Pertussis Vaccine

Types Of Pertussis Vaccines

Whole-Cell Pertussis Vaccine

• Contains killed Bordetella pertussis bacilli.
• Adsorbed on insoluble aluminum salts acting as adjuvants.
• Vaccine efficacy ranges from 61% to 89%.
• Elicits Th1 and Th17 biased immune responses.
• Associated with longer-lasting immunity and documented herd effect.
• Immunity wanes over 6-12 years requiring periodic boosters.

Acellular Pertussis Vaccine

• Developed primarily due to reactogenicity concerns of whole-cell preparations.
• Formulated with purified antigens including inactivated pertussis toxin, filamentous hemagglutinin, pertactin, and fimbriae.
• Multicomponent vaccines containing three or more antigens show higher efficacy compared to one or two component vaccines.
• Elicits Th2 biased immune responses.
• Associated with two-thirds reduction in minor and major adverse effects.
• Exhibits shorter duration of protection with faster waning.
• Lacks documented herd immunity effect.

Immunization Schedule And Administration

Primary And Booster Immunization

• Administered as 0.5 mL dose via intramuscular route.
• Preferred anatomical site is anterolateral aspect of thigh.
• Three primary doses given at 6, 10, and 14 weeks.
• First booster administered at 15-18 months.
• Second booster given at 4-6 years.
• Standard pertussis vaccines contraindicated beyond 7 years due to increased reactogenicity.

Catch-Up Immunization

• Children below 7 years require three doses at 0, 1, and 6 months.
• Second childhood booster omitted if last dose given beyond 4 years.

Adolescent And Maternal Immunization

• Reduced antigen vaccine administered as single dose at 10-12 years.
• Pregnant women require single dose during each pregnancy.
• Optimal administration timing during pregnancy is 27-36 weeks gestation.
• Maternal immunization protects vulnerable neonates via transplacental antibodies.

Adverse Effects And Contraindications

Adverse Effects

• Minor reactions include local pain, swelling, redness, fever, and fussiness.
• Serious events include hyperpyrexia, persistent crying, hypotonic-hyporesponsive episodes, and seizures.
• Incidence of systemic reactions decreases with subsequent doses.
• Incidence of local reactions increases with subsequent doses.

Contraindications And Precautions

• Absolute contraindication includes anaphylaxis following previous dose, encephalopathy within 7 days of previous dose.
• Progressive neurologic disease considered relative contraindication.
• Hyperpyrexia or hypotonic-hyporesponsive episodes considered precautions, not absolute contraindications.

Comparative Analysis Of Pertussis Vaccines

Feature	Whole-Cell Vaccine	Acellular Vaccine
Antigen Content	Killed whole bacilli	Purified specific antigens
Immune Response	Th1 and Th17 bias	Th2 bias
Efficacy	Variable but robust	Dependent on number of components
Duration Of Protection	Longer lasting	Shorter duration
Herd Effect	Well documented	Not documented
Adverse Effects	Higher frequency	Lower frequency
Global Acceptance	Poor in developed nations	Good