Uptake of the human papillomavirus-vaccination within the free-of-charge childhood vaccination programme in Denmark

Background

Persistent infection with human papillomavirus (HPV) is a prerequisite for cervical cancer, which causes 175 yearly deaths and substantial morbidity in Denmark. In January 2009, HPV-vaccination for 12 year-old girls was introduced into the free-of-charge childhood vaccination programme. Due to concerns about potential poor compliance we determined the uptake and identified determinants for vaccination after the first year of the programme.

Methods

All vaccinations given within the vaccination programme are reported to a central register, which we linked to demographic information found in the Danish civil register. We calculated vaccination uptake and used Cox regression survival analysis to compare the uptake rates between demographic subgroups in the population, e.g. by number of siblings, age of mother (at the daughter's birth) and place of origin.

Results

The uptake among the 33,838 eligible girls was 80%, 75% and 62% respectively for the three HPV-doses. All subgroups had uptake above 68% for the first HPV-vaccination. Girls with mothers younger or older than the reference group of 25-34 years had a lower uptake rate (adjHR 0.94, 95% CI 0.91-0.97 and adjHR 0.91, 95% CI 0.88-0.94 respectively). Girls with 5 or more siblings had lower uptake rate than girls without siblings (adjHR 0.79, 95% CI 0.71-0.87). Girls born in other EU/EFTA-countries had lower uptake rate than Danish-born girls with Danish-born parents (adjHR 0.74, 95% CI 0.67-0.82).

Conclusions

The introduction of routine HPV-vaccination in Denmark resulted in a relatively high uptake, indicating little reason for major concern about barriers towards the vaccination in Denmark. Population groups with reduced uptake were identified, but as they were small in number their effect on the overall vaccination coverage was marginal. Nonetheless, these groups should be targeted in future acceptance studies and vaccination awareness campaigns.     

Associations of trust and healthcare provider advice with HPV vaccine acceptance among African American parents

ObjectiveHealthcare providers (HCPs) are advised to give all parents a strong recommendation for HPV vaccination. However, it is possible that strong recommendations could be less effective at promoting vaccination among African Americans who on average have greater mistrust in the healthcare system. This study examines the associations of parental trust in HCPs and strength of HCP vaccination recommendation on HPV vaccine acceptance among African American parents.MethodsParticipants were recruited from an urban, academic medical center between July 2012 and July 2014. We surveyed 400 African American parents of children ages 10–12 years who were offered HPV vaccine by their HCPs to assess sociodemographic factors, vaccine beliefs, trust in HCPs, and the HPV vaccine recommendation received. Medical records were reviewed to determine vaccination receipt.ResultsIn multivariable analysis, children whose parents were “very strongly” recommended the HPV vaccine had over four times higher odds of vaccine receipt compared with those whose parents were “not very strongly” recommended the vaccine. Having a parent with “a lot of” versus “none” or only “some” trust in HCPs was associated with over twice the odds of receiving HPV vaccine. Very strong HCP recommendations were associated with higher odds of vaccination among all subgroups, including those with more negative baseline attitudes toward HPV vaccine and those with lower levels of trust. Adding the variables strength of HCP recommendation and parental trust in HCPs to a multivariable model already adjusted for sociodemographic factors and parental vaccine beliefs improved the pseudo R² from 0.52 to 0.55.ConclusionsAmong participants, receiving a strong vaccine recommendation and having a higher level of trust in HCPs were associated with higher odds of HPV vaccination, but did not add much to the predictive value of a model that already adjusted for baseline personal beliefs and sociodemographic factors.     

Development of a cumulative metric of vaccination adherence behavior and its application among a cohort of 12-month-olds in western Kenya

ObjectivesThe timely receipt of the recommended vaccination regimen, i.e. vaccination maintenance, is an underexplored, but important, indicator of public health. There is currently no standardized method for quantifying cumulative vaccination maintenance, however, and no simple way to explore predictors of adherence to vaccination schedules. We therefore sought to (1) develop a Vaccination Maintenance Score (VMS) and (2) apply this score to determine the predictors of vaccination behavior among infants in western Kenya (n = 245).MethodsWomen in western Kenya were enrolled during pregnancy and surveyed repeatedly through one year postpartum. Data were collected on a range of sociodemographic and health indicators and vaccinations. For each infant, we analyzed receipt of 11 vaccines recommended by the Kenyan Ministry of Health. We operationalized VMS as the total number of vaccines received on schedule. Vaccines that were not received or received off schedule were scored 0. VMS was modeled using multivariable tobit regression models.ResultsWe found that 85.7% of infants were fully immunized, but only 42.4% had optimal VMS, i.e. scored 11. The median (IQR) VMS was 10 (3). In multivariable regression, each one-point increase in maternal quality of life score (range: 0–32) was associated with a 0.22-point increase in VMS; each additional child in the household was associated with a 0.34-point increase in VMS; and initiating breastfeeding at birth was associated a 2.01-point increase in VMS.ConclusionsCoverage of the recommended vaccinations (85.7%) was nearly twice as high as cumulative timely receipt (42.4%). The VMS satisfies a need for a location-specific but easily adaptable metric of vaccination adherence behavior. It can be used to complement traditional methods of vaccination coverage and timeliness to better understand underlying behaviors that influence vaccination events, and thereby inform interventions to improve vaccination rates and decrease the burden of vaccine-preventable disease.Clinical Trial RegistrationNCT02974972 and NCT02979418.