Incidence of pertussis in persons < or =15 years of age in Valencia, Spain: seroprevalence of antibodies to pertussis toxin (PT) in children, adolescents and adults.
OBJECTIVE
To determine the incidence of pertussis in persons < or =15 years in age in Valencia, Spain. To assess the prevalence of IgG antibodies to pertussis toxin (PT) in children, adolescents and adults.


METHODS
Prospective study conducted at paediatric primary care centres. All persons < or =15 years in age presented with persistent cough were enrolled. Parents completed a brief questionnaire and immunization history was obtained from paediatrician records. A blood sample was obtained, for determination of IgG antibodies to Bordetella pertussis toxin (PT) by an ELISA method. A study confirmed-case was the presence of two conditions: (1) cough illness of > or =14 days duration; and (2) ELISA absorbance value of IgG to PT > or =2. Two subjects per clinical-case (same centre and range of age) and parents were asked to participate in the prevalence study.


RESULTS
Sixty-one children < or =15 years in age presented with symptoms leading to a clinical diagnosis of pertussis were detected. Serological evidence of recent pertussis was found in five of these patients (incidence of 46.0/100,000 persons < or =15 years in age). Prevalence of antibodies to B. pertussis (> or =0.3) in children < or =15 years in age and adults was 39 and 33%, respectively. Only a minority of children, adolescents and adults had absorbance values indicative of immunity (> or =1).


CONCLUSIONS
These incidence and seroprevalence results show that despite high immunization rates in infancy, B. pertussis is circulating in Spain.
Diez-Domingo
Javier
J
Pediatrics, Primary Care, Generalitat Valenciana, and Vaccine Institute of Valencia (VIVA), Valencia, Spain. diez_jav@gva.es
Ballester
Alfredo
A
Baldó
José-María
JM
Planelles
María-Victoria
MV
Villarroya
José V
JV
Alvarez
Trinidad
T
Carmen Peidró
M
M
Calero
Pura
P
Garcés
María D
MD
Sorribes
Ignacio
I
Graullera
Marta
M
Jubert
Angels
A
San-Martín
María
M
González
Antonio
A
D000293:Adolescent; D017677:Age Distribution; D000907:Antibodies, Bacterial / Q000097:blood*; D001886:Bordetella pertussis / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D037342:Pertussis Toxin / Q000276:immunology*; D016036:Seroepidemiologic Studies; D013030:Spain / Q000453:epidemiology; D014917:Whooping Cough / Q000453:epidemiology* / Q000276:immunology
D000907:Antibodies, Bacterial; D037342:Pertussis Toxin