Abstract
Background: Underimmunization was the primary cause of the 1990 measles outbreak in the United States. We examined the level and causes of underimmunization in a family practice residency clinic that received free vaccine supplies from the county health department.
Methods: The office computer selected 286 patients aged 2 to 3 years. From these 286 patients, 175 were sampled. Their charts were audited for immunization barriers, looking specifically for (1) valid reasons; (2) overly cautious interpretation of contraindications, especially minor illnesses; (3) missed opportunities (failure to address immunization status during acute care visits or lack of simultaneous vaccine administration); (4) parental refusal; and (5) delayed immunizations resulting from gaps in clinic attendance.
Results: There were 174 delayed doses; 90 were due to gaps in clinic attendance, 42 due to valid reasons, 33 due to invalid contraindications, and 25 due to missed opportunities. Some doses were delayed on more than one occasion and for more than one reason. Two parents refused initial immunizations, claiming that the children were too small.
Conclusion: Important causes of delayed immunizations in this residency clinic were gaps in attendance, overly cautious interpretations of contraindications, missed opportunities, and lack of simultaneous vaccine administration.