Using classification and regression tree analysis to explore parental influenza vaccine decisions

Background and objectivesInfluenza poses a public health threat for children and adults. The CDC recommends annual influenza vaccination for children <18 years, yet vaccine uptake remains low for children (57.9%) and adults (37.1%). Given that parental decision-making is key in childhood vaccine uptake, there is a critical need to understand vaccine hesitancy among parents who decide not to vaccinate their children. This study aims to explore predictors of children’s influenza vaccine status given parental vaccination status and examine the factors that contribute to concordance or discordance between parental and children’s vaccine uptake.MethodsClassification and regression tree (CART) analyses were used to identify drivers of parental decisions to vaccinate their children against influenza. Hierarchy and interactions of these variables in predicting children’s vaccination status were explored.ResultsFrom a nationally representative sample of non-Hispanic Black and White parents who completed an online survey (n = 328), the main factors influencing parents’ decisions to vaccinate their children were vaccine behavior following physician recommendation, knowledge of influenza recommendations for children, influenza vaccine confidence and disease risk. Among unvaccinated parents, the greatest concordance was observed among parents who usually do not get vaccinated following physician recommendation and had lower knowledge of recommendations for influenza vaccination for children. The greatest discordance was observed among unvaccinated parents who had lower hesitancy about recommended vaccines.ConclusionsUnderstanding drivers of parental decisions to vaccinate themselves and their children can provide insights on health communication and provider approaches to increase influenza vaccine coverage and prevent influenza related mortality.     

Addressing logistical barriers to childhood vaccination using an automated reminder system and online resource intervention: A randomized controlled trial

BackgroundAs the rates of vaccination decline in children with logistical barriers to vaccination, new strategies to increase vaccination are needed. The goal of this study was to develop and evaluate the effectiveness of the Vaccines For Babies (VFB) intervention, an automated reminder system with online resources to address logistical barriers to vaccination in caregivers of children enrolled in an integrated healthcare system. Effectiveness was evaluated in a randomized controlled trial.MethodsQualitative interviews were conducted with parents of children less than two years old to identify logistical barriers to vaccination that were used to develop the VFB intervention. VFB included automated reminders to schedule the 6- and 12-month vaccine visit linking caregivers to resources to address logistic barriers, sent to the preferred mode of outreach (text, email, and/or phone). Parents of children between 3 and 10 months of age with indicators of logistical barriers to vaccination were randomized to receive VFB or usual well child care (UC). The primary outcome was percentage of days undervaccinated at 2 years of life. A difference in differences analysis was conducted.ResultsQualitative interviews with 6 parents of children less than 2 years of age identified transportation, scheduling challenges, and knowledge of vaccine timing as logistical barriers to vaccination. We enrolled 250 participants in the trial, 45% were loss to follow-up. There were no significant differences in vaccination uptake between those enrolled in UC or the VFB intervention (0.51%, p = 0.86). In Medicaid enrolled participants, there was a modest decrease in percentage of days undervaccinated in the VFB intervention compared to UC (6.3%, p = 0.07).ConclusionAutomated Reminders and with links to heath system resources was not shown to increase infant vaccination uptake demonstrating additional resources are needed to address the needs of caregivers experiencing logistical barriers to vaccination.     

Motivational interviewing for maternal Immunizations: Intervention development

Background and ObjectiveVaccine uptake during pregnancy remains low. Our objectives were to describe 1) development and adaptation of a clinician communication training intervention for maternal immunizations and 2) obstetrics and gynecology (ob-gyn) clinician and staff perspectives on the intervention and fit for the prenatal care context.MethodsDesign of the Motivational Interviewing for Maternal Immunizations (MI4MI) intervention was based on similar communication training interventions for pediatric settings and included presumptive initiation of vaccine recommendations (“You’re due for two vaccines today”) combined with motivational interviewing (MI) for hesitant patients. Interviews and focus group discussions were conducted with ob-gyn clinicians and staff in five Colorado clinics including settings with obstetric physicians, certified nurse midwives (CNMs), and clinician-trainees. Participants were asked about adapting training to the ob-gyn setting and their implementation experiences. Feedback was incorporated through iterative changes to training components.ResultsInterview and focus group discussion results from participants before (n = 3), during (n = 11) and after (n = 25) implementation guided intervention development and adaptation. Three virtual, asynchronous training components were created: a video and two interactive modules. This virtual format was favored due to challenges attending group meetings; however, participants noted opportunities to practice skills through role-play were lacking. Training modules were adapted to include common challenging vaccine conversations and live-action videos. Participants liked interactive training components and use of adult learning strategies. Some participants initially resisted the presumptive approach but later found it useful after applying it in their practices. Overall, participants reported that MI4MI training fit well with the prenatal context and recommended more inclusion of non-clinician staff.ConclusionsMI4MI training was viewed as relevant and useful for ob-gyn clinicians and staff. Suggestions included making training more interactive, and including more complex scenarios and non-clinician staff.     

Parental and provider vaccine hesitancy and non-timely childhood vaccination in Switzerland

ObjectiveAlthough medical providers are a trusted vaccination information source for parents, they do not universally support vaccination. Complementary medicine (CM) providers are particularly likely to hold vaccine hesitant (VH) views, and VH parents often consult with them. Little research compares VH of parents and providers, and if and how each is associated with uptake of recommended childhood vaccines.MethodsWe defined non-timely receipt as recommended vaccines given > 1 month later than officially recommended, based on vaccination records. We administered versions of the Parent Attitudes about Childhood Vaccines (PACV) 5-item survey instrument to 1256 parents and their children’s pediatricians (N = 112, 40 CM-oriented, 72 biomedical [not CM-oriented]) to identify moderately (PACV-score 5–6) and highly (PACV-score 7+) hesitant providers/parents. We obtained multivariable adjusted odds ratios to test relationships between parental VH and provider type/VH, and between non-timely receipt of selected childhood vaccines and parental VH and provider type/VH.ResultsNo biomedical providers were VH, 9 CM providers were moderately VH, and 17 were highly VH. Parents seeing moderately and highly hesitant providers had adjusted odds ratio (AOR) for being VH = 6.6 (95% confidence interval (CI), 3.1–14.0) and AOR = 31.3 (95% CI 16.8–58.3), respectively. Across all vaccine uptake endpoints, children of moderately and highly hesitant parents had 1.9–3.8 and 7.1–12.3 higher odds of non-timely vaccination, and children seeing highly hesitant CM providers had 4.9–9.4 higher odds. Children seeing moderately hesitant CM providers had 3.3 higher odds of non-timely vaccination for the 1st dose of measles and 3.5 higher odds for 1st dose of polio/pertussis/tetanus.ConclusionVH by both parents and providers each is associated with non-timely childhood vaccination. As VH parents are more likely to consult with VH providers, interventions aimed at increasing timely vaccination need to primarily target VH providers and their clients.     

Thrombosis with thrombocytopenia after AZD1222 (ChAdOx1 nCov-19) vaccination: Case characteristics and associations

BackgroundPost-marketing surveillance for COVID-19 vaccines during the pandemic identified an extremely rare thrombosis with thrombocytopenia syndrome (TTS) reported post-vaccination, requiring further characterisation to improve diagnosis and management.MethodsWe searched the AstraZeneca Global Safety Database (through April 26, 2021) for cases with co-reported thrombocytopenia and thrombosis (using standardised MedDRA queries/high-level terms) following AZD1222 (ChAdOx1 nCoV-19). Cases were adjudicated by experts as ‘typical’,’possible’, ‘no’ or ‘unknown’ according to available TTS criteria. Additional confirmatory datasets (May 20–June 20, October 1–December 28) were evaluated.FindingsWe identified 573 reports, including 273 (47.6 %) ‘typical’ and 171 (29.8 %) ’possible’ TTS cases. Of these 444 cases, 275 (61.9 %) were female, median age was 50.0 years (IQR: 38.0–60.0). Cerebral venous sinus thrombosis was reported in 196 (44.1 %) cases, splanchnic venous thrombosis in 65 (14.6 %) and thromboses at multiple sites in 119 (26.8 %). Median time to onset was 12.0 days (IQR: 9.0–15.0). Comparison with a pre-pandemic reference population indicated higher rates of autoimmune disorders (13.8 %, 4.4 %), previous heparin therapy (7.4 %, 1.2 %), history of thrombosis (5.5 %, 1.4 %), and immune thrombocytopenia (6.1 %, 0.2 %). Fatality rate was 22.2 % (127/573) overall and 23.6 % (105/444) in ‘typical’/’possible’ TTS, which decreased from 39.0 % (60/154) in February/March to 15.5 % (45/290) in April. Overall patterns were similar in confirmatory datasets.ConclusionsThe reporting rate of ‘typical’/’possible’ TTS post first-dose vaccination in this dataset is 7.5 per million vaccinated persons; few cases were reported after subsequent doses, including booster doses. Peak reporting coincided with media-driven attention. Medical history differences versus a reference population indicate potentially unidentified risk factors. The decreasing fatality rate correlates with increasing awareness and publication of diagnostic/treatment guidelines. Adjudication was hindered by unreported parameters, and an algorithm was developed to classify potential TTS cases; comprehensive reporting could help further improve definition and management of this extremely rare syndrome.     

Children vaccination coverage surveys: Impact of multiple sources of information and multiple contact attempts

BackgroundMonitoring vaccination coverage is an essential component of vaccination program evaluation. In Québec (Canada), children vaccination coverage surveys are conducted every two years since 2006. The objectives of this study were to evaluate the impact of supplementing data based on vaccination booklets with data from vaccine providers, on the final estimated vaccination coverage and to compare vaccination coverage between respondents to each survey contact attempt.MethodsData from six cross-sectional surveys were used, which included 3508 children aged 2 years. Parents were invited to transcribe the information available in their child’s vaccination booklet on the questionnaire received by mail. The survey included a maximum of 4 contact attempts to obtain a response. Data were completed among vaccine providers identified by parents. The main outcome was a complete vaccination status by 24 months of age.ResultsThe addition of data from vaccine providers to those present in vaccination booklets increased the proportion of children fully vaccinated from 5.5% to 23.7% depending on the survey year. The proportion of children fully vaccinated by 24 months of age estimated among respondents to contact 1 was only 2.1% higher than the estimates among all respondents.ConclusionsWithout validation among vaccine providers for children with missing doses according to vaccination booklets, results underestimated vaccination coverage in the target population. Conducting multiple contact attempts increased the response rate but had limited impact on the validity of estimates. It would be useful in future surveys to present the coverage obtain from respondents to each contact attempt.     

Long-term effectiveness of pentavalent and monovalent rotavirus vaccines against hospitalization in Taiwan children

BackgroundTwo rotavirus vaccines (RV1 and RV5) are available on the private market in Taiwan, not included in national immunization program. Scanty reports evaluated the rotavirus vaccine effectiveness (VE) in Asian countries.MethodsFrom February 2014-July 2017, we conducted a prospective case-control study in ten hospitals in Taiwan. Case-patients included children aged 8–59 months, and hospitalized with laboratory-confirmed rotavirus acute gastroenteritis (AGE). For each case patient, up to four controls, rotavirus-negative AGE or non-AGE illnesses, respectively, were matched by gender, age and enrolled date. Vaccination history was confirmed through vaccination card or hospital record. VE was calculated as (1 − odds ratio of vaccination) × 100%.ResultsTotally 4248 AGE patients and 2242 non-AGE controls were enrolled. A total of 330 case-patients with rotavirus AGE, 1226 rotavirus-negative AGE controls and 1122 non-AGE controls were included for analysis. Unvaccinated rate was 85.15% for rotavirus-positive cases, 42.9% for rotavirus-negative controls, and 34.31% for non-AGE controls. VE of two-dose RV1 was 84.9% (95% confidence interval [CI]:77.7%, 90.1%) for rotavirus-negative AGE and 88.9% (95% CI: 83.4%, 92.8%) for non-AGE controls, while VE of three-dose RV5 was 92.5% (95% CI: 85.1%, 96.7%) and 96.4% (95% CI: 91.9%, 98.6%), respectively. For respective vaccine, VEs were not significantly different in term of rotavirus genotypes. VEs of both vaccines declined <80% in children aged three years by combined controls.ConclusionsBoth vaccines provided excellent and sustained protection against rotavirus AGE hospitalization in children in Taiwan, but the effectiveness declined slightly in children aged three years.     

Factors associated with COVID-19 vaccination during June–October 2021: A multi-site prospective study

IntroductionVaccine hesitancy presents a challenge to COVID-19 control efforts. To identify beliefs associated with delayed vaccine uptake, we developed and implemented a vaccine hesitancy survey for the COVID-19 Community Research Partnership.MethodsIn June 2021, we assessed attitudes and beliefs associated with COVID-19 vaccination using an online survey. Self-reported vaccination data were requested daily through October 2021. We compared responses between vaccinated and unvaccinated respondents using absolute standardized mean differences (ASMD). We assessed validity and reliability using exploratory factor analysis and identified latent factors associated with a subset of survey items. Cox proportional hazards models and mediation analyses assessed predictors of subsequent vaccination among those initially unvaccinated.ResultsIn June 2021, 29,522 vaccinated and 1,272 unvaccinated participants completed surveys. Among those unvaccinated in June 2021, 559 (43.9 %) became vaccinated by October 31, 2021. In June, unvaccinated participants were less likely to feel “very concerned” about getting COVID-19 than vaccinated participants (10.6 % vs. 43.3 %, ASMD 0.792). Among those initially unvaccinated, greater intent to become vaccinated was associated with getting vaccinated and shorter time to vaccination. However, even among participants who reported no intention to become vaccinated, 28.5 % reported vaccination before study end. Two latent factors predicted subsequent vaccination—being ‘more receptive’ was derived from motivation to protect one’s own or others’ health and resume usual activities; being ‘less receptive’ was derived from concerns about COVID-19 vaccines. In a Cox model, both factors were partially mediated by vaccination intention.ConclusionThis study characterizes vaccine hesitant individuals and identifies predictors of eventual COVID-19 vaccination through October 31, 2021. Even individuals with no intention to be vaccinated can shift to vaccine uptake. Our data suggest factors of perceived severity of COVID-19 disease, vaccine safety, and trust in the vaccine development process are predictive of vaccination and may be important opportunities for ongoing interventions.     

Body mass index and vaccine responses following influenza vaccination during pregnancy

Background and AimsInfluenza vaccination is recommended by the World Health Organisation for pregnant women, offering the dual benefit of protecting pregnant women and their newborn infants against influenza infection. Various factors can influence vaccine immunogenicity, with obesity being one factor implicated in varied responses. This study aimed to investigate the impact of body mass index (BMI) on vaccine responses following influenza vaccination during pregnancy.MethodsPregnant women attending the Women’s and Children’s Hospital in South Australia during 2014–2016 were invited to participate. Participant’s clinical and demographic factors were recorded prior to administration of licensed seasonal influenza vaccination. Blood samples were collected before and one month post-vaccination to measure antibody responses by haemagglutination inhibition (HI) assay. Seroprotection was defined as a post-vaccination HI titre ≥ 1:40. Regression models assessed associations with failure to achieve seroprotective antibodies to H1, H3, and B influenza strains.ResultsA total of 96 women were enrolled in the study at a median gestation of 22 weeks with a BMI range of 18–49 kg/m². Paired sera samples were available for 90/96 (94%). Most pregnant women (72/90, 80%) demonstrated seroprotective antibody titres to all three influenza vaccine antigens (A(H1N1)pdm09, A(H3N2), B/Yamagata) following vaccination. Compared with women with BMI < 30 kg/m², those with high BMI were less likely to fail to achieve seroprotective antibodies, however this was not statistically significant (RR 0.42, 95% CI 0.11–1.68; p = 0.22). A greater proportion of women vaccinated during their second (47/53, 93%) or third trimester (18/25, 72%) demonstrated seroprotection to all three vaccine antigens following vaccination compared with women vaccinated during their first trimester (7/12, 58%).ConclusionHigh BMI did not impair seroprotection levels following influenza vaccination in pregnant women. Gestation at vaccination may be an important consideration for optimising vaccine protection for pregnant women and their newborns. Further assessment of first trimester influenza vaccine responses is warranted.     

The effects of parent’s health literacy and health beliefs on vaccine hesitancy

Parental vaccine hesitancy is a key factor influencing children’s vaccination against infectious diseases such as the COVID-19. The current study aims to investigate how parent’s health literacy and health belief affect parental hesitancy toward the COVID-19 vaccination, and navigate effective measures to help parents make vaccination decision for children. A mixed-mode web survey was conducted among parents of children aged 3–11 years. Parental vaccine hesitancy, health literacy, and health beliefs were assessed. Parallel mediation model examined whether the association between parent's health literacy and vaccine hesitancy was mediated by health beliefs. In total, 11.3% of the 346 participants reported vaccine hesitancy. Hesitant parents were more likely to be he mother (Father: 4.5%; Mother: 12.9%) and with children having allergic issues (Allergic: 18.3%; Non-allergic: 9.8%). Meanwhile, parents with lower health literacy were more likely to show hesitancy towards vaccinating their children (β = −6.87, 95% CI = [−10.50, −3.11]). This relationship was partially mediated by more perceived barriers in vaccination (β = −2.53, 95%CI = [−4.09, −1.02]), but not other health beliefs. In other words, parents with better health literacy may perceive fewer barriers in making vaccination decision for their children, thus being less hesitant. Accordingly, healthcare professionals and policy makers could design education service to promote parents’ health literacy, and remove the perceived barriers as well as increase their confidence in following the COVID-19 vaccine guidance for children.     

Motivational interviewing and vaccine acceptance in children: The MOTIVE study

Background and ObjectiveVaccine coverage have been less than desired in young children in part due to parental vaccine hesitancy. Addressing health beliefs through patient-centered communication approaches such as motivational interviewing (MI) may improve vaccine confidence. Thus, the objective of this study was to determine the difference in paediatric vaccination coverage rates based on the Advisory Committee on Immunization Practices (ACIP) and Centers for Disease Control and Prevention (CDC) recommended schedule in children 0–6 years of age after an educational intervention for providers and integration of an MI-based communication tool, MOTIVE (MOtivational Interviewing Tool to Improve Vaccine AcceptancE).MethodsPaediatric and family practice providers in a federally qualified health center in the United States completed an educational intervention regarding vaccine hesitancy and use of the MOTIVE tool. Providers then implemented the MOTIVE tool to address common health beliefs using strong, presumptive vaccine recommendations and an MI framework during encounters with patients 0–6 years of age. Data were collected from 1-year pre-educational intervention (July 2018-June 2019, N = 2504) and post-intervention (July 2019-March 2020, N = 1954) to examine differences in vaccination coverage rates and documented vaccine refusals.ResultsUse of the MOTIVE tool was associated with a statistically significant increase in IIV vaccination coverage rate in children 6 months to 6 years of age (32.4% versus 43.9%, p < 0.01). A significantly increased Hib vaccination coverage rate was observed in children 0–18 months of age. Patients with commercial insurance also had significantly higher vaccination coverage rates for the DTaP, IPV, and VAR vaccines during the intervention period. Use of the MOTIVE tool was associated with a decrease in documented vaccine refusals per 100 patients in children 0–6 years of age (31.5 versus 17.6, p < 0.01).ConclusionUse of an MI-based communication tool may decrease vaccine refusals and improve childhood vaccination coverage rates, particularly for IIV.Clinical Trial Registration: ClinicalTrials.gov, NCT03934008, https://clinicaltrials.gov/ct2/show/NCT03934008, deidentified individual participant data will not be made available.     

Economic evaluation of the introduction of rotavirus vaccine in Hong Kong

BackgroundRotavirus is a common cause of severe gastroenteritis in young children in Hong Kong (HK) with a high economic burden. This study aimed to evaluate the cost-effectiveness of introducing rotavirus vaccination into the HK Government’s Childhood Immunisation Programme (CIP) and to include the potential protective effect of the vaccine against seizures.MethodsA decision-support model was customised to estimate the potential impact, cost-effectiveness and benefit-risk of rotavirus vaccination in children below 5 years over the period 2020–2029 in HK. Two doses of Rotarix® and three doses of RotaTeq® were each compared to no vaccination. Rotavirus treatment costs were calculated from a governmental health sector perspective (i.e., costs of public sector treatment) and an overall health sector perspective (both governmental and patient, i.e., costs of public sector treatment, private sector treatment, transport and diapers). We ran probabilistic and deterministic uncertainty analyses.ResultsIntroduction of rotavirus vaccination in HK could prevent 49,000 (95% uncertainty interval: ~44,000–54,000) hospitalisations of rotavirus gastroenteritis and seizures and result in ~50 (95% uncertainty interval: ~25–85) intussusception hospitalisations, over the period 2020–2029 (a benefit-risk ratio of ~1000:1), compared to a scenario with no public or private sector vaccine use. The discounted vaccination cost would be US$51–57 million over the period 2020–2029 based on per-course prices of US$72 (Rotarix®) or US$78 (RotaTeq®), but this would be offset by discounted treatment cost savings of US$70 million (government) and US$127 million (governmental and patient health sector). There was a greater than 94% probability that the vaccine could be cost-saving irrespective of the vaccine product or perspective considered. All deterministic ‘what-if’ scenarios were cost-saving from an overall health sector perspective (governmental and patient).ConclusionsRotavirus vaccination is likely to be cost-saving and have a favourable benefit-risk profile in HK. Based on the assumptions made, our analysis supports its introduction into CIP.     

Socioeconomic disadvantage and human papillomavirus (HPV) vaccination uptake

ImportanceDespite availability of safe and effective human papillomavirus (HPV) vaccines, vaccination uptake remains low in the U.S. Research examining the impact of neighborhood socioeconomic status on HPV vaccination may help target interventions.ObjectiveTo examine the association between area deprivation and HPV vaccine initiation and completion.Design, setting, participantsRetrospective cohort study of individuals aged 11–18 years residing in the upper Midwest region. Receipt of HPV vaccination was examined over a three-year follow-up period (01/01/2016–12/31/2018).Main outcomes and measuresOutcomes of interest were initiation and completion of HPV vaccination. Demographic data were collected from the Rochester Epidemiology Project (REP). Area-level socioeconomic disadvantage was measured by calculating an Area Deprivation Index (ADI) score for each person, a measure of socioeconomic disadvantage derived from American Community Survey data. Multivariable mixed effect Cox proportional hazards models were used to examine the association of ADI quartiles (Q1-Q4) with HPV vaccine series initiation and completion, given initiation.ResultsIndividuals residing in census block groups with higher deprivation had significantly lower likelihood of HPV vaccine initiation (Q2: HR = 0.91, 0.84–0.99 Q3: HR = 0.83, 0.76–0.90; Q4: HR = 0.84, 0.74–0.96) relative to those in the least-deprived block groups (Q1). Similarly, those living in block groups with higher deprivation had significantly lower likelihood of completion (Q2: HR = 0.91, 0.86–0.97; Q3: HR = 0.87, 0.81–0.94; Q4: HR = 0.82, 0.74–0.92) compared to individuals in the least-deprived block groups (Q1).Conclusions and relevanceLower probability of both HPV vaccine-series initiation and completion were observed in areas with greater deprivation. Our results can inform allocation of resources to increase HPV vaccination rates in our primary care practice and provide an example of leveraging public data to inform similar efforts across diverse health systems.     

Serogroup B meningococcal vaccination practice patterns on college campuses

BackgroundMost Neisseria meningitidis involved in invasive disease among American college students express serogroup B antigen. The Advisory Committee on Immunization Practices (ACIP) recommends healthcare providers (HCPs) share clinical decision making with patients to determine individual value of meningococcal serogroup B vaccination (MenB) rather than routinely recommend vaccination as with the meningococcal A,C,W,Y vaccine (MenACWY). This study examines the attitudes and practices of HCPs working in college student health centers (SHCs) regarding the recommendation and administration of MenB to students.MethodsThe study was conducted as an online and phone survey of SHC HCPs from a sample of colleges across the United States between May 2017 and July 2018. Items compared college SHC policies and practices for MenB to those for MenACWY. It also assessed perceived barriers to and facilitators of MenB delivery to students.ResultsAmong the 147 respondents, almost 50% more reported their SHC stocked and administered MenACWY (54.1%) than MenB (37%) (p = .004). Almost five times as many colleges required their students receive MenACWY as MenB (53.5% vs. 10.5%, p < .001). A greater percentage requested students to submit records for MenACWY than MenB (77.3% vs. 46.9%, p < .001), and over three times as many tracked student-body coverage rates for MenACWY than MenB (55.6% vs. 15.8%, p < .001). Nearly three quarters of respondents estimated their college’s student body MenB coverage rate to be ≤ 10% or were unable to provide any estimate. Factors perceived by over half of the participants as moderate to extreme barriers to administering MenB included high upfront costs for SHCs to purchase and stock MenB (68.7%), and high out-of-pocket costs for students to receive it (82.8%).ConclusionsA minority of college SHCs require, offer or track Men B vaccination on their campuses. Financial concerns are common barriers to SHCs’ stocking and administering MenB to students.     

Trend in varicella patients 4 years after implementation of universal two-dose varicella vaccination in Japan

ObjectiveTo elucidate the trend and clinical spectrum of virologically diagnosed varicella patients after implementation of universal vaccination as a national immunization program in Japan.Patients and methodsStudy subjects were patients suspected of varicella, less than 15 years of age, who visited 14 pediatric clinics in the Nagoya VZV Study Group from September 2015 to August 2019. Practitioners collected patient samples and information such as backgrounds, clinical symptoms, and previous immunization status. All patients were confirmed as having varicella based on molecular diagnostic assays.ResultsVaricella zoster virus (VZV) DNA was detected in swab samples from 506 (83.1%) of the 609 suspected patients. The 455 varicella patients for whom vaccination status was available were divided into two groups: 180 universal vaccination targets and 275 non-targets. Numbers of monthly varicella patients decreased gradually during the observation period. In the 2016/17 season, the seasonal epidemic of varicella became undetectable in the universal vaccination target group, and starting in the 2017/18 season, it was obscured even in the non-target group. The median age of patients was significantly lower in the universal vaccination target group (3 years) than the non-target group (7 years) (P < 0.001). Vaccination status differed significantly between the two groups (P < 0.001). Most varicella patients were in the non-target group, especially those who had been vaccinated once (60.4%). Frequency of fever (P < 0.001) and number of skin rashes at the time of the first hospital visit (P = 0.001) were significantly higher in the non-target group.ConclusionsAlthough the number of childhood varicella patients declined after implementation of national immunization with two doses of varicella vaccination, sporadic outbreaks still occurred, mainly in the non–universal vaccination target group. Insufficient vaccination of members of this group is likely to be a major reason for small local outbreaks.     

Prenatal tetanus-diphtheria-acellular pertussis vaccine effectiveness at preventing infant pertussis

ObjectiveTo evaluate the effectiveness of the tetanus, diphtheria, and acellular pertussis (Tdap) vaccine containing five pertussis components (Tdap5; Adacel®, Sanofi) when given during pregnancy at preventing pertussis in infants less than 2 months of age.MethodsThe US Centers for Disease Control and Prevention (CDC), in collaboration with the Emerging Infections Program (EIP) Network, undertook a case-control study evaluating the effectiveness of Tdap vaccination in pregnancy against pertussis in infants less than 2 months of age based on data collected by the EIP Network from 2011 through 2014. The dataset from the CDC/EIP Network study was used to conduct this product-specific vaccine effectiveness analysis of Tdap5 vaccination in pregnancy to prevent disease in young infants. The main outcome of interest was vaccine effectiveness in infants whose pregnant parents were vaccinated with Tdap5 between 27 and 36 weeks’ gestation, in accordance with the ideal timing for Tdap vaccination in pregnancy recommended by the US Advisory Committee on Immunization Practices. Odd ratios (ORs) and 95 % confidence intervals (CIs) were estimated using conditional logistic regression, and vaccine effectiveness was calculated as (1–OR) × 100 %.ResultsThere were 160 infant pertussis cases and 302 matched controls included in this Tdap5-specific study. Tdap5 effectiveness in preventing pertussis in infants whose pregnant parents were vaccinated between 27 and 36 weeks’ gestation was 92.5 % (95 % CI, 38.5 %–99.1 %). Effectiveness of Tdap5 against pertussis-related hospitalization in infants whose pregnant parents were vaccinated between 27 and 36 weeks’ gestation could not be calculated due to lack of discordance among matched cases and controls. Vaccination of the parents after pregnancy or less than 14 days before delivery did not protect infants from pertussis.ConclusionsTdap5 vaccination in pregnancy between 27 and 36 weeks’ gestation is highly effective at protecting young infants from pertussis.Study registration: ClinicalTrials.gov, NCT05040802.     

Effects of measles-containing vaccination in children with severe underlying neurologic disease

BackgroundMeasles outbreaks pose significant risk for those unvaccinated.Patients and methodsMeasles-containing vaccine was offered to unvaccinated children with severe neurologic diseases during a measles outbreak. Vaccination adverse events were reported by parents 30 days following vaccination. Long term effects were evaluated 12 months post vaccination.ResultsTwenty-seven children were vaccinated (36 doses given). Half of parents (51.8%) reported no adverse events following immunization. Adverse events included afebrile seizures (6/36), fever alone (5/36) and febrile seizures (5/36). Two children required hospitalization. Quadrivalent measles-containing vaccine combined with varicella was associated with febrile seizures (p = 0.04). No child needed adjustment of the anti-epileptic treatment or exhibited developmental regression.ConclusionIn a series of children with prior severe neurologic disease, the safety-tolerability profile of vaccines containing a measles vaccine component suggests that vaccination is justified. Main side effect was seizure aggravation in children with known epileptic disease.