Prevalence of indications for adult hepatitis A vaccination among hepatitis A outbreak-associated cases,Three US States, 2016–2019

BackgroundSafe and effective hepatitis A vaccines have been recommended in the United States for at-risk adults since 1996; however, adult vaccination coverage is low.MethodsAmong a random sample of adult outbreak-associated hepatitis A cases from three states that were heavily affected by person-to-person hepatitis A outbreaks, we assessed the presence of documented Advisory Committee on Immunization Practices (ACIP) indications for hepatitis A vaccination, hepatitis A vaccination status, and whether cases that were epidemiologically linked to an outbreak-associated hepatitis A case had received postexposure prophylaxis (PEP).ResultsOverall, 74.1% of cases had a documented ACIP indication for hepatitis A vaccination. Fewer than 20% of epidemiologically linked cases received PEP.ConclusionsEfforts are needed to increase provider awareness of and adherence to ACIP childhood and adult hepatitis A vaccination and PEP recommendations in order to stop the current person-to-person hepatitis A outbreaks and prevent similar outbreaks in the future.     

The adult vaccination landscape in the United States during the Affordable Care Act era: Results from a large retrospective database analysis

BackgroundEarly provisions of the Affordable Care Act (ACA) reduced financial barriers to preventive care, including routinely recommended vaccines; however, vaccination coverage remains suboptimal. This study examined characteristics of routine adult vaccinations and potential missed opportunities for vaccinations through the lens of healthcare resource utilization among adults in the ACA era.MethodsThis was a retrospective analysis of healthcare claims from the Truven Health MarketScan Commercial Claims and Encounters (CCAE), Medicare Supplemental (MS), and Multi-State Medicaid databases among adults aged 19 years or older. Influenza, Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis), herpes zoster (HZ), and pneumococcal vaccinations were identified between 2011 and 2016. Potential missed opportunities were defined as well-visits at which individuals were age-eligible for vaccination but did not receive it, assessed during recommended windows for each vaccine. Missed encounters were defined as having no well-visits. Multivariable logistic regression was used to identify factors associated with vaccination and potential missed opportunities.ResultsFamily/internal medicine and unknown/other providers administered most influenza, Tdap, and pneumococcal vaccinations, for the CCAE/MS and Medicaid cohorts, respectively. HZ vaccinations were primarily administered through pharmacies. The proportion of vaccination events increased in the pharmacy setting between 2011 and 2016. Having preventive care visits, non-well-visits, and receiving most care from a family/internal medicine practitioner were associated with increased odds of vaccination. Missed encounters were common in Medicaid enrollees. Potential missed opportunities were more prevalent in the CCAE/MS cohort than among Medicaid enrollees. Having non-well-visits was associated with a reduced likelihood of having a missed opportunity.ConclusionSince the ACA implementation, preventive care among adults was sporadic. Many adults had limited opportunities for vaccination. The large prevalence of missed opportunities suggests vaccination uptake could be improved. Better support for vaccination or referrals for providers who may not traditionally vaccinate could improve vaccine uptake.     

Japanese encephalitis vaccination in pregnancy among U.S. active duty military women

IntroductionJapanese encephalitis (JE) vaccine is an inactivated vaccine that has shown no risks in pregnancy in animal models, but epidemiologic studies are lacking. U.S. military service members located in JE endemic regions are required to be vaccinated; understanding the potential adverse events (AEs), including AEs that may occur in pregnancy, is needed. Here, we assessed pregnancy and infant health outcomes in association with JE vaccination in pregnancy.MethodsThe study population consisted of 192,570 pregnancies to active duty women (2003–2014), captured in the Department of Defense Birth and Infant Health Research program. JE vaccine in pregnancy, vaccine count, formulation, trimester, and whether first career dose coincided with pregnancy were compared with unexposed pregnancies to assess risk of pregnancy and infant health outcomes. Adjusted risk estimates and 95% confidence intervals (CIs) were calculated by multivariable models.ResultsOf the 192,570 identifed pregnancies, 513 were exposed to the JE vaccine; 474 exposures occurred in the first trimester. For all outcomes, elevated risk estimates ranging from 1.53 to 1.70, were observed with receipt of >1 JE vaccine in pregnancy, though 95% CIs were wide and encompassed the null. First dose of JE vaccination in pregnancy was associated with a 1.87 (95% CI: 1.12–3.13) times increased risk of low birthweight (LBW) when excluding pregnancies exposed to other non-routinely recommended vaccinations in pregnancy. All other associations were null in both main and subset analyses.ConclusionsThe overall results of these analyses provide reassuring findings for the safety of JE vaccination in pregnancy. Higher counts of JE vaccine received in pregnancy yielded large yet non-statistically significant risk estimates for all outcomes, though likely driven by lack of pregnancy awareness. An association was observed with LBW in subset analyses, but it was limited to women receiving their first JE vaccine and not observed in the larger main analyses.     

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.     

Meningococcal vaccination in patients with newly diagnosed asplenia in the United States

BackgroundPatients with asplenia are recommended to receive meningococcal ACWY (MenACWY) and B (MenB) vaccines in the United States (US).ObjectivesTo examine uptake and time to receipt of meningococcal vaccines in newly diagnosed asplenia patients, and identify factors associated with vaccination.MethodsFor this retrospective database analysis, patients were identified from 1/1/2010 (MenACWY) or 1/1/2015 (MenB) through 3/31/2018 from an administrative claims database including commercially insured US patients with ≥1 inpatient or ≥2 outpatient claims with evidence of a new asplenia diagnosis (sickle cell disease was excluded); continuous enrollment for ≥12 months before and ≥6 months after the index date; and age ≥2 (MenACWY) or ≥10 (MenB) years. Co-primary outcomes were uptake and time to receipt of ≥1 dose, separately for MenACWY and MenB, by Kaplan–Meier analysis. Cox proportional hazards regression models were used to identify characteristics associated with vaccination.ResultsAmong 2,273 and 741 patients eligible for the MenACWY and MenB analyses, respectively, 28.1% and 9.7% received MenACWY and MenB in the first 3 years after a new asplenia diagnosis. Patients were more likely to receive meningococcal vaccines if they had received pneumococcal vaccines (MenACWY: hazard ratio [HR] 26.02; 95% confidence interval [CI] 21.01–32.22; MenB: HR 3.89; 95% CI 2.07–7.29) or attended ≥1 well-care visit (MenACWY: HR 6.63; 95% CI 4.84–9.09; MenB: HR 11.17; 95% CI 3.02–41.26).ConclusionsMeningococcal vaccination rates among newly diagnosed asplenia patients were low, highlighting the need to educate providers about the recommendations for high-risk conditions and ensure healthcare access for vulnerable patients.     

Flexible analytic model to inform multi-stakeholder pediatric vaccine scheduling decisions

BackgroundPediatric immunization is important for preventing potentially life-threatening diseases in children. Over time, the number of recommended pediatric vaccines has increased and is likely to increase further as new vaccines are developed. Given the different number of doses for available vaccines and various constraints (e.g., the appropriate age for each dose of a vaccine or the time between doses), it is challenging to develop a recommended vaccination schedule or a catch-up schedule when a child falls behind on one or more vaccinations.MethodsWe developed an integer programming optimization model, enabled by Python programming and embedded into an Excel-based decision tool, to recommend childhood vaccination schedules or personalized catch-up schedules. The model recommends a vaccination schedule that balances the goal of being as close as possible to the clinically-indicated dosing schedules and the goal of minimizing clinic visits, and gives users the ability to trade off between these two goals. We illustrated the broad applicability of our proposed model with commonly-faced vaccine scheduling challenges in the United States.ResultsThe illustrative computational case study confirms our model’s ability to create personalized schedules based on each child’s age and vaccination history, and to adjust appropriately when a new vaccine becomes available.ConclusionsThe model presented in this paper fills the need for an easy-to-use tool to recommend vaccination schedules for de novo and catch-up purposes. It provides straightforward recommendations that can be easily used by physicians, is flexible to handle the requirements varying by region, and can be updated as new vaccines are approved for use.     

Vaccine timeliness and prevalence of undervaccination patterns in children ages 0–19 months,U.S., National Immunization Survey-Child 2017

ObjectivesTypically, early childhood vaccination coverage in the U.S. is measured as the proportion of children by age 24 months who completed recommended vaccine series. However, these measures do not reflect whether vaccine doses were received at the ages recommended by the U.S. Advisory Committee on Immunization Practices, or whether children received vaccines concomitantly, per the ACIP recommended schedule. This study’s objective was to quantify vaccine timeliness and prevalence of specific patterns of undervaccination in U.S. children ages 0–19 months.MethodsUsing 2017 National Immunization Survey-Child data, we calculated days undervaccinated for the combined 7-vaccine series and distinguished undervaccination patterns indicative of parental vaccine hesitancy, such as spreading out vaccines across visits (“shot-limiting”) or starting some but not all recommended vaccine series (“selective vaccination”), from other non-hesitancy patterns, such as missing final vaccine doses or receiving all doses, with some or all late. We measured associations between demographic, socioeconomic and other characteristics with undervaccination patterns using multivariable log-linked binomial regression. Analyses accounted for the complex survey design.ResultsAmong n = 15,333 U.S. children, only 41.2% received all recommended vaccine doses on-time by age 19 months. Approximately 20.9% of children had an undervaccination pattern suggestive of parental vaccine hesitancy, and 36.2% had other undervaccination non-hesitancy patterns. Uninsured children and those with lower levels of maternal education were more likely to exhibit undervaccination patterns suggestive of parental hesitancy. Lower levels of maternal education were also associated with other non-hesitancy undervaccination patterns.ConclusionsMore than half of children in the U.S. are undervaccinated at some point by 19 months of age. Ongoing assessment of vaccine timeliness and immunization schedule adherence could facilitate timely and targeted public health interventions in populations with high levels of undervaccination.     

Evaluation of mortality risk after COVID-19 vaccination,Utah 2021

IntroductionIn order to evaluate trends in death after COVID-19 vaccination we analyzed the timing of death relative to vaccination date and the causes of death in vaccinated Utahns in 2021.MethodsWe matched people in the Utah immunization registry with documented COVID-19 vaccinations between December 18, 2020 and December 31, 2021 to Utah’s 2021 vital statistics death records. Vaccinated people were categorized as having one, two, or ≥ three COVID-19 vaccine doses in a time-updated metric. We examined crude mortality rates by dosing groups in two-week intervals for all deaths, and by COVID-19 versus non-COVID-19 causes, within the 44 weeks following receipt of the most recent vaccine.ResultsWe identified 2,072,908 individuals who received at least one dose of COVID-19 vaccine of whom 10,997 died in 2021. Only 17.5 % of the total vaccinated population was age 65+, while 80.9 % of those who died were over 65. In the four weeks following the first or second vaccination, all-cause mortality was low and then stabilized for the remainder of the evaluation period at a bi-weekly average of 33.0 and 39.0 deaths/100,000 people for one and two doses, respectively. Typical seasonal variation in death was observed among those with two doses. Small sample size precluded analysis of those with ≥ three doses, but trends were similar.ConclusionsMortality rates in the 44 weeks following the COVID-19 vaccination did not show trends suggesting an increase in mortality related to COVID-19 vaccination, reinforcing the safety of COVID-19 vaccines. This represents an accessible approach for local evaluation.     

Seroprevalence of anti-tetanus antibodies in mothers and cord blood and associated factors in health-care settings in Lao People’s Democratic Republic

BackgroundMaternal neonatal tetanus (MNT) was eliminated from Lao People’s Democratic Republic (PDR) in 2014. WHO recommends 80% coverage of 2 or more tetanus vaccinations (TT2+) in pregnancy to maintain MNT control. Vaccination coverage in Lao PDR varies among regions although the reasons are not clear.Methods185 pregnant women giving birth in three district hospitals in Savannakhet province, Lao PDR were recruited. A questionnaire was administered to determine factors associated with seroprotection and blood was taken from mother and cord blood to be tested for anti-tetanus antibodies by ELISA.Results77% of mothers and 79% of newborns had sufficiently protective antibody titres (>0.5 IU/ml) against tetanus. Only 70% of the mothers received one dose of TT vaccination during antenatal care (ANC) consultation and 45% received the recommended two injections. Although most of the vaccination took place during ANC 1 and 2, many were missed at these time-points. Anti-tetanus seroprotection in the mothers was associated with maternal age, number of ANC visits, number of TT vaccinations during and before pregnancy and gestational age.ConclusionSeroprevalence of anti-tetanus antibodies in mothers and newborns was intermediate but TT2+ coverage was low in healthcare settings in Lao PDR. TT2+ coverage during ANC is likely to be significantly lower in settings with less robust ANC practices. Missed opportunities to vaccinate in ANC 1 and 2 suggest a need to promote vaccine awareness and vaccination at first ANC visit. A booster dose of TT containing vaccine should be considered for children aged between 4 and 7 years old.     

Vaccination coverage and factors associated with routine childhood vaccination uptake in rural Vellore,southern India, 2017

BackgroundVellore district in southern India was selected for intensified immunization efforts through India’s Mission Indradhanush campaign based on 74% coverage in the National Family Health Survey in 2015. As rural households rely almost entirely on the Universal Immunization Program (UIP), we assessed routine immunization coverage and factors associated with vaccination status of children in rural Vellore.MethodsWe conducted a cross-sectional household survey among parents or primary caretakers of children aged 12–23 months during August–September 2017 using two-stage, EPI cluster sampling. We verified vaccination histories from vaccination cards and collected data on sociodemographic and non-socio-demographic characteristics by using mobile data capture. Associations with vaccination status were examined with univariate and multivariate logistic regression models.ResultsA total of 643 children were included. Coverage of BCG, third dose pentavalent/DPT, measles/MR vaccines and full vaccination (BCG, three doses of polio and pentavalent/DPT and measles/MR vaccines) among children with vaccination cards (n = 606) was 94%, 96%, 93% and 84%, respectively. Of children with vaccination cards, 70.8% had received all recommended doses according to the UIP schedule. No socio-demographic differences were identified, but parents’ familiarity with the schedule (Adjusted Prevalence Odds Ratio (aPOR): 2.06, 95%CI = 1.26–3.38) and receiving information on recommended vaccinations during antenatal visits (aPOR: 2.16, 95% CI = 1.13–4.12) were significantly associated with full vaccination status of the children.ConclusionsWe found higher UIP antigen coverage and proportion of fully vaccinated children than previously reported from rural Vellore. However, adherence to the recommended schedule was still not optimal. Our study highlights the potential of improving parental awareness of vaccination schedule and targeting health education interventions at pregnant women during antenatal visits to sustain and improve routine immunization coverage.     

Prevalence of influenza-specific vaccination hesitancy among adults in the United States, 2018

BackgroundThe role of vaccine hesitancy on influenza vaccination is not clearly understood. Low influenza vaccination coverage in U.S. adults suggests that a multitude of factors may be responsible for under-vaccination or non-vaccination including vaccine hesitancy. Understanding the role of influenza vaccination hesitancy is important for targeted messaging and intervention to increase influenza vaccine confidence and uptake. The objective of this study was to quantify the prevalence of adult influenza vaccination hesitancy (IVH) and examine association of IVH beliefs with sociodemographic factors and early-season influenza vaccination.MethodsA four-question validated IVH module was included in the 2018 National Internet Flu Survey. Weighted proportions and multivariable logistic regression models were used to identify correlates of IVH beliefs.ResultsOverall, 36.9% of adults were hesitant to receive an influenza vaccination; 18.6% expressed concerns about vaccination side effects; 14.8% personally knew someone with serious side effects; and 35.6% reported that their healthcare provider was not the most trusted source of information about influenza vaccinations. Influenza vaccination ranged from 15.3 to 45.2 percentage points lower among adults self-reporting any of the four IVH beliefs. Being female, age 18–49 years, non-Hispanic Black, having high school or lower education, being employed, and not having primary care medical home were associated with hesitancy.ConclusionsAmong the four IVH beliefs studied, being hesitant to receiving influenza vaccination followed by mistrust of healthcare providers were identified as the most influential hesitancy beliefs. Two in five adults in the United States were hesitant to receive an influenza vaccination, and hesitancy was negatively associated with vaccination. This information may assist with targeted interventions, personalized to the individual, to reduce hesitancy and thus improve influenza vaccination acceptance.     

Trends in vaccination schedules and up-to-date status of children 19–35 months,United States, 2015–2020

ObjectivesTo estimate trends in, and factors associated with, vaccination patterns and up-to-date immunization status of U.S. children by 19 to 35 months of age.MethodsData from the 2015 to 2020 National Immunization Surveys were used to assess trends in vaccination patterns, up-to-date status, and zero vaccination status of U.S. children by 19–35 months. Vaccination patterns were categorized as: 1) recommended, 2) alternate, or 3) unknown or unclassifiable. Multivariable analyses were conducted to examine factors associated with each vaccination pattern and up-to-date status for all recommended vaccines.ResultsFrom 2015 to 2020, the proportion of U.S. children completing the recommended schedule increased from 62.5% to 69.4%, alternative schedule decreased from 21.6% to 16.2%, and unknown or unclassifiable schedules decreased from 15.9% to 14.3%. In addition, being not up-to-date decreased from 39.7% to 35.6%. There was no change in the percentage of children receiving zero vaccinations from 2015 to 2020 (0.9% to 0.9%). Respondents with lower household income or who were uninsured were more likely to follow an alternate or unknown/unclassifiable schedule, or not be up-to-date with vaccines.ConclusionFollowing any schedule other than the recommended schedule was associated with not being up-to-date on immunizations. Increased efforts to catch up on recommended vaccines is important for protecting children’s health. Further efforts should be made to improve timely adherence to recommended vaccination schedules, particularly among populations with the largest disparities in coverage through a tailored approach to increase confidence in and access to vaccines.     

Where are children ages 5–17 years receiving their COVID-19 vaccinations? Variations over time and by sociodemographic characteristics,United States

BackgroundKnowing the settings where children ages 5–17 years received COVID-19 vaccination in the United States, and how settings changed over time and varied by socio-demographics, is of interest for planning and implementing vaccination programs.MethodsData from the National Immunization Survey-Child COVID-19 Module (NIS-CCM) were analyzed to assess place of COVID-19 vaccination among vaccinated children ages 5–17 years. Interviews from July 2021 thru May 2022 were included in the analyses for a total of n = 39,286 vaccinated children. The percentage of children receiving their COVID-19 vaccine at each type of setting was calculated overall, by sociodemographic characteristics, and by month of receipt of COVID-19 vaccine.ResultsAmong vaccinated children ages 5–11 years, 46.9 % were vaccinated at a medical place, 37.1 % at a pharmacy, 8.1 % at a school, 4.7 % at a mass vaccination site, and 3.2 % at some other non-medical place. Among vaccinated children ages 12–17 years, 35.1 % were vaccinated at a medical place, 47.9 % at a pharmacy, 8.3 % at a mass vaccination site, 4.8 % at a school, and 4.0 % at some other non-medical place. The place varied by time among children ages 12–17 years but minimally for children ages 5–11 years. There was variability in the place of COVID-19 vaccination by age, race/ethnicity, health insurance, urbanicity, and region.ConclusionChildren ages 5–17 years predominantly received their COVID-19 vaccinations at pharmacies and medical places. The large proportion of vaccinated children receiving vaccination at pharmacies is indicative of the success in the United States of expanding the available settings where children could be vaccinated. Medical places continue to play a large role in vaccinating children, especially younger children, and should continue to stock COVID-19 vaccine to keep it available for those who are not yet vaccinated, including the newly recommended group of children < 5 years.     

Meningococcal B vaccination coverage among older adolescents in the United States

BackgroundSerogroup B meningococcal (MenB) vaccination recommendations for adolescents in the United States (US) include routine vaccination for all individuals at increased risk and vaccination for individuals not at increased risk aged 16–23 years (preferred age 16–18 years) based on shared clinical decision-making. The two licensed MenB vaccines require administration of ≥2 doses.MethodsThis cross-sectional study analyzed 2017–2018 National Immunization Survey-Teen (NIS-Teen) data to evaluate ≥1 dose and ≥2 dose MenB vaccination coverage among adolescents aged 17 years. Multivariable logistic regression was used to further evaluate determinants of MenB vaccination.ResultsNationally, MenB vaccination coverage among 17-year-olds increased from 14.5% in 2017 to 17.2% in 2018 for ≥1 dose and from 6.3% to 8.4% for ≥2 doses. MenB vaccination coverage (2017–2018) was the lowest in the South (≥1 dose: 14.6%; ≥2 doses: 6.3%) and highest in the Northeast region (18.3% and 9.3%), with variation observed by census division. Adolescents were more likely to have received ≥1 dose of MenB vaccine if they had any Medicaid insurance (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.32–2.39) or had received human papillomavirus (OR, 1.94; 95% CI, 1.41–2.67) or meningococcal A, C, W, and Y (OR, 4.03; 95% CI, 2.92–5.56) vaccinations.ConclusionsMenB first-dose coverage in the US is low, and even lower for a second dose, with regional variation. Being up to date with other routinely administered vaccines increased the likelihood of receiving MenB vaccination.     

Varicella-zoster-virus vaccination of immunosuppressed children with inflammatory bowel disease or autoimmune hepatitis: A prospective observational study

Background and aimsChildren with inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH) receiving immunosuppressive treatment are at risk for severe varicella zoster virus (VZV)-induced disease. This study evaluated vaccination of susceptible patients with stable disease and documented immunoreactivity without interruption of their current immunosuppression (IS).MethodsThis prospective multicentre observational study used a prevaccination checklist to select patients with low-intensity and high-intensity IS for VZV vaccination. Tolerability and safety after immunization were assessed by questionnaire. The immune response was measured by the VZV-IgG concentration, relative avidity index (RAI), and specific lymphocyte proliferative response.ResultsA total of 29 VZV vaccinations were performed in 17 seronegative patients aged 3–16 years (IBD n = 15, AIH n = 2). Eight patients received high-intensity immunosuppression, another six low-intensity immunosuppression, and three patients interrupted IS before VZV vaccination.All 29 vaccinations were well tolerated; only minor side effects such as fever and abdominal pain, were reported in two patients. One patient experienced a flare of Crohn’s disease the day after vaccination.The VZV-IgG-concentration increased significantly (p = 0.018) after vaccination, and a specific lymphocyte response towards VZV in vitro was detected in all tested patients which correlated with the RAI (r = 0.489; p = 0.078).ConclusionsVZV vaccination was well tolerated, safe and immunogenic in children receiving ongoing IS due to IBD and AIH. Ensuring immunoreactivity by clinical and laboratory parameters, rather than the type and dosage of IS, is a reasonable approach to decide on live-attenuated virus vaccinations in immunosuppressed children (German clinical trials DRKS00016357).     

Vaccine exposure during pregnancy among privately and publicly insured women in the United States, 2016–2018

BackgroundVaccine use during pregnancy affects maternal and infant health. Many women do not receive vaccines recommended during pregnancy; conversely, inadvertent exposure to vaccines contraindicated or not recommended during pregnancy may occur. We assessed exposure to two recommended vaccines and two vaccines not recommended during pregnancy among privately and Medicaid-insured women in the United States.MethodsThis study includes a retrospective cohort of pregnancies in women aged 12–55 years resulting in live birth, spontaneous abortion, or stillbirth identified in the IBM® MarketScan® Commercial, Blue Health Intelligence® (BHI®) Commercial, and IBM MarketScan Multi-State Medicaid Databases from August 1, 2016, to December 31, 2018. Gestational age at vaccination was determined using a validated algorithm. We examined vaccines (1) recommended by the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices (ACIP) (tetanus, diphtheria, and acellular pertussis [Tdap]; inactivated influenza) and (2) not recommended (human papillomavirus [HPV]) or contraindicated (measles, mumps, and rubella [MMR]).ResultsWe identified 496,771 (MarketScan Commercial), 858,961 (BHI), and 289,573 (MarketScan Medicaid) pregnancies (approximately 75% aged 20–34 years). Across these three databases, 52.1%, 50.3%, and 31.3% of pregnancies, respectively, received Tdap, most often at a gestational age of 28 weeks, and influenza vaccination occurred in 32.1%, 30.8%, and 18.0% of pregnancies, respectively. HPV vaccination occurred in < 0.2% of pregnancies, mostly in the first trimester among women aged 12–19 years, and MMR was administered in < 0.1% of pregnancies. Use of other contraindicated vaccines per ACIP (e.g., varicella, live attenuated influenza) was rare.ConclusionMaternal vaccination with ACIP-recommended vaccines was suboptimal among privately and Medicaid-insured patients, with lower vaccination coverage among Medicaid-insured pregnancies than their privately insured counterparts. Inadvertent exposure to contraindicated vaccines during pregnancy was rare. This study evaluated only vaccinations reimbursed among insured populations and may have limited generalizability to uninsured populations.     

Healthcare workers’ knowledge,beliefs, and coverage regarding vaccinations in critical care units in Italy

BackgroundLow rates of vaccine coverage have resulted in a resurgence of several vaccine-preventable diseases in many European countries. Routine vaccination of healthcare workers (HCWs) is important to reduce disease transmission, and to promote vaccine awareness and acceptance in the population. The objectives of this cross-sectional study were to investigate knowledge and beliefs about vaccines and to evaluate self-reported immunization coverage with vaccines recommended for HCWs. Additionally, the effects of several factors on these outcomes have been evaluated.MethodsA survey was conducted between September and November 2018 among a random sample of HCWs in cardiac, adult, and neonatal critical care units of 8 randomly selected hospitals across the Campania and Calabria Regions in Italy. Multivariate logistic and linear regression analysis has been performed.ResultsA total 531 HCWs returned the questionnaire for a response rate of 54.9%. Based on a vaccination knowledge score ranging from 0 to 9, more than half of the participants (55.4%) knew few of the vaccines recommended for HCWs (≤3 correct answers), 16.2% knew some vaccines (4–6 correct answers), and 28.4% knew most vaccines (≥7 correct answers), and only 13.2% knew all the vaccines recommended for HCWs. However, two-thirds (62.2%) knew that hepatitis B and influenza vaccines were recommended, and this knowledge was significantly higher among females (p < 0.001), among HCWs aged between 50 and 59 years (p = 0.01) compared with those aged < 30 years, and in those who search for information about recommended vaccines for HCWs (p = 0.012). The vaccine knowledge was significantly lower among nurses and nursing supporting staff compared with physicians (p = 0.032). Approximately two-thirds (62.7%) of HCWs considered themselves at risk of contracting vaccine-preventable infectious diseases during their professional practice. High rates of coverage were self-reported for hepatitis B (96.3%), tetanus and pertussis (93.7%), whereas they were lower for measles/mumps/rubella (80.5%), chickenpox (65.3%), and influenza (35.8%). Only 9.2% of HCWs reported prior receipt of all recommended vaccines. Male HCWs were less likely to report prior receipt of all recommended vaccines (p = 0.011). HCWs aged between 30 and 39 years compared with those aged < 30 years (p = 0.001) and those who knew some (p < 0.001) and most (p = 0.007) of all vaccines recommended for HCWs were more likely to self-report to be immunized.ConclusionsAdditional training about the vaccinations is needed to improve HCWs knowledge and to address specific concerns which may lead to better uptake among this group.     

Impact of prior vaccination on antibody response and influenza-like illness among Australian healthcare workers after influenza vaccination in 2016

BackgroundEpidemiological studies suggest that influenza vaccine effectiveness decreases with repeated administration. We examined antibody responses to influenza vaccination among healthcare workers (HCWs) by prior vaccination history and determined the incidence of influenza infection.MethodsHCWs were vaccinated with the 2016 Southern Hemisphere quadrivalent influenza vaccine. Serum samples were collected pre-vaccination, 21–28 days and 7 months post-vaccination. Influenza antibody titres were measured at each time-point using the haemagglutination inhibition (HI) assay. Immunogenicity was compared by prior vaccination history.ResultsA total of 157 HCWs completed the study. The majority were frequently vaccinated, with only 5 reporting no prior vaccinations since 2011. Rises in titres for all vaccine strains among vaccine-naïve HCWs were significantly greater than rises observed for HCWs who received between 1 and 5 prior vaccinations (p < 0.001, respectively). Post-vaccination GMTs against influenza A but not B strains decreased as the number of prior vaccinations increased from 1 to 5. There was a significant decline in GMTs post-season for both B lineages. Sixty five (41%) HCWs reported at least one influenza-like illness episode, with 6 (4%) identified as influenza positive.ConclusionsVarying serological responses to influenza vaccination were observed among HCWs by prior vaccination history, with vaccine-naïve HCWs demonstrating greater post-vaccination responses against A(H3N2).