Background: This study characterizes the healthcare visits at which childre
n receive vaccinations, including the number of these visits and the number
of vaccinations that are administered.
Methods: The 1999 National Immunization Survey (NIS) is a nationally repres
entative sample of children aged 19 to 35 months, verified by provider reco
rds, that is conducted to obtain estimates of vaccination coverage rates. W
e describe the number of healthcare visits in which one or more vaccination
s were given, the number of vaccinations given at these visits, and the num
ber of visits and vaccinations needed for an underimmunized child to comple
te the recommended vaccination series.
Results: Of the children who did not receive all doses of the recommended v
accinations (4:3:1:3:3 vaccination series), three fourths had four or more
immunization visits. Vaccination coverage increased as the number of visits
increased, and children who had completed the series were more likely to r
eceive multiple vaccinations than those who had not. Most children (70.7%)
received a maximum of four vaccinations in any immunization visit. The majo
rity of children (73.5%) who had not completed the 4:3:1:3:3 vaccination se
ries needed only a single visit to complete the series. The majority (61.7%
) of children who needed only one visit also needed only one additional vac
cination.
Conclusion: While estimated national coverage for all recommended vaccinati
ons is considerably below the Healthy People 2000 and Healthy People 2010 g
oal of 90%, achieving this goal is in essence just one visit away. If all c
hildren who needed one more visit were to receive that final visit, the nat
ional coverage among children 19 to 35 months for all recommended vaccinati
ons would be 93%.