and diphtheria vaccine for use in adolescents and adults is licensed in Canada. In this statement, NACI is making preliminary recommendations on its use based on limited data. The goal for pertussis immunization in Canada is to reduce the morbidity and mortality related to pertussis infection. There has been no study on the efficacy of this vaccine in preventing disease or on the safety of repeated booster doses and it is unlikely that such data will be available on the short-term. There are no data on the effect of booster doses on the epidemiology of pertussis. As new data accumulate through postmarketing studies, NACI will review and possibly modify these recommendations.
 

The combined acellular pertussis, tetanus and diphtheria vaccine (ADACEL^TM) manufactured by Aventis Pasteur Limited was licensed for use in persons aged 12 to 54 years. This product has been licensed only to be given as booster dose. It is the first vaccine formulation containing a pertussis component approved in Canada for immunization of adolescents and adults.

EPIDEMIOLOGY OF PERTUSSIS IN ADOLESCENTS AND ADULTS IN CANADA

Whole cell pertussis vaccine was used in Canada for > 50 years. It has long been recognized that protection provided by the whole cell pertussis vaccine waned with time^(1,2). Nevertheless, the use of this vaccine was restricted to children < 7 years of age because the severity of local reactions increased with age. Because of waning immunity, many vaccinated children became susceptible to pertussis in adolescence or adulthood^(3,4). Pertussis is a frequent cause of cough illness in adolescents and adults ^(5-16) who constitute a major reservoir of the disease and are an important source of transmission to infants^(17,18).

The incidence of pertussis in Canada was low during the eighties but has increased since 1990 in spite of high vaccine coverage^(19,20). The resurgence of pertussis was partly attributable to a low vaccine efficacy which has been estimated to be in the range of 50% to 60% in children^(19-21). While children < 10 years of age are by far the most affected group, both the number and proportion of older cases have increased over the last decade. This increase may be attributable in part to a better recognition and reporting of pertussis in adolescents and adults. The higher incidence in adolescents and adults parallels the increase observed in children. During the last decade the average annual incidence rate was 24.3 per 100,000 for those 10 to 19 years of age and was 2.7 per 100,000 for those >= 20 years of age.
 

While there has been no large scale assessment of the proportion of susceptible adolescents and adults, three Canadian studies estimated the secondary attack rate (SAR) in household contacts of pertussis cases^(22-24) A re-analysis of these data looking at the SAR only in households where the reported case was also the first case shows the SAR ranged between 12% and 14% in contacts aged 12 to17 years, between 11% and 18% in adults aged 18 to 29 years, and between 8% and 33% in those >= 30 years.

The Sentinel Health Unit Surveillance System also documented pertussis infection in Canadian adolescents and adults with non-improving cough illness lasting >= 7 days. Using a combination of laboratory methods, 9% to 20% of these patients were found to be infected depending on the case definition.

It can be concluded that 10% to 25% of adolescents and adults in Canada are susceptible to pertussis and that these individuals play a role in its transmission.

EFFICACY AND IMMUNOGENICITY

The immunogenicity of the diphtheria and tetanus components of ADACEL^TM is equivalent to that obtained with tetanus toxiod and diptheria toxoid (Td) vaccines.

There are no data about the efficacy of a single dose of ADACEL^TM given to previously immunized adolescents or adults in the prevention of pertussis infection, disease, and transmission. However, it has been shown that this dose increases their pertussis antibody levels far in excess of those observed in Sweden in infants who received three doses of acellular pertussis vaccine (Table 1). This is true for all three antibodies (PT, pertactin, fimbriae) that were associated with protection in previous studies^(25,26). As the efficacy demonstrated in the Swedish trial was 85% (95% confidence interval: 81% to 89%)⁽²⁷⁾, it is reasonable to expect that the protection against severe disease in adolescents and adults would be of the same order, and this may lead to reduced transmission. However, the magnitude of the protection, its duration and its effect on transmission is still unknown. Other indirect evidence supporting that a single dose of ADACEL^TM will be protective comes from recent data showing the efficacy of a single booster dose of acellular pertussis vaccine in infants or preschool aged children (Dr. G. De Serres, unpublished data). In this study, the interval since the previous dose was between 1 and 3.5 years, a much shorter period than in adolescents or in adults.

PREPARATION USED FOR IMMUNIZATION

ADACEL^TM is a sterile, cloudy, uniform suspension of tetanus and diphtheria toxoids adsorbed on aluminum phosphate, combined with component pertussis vaccine and suspended in water for injection. Component pertussis vaccine is an acellular pertussis vaccine composed of five pertussis antigens. Each dose (0.5 mL) contains

The antigen content of this vaccine (including the pertussis content) is lower than the one found in the vaccines used in preschool children.

DOSAGE AND ADMINISTRATION

When used in people who have been previously immunized against tetanus, diphtheria, and pertussis a dose of 0.5 mL should be administered intramuscularly as a booster dose. The preferred site is the deltoid muscle.

STORAGE AND HANDLING REQUIREMENTS

ADACEL^TM should be stored between 2° C and 8° C. Do not freeze. Product which has been exposed to freezing should not be used.

RECOMMENDED USAGE

ADACEL^TM has been licensed for the prevention of tetanus, diphtheria, and pertussis in previously immunized adolescents and adults aged 12 to 54 years. It can be used to replace the adolescent booster of Td for those individuals who wish to have protection. There are no data available at the moment on which to base a recommendation for universal routine use. It can also be used instead of Td in adults who have to be protected against diphtheria and tetanus and also wish to decrease their risk of pertussis. Until data about safety of repeated doses is available, more than one dose cannot be recommended. This vaccine has not been licensed for primary immunization and should not be used for this indication except under clinical trial conditions.

CONTRAINDICATIONS

A history of hypersensitivity to any component of the vaccine is a contraindication.

PRECAUTIONS

Inactivated vaccines and toxoids are usually considered safe for the fetus, but the effect of administration of ADACEL^TM on the development of the embryo and the fetus has not been assessed. Immunization of a pregnant woman may be indicated when the risk of disease outweighs the risk of vaccine both for the mother and the fetus. If this condition is not met, vaccination should be deferred until after delivery.

Moderate to severe illness with or without fever is a reason to defer immunization. This precaution avoids superimposing adverse effects from the vaccine on the underlying illness or mistakenly attributing to the vaccine an adverse manifestation which is a symptom or sign of the underlying illness.

No data is available about the immune response of patients who receive immonosuppressive therapies or who are otherwise immunocompromised but it is possible that the vaccine may not elicit the expected immune response in these people.

ADVERSE REACTIONS

In a clinical trial comparing adolescents and adults given ADACEL^TM or Td, the adverse reaction rates observed with ADACEL^TM were comparable to those seen with Td adsorbed (Table 2). Local reaction was the most frequent event with pain occurring in 89%, erythema in 12%, and swelling 17%. These local reaction were generally mild and transient. By decreasing order of frequency the systemic adverse events were headache (39%), decreased energy (29%), generalized bodyache (20%), nausea (15%), chills (13%), diarrhea (10%), fever (9%), sore and swollen joints (9%), and vomiting (2%). These systemic events were rarely severe (Table 2).

RECOMMENDATION

Table 3 below presents evidence-based medicine categories for the strength and quality of the evidence for the recommendation that follows:

One booster dose in individuals previously immunized against tetanus, diphtheria and pertussis (C III).

References

1. Lambert HP. Epidemiology of a small pertussis outbreak. Public Health Reports 1965;80:365-69.

2. Jenkinson D. Duration of effectiveness of pertussis vaccine: evidence from a 10 year community study. Brit Med J 1988;296:612-14.

3. Fine PEM, Clarkson JA. Distribution of immunity to pertussis in the population of England and Wales. J Hyg Camb 1984;92:21-26.

4. Cattaneo LA, Reed GW, Haase DH et al. The seroepidemiology of Bordetella pertussis infections: a study of persons ages 1-65 years. J Infect Dis 1996;173:1256-59.

5. Robertson PW, Goldberg H, Jarvie BH et al. Bordetella pertussis infection: a cause of persistent cough in adults. Med J Australia 1987;146:522-25.

6. Aoyama T, Takeuchi Y, Goto A et al. Pertussis in adults. Am J Dis Child 1992;146:163-66.

7. Cromer BA, Goydos J, Hackell J et al. Unrecognized pertussis infection in adolescents. Am J Dis Child 1993;147:575-77.

8. Wirsing von Konig CH, Postels-Multani S, Bock HL et al. Pertussis in adults: frequency of transmission after household exposure. Lancet 1995;346:1326-29.

9. Wright SW, Edwards KM, Decker MD et al. Pertussis infection in adults with persistent cough. JAMA 1995;273:1044-46.

10. Postels-Multani S, Schmitt HJ, Wirsing von König CH et al. Symptoms and complications of pertussis in adults. Infection 1995;23:13-16.

11. Schmitt-Grohé S, Cherry JD, Heininger U et al. Pertussis in German adults. Clin Infect Dis 1995;21:860-66.

12. Aoyama T, Harashima M, Nishimura K et al. Outbreak of pertussis in highly immunized adolescents and its secondary spread to their families. Acta Paediatr Jap 1995;37:321-24.

13. Mink CM, Sirota NM, Nugent S. Outbreak of pertussis in a fully immunized adolescent an adult population. Arch Pediatr Adolesc Med 1994;148:153-57.

14. Rosenthal S, Strebel P, Cassiday P et al. Pertussis infection among adults during the 1993 outbreak in Chicago. J Infect Dis 1995;171:1650-52.

15. Deville JG, Cherry JD, Chirstenson PD et al. Frequency of unrecognized Bordetella pertussis infections in adults. Clin Infect Dis 1995;21:639-42.

16. Nennig ME, Shinefield HR, Edwards KM et al. Prevalence and incidence of adult pertussis in an urban population. JAMA 1996:275;1672-74.

17. Nelson JD. The changing epidemiology of pertussis in young infants. Am J Dis Child 1978;132:371-73.

18. Mortimer EA. Pertussis and its prevention: a family affair. J Infect Dis 1990:161:473-79.

19. De Serres G, Boulianne N, Duval B et al. Effectiveness of a whole cell pertussis vaccine in child-care centers and schools. Ped Infect Dis J 1996;15:519-24.

20. Bentsi-Enchill AD, Halperin SA, Scott J et al. Estimates of the effectiveness of a whole-cell pertussis vaccine from an outbreak in an immunized population. Vaccine 1997;15:301-06.

21. Halperin SA, Bortolussi R, MacLean D et al. Persistence of pertussis in an immunized population: results of the Nova Scotia enhanced pertussis surveillance program. J Pediatr 1989;115:686-93.

22. De Serres G, Boulianne N, Duval B. Field effectiveness of erythromycin prophylaxis to prevent pertussis within families. Ped Infect Dis J 1995;14:969-75.

23. Halperin SA, Bortolussi R, Langley JM et al. A randomized, placebo-controlled trial of erythromycin estolate chemoprophylaxis for household contacts of children with culture-positive Bordetella pertussis infections. URL: <http://www.pediatrics.org/cgi/content/full/104/4/e42>. Date of access: Oct. 2000.

24. De Serres G, Shadmani, R, Duval B et al. Morbidity of pertussis in adolescents and adults. J Infect Dis. In press.

25. Cherry JD, Gornbein J, Heininger U et al. A search for serologic correlates of immunity to Bordetella pertussis cough illnesses. Vaccine 1998;16:1901-06.

26. Storsaeter J, Hallander HO, Gustafsson L et al. Levels of anti-pertussis antibodies related to protection after household exposure to Bordetella pertussis. Vaccine 1998;16:1907-16.

27. Gustafsson L, Hallander HO, Olin P et al. A controlled trial of a two-component acellular, a five-component acellular, and a whole-cell pertussis vaccine. N Engl J Med 1996;334:349-55.
 

*    Members: Dr. V. Marchessault (Chairperson), Dr. J. Spika (Executive Secretary), N. Armstrong (Advisory Secretary), Dr. I. Bowmer, Dr. G. De Serres, Dr. P. DeWals, Dr. J. Embree, Dr. I. Gemmill, Dr. M. Naus, Dr. P. Orr, Dr. B. Ward, A. Zierler

Liaison Representatives: Dr. J. Carsley (CPHA), Dr. G. Delage (CPS), Dr. M. Douville-Fradet (ACE), Dr. T. Freeman (CFPC), Dr. J. Livengood (CDC), Dr. A.E. McCarthy (ND), Dr. J. Salzman (CATMAT), Dr. L. Samson (CIDS), Dr. J. Waters (CCMOH).

Ex-Officio Representatives: Dr. J. Calver (BBR), Dr. A. King (LCDC), Dr. P. Riben (MSB).

^†    This statement was prepared by Dr. G. De Serres and approved by NACI.

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Last Modified: 2000-05-01