title: Impact of the 2004 influenza vaccine shortage on repeat immunization rates.
abstract: OBJECTIVE
  We assessed the impact of the severe influenza vaccine shortage of 2004 on individual physicians' immunization performance.
  
  
  METHODS
  Using 1998-2004 Medicare claims data, we monitored the physician continuity rate (proportion of patients receiving influenza immunization from a physician in 1 year who received a subsequent immunization from the same physician the subsequent year) and other clinician rate (proportion of patients with claims from 1 physician in 1 year with a claim from another clinician the subsequent year) in West Virginia Medicare beneficiaries from 2000-2004. We examined vaccine claim trends by clinician and surveys of self-reported immunization to determine whether patients received vaccine from nonphysician clinicians or went without immunization each year.
  
  
  RESULTS
  Claims-based influenza vaccination rates increased from 35.5% to 41.3% from 2000-2003, reflecting historical trends, before declining 14.1% in 2004. Median continuity rates among the 723 to 849 physicians claiming 25 or more influenza immunizations from 2000-2003 increased from 47% in 2000-2001 to 54% in 2002-2003; then fell to 3% in 2003-2004. The number of physicians filing 100 or more claims declined from 337 in 2003 to 130 in 2004. More than 25% of physicians had no repeat vaccinations of the same beneficiaries in 2004. Trends in clinician type and survey data indicated a shift of many beneficiaries to mass vaccinators and institutional providers; however, compared with previous years, there was an estimated 8% increase in 2004 in the number of West Virginia beneficiaries who did not receive vaccine.
  
  
  CONCLUSIONS
  The 2004 vaccine shortage had a severe impact on influenza immunization rates in private physician's offices, disrupting continuity of care.
authors.affiliation: West Virginia Medical Institute, 3001 Chesterfield Avenue, Charleston, WV 25304, USA. khannah@wvmi.org
authors.forename: Charles P
authors.initials: CP
authors.lastname: Schade
authors.forename: Karen L
authors.initials: KL
authors.lastname: Hannah
mesh_terms: D003266:Continuity of Patient Care; D019538:Health Care Surveys; D006801:Humans; D007252:Influenza Vaccines / Q000600:supply & distribution*; D006278:Medicare / Q000706:statistics & numerical data; D011787:Quality of Health Care; D014481:United States; D014611:Vaccination / Q000706:statistics & numerical data*; D014903:West Virginia
chemical_list: D007252:Influenza Vaccines