Herd protection can have an important role in the reduction of disease in both vaccinated and unvaccinated people, through decrease in the nasopharyngeal carriage of vaccine serotypes [ 42, 43].
Although the decrease in carriage in the year 2002 could reflect spontaneous changes in epidemiologic features of the outbreak, a number of public health interventions may have played a role.
Moreover, this reduction was associated with a decrease (−20 %) in the carriage of ß-lactamase producing Hi strains.
Almost complete vaccine coverage of 2 million pilgrims may have therefore contributed to a decrease in the spread of carriage within this pilgrim population and consequently reduced transmission of carriage from returning pilgrims to their contacts.
In the vaccinated villages, there was a significant decrease in the density of carriage with any pneumococcus following vaccination in individuals older than 5 years (from 2.44 to 1.88; difference = −0.56; P = .001) and a decrease of borderline significance among the younger age group (from 2.57 to 2.11; difference = −0.46; P = .07) (Table 3 A).
Increasing the uptake of the quadrivalent meningococcal vaccine (now mandatory for all pilgrims) may have a beneficial effect in decreasing the carriage of W135 (6 ).
And in France, a country with a high prevalence of antibiotic-resistant pneumococci, implementation of PCV, combined with a reduction in antibiotic use, decreased the carriage of penicillin nonsusceptible pneumococci in children with AOM [ 34].
There was a decrease in the density of VT carriage following vaccination in individuals older than 5 years (from 2.44 to 1.88; P = .001) and in younger individuals (from 2.57 to 2.11; P = .070) in the vaccinated villages.
The 47% decrease in MRSA carriage rate (from 11.3 to 6.1%) within a short time period is consistent with the effect of the active screening and decolonization program in period 2 on blocking nosocomial MRSA transmission [ 22].
