Tuesday, May 13, 2014

Normal DPT (wP) versus "Painless DPT (aP)" - what does the science say?

SAGE-WHO recommendations vindicated IAP ACVIP stand on Pertussis vaccination:

wP Versus aP vaccines:

Acellular vaccines
Lower initial efficacy
Faster waning of immunity
Possible reduced impact on transmission
Likely to result in resurgence
o Magnitude and timing of resurgence difficult to predict
o Potential increased risk of death in those too young to be vaccinated

Must consider overall goal of national immunization program
1. Protection of infants ? No benefit of aP over wP vaccines
o disease-related mortality significantly reduced with either wP or aP vaccination
2. Protection of older children or adults ? Multiple doses of aP required
o Only possible with aP vaccines (less reactogenic)
o Requires repeat boosting (limited duration of efficacy) to limit/prevent resurgence and increased risks to infants
o Increased program cost
wP vaccines preferred when:
o Program target is prevention of infant disease
o Limited number of pertussis doses delivered / affordable

 aP vaccines should only be considered when:
o Program objectives include older children and adults
o Large numbers of doses may be included in a national immunization schedule
o Cost implications (higher unit cost & number of required doses)

SAGE concluded that the licensed acellular pertussis vaccines (aP) lower initial efficacy, have faster waning of immunity, and possibly a reduced impact on disease transmission relative to currently internationally available whole-cell vaccines (wP). The risk of resurgence of pertussis associated with the use of aP vaccines including increased infant disease, indicates that countries currently using wP should continue using wP vaccines for early infant vaccination.
As communicated by Dr Naveen Thacker 

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