Meeting in Atlanta, the Advisory Committee on Immunization Practices voted on October 27 for new recommendations regarding Tdap vaccination.
Tdap, the booster vaccine for tetanus, diphtheria and pertussis (whooping cough) has been a source of confusion in recent months. In light of the pertussis outbreak that began in California, health authorities had issued reminders about the adult Tdap recommendation: adults aged 19-64 should substitute one Td booster (recommended every ten years to protect against tetanus and diphtheria) with a single Tdap booster, which also offers protection against pertussis. This is recommended to limit the disease’s ability to spread; while adult pertussis cases are generally milder than those in children, adult patients can still spread the disease to young children, including those too young to be vaccinated. The adult vaccination schedule did not include a recommendation about Tdap for adults aged 65 and older, however, which includes many grandparents concerned about passing pertussis on to their grandchildren. (Household members are primarily responsible for transmission to infants–upwards of 75% of pertussis cases are transmitted this way. Study data has indicated that grandparents are the ultimate source of pertussis transmission for 6-8% of cases, although this includes grandparents younger than 65 years of age.)
The United States childhood immunization schedules (“Recommended Immunization Schedules for Persons Aged 0 Through 18 Years”) are approved by three groups: the Advisory Committee on Immunization Practices (ACIP), the American Academy of Pediatrics, and the American Academy of Family Physicians (AAFP). The adult schedule is similarly approved by the American College of Physicians, the American College of Obstetricians and Gynecologists, AAFP, and ACIP, which reviews the adult schedule annually.
ACIP voted to issue a new recommendation on Tdap vaccination for adults 65 years of age or older. The new language states that adults in this age group who anticipate being in close contact with an infant younger than 12 months of age and have not received a prior dose of Tdap should receive the Tdap booster. In other words, if all of the checkpoints in this list are met…
- Adult aged 65 or older
- Has not received a prior Tdap vaccination
- Has or anticipates having close contact with an infant younger than 12 months of age
…then the person should receive one dose of the Tdap vaccine to prevent transmission of pertussis to the infant. The committee also stated that Tdap vaccination would provide direct pertussis protection for vaccinated individuals, noting that the incidence of the disease is higher for adults 65+ than in the 28-64 year-old age group.
This recommendation was based on safety data from multiple trials performed in the 65+ age group since the previous adult recommendation for Tdap (limited to adults aged 64 or younger) was made.
In addition to the new recommendation for adults aged 65 and older, the committee also voted to remove a minimum recommended interval between Td and Tdap vaccinations. Previous recommendations were vague and varied in this regard, and led to individuals not receiving Tdap vaccination because of uncertainty about the date of previous Td vaccination. The new recommendation states that if an individual has not received Tdap, he or she can receive a Tdap vaccination at any time regardless of the date of the last Td vaccination. This recommendation was also made based on new data available since the 2005 recommendation, and on the increased incidence of pertussis. (Both Canada and Australia also allow the administration of Tdap at any time following Td vaccination.)
Sources and related information
A Trial to Evaluate the Safety and Immunogenicity of ADACEL Vaccine in Persons 65 Years of Age and older. (Study data presented at ACIP meeting.) Study information available at http://clinicaltrials.gov/ct2/show/NCT00457249.
Evaluation of GSK Biologicals’ Boostrix® vaccine when compared with Decavac™ in adults aged 65 years or older. (Study data presented at ACIP meeting.) Study information and results available at http://download.gsk-clinicalstudyregister.com/files/24200.pdf.
Halperin SA et al. How soon after a prior tetanus-diphtheria vaccination can one give adult formulation tetanus-diphtheria-acellular pertussis vaccine? Pediatr Infect Dis J. 2006 Mar;25(3):195-200.