Pertussis: New Vaccine, New Strategies March 22, 2005 National Immunization Conference Washington, D.C. Karen R. Broder, MD, FAAP LCDR, United States Public Health Service Christina M. Mijalski, MPH National Immunization Program

Vaccinating to Prevent Pertussis throughout the Lifecycle Routine pertussis vaccination: DTaP at 2 months to 6 years

Major Pertussis Vaccination Challenges Adolescent/Adults: Immunity wanes ~5-10 years after completing childhood vaccination Young infants: - Not protected, incomplete 3-dose DTaP series - Increased risk of pertussis-related death - Adults and adolescents can be the source of pertussis

Vaccinating to Prevent Pertussis throughout the Lifecycle Pertussis vaccination - Accelerated DTaP schedule - Vaccination (“cocoon”) close contacts of infants Additional vaccinations - Vaccination during Pregnancy - Neonatal vaccination Pertussis vaccination, acellular pertussis vaccine - Universal - Selected populations Routine pertussis vaccination: DTaP at 2 months to 6 years

Timeline: Childhood Pertussis Vaccination in the United States 1940s: Whole cell pertussis vaccines (DTP) recommended 1992: Advisory Committee on Immunization Practices (ACIP) published recommendations for use of acellular pertussis vaccines (DTaP) for 4th and 5th doses 1997: ACIP published recommendations for use of DTaP for all 5 doses from 2 months to 6 years of age 1994-2003: Coverage 3+ doses DTP/DTaP: >90%

Childhood DTaP Vaccines Licensed in United States, 2005 Vaccines vary by type and quantity of pertussis components: - Tripedia®, sanofi pasteur - Infanrix™, Pediarix™, GlaxoSmithKline DAPTACEL™, sanofi pasteur Vaccine efficacy for 3 doses DTaP*: 80%-93% * WHO case definition: 21 days paroxysmal cough, laboratory confirmation or epi-link to a lab-confirmed case

Acellular Pertussis Vaccines for Adolescents and Adults, United States Safe and immunogenic Licensure status: - US: Biologics License Applications submitted to US FDA, summer 2004 for two adolescent/adult acellular pertussis vaccines combined with tetanus and diphtheria toxoids (Tdap)** **Tetanus toxoids, reduced diphtheria toxoid and acellular pertussis vaccine adsorbed (Tdap)

Tdap Vaccines Under FDA Review • GlaxoSmithKline: Boostrix™: indicated 10-18 years of age - Pertussis components reduced quantity and similar to Infanrix™ DTaP - Diphtheria and tetanus similar to Td* • sanofi pasteur: Adacel™: indicated 11-64 years of age - Pertussis reduced quantity and similar to DAPTACEL™ DTaP *composition of Td manufactured by sanofi pasteur

Potential Tdap Vaccination Strategies, United States ACIP currently developing recommendations for potential Tdap use First US recommendation will likely focus on adolescents Substantial pertussis morbidity Existing infrastructure for vaccination

Recommended Adolescent Immunization Schedule ─ United States, January 2005

Adolescent Tdap Recommendations Under Consideration Routine Tdap vaccination at 11-12 years of age instead of Td (yellow bar) - Vaccinate at 13-18 years of age only if adolescent missed the Td dose (green bar) Same as above − PLUS - Routine Tdap vaccination for older adolescents who received Td ≥5 years earlier* *Td and Tdap may need to be spaced by ≥5 years to minimize adverse events

National Physicians’ Survey: Perspectives on Potential Adolescent Pertussis Vaccination (Tdap) Recommendations University of Michigan and CDC Preliminary Results

Recommended Adolescent Immunization Schedule ─ United States, January 2005

Adolescent Td Coverage Levels Data sources Method (age-group) Coverage National Health Interview Survey, 2002* Td dose per shot card (13-15 yrs) 33% Schools: 3 states with Td school laws, 2000 and 2002 (FL†, MO*, KS*) School immunization records (middle school) 48%-97% * CDC, unpublished data † Fogarty et al. Public Health Rep., 2004

Question: Would Physicians Accept the Adolescent Tdap Recommendations under Consideration? Routine Tdap vaccination at 11-12 years of age instead of Td (yellow bar) - Vaccinate at 13-18 years of age only if adolescent missed the Td dose (green bar) Same as above − PLUS - Routine Tdap vaccination for older adolescents who received Td ≥5 years earlier* *Td and Tdap may likely need to be spaced by ≥5 years to minimize adverse events

Methods Questionnaire: A national, cross-sectional mailed survey administered by the University of Michigan, January 2005 - Fact sheet about pertussis and Tdap included Population: Pediatricians and family physicians (~300 from each group) randomly selected from the AMA Physician Masterfile Eligibility: Provide outpatient primary care to ≥1 adolescent patient per week

Survey Response 594 surveys mailed 321 responses Final sample (n=297) 298 Pediatricians 296 Family physicians 594 surveys mailed 19 undeliverable 9 Peds/10 FPs 165 Pediatricians (57%) 321 responses 156 Family physicians (55%) 24 not eligible (no adolescent patients) 11 Pediatricians 13 Family physicians 154 Pediatricians Final sample (n=297) 143 Family physicians

Practice Settings of Eligible Physicians Proportion of Physicians Peds n=154 FPs n=143 Private, independent office 75% 66% Practice network/ HMO 7% 19% Hospital/ medical center 3% 1% University health system 8% 10% Public Clinic/ Community Health Center 5% Peds: Pediatricians FPs: Family physicians

Adolescent Patients 11-18 Years of Age Seen for Outpatient Primary Care by Physician Type P<.0001 for comparison of PDs vs FPs

Reported Practice’s “Routine” Approach to Administering Td to Adolescents* † ‡ * When indicated

Reported “Major” Barriers to Adolescent Td Vaccination † ‡ * †

Physicians’ Beliefs Agree pertussis is a “serious enough disease” to use Tdap for adolescents, rather than Td P<.0001

Physician Preference: How should adolescent vaccination recommendations “be structured”?

Additional Data from Meningococcal Conjugate Vaccine Survey Comparable sample (different Peds, FPs) Comparable response rate Peds: 59% FPs: 55% Comparable volume of adolescent patients Also administered January 2005

Meningococcal Survey Healthcare Practices Proportion of physicians reporting more than half of their adolescent patients have… † † ‡ † P<.001 ‡ P<.01 † Percent of Physicians

Conclusion (1) Physicians will likely accept routine adolescent Tdap vaccination instead of Td (target: 11-12 years of age) - Most physicians report routinely administering Td to adolescents during preventive care visits - Few physicians report they disagree with replacing Td with Tdap for adolescents

Conclusion (2) Routine Tdap vaccination for older adolescents who received Td ≥5 years earlier might pose challenges - Less than 1/3 of physicians report the majority of adolescent patients 17-18 years of age have a preventive care visit - Lack of adolescent patient visits reported as barrier for Td vaccination

Conclusion (3) Adolescent Tdap vaccination practices will likely differ between pediatricians and family physicians - Peds more commonly report routinely vaccinating adolescents with Td at the 11-12 year preventive visit than FPs - FPs more commonly report barriers to Td vaccination than Peds - Peds and FPs report different beliefs about pertussis

Acknowledgements CDC University of Michigan Shannon Stokley Sarah Clark Matt Davis Anne Cowan CDC Shannon Stokley Katrina Kretsinger Amanda Cohn Trudy V. Murphy Barbara Slade Margaret Cortese Marty Roper Tej Tiwari Daniel Fishbein Oleg Bilukha Nancy Rosenstein John Moran Gregory Wallace ACIP Pertussis Working Group Jon Abramson Members and Consultants