ATLANTA – In the face of an ongoing pertussis outbreak in California, a series of three votes by the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices aimed to expand and clarify recommendations for pertussis vaccination.
The votes taken at the meeting removed previous language restricting the interval for receipt of the adolescent-adult formulation of the tetanus-diphtheria-pertussis vaccine, and expanded the use of Tdap to adults aged 65 years and older and to undervaccinated children aged 7-10 years.
Kathleen Harriman, Ph.D., of the California Department of Public Health's Immunization Branch updated the committee on the California outbreak. A total of 6,978 cases had been reported as of Oct. 19, 2010, for a rate of 16 cases per 100,000 population. Ten deaths have been reported among infants aged 2 months or younger.
The California state health department has recommended Tdap for all individuals aged 10 years and older who have not yet received it – particularly women of childbearing age (including those who are pregnant), others who have contact with young infants, and individuals older than 64 years of age – and also as a replacement for the old tetanus-diphtheria (Td) vaccine for wound management, even though the vaccine is not licensed for those aged 7-9 years or 64 years and older. The state also said that Tdap should be given without regard to the interval since the previous Td dose, said Dr. Harriman, who is also a registered nurse.
Dr. Jennifer Liang of the CDC's National Center for Immunization and Respiratory Diseases (NCIRD) presented similar draft document language for the ACIP to vote on. In 2005, the ACIP adolescent recommendation (for those aged 11-12 years) had said that an interval of at least 5 years between Td and Tdap was “encouraged” to reduce the risk for local and systemic reactions, particularly the limb swelling that – although usually benign – can be frightening for parents.
The new language, unanimously approved by ACIP (with one abstention), says that adolescents aged 11-18 years who have completed the recommended five-dose childhood diphtheria and tetanus toxoids and whole-cell pertussis vaccine (DTP)/diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP) vaccination series and adults age 19-64 years should receive a single dose of Tdap in place of one Td dose. Adolescents should receive Tdap at a preventive care visit at 11-12 years of age, Dr. Liang said.
In addition, adolescents or adults who have not received a dose of Tdap – or for whom the status is unknown – should be immunized as soon as feasible, regardless of the interval since the last tetanus- or diphtheria-containing vaccine.
The second vote, to recommend Tdap for adults aged 65 years and older, was taken following presentations by Dr. Wayde Weston of GlaxoSmithKline and Dr. Michael Decker of Sanofi Pasteur, demonstrating immunogenicity and safety of Boostrix and Adacel, respectively, in adults aged 64 and older. GSK has filed an application with the Food and Drug Administration for an indication in that age group; Sanofi Pasteur is working on its application.
The recommendation says that adults aged 65 years and older who have or who anticipate having close contact with an infant aged younger than 12 months (such as a grandparent, child care provider, or health care provider) should receive a single dose of Tdap to protect against pertussis and to reduce the likelihood of transmission of pertussis to infants aged younger than 12 months (who are not yet fully immunized).
In addition, for adults aged 65 and older, a single dose of Tdap vaccine may be given in place of a Td vaccine in those who have not previously received Tdap.
Finally, the committee voted another off-label use of Tdap in children aged 7-10 years with incomplete or unknown pertussis vaccine history. For those children, a single dose of Tdap is recommended to protect against pertussis. If further doses of tetanus- and diphtheria-containing vaccines are needed, then children aged 7-10 years should be vaccinated according to catch-up guidance. Further guidance is forthcoming regarding revaccination.
Children aged 7-10 years who have never been vaccinated against tetanus, diphtheria, or pertussis or who have unknown vaccine status should receive a series of three vaccinations containing tetanus and diphtheria toxoids.
The preferred schedule is a single dose of Tdap, followed by a dose of Td more than 4 weeks after Tdap and another dose of Td 6-12 months later. If not given as the first dose, Tdap can be substituted for any of the other Td doses in the series.