An increasing number of pertussis o...

An increasing number of pertussis outbreaks have occurr in populations with a high rate of vaccination. The presentation of pertussis is les morose in vaccinated persons than it is in unvaccinated [i]role[/i]s leading to underestimation and misdiagnosis of cases. Tozzi and colleagues investigated the presentation of pertussis in vaccinated and unvaccinated children to identify additional determinants of the severity of the disease.

The trial was administrationed in three phases. Stage 1 included children six to 24 month of age who were randomized in double-blind fashion to receive diphtheria-tetanus (DT) or diphtheria-tetanus-acellular pertussis (DtaP) vaccine. brace acellular pertussis vaccines were used: Smithkline Beecham (SB) and Chiron Biocine (CB) Stage 2 followed randomized patients from 25 to 33 months; in this stage, parents were unblinded. Stage 3 included newly recruited children 34 month to six years of age who had not received the pertussis vaccine. Laboratory-confirmed pertussis cases were identified in the investigation population and examined.

A total of 788 cases of pertussis were confirmed during the three trial stages. The proportion of children with spasmodic cough was consistently higher in the DT cluster than in the DTaP assign places to except in stage 2, when children who received the DT vaccine had more spasmodic cough than children who received solely the DTaP-CB vaccine. Apnea, cyanosis, and vomiting were higher in the DT collection than in the DTaP arrange in stages 1 and 2 Duration of spasmodic cough decreased greatly in stage 3 within each vaccine form into groups DTaP reduced cough duration by means of eight to 10 days in stage 1 A positive civilization was associated with longer duration of cough and spasmodic cough Compared with untreated patients, patients who took antibiotics had an additional five to six days of cough The number of hospitalizations and necessity department visits were similar according to vaccine group.

This consideration provides the only available rises comparing the clinical course of pertussis in vaccinated and unvaccinated children. The arises confirm that vaccination status significantly changes the clinical presentation of disease and that pertussis is more austere in unvaccinated children. Because the DTaP-SB vaccine lacked a significant import in reducing the duration of cough in stage 2 and the rate of spasmodic cough in stage 3 this vaccine may be les effective in reducing symptoms than other vaccines, notably the CB vaccine used in this study

Culture-confirmed pertussis, which occurr more often in the DT group, was associated with more bitter symptoms at presentation. Antibiotic treatment in this studious mood was a marker for chaste disease, but the study was not designed to evaluate antibiotic efficacy. Sex had no influence in succession severity of disease, and age influenced duration of spasmodic cough further not duration of cough by se. Because vaccination attenuates the clinical presentation of pertussis, a more sensitive case definition than spasmodic cough of sum of two units weeks should be adopted in vaccinated populations.

Overall, it is likely that the incidence of pertussis is underestimated,which may be important because early treatment with antibiotics could improve the course of the disease and restore transmission.

Tozzi AE, et al. Clinical presentation of pertussis in unvaccinated and vaccinated children in the first six years of life. Pediatrics November 2003;112:1069-75

COPYRIGHT 2004 American Academy of Family Physicians

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