Family Characteristics Associated with Likelihood of Varicella Vaccination.

CONTEXT: The introduction of the varicella vaccine as a routine pediatric immunization in the US, in 1995, provided an opportunity to assess factors associated with uptake of new vaccines in the member population of the Kaiser Permanente Northwest (KPNW) Health Plan. OBJECTIVE: Identify factors associated with varicella vaccination in the KPNW population in the first five years after varicella vaccine was introduced. DESIGN: A retrospective cohort of children under age 13 years between June 1995 and December 1999, without a history of varicella disease was identified using KPNW automated data. Membership records were linked to vaccine databases. Cox regression was used to estimate likelihood of varicella vaccination during the study period in relation to age, sex, primary clinician's specialty, and Medicaid eligibility. For a subset whose parents answered a behavioral health survey, additional demographic and behavioral characteristics were evaluated. MAIN OUTCOME MEASURE: Varicella vaccination. RESULTS: We identified 88,646 children under age 13 years without a history of varicella; 22% were vaccinated during the study period. Varicella vaccination was more likely among children who were born after 1995, were not Medicaid recipients, or had pediatricians as primary clinicians. In the survey-linked cohort, positively associated family characteristics included smaller family size; higher socioeconomic status; and parents who were older, were college graduates, reported excellent health, and received influenza vaccination. CONCLUSION: Understanding predictors of early varicella vaccine-era vaccine acceptance may help in planning for introduction of new vaccines to routine schedules.

Reported adverse events in young women following quadrivalent human papillomavirus vaccination.

PURPOSE: To assess and describe young women's experiences with their first dose of quadrivalent human papillomavirus vaccine (HPV4) (Gardasil®) in a large managed care organization. METHODS: We collected survey and electronic medical record (EMR) data for 899 young women aged 11-26 receiving their first HPV4 injection from February through September 2008. Survey items included questions about adverse events, interactions with healthcare providers, and knowledge and attitudes toward HPV disease and HPV4. RESULTS: Six hundred ninety-six (78%) participants reported pain at the injection site. Other common reactions included injection site bruising or discoloration (n=155, 17%) or swelling (n=127, 14%) and presyncope or syncope (n=134, 15%). Overall, preteens and teens were more likely than adult participants to report vaccine adverse events. Most respondents, particularly in the adult age group, reported that their healthcare provider reviewed important information about HPV infection and about the risks and benefits of receiving the vaccine. Knowledge and attitudes about HPV and HPV4 also varied by age, with older women generally exhibiting more accurate knowledge about HPV and perceived susceptibility to cervical cancer. CONCLUSIONS: There were significant age differences in young women's experiences with their first HPV4 injection. These findings highlight the importance of age-appropriate education and provider communications about HPV disease and vaccination.

Wheezing lower respiratory disease and vaccination of premature infants.

PURPOSE: Premature infants are at increased risk of wheezing in association with respiratory syncytial virus (RSV) and rhinovirus infections. We assess possible associations between wheezing and routine vaccinations of premature infants. METHODS: We conducted a self-controlled case series (SCCS) study of premature infants born at five health maintenance organizations (HMO's) from 1997 to 2002 (N=18,628). Episodes of medically attended wheezing lower respiratory diseases (WLRD) were ascertained from ICD-9 coded database records. Relative risks of WLRD during post-vaccination exposure windows were estimated by Cox proportional hazard regression with time-dependent vaccine exposure variables, adjusted for age, season, and frequency of well-baby visits. RESULTS: WLRD hazard ratios (HR) were not significantly elevated for any vaccine type among non-fragile or fragile premature infants. Among non-fragile infants the 8-14 days HR was significantly reduced for live attenuated MMR (0.68, 0.52-0.88) and Varicella (0.71, 0.53-0.94) vaccines, and similarly but insignificantly reduced for infrequently used live attenuated OPV vaccine (0.70, 0.46-1.06). There was a smaller significant reduction (0.83, 0.69-0.998) in the 15-30 days HR for MMR and a similar but not significant reduction (0.86, 0.71-1.05) in the 31-44 days HR for MMR. Hepatitis B vaccine (HBV), which is not a live vaccine, had significantly reduced 8-14 days (0.84, 0.72-0.98) and 31-44 days (0.88, 0.78-0.98) HRs among non-fragile infants. The apparent protective effect of HBV may be confounded by live vaccines administered simultaneously with the third dose of HBV. Among fragile infants there was a large significant reduction in the 8-14 days HR for live attenuated OPV vaccine (0.40, 0.23-0.70) and smaller significant reductions in the 8-14 days HR for inactivated DTaP (0.82, 0.71-0.95), Hib (0.83, 0.73-0.96), and PCV7 (0.84, 0.70-0.997) vaccines. Delays in vaccinating fragile infants may have made simultaneous administration of live vaccines and third doses of these inactivated vaccines more likely. CONCLUSIONS: We found no evidence of increased WLRD risk following routine vaccinations of premature infants. WLRD risk among non-fragile premature infants appears to be reduced for a few weeks after live attenuated vaccinations.

Evaluation of the impact of an HMO's varicella vaccination program on incidence of varicella.

The impact of a varicella vaccination program on disease in a large HMO population during 1996-1999 was assessed by multiple cross-sectional analyses of automated database records of vaccinations and varicella diagnoses for children (0-18 years). The cumulative proportion of the population vaccinated reached 73% among 2-year-olds, and 22% overall. An overall 49.7% reduction in varicella incidence was estimated to be attributable to an 18.5% point increase in the proportion of the population vaccinated.

Infant vaccinations and childhood asthma among full-term infants.

PURPOSE: To determine if infant vaccinations are associated with childhood asthma among full-term infants. The secondary objective was to describe relationships between characteristics of infant wheezing and childhood asthma. METHODS: We used baseline data from a study of infant wheezing that selected full-term infants born into a health maintenance organization (HMO) during 1991-1994, continuously enrolled for at least 12 months and without perinatal pulmonary or other selected conditions. Information had been abstracted for infancy (0-18 months) regarding wheezing, vaccinations and asthma risk factors. Using automated data, we identified asthma cases in 1998 among those enrolled for at least 6 months during the year. RESULTS: A total of 1778 full-term infants met our study criterion and 9% had asthma in 1998. Childhood asthma was not significantly associated with having received Hepatitis B vaccine or age at first Hepatitis B vaccine; number of whole-cell pertussis, Haemophilis influenzae type b or oral polio vaccine doses; having received measles, mumps, rubella vaccine; or total number of vaccine doses combined. Childhood asthma was significantly associated with number of infant wheezing episodes. CONCLUSIONS: Our findings do not support concerns that vaccines are associated with increased risk of asthma but confirm that frequency of infant wheezing is associated with childhood asthma.

Wheezing lower respiratory disease and vaccination of full-term infants.

PURPOSE: There have been speculations that increases in vaccinations have caused recent increases in wheezing lower respiratory disease during infancy. We assess possible associations between vaccines and incidence of wheezing in full-term infants. METHODS: We conducted a matched case-control study of full-term infants born into the Kaiser Permanente Northwest health plan during 1991-1994 and continuously enrolled for at least 12 months (n = 1366 case-control pairs). Potential cases of wheeze were ascertained from medical care databases and verified by chart review. Vaccinations, demographic factors, and wheeze risk factors were abstracted from charts. Adjusted relative risks of first onset of wheeze during post-vaccination exposure windows were estimated by conditional logistic regression. We also conducted case-series analyses of wheeze onsets. RESULTS: We found no evidence that risk of wheeze during infancy is associated with recency of vaccination with whole-cell pertussis (DTP), hepatitis b (HBV), Haemophilus influenzae type b (HIB), oral polio (OPV), or measles, mumps and rubella (MMR) vaccines. We also found no evidence that risk of first wheeze is associated with exposure to HBV or MMR. CONCLUSIONS: Recent increases in wheezing during infancy do not appear to be related to increases in vaccinations of full-term infants.