178.3 🩺 內科專科考前版

178.3.0.1 1⃣ Waning Immunity Lesson

  • DTaP (acellular) immunity wanes 5-10 yr
  • Lower compared to whole-cell DTP (1940s-90s) which had longer durability but more reactogenicity
  • Adolescent + adult booster (Tdap) crucial
  • Maternal Tdap each pregnancy + cocooning

178.3.0.2 2⃣ 2024 Pertussis Surge Reasons

  • Post-COVID immunity gap (less circulation, less natural boost)
  • Waning DTaP cohorts
  • Anti-vaccine sentiment (post-pandemic)
  • PRN-deficient strains (vaccine escape — some studies)
  • Increased awareness + PCR testing

178.3.0.3 3⃣ Erythromycin Pyloric Stenosis Risk

  • Infants ≀ 1 mo with erythromycin — 7-10× pyloric stenosis risk
  • Azithromycin preferred in neonates
  • FDA labeling caution

178.3.0.4 4⃣ PRN-Deficient Strains

  • Some recent isolates (US, EU, Australia) lack pertactin
  • Acellular vaccines contain pertactin antigen — these strains may evade vaccine
  • Surveillance ongoing
  • Whole-cell vaccine (DTP) is still used in some lower-income countries — different durability

178.3.0.5 5⃣ Adolescent / Adult Persistent Cough

  • 2 wk paroxysmal cough + post-tussive emesis + 100-day cough → consider pertussis even with prior vaccination

  • PCR within 3 wk onset
  • Treatment improves transmission reduction even late

178.3.0.6 6⃣ Pregnancy Tdap Timing

  • Recommended 27-36 wk (early third trimester)
  • Optimal antibody transfer to fetus
  • Even in second pregnancy within 1 year — repeat Tdap (continued protection for new infant)

178.3.0.7 7⃣ 健保 / Taiwan

  • DTaP / Tdap NIP (national immunization)
  • 2017 + Tdap pregnancy booster (公費)
  • 2024 surge — increasing case reports; physician awareness
  • 通報 — Public Health

178.3.0.8 8⃣ Vaccines Future

  • Whole-cell DTP — being reconsidered in some countries (longer immunity vs reactogenicity)
  • Nasal live attenuated vaccine — Phase 2 (BPZE1)
  • Multi-component DTaP with broader antigens