Tdap5 Vaccine (Covaxis®)

Abstract

Covaxis (also licensed as Triaxis or Adacel in individual countries) is a combined tetanus toxoid, reduced diphtheria toxoid, five component acellular pertussis (namely detoxified pertussis toxin, filamentous hemagglutinin, pertactin, and fimbriae types 2 and 3) vaccine for the prevention of diphtheria, tetanus, and pertussis. It is approved for use in Europe as a single intramuscular booster dose in children (aged ≥ 4 years), adolescents, and adults, and in the US it is approved for use in individuals aged 11-64 years. In large, randomized, controlled clinical trials conducted in the UK and North America, a single intramuscular booster dose of Covaxis induced robust immune responses for all of its component antigens when given to children (aged ≥ 4 years), adolescents, and adults. In addition, Covaxis vaccine was safe and generally well tolerated in terms of solicited and unsolicited local injection-site and systemic adverse events, most of which were of mild intensity and resolved without sequelae. Furthermore, the immunogenicity of each individual component and the reactogenicity of Covaxis vaccine in children, adolescents, and adults was generally similar to that of comparator vaccines. Despite being a vaccine-preventable disease and having >90% primary vaccination coverage worldwide, pertussis remains uncontrolled, particularly amongst adolescents and adults. Given the changing epidemiology of pertussis and the requirement to reduce infection in adolescents and adults (including healthcare workers) and thereby prevent transmission of the disease from these individuals to very young infants, the new 'cocoon strategy' recommended in current vaccination guidelines has become a key strategy in the management of morbidity and mortality associated with pertussis. This strategy focuses on the immunization of healthcare workers, and the parents and family members of infants who are too young to have undergone primary immunization, so as to prevent the transmission of pertussis to these young at-risk infants. The implementation of the 'cocoon strategy' may finally give countries the ability to control pertussis infections in these at-risk infants and ultimately provide the desired herd immunity against pertussis. In line with this strategy, a booster dose of Covaxis vaccine provides a valuable option to reduce pertussis morbidity and mortality, and to maintain seroprotection against diphtheria and tetanus in children (aged ≥ 4 years), adolescents, and adults.

Pertussis re-emergence in the post-vaccination era

“…Boostrix, Adacel) containing reduced quantities (10-50%) of all antigens [20] to decrease the risk of injection site reactions occurring more frequently after the fifth dose of DTaP [23]. As an example, Boostrix is licensed for individuals from age 10 years onwards in the United States and from age 4 years onwards in Europe [24], while Adacel is approved in those aged 11–64 years in the United States and in children (aged ≥ 4 years), adolescents and adults in Europe [25]. …”

Immunogenicity and safety results from a randomized multicenter trial comparing a Tdap-IPV vaccine (REPEVAX®) and a tetanus monovalent vaccine in healthy adults

“…Additionally, in France, 12 Germany 13 and the USA, 14 a single dose of pertussis vaccine is recommended in adulthood 15 . Other countries (e.g., Austria, 16 Luxembourg 17 and Norway 18 ) recommend a pertussis booster every 10 y 15 …”