Increased incidence of pertussis has been noted among infants too young to be immunized. We studied the disease burden of pertussis in pediatric intensive care units and the source of infection in several Asian, European and Latin American countries.
The study was conducted in 7 countries from September 2001 to January 2004. Children <1 year of age were enrolled from pediatric intensive care units (PICU) and pediatric wards if they presented with respiratory failure, apnea, bradycardia, or cough accompanied by paroxysms, vomiting, whoop or cyanosis. Household members of pertussis-positive index cases were asked to answer a questionnaire and provide diagnostic specimens.
Pertussis was confirmed in 99 infants (12%) of 823 infants included in the analysis: 10 of 90 (11%) in Brazil, 9 of 88 (10%) in Costa Rica, 11 of 145 (8%) in Germany, 13 of 147 (9%) in Singapore, 29 of 67 (43%) in Spain, 2 of 86 (2%) in Taiwan and 25 of 200 (13%) in Uruguay. However, sensitivity analysis indicated that these figures were conservative. The mean (±SD) average age of infection was 2.6 ± 2.2 months. Pertussis was found among 96 of 269 (36%) of household contacts investigated. At least one household contact was identified as the source of infection in 24 of 88 (27%) of the PICU cases and mothers were identified as being the most frequent source of infection.
Although regional differences exist, severe pertussis represents a considerable global disease burden. Since most infants are infected before vaccination and concomitant protection is completed, household contacts should be targeted for booster vaccination to reduce the pertussis reservoir.
From the *University of Mainz, Mainz, Germany; †Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; ‡Hospital Infantil Joana de Gusmão, Florianopolis, Brazil; §Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; ∥Hospital Nacional de Niños, San Jose, Costa Rica; ¶National University Hospital, Singapore; #KK Women’s and Children’s Hospital, Singapore; **Hospital Materno Infantil La Paz, Madrid, Spain; ††Hospital Materno Infantil Vall d’Hebron, Barcelona, Spain; ‡‡Hospital Sant Joan de Deu, Barcelona, Spain; §§Universita Autónoma de Barcelona, Barcelona, Spain; ∥∥National Taiwan University Hospital, Taipei, Taiwan; ¶¶Hospital Pereira Rossel, Montevideo, Uruguay; and ##GlaxoSmithKline Biologicals, Rixensart, Belgium.
Supported by GlaxoSmithKline Biologicals, Rixensart, Belgium.
Address for correspondence: Thomas Verstraeten, MD, GlaxoSmithKline Biologicals, Rue de l’Institut 89, B-1330 Rixensart, Belgium. E-mail: email@example.com.