This is thought to be primarily a metabolic attribute of the vaccinating bacteria but may also involve competition for attachment sites.
This allows the coverage to be estimated from ageserological data if we make a further assumption about the timing and age-range vaccinated.
There is increasing evidence that pertussis continues to affect adolescents and young adults who were vaccinated as infants, albeit in a less severe form.
In fact, 85 % of the population is effectively vaccinated and will be protected against infection for life.
Sera has been systematically collected from mice and rats either harbouring a schistosome infection, or vaccinated with the isolated membrane preparation.
Of these, all but five (0.6 %) had been vaccinated at least 2 weeks prior to the cruise.
Four infants whose vaccination had not been completed at the time of pertussis were vaccinated shortly thereafter.
For reasons discussed above, reliable comparison of the tick populations on control and vaccinated cattle under comparable conditions was impossible to achieve in all cases.
