N S Crowcroft, R Booy, T Harrison, et al. Severe and unrecognised: pertussis in UK infants (Arch Dis Child 2003;88:802–6).

In the process of carrying out further analysis of the data from this study and to examine the role of respiratory syncytial virus (RSV) the author uncovered a single data entry error in the date of onset of disease in one contact of a case when looking back at the original questionnaires. Unfortunately this changes the order of cases in one family, which affects table 4⇓ (the corrected table 4⇓ is shown below).

The penultimate and last sentences of the Results section of the Abstract should have read:

Pertussis was confirmed in 21/33 (64%) of those who were first to become ill in the family. For 13/33 children the source of infection was a parent; for 10/33 the source of pertussis was an older fully vaccinated child in the household.

In the third to last paragraph of the Results section the first sentence should read:

Primary cases (the source of infection) included parents and other children in the households (table 4⇑); 64% of primary cases were laboratory confirmed.

The error has no implications for the methods, discussion or conclusions of the paper.