[Factors associated with reported vaccination coverage in early infancy: results of a telephone survey]

Barcelona's Continuing Immunization Plan affords the possibility Of monitoring the immunization coverage of the population by means of the voluntary family postal notification system. Prior studies have revealed that some families fail to provide notification while being correctly vaccinated, which can lead to actual coverage being underestimated. The objectives of this study are to estimate the early childhood immunization coverage of the population and to ascertain the factors associated with failure to provide notification of immunization.

A phone survey was conducted on a sample of 500 children regarding whom there was no record of any notification of the first three childhood vaccine doses (diphtheria, tetanus, whooping cough and oral polio), in addition to a sample of 500 children who were on record as having been immunized. To estimate the actual immunization coverage, all children were considered to have been properly immunized when their family members did provide notification. As regards those who failed to reply, it was considered in the worst of cases that these were cases of children who had not be immunized. In the best of cases scenario, a coverage similar to those of the responses was assumed.

The response to the questionnaire was higher among those who had previously provided notification of immunization by way of the postal notification system (79.1%) than among those who had failed to provide notification of immunization (67%). The leading factors associated with failure to report immunization status were the size of the families, the use of private health care services and the place of birth of the parents. Solely six (6) cases of those who had failed to report immunization admitted to not having immunized their children, totaling 1.9% of the responses. The immunization coverage of the population in question would total 99.7% in the best of cases and 93.7% in the worst of cases scenario.

Immunization coverage of the population in question is quite high. The results underline the importance of promoting immunization notification among health care professionals, especially in the private sector.