High-Yield Immunization Traps

• Pregnancy: Tdap every pregnancy; avoid live vaccines such as MMR/varicella during pregnancy.
• Live vaccines: MMR/varicella same day or separate by at least 4 weeks; avoid in significant immunosuppression.
• Post-exposure prophylaxis: measles, varicella, rabies, hepatitis B, tetanus, and meningococcal contacts all have different logic.
• Catch-up: do not restart valid series unnecessarily, but some vaccines like rotavirus have strict age limits.
• Common distractors: mild URI, egg allergy, verbal vaccine history, “no bite mark,” and “not sexually active.”