Vaccination Adherence Research Articles

Vaccination rates and adherence in pneumococcal conjugate vaccination in mature born infants before and after vaccination schedule change – A claims database analysis

BackgroundIn August 2015, the German Standing Committee on Vaccination (STIKO) changed the pneumococcal conjugate vaccination (PCV) schedule for mature infants from a 3+1 scheme to a 2+1 scheme. It was expected that a reduction of doses would be associated with a higher acceptance of the vaccination. Aim of this study was to assess vaccination rates and adherence for PCV after the change of recommendation based on real-world data. MethodsA retrospective claims data analysis using the InGef Research Database was conducted. The study population consisted of all mature infants born in 2013 (last birth cohort completely under 3+1 recommendation) or 2016 (first birth cohort completely under 2+1 recommendation) with an individual follow-up of 24 months. Hexavalent combination vaccination (HEXA) with a consistent 3+1 recommendation was analyzed as reference. ResultsAfter follow-up of 24 months, 90.9% (91.2%) of the 2016 (2013) cohort received at least one dose of PCV. At the same age, 67.7% of the 2013 cohort received a booster dose according to the 3+1 schedule and 75.6% of the 2016 cohort received a booster dose presumably either according to the 2+1 (71.7%) or 3+1 (3.9%) schedule. Of those receiving the booster dose, only 46.3% (2016) and 45.1% (2013) received the booster dose on time as recommended. The HEXA vaccination rate increased from 88.9% (2013) to 91.6% (2016) with a full series completion in 69.1% (2013) vs 72.9% (2016). The proportion of infants receiving the booster vaccination on time rose to 50.0% in 2016 (47.8% in 2013). ConclusionsAlthough the rate for the PCV booster dose slightly increased, nearly a quarter of the infants born in 2016 did not receive a booster dose at all. Furthermore, vaccinations were still frequently delayed, and the rate of unvaccinated infants remained constant.

Hepatitis B vaccine adherence among homeless people

Objective: to estimate the adherence to hepatitis B vaccine in homeless people. Methods: a cross-sectional study with 90 homeless people, with the collection of 5 ml of blood for the detection of antibody against the surface antigen of the hepatitis B virus. Results: of the total, 89 (98.9%) were vaccinated with the first dose; of these, 45 (50.7%) had antibodies against hepatitis B virus surface antigen lower than 10 IU/L; 25 (53.3%) received the second dose of hepatitis B vaccine, and nine (45.8%) participants received the third dose of vaccine. Individuals who were related to both genders were more likely to adhere to the full hepatitis B vaccine schedule. Conclusion: the low adherence to hepatitis B vaccination and the small number of participants with antibodies that confer immunity against this infection were evidenced.

A study of ethnic, gender and educational differences in attitudes toward COVID-19 vaccines in Israel \u2013 implications for vaccination implementation policies

BackgroundVaccines for COVID-19 are currently available for the public in Israel. The compliance with vaccination has differed between sectors in Israel and the uptake has been substantially lower in the Arab compared with the Jewish population.AimTo assess ethnic and socio-demographic factors in Israel associated with attitudes towards COVID-19 vaccines prior to their introduction.MethodsA national cross-sectional survey was carried out In Israel during October 2020 using an internet panel of around 100,000 people, supplemented by snowball sampling. A sample of 957 adults aged 30 and over were recruited of whom 606 were Jews (49% males) and 351 were Arabs (38% males).ResultsThe sample of Arabs was younger than for the Jewish respondents. Among the men, 27.3% of the Jewish and 23.1% of the Arab respondents wanted to be vaccinated immediately, compared with only 13.6% of Jewish women and 12.0% of Arab women. An affirmative answer to the question as to whether they would refuse the vaccine at any stage was given by 7.7% of Jewish men and 29.9% of Arab men, and 17.2% of Jewish women and 41.0% of Arab women. Higher education was associated with less vaccine hesitancy. In multiple logistic regression analysis, the ethnic and gender differences persisted after controlling for age and education. Other factors associated with vaccine hesitancy were the belief that the government restrictions were too lenient and the frequency of socializing prior to the pandemic.ConclusionsThe study revealed a relatively high percentage reported would be reluctant to get vaccinated, prior to the introduction of the vaccine. This was more marked so for Arabs then Jews, and more so for women within the ethnic groups. While this was not a true random sample, the findings are consistent with the large ethnic differences in compliance with the vaccine, currently encountered and reinforce the policy implications for developing effective communication to increase vaccine adherence. Government policies directed at controlling the pandemic should include sector-specific information campaigns, which are tailored to ensure community engagement, using targeted messages to the suspected vaccine hesitant groups. Government ministries, health service providers and local authorities should join hands with civil society organizations to promote vaccine promotion campaigns.

Adherence Population to Vaccination of Influenza: Survey Results

Influenza remains one of the most pressing medical and socio-economic problems . Vaccination is the most effective way to reduce the incidence and mortality of influenza and its complications. Рurpose: estimate the awareness of parents , doctors of various specialties and students of the medical University about the issues of influenza vaccination, identify factors that affect the reduction of vaccination adherence and determine the best apt ways to increase adherence to influenza immunoprophylaxis. Methods. A descriptive retrospective epidemiological study between 2004 and 2018 Conducted a survey among three groups of respondents: parents of children enrolled in the children's clinic or treated at a pediatric hospital (n=1620); doctors of different specialties (n = 324); the medical students (n = 433). Resalts. Against the background of increasing coverage of the population with preventive vaccinations, there is a decrease in the incidence of influenza among the total population (TPR.=-14.7%). There was a weak correlation between the number of vaccinated and the incidence in the following year (ρ =-0.38 p>0.05). Only 22.2% of respondents vaccinate a child, and only adults are vaccinated in 13.8% of cases. Among doctors of different specialties, 36.7% are vaccinated against the flu, and 58.7% of respondents additionally vaccinate their children against the flu. Of the total number of students surveyed, 17.3% are vaccinated annually. Conclusions. Increasing adherence to flu vaccination among medical students and doctors will help increase adherence to vaccination among the population, increase coverage of preventive vaccinations, and reduce the incidence of influenza.

Machine learning models to identify low adherence to influenza vaccination among Korean adults with cardiovascular disease

BackgroundAnnual influenza vaccination is an important public health measure to prevent influenza infections and is strongly recommended for cardiovascular disease (CVD) patients, especially in the current coronavirus disease 2019 (COVID-19) pandemic. The aim of this study is to develop a machine learning model to identify Korean adult CVD patients with low adherence to influenza vaccinationMethodsAdults with CVD (n = 815) from a nationally representative dataset of the Fifth Korea National Health and Nutrition Examination Survey (KNHANES V) were analyzed. Among these adults, 500 (61.4%) had answered "yes" to whether they had received seasonal influenza vaccinations in the past 12 months. The classification process was performed using the logistic regression (LR), random forest (RF), support vector machine (SVM), and extreme gradient boosting (XGB) machine learning techniques. Because the Ministry of Health and Welfare in Korea offers free influenza immunization for the elderly, separate models were developed for the < 65 and ≥ 65 age groups.ResultsThe accuracy of machine learning models using 16 variables as predictors of low influenza vaccination adherence was compared; for the ≥ 65 age group, XGB (84.7%) and RF (84.7%) have the best accuracies, followed by LR (82.7%) and SVM (77.6%). For the < 65 age group, SVM has the best accuracy (68.4%), followed by RF (64.9%), LR (63.2%), and XGB (61.4%).ConclusionsThe machine leaning models show comparable performance in classifying adult CVD patients with low adherence to influenza vaccination.

Influenza and Pneumonia Vaccinations among North Carolina Adults with Diabetes.

Objectives: In this study, we sought to elucidate the influenza and pneumonia vaccination practices of adults with diabetes in North Carolina. Methods: Using North Carolina Behavioral Risk Factor Surveillance System data, we examined 2011-2018 trend data and demographic and health factors (2014-2018) in influenza (influenza vaccine receipt in the past year among adults ages 18+ years) and pneumonia (lifetime pneumonia vaccination receipt for adults ages 65+ years) vaccination adherence. Results: Influenza and pneumonia vaccination adherence rates were consistently higher for adults with versus without diabetes and remained relatively stable over the study period for both groups. Among adults with diabetes, factors associated with higher influenza vaccination rates included non-Hispanic white race, age 65+ years, poorer health, having insurance, and being a non-smoker. Pneumonia vaccination rates among adults with diabetes were higher for non-Hispanic Whites and those in poorer health. Conclusions: Adults with diabetes may be more likely to receive influenza and pneumonia vaccinations compared to adults without diabetes, but these rates remain below recommended levels. African Americans, younger adults, those without health insurance and cigarette smokers are vulnerable to being non-compliant with vaccination recommendations that could reduce their risk of developing and suffering complications from these diseases.

Inattention or reluctance? Parental responses to vaccination reminder letters

This paper studies non-adherence in the Danish Childhood Vaccination Program using a nationwide introduction of a vaccination reminder letter policy and administrative data from 2011–2017. First, I provide causal estimates of how the reminder letter policy affects vaccination adherence using a Regression Discontinuity Design (RDD). Second, I link parental responses to the reminder letter to parents’ causes for being non-adherent. I find that the reminder letter policy positively affects adherence. However, 72% of non-adherent parents are non-responsive to the reminder letter indicating that reluctance and not inattention is the leading cause for non-adherence. Thus, other policies beyond reminder letters – such as mandatory vaccination laws – are necessary to substantially increase vaccination coverage.

Pediatric Immunization Practices in Nephrotic Syndrome: An Assessment of Provider and Parental Knowledge.

Background: Children with nephrotic syndrome (NS) are at high risk for vaccine-preventable infections due to the immunological effects from the disease and concurrent treatment with immunosuppressive medications. Immunizations in these patients may be deferred due to their immunosuppressive treatment which may increase the risk for vaccine-preventable infections. Immunization practices in children with NS continue to vary among pediatric nephrologists. This raises the question of whether children with NS are receiving the recommended vaccinations at appropriate times. Therefore, it is critical to understand the practices and patient education provided by physicians to patients on the topic of vaccinations.Methods: After informed consent, parents/guardians of 153 pediatric patients (<18 years old) diagnosed with NS from 2005 to 2018 and 50 pediatric nephrologists from 11 participating centers completed anonymous surveys to evaluate immunization practices among pediatric nephrologists, assess the vaccine education provided to families of children with NS, assess the parental knowledge of immunization recommendations, and assess predictors of polysaccharide pneumococcal vaccine adherence. The Advisory Committee on Immunization Practices (ACIP) Immunization 2019 Guideline for those with altered immunocompetence was used to determine accuracy of vaccine knowledge and practices.Results: Forty-four percent of providers self-reported adherence to the ACIP guidelines for inactive vaccines and 22% to the guidelines for live vaccines. Thirty-two percent of parents/guardians reported knowledge that aligned with the ACIP guidelines for inactive vaccines and 1% for live vaccines. Subjects residing in the Midwest and provider recommendations for vaccines were positive predictors of vaccine adherence (p < 0.001 and p 0.02, respectively).Conclusions: Vaccine recommendation by medical providers is paramount in vaccine adherence among pediatric patients with NS. This study identifies potential educational opportunities for medical subspecialty providers and family caregivers about immunization recommendations for immunosuppressed patients.

DTaP combination vaccine use and adherence: A retrospective cohort study

Despite universal recommendation of the 4-dose diphtheria, tetanus, and pertussis (DTaP) vaccine series, coverage and timeliness in the US remain suboptimal. DTaP-containing combination vaccines (i.e. quadrivalent and pentavalent) are presumed to improve vaccine coverage rates and timeliness, but research supporting this claim is limited. We sought to investigate the associations between DTaP-containing vaccine use and adherence to the recommended DTaP immunization schedule among children in the US. Using a large claims database, we identified privately insured children born between 2009 and 2016 that received ≥1 DTaP-containing vaccine and had ≥24 months of enrollment from birth, excluding those with DTaP vaccinations not aligned with approved dose indications. Children were classified by DTaP-containing vaccine receipt: combination vaccines only, stand-alone vaccines only, or a mixture of both. Outcome measures included: 1) completion of the 4-dose series and 2) timely receipt of doses. Outcomes were adjusted for gender, birth year, race, and socioeconomic status. The study cohort contained 412,441 children. Of these, 40.5% (167,084) received combination vaccines only, 14.9% (61,342) received stand-alone vaccines only, and 44.6% (184,015) received a mixture of both. Combination vaccine recipients were nearly 3 times as likely to complete the 4-dose series (OR 2.93 (95% CI: 2.88, 2.99)) and for all doses received, more than 4 times as likely to receive doses on time (OR 4.12 (4.04, 4.21), relative to stand-alone vaccine recipients. Significance disparities in adherence were also observed, where minorities were up to 30% less likely (OR 0.70 (0.68, 0.71)) to complete the 4-dose series and up to 27% less likely (OR 0.73 (0.72, 0.75)) to receive doses on time, relative to white children. Our findings demonstrated that adherence to the recommended DTaP immunization schedule was significantly greater among combination vaccine recipients, relative to stand-alone recipients. Further research is needed to investigate underlying causes of disparities in adherence.

Looking to the empirical literature on the potential for financial incentives to enhance adherence with COVID-19 vaccination

COVID-19 vaccination efforts are underway offering hope for saving lives and eliminating the pandemic. The most promising vaccines require two injections separated 3-4 weeks apart. To achieve heard immunity, 70-90% of the population or perhaps more must be inoculated. Anticipation of adherence challenges has generated commentaries on strategies to enhance adherence including financial incentives. A notable gap in these commentaries is any discussion of the scientific evidence regarding the efficacy of financial incentives for increasing vaccine adherence. This commentary addresses that gap. There is a body of controlled trials on incentivizing vaccine adherence, mostly to the hepatitis B virus (HBV) vaccine among injection drug users (IDUs). Prevalence of HBV infection is increasing as part of the opioid addiction crisis. The HBV vaccine entails a three-dose regimen (typically 0, 1, and 6 months) which has created adherence challenges among IDUs. Systematic literature reviews document significant benefit of financial incentives. For example, a 2019 meta-analysis (Tressler & Bhandari, 2019) examined 11 controlled trials examining HBV-vaccine adherence strategies, including financial incentives, accelerated dosing schedules, and case-management/enhanced services. Financial incentives were most effective resulting in a 7-fold increase in adherence to the vaccination regimen relative to no financial incentives (OR, 7.01; 95% CI, 2.88-17.06). Additional reviews provide further support for the efficacy of financial incentives for promoting adherence with vaccination (HBV & influenza). Overall, this literature suggests that financial incentives could be helpful in promoting the high levels of adherence to COVID-19 vaccines that experts project will be necessary for herd immunity.

Impact of Recommended Maternal Vaccination Programs on the Clinical Presentation of SARS-CoV-2 Infection: A Prospective Observational Study.

The COVID-19 pandemic has raised questions about the possible cross immunity resulting from common vaccination programs and SARS-CoV-2 infection. Therefore, the Spanish Obstetric Emergency group performed a multicenter prospective study on the vaccination status of Influenza and Tdap (diphtheria, tetanus and pertussis vaccine boost administered in adulthood) in consecutive cases of SARS-CoV-2 infection in a pregnancy cohort, in order to assess its possible association with the clinical presentation and severity of symptoms of SARS-CoV-2 infection, as well as to determine the factors that may affect vaccination adherence. A total of 1150 SARS-CoV-2 positive pregnant women from 78 Spanish hospitals were analyzed: 183 had not received either vaccine, 23 had been vaccinated for Influenza only, 529 for Tdap only and 415 received both vaccines. No association was observed between the vaccination status and the clinical presentation of SARS-CoV-2 infection and/or the severity of symptoms. However, a lower adherence to the administration of both vaccines was observed in the Latin-American subgroup. Based on the results above, we reinforce the importance of maternal vaccination programs in the actual pandemic. Health education campaigns should be specially targeted to groups less likely to participate in these programs, as well as for a future SARS-CoV-2 vaccination campaign.

Evaluation of the anti-COVID-19 vaccination campaign in the Metropolitan Area of Milan (Lombardy Region, Northern Italy).

to present an evaluation of the campaign for vaccination against COVID-19 in the territory covered by the Agency for Health Protection of the Metropolitan Area of Milan from 01.01.2021 to 30.09.2021. descriptive study of vaccine adherence; predictive study of the factors associated with vaccine adherence, efficacy of vaccination in terms of hospitalization and mortality, and factors that increase the risk of hospital admission following full vaccination. population-based study with subjects aged >18 years eligible for vaccination (N. 2,981,997). An information system obtained by integrating various administrative healthcare sources made it possible to analyse socioeconomic characteristics, COVID-19 related hospitalizations, and general mortality in subjects eligible for vaccination. full vaccination (2 doses); COVID-19-related hospitalizations, COVID-19-related hospitalizations occurring more than 15 days after the second dose, general mortality. in the first nine months of the vaccination campaign, 74.7% of the subjects (N. 2,228,915) was fully vaccinated, whereas 15.6% (N. 465,829) did not even receive one dose. Women have a lower probability of getting vaccinated than men; the 50-59 years and 70+ years age groups emerge as the most problematic to reach, while the younger one (<40) is the most adherent. A social gradient emerged, with residents of more disadvantaged areas progressively less incline to get vaccinated than those living in more affluent areas. Adherence is greater in Italian citizenship and is likely to increase with an increase in the number of chronic conditions. Hospitalizations amounted to 1.22% (N. 5,672) in the unvaccinated population compared to 0.05% (N. 1,013) in the vaccinated population; general mortality was 4.51% (N. 15,198) in the unvaccinated population against 0.32% (N. 8.733) in the vaccinated population. Sociodemographic factors and the presence of previous health conditions are important predictors of hospitalization outcomes even within the fully vaccinated population. Specifically, the highest hazard ratios are found in subjects with heart failure (HR 2.15; 95%CI 1.83-2.53), in immunocompromised patients (HR 2.02; 95%CI 1.52-2.69), and in transplant recipients (HR 1.92; 95%CI 1.10-3.33). vaccination campaign adherence is affected by the sociodemographic characteristics of the population and is a determining factor in preventing hospitalizations for COVID-19 and death. The persistent higher risk of hospitalization in chronic subjects following the second dose emphasizes the need to direct booster doses to the more vulnerable. Information systems proved to be effective monitoring tools in the absence of specific trials.

Acceptance of yellow fever vaccine in the older traveller: a cohort study.

Background and aim:Current demographic changes and improvement of quality of life of elderly population have direct consequences on international travelling. The older traveller demands for specific care and precautions to be observed, as for the yellow fever (YF) vaccination, due to the increased incidence rate of adverse events following immunization (AEFI) in people aged 60 years or over. The aim of our study was to determine the adherence to YF vaccine and travel behaviours in a sample of elderly travellers moving to YF endemic areas.Methods:Participants in this cohort study were offered YF vaccine, and informed about the increased risk of AEFIs and the unavoidable risk of acquiring YF at the destination. The research was planned on survey-based design, using pre- and post-travel questionnaires.Results:In 2018, 239 travellers aged 60 years or older attended our travel clinic, of whom 36.8% (n = 88) planned to travel to YF endemic areas and 23.0% (n = 55) for the first time. Of these, 63.6% accepted and 36.4% rejected the vaccination, with 15 travellers moving to endemic areas without immunization, including one patient who presented contraindications to YF vaccine.Conclusions:The presence of more than a third of elderly travellers who travelled without vaccination is a substantial public health problem and, since the number of older travellers continues to increase, it becomes necessary to implement robust actions to improve YF vaccine advocacy and adherence. (www.actabiomedica.it)

Vaccination rate and adherence of tick-borne encephalitis vaccination in Germany

BackgroundTick-borne encephalitis (TBE) is an arboviral infection of the central nervous system. As there is no causal treatment of TBE, disease prevention by vaccination is especially important. Immunization consists of a three-dose primary vaccination schedule, followed by regular booster doses. In Germany, the Standing Committee on Vaccination (STIKO) at the Robert Koch-Institute recommends TBE vaccination for all those at high risk of contracting TBE. This includes individuals living in, traveling to and/or working in risk areas, and being exposed to ticks. To our knowledge, there are currently no reliable data on TBE vaccination rates in Germany available. MethodsThis retrospective cohort study based on anonymized German health claims data was conducted to determine vaccination rates of TBE primary immunization in 2012 to 2015 by federal state, compliance with the vaccination schedule, and TBE vaccination uptake for the 2011 birth cohort. Vaccination protection rates for each federal state were simulated based on a compartmental model. ResultsVaccination rates of an initiated primary immunization ranged from about 3% in the southern federal states to <1% in the northern federal states. Across all federal states, compliance with the vaccination schedule decreased with each subsequent vaccination. Slightly higher TBE vaccination uptake was determined in the 2011 birth cohort, as compared to the German school entry health examination statistics in 2017. Simulated vaccination protection rates for each federal state ranged from 10% in Hamburg to 51% in Baden-Wuerttemberg. ConclusionsWhile there was an overall low vaccination uptake and a discrepancy between areas of high vs. low TBE risk, this study also indicates a concerning decline in vaccination compliance. Vaccinating physicians should address the importance of adherence upon initiation of TBE vaccination.

1139. Adherence to Zika virus-related Pediatric Follow-up Care in Puerto Rico

BackgroundOver three thousand children in Puerto Rico were potentially exposed to Zika virus infection during pregnancy during the 2016 Zika virus epidemic. This congenital exposure is an established risk factor for birth defects and neurodevelopmental abnormalities, which may appear after birth. Puerto Rico guidelines require consistent pediatric monitoring for early identification and intervention of children up to age five.MethodsOur objective was to assess factors that influence caregiver adherence to Zika-related follow-up pediatric services in Puerto Rico. We conducted qualitative semi-structured focus groups and individual interviews with 57 individuals, including 35 caregivers (aged ≥18 years and a primary caregiver for a child with laboratory evidence of confirmed or possible Zika virus infection during pregnancy) and 22 healthcare providers or service coordinators. We explored participants’ views on barriers to Zika-related pediatric services and suggestions for improving appointment attendance. Interviews were recorded, transcribed, and translated. We developed and applied a coding scheme based on barriers and facilitators from the Andersen Model of Health Care Utilization and Katz Model for Adolescent Vaccine Adherence (a multi-step process influenced by adolescent and caregiver factors). Data were analyzed using thematic analysis.ResultsThree themes influencing adherence to Zika-related pediatric follow-up care were consistently reported throughout the interviews and focus groups discussions: (1) logistics of getting child to appointments based on clinic location, availability and costs associated with transportation, and physical requirements to transport child or multiple children; (2) complexity of requirements for follow-up appointments; and (3) caregiver burden including emotional, social, and time.ConclusionBarriers to Zika-related pediatric follow-up care in Puerto Rico are complex and multi-level. Core intervention targets should include caregiver burden, health system navigation, and coaching caregivers in communication with pediatric providers. Use of a caregiver-delivered manualized intervention led by community health workers seems appropriate to achieve these goals.Disclosures All Authors: No reported disclosures

1388. DTaP-containing combination vaccines use and adherence to the recommended infant-toddler vaccination series among privately insured children in the US

BackgroundDespite universal recommendation of the 3 + 1 diphtheria, tetanus, and pertussis (DTaP) vaccine series in infants and toddlers, adherence (i.e. coverage and timeliness) remain suboptimal in the US. DTaP-containing combination vaccines are presumed to improve vaccine coverage rates and timeliness, but research on this topic is limited. The purpose of this study was to compare adherence to the recommended infant-toddler vaccination series between recipients of DTaP-containing combination vaccines (i.e. quadrivalent/pentavalent) and stand-alone vaccines (i.e. trivalent).MethodsWe used the Optum de-identified Clinformatics Data Mart database to create a cohort of children born between 2009 and 2016 with > 24 months of continuous enrollment from birth, and records of > 1 DTaP vaccine receipt. Patients were classified by DTaP-containing vaccine receipt: combination vaccines only, stand-alone vaccines only, or a mixture of both. The primary adherence outcome was completion of the 4-dose series within 20 months of life. We adjusted outcomes for gender, birth year, race, and socioeconomic status via a logistic regression model.ResultsThe cohort contained 200,568 female (48.6%) and 211,882 male (51.4%) children. Of these children, 167,091 received combination vaccines only (40.5%), 61,342 received stand-alone vaccines only (14.9%), and 184,017 received a mixture of both (44.6%). Completion of the 4-dose series was highest among children who received combination vaccines only (75.5%), followed by those who received a mixture of vaccines (72.7%) and those who received stand-alone vaccines only (54.5%). Relative to those who received stand-alone vaccines only, adjusted odds of completion were approximately 2.9 times higher among combination vaccine recipients (odds ratio, OR = 2.93 [95% CI: 2.87, 2.98]) and 2.5 times higher among those who received a mixture of vaccines (OR = 2.54 [2.49, 2.59]).ConclusionDTaP-containing combination vaccine use was associated with significantly greater adherence. Although these results warrant further investigation to better understand the determinants of infant vaccination adherence, such evidence may further support preferential recommendations for combination vaccine use.DisclosuresMatthew M. Loiacono, MSc, Sanofi Pasteur (Employee) Vitali Pool, MD, Sanofi Pasteur (Employee) Robertus Van Aalst, MSc, Sanofi Pasteur (Employee)

Vaccination coverage and adherence to a dengue vaccination program in the state of Paraná, Brazil

The success of vaccination programs depends on the level of acceptance of the vaccine to achieve high vaccine coverage rates (VCR). Vaccine hesitancy is a challenge, especially concerning new vaccines. Dengue vaccine, Dengvaxia®, was licensed in Brazil in 2015 and implemented, in a pioneering publicly-funded initiative in the state of Paraná, between 2016 and 2018. The vaccination program took place in five phases in the 30 municipalities most affected by dengue in the state, targeting individuals from nine to 44 years-old in two cities and from 15 to 27 years-old in the other 28 municipalities, totaling a target population of 500,000 individuals. A cross-sectional descriptive study was carried out to assess VCR and adherence to the dengue vaccine in this program. VCR, dropout ratio (DR), and compliance with the vaccination schedule (CVS) were analyzed by sex, age group, and municipality size. A total of 302,603 individuals (60.5%) received ≥ 1 dose, 44.2% received ≥ 2 doses, and 28.6% 3 doses. The DR was 52.8%. Among individuals who started vaccination, 40.6% achieved CVS. The highest VCR, highest CVS, and lowest DR occurred in the age group from 9 to 14 years old and from 28 to 44 years old and in smaller municipalities. A greater proportion of men started vaccination (male 64.0%; female 57.1%) however, the DR was higher in men (male 55.4%; female 49.9%), and a higher percentage of women completed the vaccination schedule according to the recommendations (CVS male 37.8%; female 43.6%). Differences were noted in the CVS according to the initial phase of the program (first phase 50.8%; second phase 18.8%). The heterogeneity in vaccine uptake and compliance according to sex, age, and municipality size suggests the need for differentiated strategies to address challenges with new and multiple-dose vaccines.

Effectiveness of quadrivalent influenza vaccination in the first year of a funded childhood program in Queensland, Australia, 2018

BackgroundFollowing high influenza activity in 2017, the state of Queensland, Australia, funded a quadrivalent inactivated influenza vaccination program for children aged 6 months to <5 years in 2018. We calculated influenza vaccine effectiveness (VE) among children eligible for this program. MethodsA matched case-control study was conducted. Cases were identified using Queensland 2018 influenza notification data among children age-eligible for funded vaccination. Controls were drawn from Australian Immunisation Register records of Queensland resident children age-eligible for funded influenza vaccine. Up to 10 controls per case were matched for location and birthdate. First dose vaccination was valid if received ≥14 days prior to specimen collection; a second dose was valid if received ≥28 days after first dose receipt. VE was calculated for vaccine doses and adherence to national recommendations for two doses in the first season (schedule completeness) and adjusted (VEadj) for sex and First Nations status. ResultsThere were 1,125 cases and 10,645 matched controls analysed. Overall VEadj against laboratory-confirmed influenza was 51% (95% confidence interval (CI) 41–60). VEadj was 60% (95% CI 46–70) for children who received two doses in 2018, and 60% (95% CI 48–69) for children vaccinated appropriately according to schedule completeness. VE increased with age. ConclusionsModerate vaccine effectiveness was observed for children eligible for the funded program in Queensland in 2018, adding to the sparse evidence for influenza vaccine use in Australian children. Adhering to the national first season two dose schedule for influenza vaccine receipt in children ensures maximum protection.

Attitudes and Perception of Healthcare Workers Concerning Influenza Vaccination during the 2019/2020 Season: A Survey of Sicilian University Hospitals.

Influenza is an infectious disease with a high impact on the population in terms of morbidity and mortality, but despite International and European guidelines, vaccination coverage rates among healthcare workers (HCWs) remain very low. The aim of the present study was to evaluate influenza vaccination adherence in the three Sicilian University Hospitals of Catania, Messina, and Palermo and to understand the attitudes and perceptions of vaccinated healthcare workers and the main reasons for vaccination refusal. A cross-sectional survey through a self-administered questionnaire was conducted during the 2019/2020 influenza season. Overall, 2356 vaccinated healthcare workers answered the questionnaire. The main reason reported for influenza vaccination adherence during the 2019/2020 season was to protect patients. Higher self-perceived risk of contracting influenza and a positive attitude to recommending vaccination to patients were significantly associated with influenza vaccination adherence during the last five seasons via multivariable analysis. Fear of an adverse reaction was the main reason for influenza vaccine refusal. In accordance with these findings, Public Health institutions should develop and tailor formative and informative campaigns to reduce principal barriers to the immunization process and promote influenza vaccination adherence among HCWs.

Effect of a vaccine information statement (VIS) on immunization status and parental knowledge, attitudes, and beliefs regarding infant immunization in Japan

BackgroundBecause of the overabundance of vaccination information on the internet, in the media, and on social media, providing clear and correct information on immunization is critical for parental decision-making. In 2018, the Japan Pediatric Society created and distributed a Vaccine Information Statement (VIS) to provide appropriate immunization information to caregivers. The objectives of the present study were to evaluate the effect of the VIS on immunization rates, adherence to schedule, and parental understanding of immunization in Japan. MethodsThis cross-sectional study was conducted at 18 centers in 2 prefectures in Japan. Caregivers were assigned to an intervention group, which received the VIS and a questionnaire when their child reached the age of 1 month, and a control group, which received only the questionnaire. Using the self-reported questionnaires, we evaluated vaccination rates and schedule adherence at age 2 months, and parental knowledge, attitudes, and beliefs regarding immunization. Three months later, the questionnaires were returned, and the findings were compared between the 2 groups. ResultsWe contacted 422 and 428 persons in the intervention and control groups, respectively, and 111/422 (26.3%) and 119/428 (27.8%) returned the surveys. Vaccination rates and adherence rates for the first dose of 4 recommended vaccines did not differ significantly (P > 0.25); however, there were some positive effects on items related to vaccine knowledge (P = 0.03), perceived benefits (P = 0.02), perceived barriers (P < 0.001), and perceived behavioral control (P = 0.01). ConclusionThe VIS improved parent comprehension of infant immunization. Future studies should examine if the effects of such an intervention persist and affect vaccine uptake throughout childhood.