How increased pertussis vaccination coverage is changing the epidemiology of pertussis in Italy

Assessment of humoral and cell-mediated immunity againstBordetella pertussisin adolescent, adult, and senior subjects in Italy

“…A more recent national study in 1996-1997 found a 77 . 6% prevalence of positive subjects to IgG anti-PT [30]. Thus, data collected in this study, even if higher, are in line with former studies and confirm the existence of immune priming in each studied age group.…”

“…Recent epidemiological studies performed in Italy have shown that despite a decrease in the total incidence rate, the number of cases in age groups 5-9 years and 10-14 years, and the average age of cases are increasing. Notably, no epidemic peak has been registered since 1998, probably reflecting the high vaccination coverage rate reached in the last few years [30].…”

Pertussis in infants less than 6 months of age and household contacts, Italy, April 2014

“…4 After 2002, the pertussis vaccine started to be offered free of charge by all Italian Regions. 5 Based on routine surveillance data, Italy is currently a low incidence country and outbreaks or incidence peaks have been rarely reported after the achievement of a high immunization coverage. 6 Even if it is a vaccine-preventable disease, pertussis is still circulating and the need to study the genotypic variation of the bacterium in terms of gene sequencing of pertussis toxin and pertactin, as the main acellular vaccine components, deserves particular interest for the efficacy of vaccine coverage in the population.…”

Pertussis

“…29 According to the ICONA 2008 coverage study, that year vaccine coverage rate (VC%) reached 96.6% in children aged 12-24 months and 45.6%, 26.7% and 14.1% in adolescents with 3, 4, and 5 doses, respectively. 30 The impact of the increasing vaccine coverage is very clear when different periods with a low (1971)(1972)(1973)(1974)(1975)(1976)(1977)(1978)(1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989), intermediate (1990)(1991)(1992)(1993)(1994)(1995)(1996) and high (1998-2002) VC% are compared.…”

“…The comparison of the period 1971-1989 (low VC%) with the period 1998-2002 (high VC%) shows that the percent distribution of cases has changed remarkably, declining by half in the 0-4 year age group, while increasing by 1.5-fold in the 5-9 year age group and three-fold in the 10-14 year age group. 29 Therefore, pertussis epidemiology is changing in Italy, too, with a lower incidence in children and an increased incidence in adolescents and adults. 31,32 Both national and international notification data show that pertussis continues to be an important public-health issue.…”