Knowledge and attitiudes of pregnant women and their providers towards recommendations for immunization during pregnancy

ObjectivesTetanus, diphtheria and acellular pertussis (Tdap) and influenza vaccination is recommended during each pregnancy but uptake is suboptimal. We evaluated knowledge and acceptance of vaccination recommendations among pregnant women.MethodsProspective, convenience survey of pregnant women presenting for antenatal care at the Pavilion for Women, Texas Children's Hospital, Houston, and their healthcare providers.Results796 of 825 (96.5%) of women and 63 of 87 (72.4%) providers completed surveys. Mean age of pregnant women was 30.2 (18–45) years. Self-identified race/ethnicity was 45% white, 26% Hispanic, 13% black, 12% Asian and 4% other. Most women had college degrees (84%) and private health insurance (83%). Mean gestation was 28.5 weeks with 4.8%, 37.8% and 57.4%, in the 1st, 2nd and 3rd trimesters, respectively. Women used various sources for pregnancy information (personal contacts, providers, print, audiovisual and online media) but 89.1% cited a provider as their most trusted source, predominantly (85.8%) their physician. 668 (84%) knew vaccines are recommended during pregnancy, specifically influenza (77%) and Tdap (61%) vaccines. 659 (83%) were willing to receive vaccines if recommended by their physician. Factors impacting vaccination decisions included safety for baby, safety for mother and sufficient information, scoring 4.7, 4.5 and 4.2, respectively, on a 5-point scale; less important were additional visit time (2.6), cost (1.9) or needle phobia (1). Women surveyed in the 3rd trimester showed greater acceptance than those earlier in gestation (87% vs 78%; P0.003). Maternal education, ethnicity, insurance, multiple gestation or history of serious illness in a prior infant did not affect willingness to receive vaccines.ConclusionsPregnant women are willing to accept vaccination in pregnancy if recommended by their physician and if sufficient discussion of safety and rationale occurs. Strong physician recommendation, as reported for pediatric vaccination, is essential to optimizing uptake of vaccines during pregnancy.     

Pertussis Immunisation in Pregnancy Safety (PIPS) Study: A retrospective cohort study of safety outcomes in pregnant women vaccinated with Tdap vaccine

BackgroundNew Zealand has funded the administration of tetanus, diphtheria and acellular pertussis (Tdap) vaccine during pregnancy to prevent infant pertussis since 2013. The aim of this study was to assess the safety of Tdap vaccine administered to pregnant women as part of a national maternal immunisation programme.MethodsWe conducted a national retrospective observational study using linked administrative New Zealand datasets. The study population consisted of pregnant women eligible to receive funded Tdap vaccination from 28 to 38 weeks gestation in 2013. Primary study outcomes were based on prioritised adverse events for the assessment of vaccine safety in pregnant women, as defined by WHO and Brighton Collaboration taskforces. We examined the effect of Tdap vaccination on prioritised maternal outcomes using Cox proportional hazard models. Adjusted hazard ratios controlled for key confounding variables.ResultsIn the cohort of 68,550 women eligible to receive funded antenatal Tdap vaccination during 2013, 8178 (11.9%) were vaccinated and 60,372 (88.1%) were unvaccinated. The use of Tdap in pregnancy was not associated with an increase in the rate of primary outcomes, including preterm labour; pre-eclampsia; pre-eclampsia with severe features; eclampsia; gestational hypertension; fetal growth restriction; or post-partum haemorrhage. Tdap also did not increase secondary outcomes, including gestational diabetes mellitus; antenatal bleeding; placental abruption; premature rupture of membranes; preterm delivery; fetal distress; chorioamnionitis; or, maternal fever during or after labour. Lactation disorders was the only secondary maternal outcome with a significantly increased hazard ratio. Tdap vaccine had a protective effect on pre-eclampsia with severe features, preterm labour, preterm delivery, and antenatal bleeding.ConclusionWe did not detect any biologically plausible adverse maternal outcomes following Tdap vaccination during pregnancy. This study provides further assurance that Tdap administration during pregnancy is not associated with unexpected safety risks.     

Using the 4 Pillars™ Practice Transformation Program to increase adolescent human papillomavirus,meningococcal, tetanus-diphtheria-pertussis and influenza vaccination

ObjectivesTo report the results of an intervention using the 4 Pillars™ Practice Transformation Program (4 Pillars™ Program) to increase adolescent vaccinations including human papillomavirus vaccine (HPV) and influenza vaccines, which remain underutilized in this population.Study designEleven pediatric and family medicine practices, previously control sites from a randomized controlled cluster trial, with ≥50 adolescent patients participated. The 4 Pillars™ Program was the foundation of the intervention. De-identified demographic, office visit and vaccination data were derived from electronic medical record extractions for patients whose date of birth was 4/1/1997 to 4/1/2004 (ages 11–17 years at baseline). Vaccination rates for HPV, influenza, tetanus-pertussis-diphtheria (Tdap) and meningococcal (MenACWY) vaccines were determined for all eligible patients pre- and post intervention (i.e., vaccination rates on 4/1/2015 and 4/30/2016).ResultsAmong 9473 patients ages 11–17 years at baseline (4/1/2015), mean pre-intervention vaccination rates for HPV initiation and completion, meningococcal, Tdap and influenza vaccines were below national levels. Rates increased significantly post intervention (P < 0.001) for HPV initiation which increased 17.1 percentage points (PP) from 51.4%; HPV completion increased 14.8 PP from 30.7%, meningococcal vaccine uptake increased 16.6 PP from 79.1%, Tdap vaccine uptake increased 14.6 PP from 76.9%. Influenza vaccine uptake did not increase significantly (2.3 PP from 40.1%). In the regression using generalized estimating equations, odds of vaccination were higher for younger, non-white adolescents for all vaccines; being in a smaller practice decreased the odds of Tdap vaccination but increased the odds of influenza vaccination.ConclusionClinically and statistically significant improvements in HPV series initiation and completion, and meningococcal and Tdap vaccinations were observed in primary care practices implementing the 4 Pillars™ Practice Transformation Program.Clinical Trial Registry Number: NCT02165722.     

Tetanus,diphtheria, and acellular pertussis vaccination during pregnancy and reduced risk of infant acute respiratory infections

BackgroundTo protect infants from pertussis infection, the Advisory Committee on Immunization Practices (ACIP) recommends women receive the tetanus toxoid, reduced diphtheria toxoid, acellular pertussis (Tdap) vaccine between 27 and 36 weeks of pregnancy. Here, we assessed the association between timing of maternal Tdap vaccination during pregnancy and acute respiratory infection (ARI) in infants <2 months of age.MethodsThis retrospective cohort study included 99,434 infants born to active duty military women in the Department of Defense Birth and Infant Health Registry from 2006 through 2013. Multivariable log-binomial regression was used to calculate relative risks (RRs) and 95% confidence intervals (CIs) for the association between maternal Tdap vaccination during pregnancy and infant ARI at <2 months of age.ResultsInfants of mothers who received Tdap vaccination during pregnancy vs those who did not were 9% less likely to be diagnosed with an ARI at <2 months of age (RR, 0.91; 95% CI, 0.84–0.99), and the risk was 17% lower if vaccination was received between 27 and 36 weeks of pregnancy (RR, 0.83; 95% CI, 0.74–0.93). Similar results were observed when comparing mothers who received Tdap vaccination prior to pregnancy in addition to Tdap vaccination between 27 and 36 weeks of pregnancy versus mothers who only received vaccination prior to pregnancy (RR, 0.85; 95% CI, 0.74–0.98).ConclusionsMaternal Tdap vaccination between 27 and 36 weeks of pregnancy was consistently protective against infant ARI in the first 2 months of life vs no vaccination during pregnancy, regardless of Tdap vaccination prior to pregnancy. Our findings strongly support current ACIP guidelines recommending Tdap vaccination in late pregnancy for every pregnancy.     

Predictors of influenza vaccination in the U.S. among children 9–13 years of age

Background and objectivesU.S. estimates of seasonal influenza (flu) vaccine uptake in 2014–2015 were 62% for 5–12 year olds, dropping to 47% for 13–17 year olds. The Healthy People 2020 goal for these age groups is 80%. It is important to understand factors associated with influenza vaccination, especially for those ages where rates begin to decline. The objective of this study was to identify factors associated with influenza vaccination acceptance in 9–13 year old children.MethodsAn online U.S. survey of mothers of children aged 9–13 assessed children's influenza vaccine uptake in the previous season, healthcare utilization, sociodemographics, and vaccine attitudes. Multivariable logistic regression identified independent predictors of influenza vaccine status.ResultsThere were 2363 respondents (Mean age = 38 years old). Referent children were 57% female and 66% non-minority race/ethnicity with a mean age of 10.6 years. By maternal report, 59% of children had received an influenza vaccine in the previous season. Predictors of influenza vaccine uptake included a recommendation or strong recommendation from a health care provider, seeing a health care provider in the past year, positive attitudes regarding the influenza vaccine, and being a minority race. Child gender, age, insurance coverage, and whether the child had a regular healthcare provider were not associated with influenza vaccine uptake (p = n.s.).ConclusionsThis sample reported overall rates of influenza vaccine uptake similar to national surveillance data, but still lower than national goals. Provider recommendations along with health attitudes and seeing a health care provider were associated with vaccine uptake. Promising interventions may include more directive physician messaging for influenza vaccine uptake in youth, encouraging more regular well-child visits during the adolescent years, and promoting influenza vaccination at alternative sites.     

Why do we not want to recommend influenza vaccination to young children? A qualitative study of Australian parents and primary care providers

IntroductionInfluenza vaccination has been shown to be safe and effective against influenza and in the prevention of complicating secondary respiratory illnesses. However, its uptake in young children remains low. This study explored the views, attitudes and practices of parents and primary care providers (PCPs) on their knowledge and acceptance of influenza vaccination in children under 5.MethodsUsing a cross-sectional qualitative research design, we conducted 30 in-depth interviews with PCPs (i.e., general practitioners, practice nurses, maternal and child health nurses, and pharmacists) and five focus groups with parents (n = 50) between June 2014 and July 2015 in Melbourne, Australia. Data were thematically analysed.ResultsParents thought the vaccine could cause influenza, and influenza vaccination was not necessary for their children as they needed to build their own ‘immunity’. Parents said that they would consider vaccinating their children if recommended by their GP and if the influenza vaccine was part of the immunisation schedule. PCPs also expressed concerns regarding the efficacy of the vaccine as well as out-of-pocket costs incurred by families, and uncertainty regarding the mortality and morbidity of influenza in otherwise healthy children. However, they said they would recommend the vaccine to high-risk groups (e.g. children with chronic disease(s), and asthma).ConclusionDespite the established safety of influenza vaccines, barriers to uptake include concerns regarding the iatrogenic effects of vaccination, its administration schedule, and knowledge of influenza severity. Updated information on influenza and the efficacy of the vaccine, and incorporating influenza vaccination into the immunisation schedule may overcome some of these barriers to increase influenza vaccination in this vulnerable cohort.     

Antibody persistence and safety and immunogenicity of a second booster dose nine years after a first booster vaccination with a reduced antigen diphtheria-tetanus-acellular pertussis vaccine (Tdap) in adults

BackgroundOver the last decades, pertussis showed periodic increases in its incidence among adults, despite being a vaccine-preventable disease.MethodsThis phase III, multicenter, extension study (NCT00489970) was conducted in adults from the United States, followed at Year (Y) 5 and Y9 post-vaccination with a dose of reduced-antigen-content tetanus-diphtheria-acellular pertussis vaccine containing either 3 (Tdap-B group) or 5 pertussis components (Tdap-A group). Willing participants in Tdap groups and newly-recruited participants (Control group) received one Tdap-B dose at Y9. Antibody persistence (at Y5 and Y9) and safety of Tdap-B at Y9 were assessed. Non-inferiority of immune response elicited by 2 Tdap doses was evaluated at Y9: (i) versus one Tdap-B dose for diphtheria and tetanus in terms of seroprotection rates; (ii) for all antigens in terms of booster response rates (Tdap-B and Tdap-A groups versus Control group); and (iii) for pertussis antigens in terms of geometric mean concentrations (GMCs) versus a 3-dose series of a combined diphtheria-tetanus-acellular pertussis vaccine (DTPa) administered during infancy.Results1257 participants were enrolled at Y5 and 809 participants were vaccinated at Y9. Seroprotection rates in both Tdap groups were ≥98.4% and ≥98.0% (Y5) and ≥98.3% and ≥98.1% (Y9) for diphtheria and tetanus, respectively. For pertussis antigens, antibody concentrations above assay cut-offs were observed for ≥76.6% (Y5) and ≥84.9% (Y9) of participants in Tdap groups. At Y9, one month post-Tdap vaccination, comparable seroprotection/seropositivity rates and antibody GMCs were observed among groups. Non-inferiority of immune responses in both Tdap groups was demonstrated when compared to the Control group for diphtheria and tetanus and to a 3-dose DTPa series for pertussis antigens. Non-inferiority criteria in terms of booster response were not met for all antigens. No safety concerns were raised.ConclusionA second dose of Tdap-B administered in adults, 9 years after initial Tdap vaccination, is immunogenic and well-tolerated.     

Maternal Tdap vaccination and risk of infant morbidity

IntroductionAn increased risk of diagnosed chorioamnionitis in women vaccinated with Tdap during pregnancy was previously detected at two Vaccine Safety Datalink (VSD) sites. The clinical significance of this finding related to infant outcomes remains uncertain.MethodsRetrospective cohort study of singleton live births born to women who were continuously insured from 6 months prior to their last menstrual period through 6 weeks postpartum, with ≥1 outpatient visit during pregnancy from January 1, 2010 to November 15, 2013 at seven integrated United States health care systems part of the VSD. We re-evaluated the association between maternal Tdap and chorioamnionitis and evaluated whether specific infant morbidities differ among infants born to mothers who did and did not receive Tdap during pregnancy. We focused on 2 Tdap exposure windows: the recommended 27–36 weeks gestation or anytime during pregnancy. We identified inpatient diagnostic codes for transient tachypnea of the newborn (TTN), neonatal sepsis, neonatal pneumonia, respiratory distress syndrome (RDS), and newborn convulsions associated with an infant's first hospitalization. A generalized linear model with Poisson distribution and log-link was used to estimate propensity score adjusted rate ratios (ARR) with 95% confidence intervals (CI).ResultsThe analyses included 197,564 pregnancies. Chorioamnionitis was recorded in 6.4% of women who received Tdap vaccination any time during pregnancy and 5.2% of women who did not (ARR [95% CI]: 1.23 [1.17, 1.28]). Compared with unvaccinated women, there were no significant increased risks (ARR [95% CI]) for TTN (1.04 [0.98, 1.11]), neonatal sepsis (1.06 [0.91, 1.23]), neonatal pneumonia (0.94 [0.72, 1.22]), RDS (0.91 [0.66, 1.26]), or newborn convulsions (1.16 [0.87, 1.53]) in infants born to Tdap-vaccinated women.Conclusions and RelevanceDespite an observed association between maternal Tdap vaccination and maternal chorioamnionitis, we did not find increased risk for clinically significant infant outcomes associated with maternal chorioamnionitis.     

Association between provider recommendation and influenza vaccination status among children

BackgroundProvider recommendation is associated with influenza vaccination receipt. The objectives of this study were to estimate the percentage of children 6 months–17 years for whom a provider recommendation for influenza vaccination was received, identify factors associated with receipt of provider recommendation, and evaluate the association between provider recommendation and influenza vaccination status among children.MethodsNational Immunization Survey-Flu (NIS-Flu) parentally reported data for the 2013–14, 2014–15, and 2015–16 seasons were analyzed. Tests of association between provider recommendation and demographic characteristics were conducted using Wald chi-square tests and pairwise comparison t-tests. Multivariable logistic regression was used to determine variables independently associated with receiving provider recommendation and the association between provider recommendation and influenza vaccination status.ResultsApproximately 70% of children had a parent report receiving a provider recommendation for influenza vaccination for their child. The strongest association between receipt of provider recommendation and demographic characteristics was with child’s age, with younger children (6–23 months, 2–4 years, and 5–12 years) being more likely to have a provider recommendation than older children (13–17 years). In addition, children living in a household above poverty with household income >$75,000 were more likely to have a parent report receipt of a provider recommendation than children living below poverty. Children with a provider recommendation were twice as likely to be vaccinated than those without.ConclusionsThis study affirms the importance of provider recommendation for influenza vaccination among children. Ensuring that parents of all children receive a provider recommendation may improve vaccination coverage.     

Pediatric provider vaccine hesitancy: An under-recognized obstacle to immunizing children

ObjectiveTo describe vaccine attitudes among pediatric healthcare providers attending immunization conferences.Study designAttendees of 5 American Academy of Pediatrics (AAP)-sponsored vaccine conferences held between June and November 2013 anonymously completed a questionnaire assessing vaccine attitudes and practices prior to the opening of educational sessions. Pearson's chi-square tests and Fisher's exact tests were used to analyze associations between vaccine attitudes, vaccine practices and provider characteristics.Results680 providers attending AAP-sponsored vaccine conferences were included. 661/666 (99%) enrolled providers state they routinely recommend standard pediatric vaccines, yet, 30 (5%) state that they do not routinely recommend influenza and/or human papillomavirus (HPV) vaccines. These providers expressed vaccine safety (87/680 (13%)) and efficacy (21/680 (31%)) concerns and stated belief in vaccine misperceptions: vaccine causes autism (34/668, 5%), multiple vaccines at a single visit reduces vaccine efficacy (43/680, 6%) or overwhelms the immune system (63/680, 9%), and administering HPV vaccine will increase the likelihood of unprotected adolescent sexual activity (29/680, 4%). Six percent of providers who do not routinely recommend all pediatric vaccines correctly identified themselves as vaccine hesitant.ConclusionVaccine hesitancy is under-recognized among pediatric providers attending AAP-sponsored immunization conferences. Educational interventions tailored to address provider vaccine concerns are needed to improve provider vaccine confidence.     

Influenza and pertussis vaccination coverage in pregnant women

BackgroundPregnant women have an increased risk for complications and hospitalizations when infected with the influenza virus in the second or third trimester. Additionally, infants under six months of age are most vulnerable when contracting pertussis. Immunization against influenza and pertussis during pregnancy provides protection for mother and neonate against influenza and for neonates against pertussis pending protection through infant immunization. In Belgium, a gradual increase in pertussis cases over the past decade was observed. This study was undertaken to document vaccination coverage for influenza and pertussis and factors related to vaccination status in pregnant women.MethodsTwo hundred and fifty pregnant women completed a questionnaire during their third trimester. Vaccination data were collected and reasons for non-vaccination were noted as well as socio-demographic data which are known to influence vaccination coverage.ResultsA documented vaccination coverage of 42.8% for influenza and 39.2% for pertussis was observed. Taking into account doses which were not documented, but administered according to the expectant mother, coverage for influenza would increase to 62% and for pertussis to 46%. The most important reasons for non-vaccination were the absence of a recommendation by medical staff (9.6%) and delay in vaccination (8.4%). The GP was the most important vaccinator. Pregnant women with a lower education and those with a foreign origin were more vulnerable for non-vaccination.ConclusionIncomplete documentation is the most important barrier in determining the vaccination status of pregnant women. Immunization during pregnancy needs further integration through vaccination campaigns aimed at both health care providers and pregnant women.     

Immunogenicity and safety of double versus standard dose of the seasonal influenza vaccine in solid-organ transplant recipients: A randomized controlled trial

BackgroundThe use of vaccines with higher doses of antigen is an attractive strategy to improve the immunogenicity of influenza vaccination in transplant recipients. However, the effect of vaccination with a double-dose (DD) containing 30 µg of antigen in this population remains unknown.MethodsWe performed a randomized controlled trial to compare the immunogenicity and safety of DD (30 µg) vs. standard dose (SD, 15 µg) of a trivalent inactivated influenza vaccine in kidney and liver transplant recipients. Immunogenicity was assessed by hemagglutination-inhibition assay. Vaccine response was defined as seroconversion to at least one viral strain 2 weeks after vaccination and seroprotection as a titer ≥40.ResultsSixty-three kidney and 16 liver transplant recipients were enrolled. Forty patients received the DD and 39 the SD vaccine. Overall, 40% of patients in the DD compared to 26% in the SD group (P = 0.174) responded to vaccine. In the DD arm, more patients were seroprotected to all viral strains after vaccination (88% vs 69%, P = 0.048). Post vaccination geometric mean titers of antibodies were 131.9 vs. 89.7 (P = 0.187) for H1N1, 185.4 vs. 138.7 (P = 0.182) for H3N2, and 96.6 vs. 68.8 (P = 0.081) for influenza B with the DD vs. SD. In both groups, most of the adverse events were mild and no vaccine-related severe adverse events were observed.ConclusionDouble-dose influenza vaccine is safe and may increase antibody response in transplant recipients. In this population, DD vaccination could be an alternative when high-dose vaccine is not available. NCT02746783.     

A follow-up comparative safety analysis of pandemic H1N1 vaccination during pregnancy and risk of infant birth defects among U.S. military mothers

ObjectiveTo update a previous assessment of birth defects among infants born to active duty U.S. military mothers who received the 2009–2010 pandemic H1N1 vaccine, in comparison to the 2008–2009 seasonal influenza vaccine, during pregnancy. Here, we updated the previous comparative analyses with a more refined definition for birth defects using an additional year of follow-up data from both inpatient and outpatient medical encounters.MethodsThe study population included 15,510 live born infants born to active duty mothers vaccinated during pregnancy with either the 2009–2010 pandemic H1N1 vaccine (n = 9033) or the 2008–2009 seasonal influenza vaccine (n = 6477). Birth defect cases were defined as those infants who received a birth defect diagnosis on one inpatient record or two outpatient records on different days within the first year of life. Multivariable logistic regression models were conducted to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for the association between birth defects and maternal vaccination during pregnancy with pandemic H1N1 vaccine versus seasonal influenza vaccine.ResultsInfants born to mothers vaccinated during pregnancy with the pandemic H1N1 vaccine, versus the seasonal influenza vaccine, were not at increased odds of birth defects in univariable (OR: 1.13, 95% CI: 0.95–1.34) or multivariable (OR: 1.14, 95% CI: 0.96–1.35) models. Findings were not significant when further limited to first trimester exposure. Multivariable models were adjusted for infant sex and plurality; maternal age, race/ethnicity, marital status, service branch, military rank, and occupation; timing of vaccination; and receipt of vaccination(s) not routinely recommended during pregnancy.ConclusionComparable to our previous analyses assessing birth defects diagnosed at birth, no significant association was found between the pandemic H1N1 vaccination during pregnancy and birth defects, versus the seasonal influenza vaccine. These findings are reassuring and provide additional support for H1N1-containing seasonal influenza vaccination during pregnancy.     

Influenza vaccination: Uptake and associations in a cross-sectional study of children with special risk medical conditions

ObjectiveTo determine uptake of influenza vaccination in children with special risk medical conditions (SRMC) and to explore associations with vaccination.DesignCross-sectional study.Setting/participantsParents of children with a SRMC attending either outpatient department clinics or being an inpatient at the Women’s and Children’s Hospital (WCH), Adelaide, Australia from September 2015 to February 2016 were recruited using convenience sampling.MethodsData were collected using a face-to-face survey. Influenza vaccination was verified with providers. Characteristics associated with uptake were explored using univariable and multivariable analyses.ResultsThere were 410 participants with complete data. Confirmed influenza vaccination at least once in the last two years was 50%, annual uptake was 32.8%. 63.9% of parents were aware of the vaccination recommendation and 57.9% had been recommended by a specialist or general practitioner (GP). Characteristics strongly associated with uptake included: receiving a recommendation from a specialist or GP and having a parent receive the influenza vaccine annually.ConclusionsDespite a long standing funded program, influenza vaccination uptake in children with SRMC is suboptimal. Parental vaccination behaviour, along with medical practitioner recommendation, particularly specialist recommendation, appear to be key influences in facilitating vaccination. Potential interventions could target the family rather than just the individual child. Understanding the barriers to recommendation from the perspective of general medical practitioners and specialists who treat these children is needed.     

Association of spontaneous abortion with receipt of inactivated influenza vaccine containing H1N1pdm09 in 2010–11 and 2011–12

IntroductionInactivated influenza vaccine is recommended in any stage of pregnancy, but evidence of safety in early pregnancy is limited, including for vaccines containing A/H1N1pdm2009 (pH1N1) antigen. We sought to determine if receipt of vaccine containing pH1N1 was associated with spontaneous abortion (SAB).MethodsWe conducted a case-control study over two influenza seasons (2010–11, 2011–12) in the Vaccine Safety Datalink. Cases had SAB and controls had live births or stillbirths and were matched on site, date of last menstrual period, and age. Of 919 potential cases identified using diagnosis codes, 485 were eligible and confirmed by medical record review. Exposure was defined as vaccination with inactivated influenza vaccine before the SAB date; the primary exposure window was the 1–28 days before the SAB.ResultsThe overall adjusted odds ratio (aOR) was 2.0 (95% CI, 1.1–3.6) for vaccine receipt in the 28-day exposure window; there was no association in other exposure windows. In season-specific analyses, the aOR in the 1–28 days was 3.7 (95% CI 1.4–9.4) in 2010–11 and 1.4 (95% CI 0.6–3.3) in 2011–12. The association was modified by influenza vaccination in the prior season (post hoc analysis). Among women who received pH1N1-containing vaccine in the previous influenza season, the aOR in the 1–28 days was 7.7 (95% CI 2.2–27.3); the aOR was 1.3 (95% CI 0.7–2.7) among women not vaccinated in the previous season. This effect modification was observed in each season.ConclusionSAB was associated with influenza vaccination in the preceding 28 days. The association was significant only among women vaccinated in the previous influenza season with pH1N1-containing vaccine. This study does not and cannot establish a causal relationship between repeated influenza vaccination and SAB, but further research is warranted.     

Association between patient reminders and influenza vaccination status among children

BackgroundPatient reminders are recommended to increase vaccination rates. The objectives of this study were to estimate the percentage of children 6 months–17 years for whom a patient reminder for influenza vaccination was received by a child’s parent or guardian, estimate influenza vaccination coverage by receipt of a patient reminder, and identify factors associated with receipt of a patient reminder.MethodsNational Immunization Survey-Flu (NIS-Flu) data for the 2013–14 influenza season were analyzed. Tests of association between patient reminders and demographic characteristics were conducted using Wald chi-square tests and pairwise comparison t-tests. Multivariable logistic regression was used to determine variables independently associated with receiving a patient reminder.ResultsApproximately 22% of children had a parent or guardian report receiving a patient reminder for influenza vaccination for their child, ranging from 12.9% in Idaho to 41.2% in Mississippi. Children with a patient reminder were more likely to be vaccinated compared with children without a patient reminder (73.7% versus 55.5%). In the multivariable model, reminder receipt was higher for children 6–23 months compared with children 13–17 years, black children compared with white children, and children whose parent completed the survey in English compared with children whose parent completed the survey in a language other than English or Spanish.ConclusionsAlthough patient reminders are associated with a higher likelihood of influenza vaccination, nationally, less than one-fourth of children had a parent report receiving one. Despite being based on parental report, with its limitations, this study suggests that increasing the number of parents who receive patient reminders for their children may improve vaccination coverage among children.     

Improved immunogenicity of high-dose influenza vaccine compared to standard-dose influenza vaccine in adult oncology patients younger than 65 years receiving chemotherapy: A pilot randomized clinical trial

PurposePatients undergoing chemotherapy often fail to develop robust responses to influenza vaccination. Compared to standard-dose influenza vaccine (SD), high-dose influenza vaccine (HD) has shown improved immunogenicity and protection against influenza illness in adults 65 years and older. This study compared the immunogenicity and tolerability of HD to SD in adults younger than 65 years of age receiving chemotherapy.MethodsThis double-blind study randomized patients receiving chemotherapy to vaccination with either SD or HD influenza vaccine. Hemagglutination inhibition assays (HAI) were performed prior to and 4 weeks after vaccination. HAI were summarized as geometric mean titers (GMT), seroconversion rates, and seroprotection rates.ResultsA total of 105 subjects were enrolled in the trial (51 received SD and 54 received HD). Subjects were well matched for demographic and medical conditions. Both vaccines were well tolerated with no SAEs. Of the 100 subjects with evaluable data, seroconversion rates for all 3 influenza antigens & post-vaccination GMTs for H3N2 & B strains were significantly improved with HD compared to SD. Seroprotection was excellent and equivalent in both groups.ConclusionsTrivalent high-dose influenza vaccine can be safely administered to patients receiving chemotherapy with improved immunogenicity and seroconversion compared to standard-dose vaccine. Post-vaccination seroprotection rates were similar in both groups. A larger study is needed to show clinical benefits with HD in this population.This study was registered at ClinicalTrials.gov as NCT01666782.     

Caregiver and adolescent factors associated with delayed completion of the three-dose human papillomavirus vaccination series

BackgroundDelayed completion of human papillomavirus vaccination (4vHPV) series is common. We sought to identify factors associated with delay.MethodsThis substudy was part of a large prospective, multi-site study recruiting 9–17 year old girls at the time of their third 4vHPV dose to assess immunogenicity associated with prolonged dosing intervals. At participating sites, parents/legal guardians (caregivers) of all enrolled girls (9–17 years old) and enrolled girls aged 14–17 years were approached for participation. Caregivers completed a questionnaire measuring adolescent and caregiver sociodemographic characteristics, caregiver attitudes and beliefs about on-schedule HPV vaccination and HPV vaccine safety, adolescent’s health behaviors, barriers to accessing health care, provider office vaccination practices and a Rapid Estimate of Adult Literacy in Medicine (REALM). Participating girls completed a separate questionnaire measuring their attitudes and beliefs about on-schedule HPV vaccination and HPV vaccine safety. Delay was defined as receiving the third 4vHPV dose >12 months after the first. Bivariate, multinomial logistic regression and multivariate logistic regression analyses were used to identify factors predicting delayed completion.ResultsQuestionnaires were completed by 482 caregivers and 386 adolescents; 422 caregivers completed a REALM. Delayed 4vHPV dosing occurred in most adolescents (67%). In multivariate analyses, predictors of delayed completion included caregiver demographic factors (self-reported black vs. white race and high school or less education vs. college or more) and an interaction between caregiver’s inability to get an immunization appointment as soon as needed and adolescent’s type of insurance.ConclusionsCaregiver’s race and educational level, accessibility of immunization appointments, and adolescent’s insurance type were found to be related to delays in completion of 4vHPV, but caregiver or adolescent attitudes and beliefs about on-schedule HPV vaccination or HPV vaccine safety were not. Therefore, interventions to improve adherence to recommended vaccination schedules could benefit from a focus on improving access to immunizations.ClinicalTrials.gov (NCT01030562).     

Immunogenicity and safety of the quadrivalent meningococcal vaccine MenACWY-TT co-administered with a combined diphtheria-tetanus-acellular pertussis vaccine versus their separate administration in adolescents and young adults: A phase III,randomized study

BackgroundThis study evaluated the immunogenicity and safety of quadrivalent meningococcal conjugate vaccine using tetanus (T) toxoid as carrier protein (MenACWY-TT) co-administered with combined diphtheria-tetanus-acellular pertussis vaccine (Tdap) versus their separate administration in adolescents and young adults.MethodsIn this phase III, randomized, partially-blind study (NCT01767376), healthy 11–25-year-olds (N = 660) were randomized (1:1:1) to receive MenACWY-TT and Tdap at Month 0 (Co-ad group), MenACWY-TT at Month 0 and Tdap at Month 1 (ACWY_Tdap group) or Tdap at Month 0 and MenACWY-TT at Month 1 (Tdap_ACWY group). Immune responses to MenACWY-TT were measured by serum bactericidal assay using rabbit complement (rSBA). Anti-diphtheria (D), anti-tetanus (T), anti-pertussis toxin (PT), anti-filamentous hemagglutinin (FHA) and anti-pertactin (PRN) antibody concentrations were assessed using enzyme-linked immunosorbent assays. Non-inferiority of immunogenicity was assessed using pre-defined clinical criteria. Safety was also evaluated.ResultsNon-inferiority of immunogenicity of MenACWY-TT and Tdap when co-administered versus their separate administration was demonstrated in terms of rSBA geometric mean titers (GMTs) for 4 meningococcal serogroups and of the percentage of participants with antibody concentrations >1 IU/ml for D and T. Among the pertussis antigens, non-inferiority criteria for geometric mean concentrations (GMCs) were reached for PT, but not met for FHA and PRN. Across all groups, ≥93.2% of participants had vaccine responses to each meningococcal serogroup, ≥99.1% were seroprotected against T and D, and ≥85.5% had booster responses to each pertussis antigen. Robust increases in antibody GMTs/GMCs were observed for all antigens between pre-and post-vaccination. Both vaccines had clinically acceptable safety profiles.ConclusionImmune responses to MenACWY-TT and to the T and D antigens from Tdap were not impacted by their co-administration. The lower antibody concentrations observed against the pertussis components may be of limited clinical relevance since robust anti-pertussis booster responses were observed. This study supports concurrent administration of the 2 vaccines in adolescents.     

Increasing influenza vaccine uptake in children: A randomised controlled trial

BackgroundInfluenza vaccine is not included in the Hong Kong Government’s universal Childhood Immunisation Programme but eligible children can receive subsidised vaccine through the private sector using the Vaccination Subsidy Scheme (VSS). This study examined whether a simple intervention package can increase influenza vaccine uptake in Hong Kong children.MethodsTwo study samples were enrolled: families of children who had participated in a previous knowledge, attitudes and practices study; and mother-infant pairs recruited from postnatal wards. Control groups received publicly available leaflets about VSS. Intervention groups additionally received: (1) a concise information sheet about influenza and its vaccine; (2) semi-completed forms to utilise the subsidy; (3) contacts of VSS clinics that did not charge above the subsidy; and (4) text message reminders for vaccination. Enrolled mothers were contacted when children were approximately 1 and 2 years old to determine influenza vaccination status of the families and their plan to vaccinate their children. Mothers’ attitudes towards influenza vaccine were assessed at enrolment and at the end of the study.ResultsA total of 833 eligible mother-infant pairs were enrolled from the two samples. The intervention package improved influenza vaccine uptake by 22% at one year and 25% at two years of age. Maternal influenza vaccine uptake in intervention group was higher during this two-year period in those who had never been previously vaccinated. Mothers’ self-efficacy regarding the use of influenza vaccine in her child i.e. belief and confidence in her own ability to make a good decision, was also improved with the intervention.ConclusionsA four-component intervention package could improve influenza vaccine uptake in Hong Kong children and their mothers during the first two years of life and depending on vaccine effectiveness could potentially reduce influenza-associated hospital admissions in children below 2 years old by 13–24%.