Overcoming barriers to adolescent vaccination: perspectives from vaccine providers in North Carolina.

To capture strategies for achieving high adolescent coverage of tetanus-diphtheria-acellular pertussis (Tdap), meningococcal conjugate (MenACWY), and human papillomavirus (HPV) vaccination, we surveyed employees of 20 North Carolina (N.C.) clinics that achieved adolescent vaccination coverage higher than the state average. One employee per clinic completed a surveysummarizing clinic practices regarding adolescent vaccination; perceived barriers and facilitators to Tdap/MenACWY/HPV vaccination; and the role of "champions" who made special efforts to promote adolescent vaccination. Common perceived barriers for all vaccinations were parental opposition and logistical barriers to receiving vaccination. For HPV vaccination, employees cited parental concerns about sexual behavior and injection site pain; no school vaccination requirement; and low-perceived benefit in boys. Most clinics (80%) implemented successful changes to increase adolescent vaccination: consistently offering vaccination, tracking vaccination status using existing data, providing appointment reminders, updating providers on vaccination recommendations, and expanding vaccination hours. Strategies to improve HPV vaccination included co-administration with Tdap and MenACWY, and providing reminders to complete the vaccination series. Vaccine champions strongly recommended vaccination to parents (55%) and educated parents on vaccination recommendations (36%). Clinics in N.C.and similar settings can implement these and other low-resource strategies to overcome adolescent vaccination barriers. ABBREVIATIONS: CDC=Centers for Disease Control and Prevention; EHR=Electronic health record; HPV=Human papillomavirus; Tdap=Tetanus-diphtheria-acellular pertussis vaccine; MenACWY=Meningococcal Conjugate Vaccine; NCIB=North Carolina Immunization Branch; NCIR=North Carolina Immunization Registry; ACIP=Advisory Committee on Immunization Practices.

The Decline of Pertussis-Specific Antibodies After Tetanus, Diphtheria, and Acellular Pertussis Immunization in Late Pregnancy.

We prospectively measured pertussis-specific antibodies 9-15 months after delivery in women immunized with tetanus, diphtheria, and acellular pertussis (Tdap) after the 20th week of their recent pregnancy. The Tdap-immunized women (n = 38) exhibited a decline in geometric mean concentrations between their peripartum and follow-up levels for immunoglobulin G to pertussis toxin (21.48 [95% confidence interval, 12.51-36.89] vs 11.72 [7.09-19.37] IU/mL];); filamentous hemagglutinin (185.95 [157.93-218.94] vs 140.33 IU/mL [113.46-173.57] IU/mL); and pertactin (171.52 [120.73-243.67] vs 83.74 [60.58-115.75] IU/mL) (all P < .001). For women immunized with Tdap during late pregnancy, pertussis-specific immunoglobulin G levels decreased significantly 9-15 months after delivery.

Estimating the effectiveness of tetanus-diphtheria-acellular pertussis vaccine (Tdap) for preventing pertussis: evidence of rapidly waning immunity and difference in effectiveness by Tdap brand.

BACKGROUND: We estimated the vaccine effectiveness (VE) of tetanus-diphtheria-acellular pertussis vaccine (Tdap) for preventing pertussis among adolescents during a statewide outbreak of pertussis in Wisconsin during 2012. METHODS: We used the population-based Wisconsin Immunization Registry (WIR) to construct a cohort of Wisconsin residents born during 1998-2000 and collect Tdap vaccination histories. Reports of laboratory-confirmed pertussis with onset during 2012 were matched to WIR clients. Incidence rate ratios (IRRs) of pertussis and Tdap VE estimates [(1 - IRR)*100%], by year of Tdap vaccine receipt and brand (Boostrix/Adacel), were estimated using Poisson regression. RESULTS: Tdap VE decreased with increasing time since receipt, with VEs of 75.3% (95% confidence interval [CI], 55.2%-86.5%) for receipt during 2012, 68.2% (95% CI, 60.9%-74.1%) for receipt during 2011, 34.5% (95% CI, 19.9%-46.4%) for receipt during 2010, and 11.9% (95% CI, -11.1% to 30.1%) for receipt during 2009/2008; point estimates were higher among Boostrix recipients than among Adacel recipients. Among Tdap recipients, increasing time since receipt was associated with increased risk, and receipt of Boostrix (vs Adacel) was associated with decreased risk of pertussis (adjusted IRR, 0.62 [95% CI, .52-.74]). CONCLUSIONS: Our results demonstrate waning immunity following vaccination with either Tdap brand. Boostrix was more effective than Adacel in preventing pertussis in our cohort, but these findings may not be generalizable to adolescent cohorts that received different diphtheria-tetanus-acellular pertussis vaccines (DTaP) during childhood and should be further examined in studies that include childhood DTaP history.

Tetanus, diphtheria, acellular pertussis vaccine during pregnancy: pregnancy and infant health outcomes.

OBJECTIVE: To assess pregnancy and birth outcomes in infants born to women who did or did not receive tetanus, diphtheria, acellular pertussis (Tdap) vaccine during pregnancy. STUDY DESIGN: Retrospective cohort. Pregnant women 12-45 years of age who received Tdap at Intermountain Healthcare facilities and their infants were identified and compared with mother-infant pairs without documented Tdap from May 2005 through August 2009. Primary measures included pregnancy outcomes and infant health outcomes at birth through 12 months. RESULTS: From 162,448 pregnancies we identified 138 women (0.08%) with documented Tdap administration during pregnancy (cases); 552 pregnant women without documented Tdap were randomly selected as controls. Of 138 immunized women, 63% received Tdap in the first trimester and 37% after. Tdap was given most commonly as wound prophylaxis. The incidence of spontaneous or elective abortion was no greater in Tdap cases than in controls. There were no significant differences in preterm delivery, gestational age, or birth weight between groups. One or more congenital anomaly was identified in 3.7% (95% CI 1.2%-8.5%) of case infants and 4.4% (95% CI 2.7%-6.5%) of control infants (P = .749). In infants born to women receiving Tdap during pregnancy, 3.6% (0.8%-10.2%) had International Classification of Diseases, Ninth Revision, Clinical Modification diagnoses consistent with complex chronic conditions within 12 months compared with 10.4% (95% CI 7.2%-14.4%) of infants of controls (P = .054). CONCLUSIONS: Documented Tdap administration during pregnancy was uncommon and occurred most often in the first trimester as prophylaxis following trauma. No increase in adverse outcomes was identified in infants born to women receiving Tdap compared with infants of controls.

Pertussis antibodies and vaccination coverage among healthcare professionals in Brazil is inadequate: A cross-sectional serological study.

INTRODUCTION: Worldwide, tetanus-diphtheria-acellular pertussis (Tdap) vaccination coverage of healthcare professionals (HCPs) is below 40%, but this data is not available for Brazil. We hypothesize that a high number of HCPs are not immune to pertussis in Brazil. Main objective was to determine the seroprevalence of anti-pertussis toxin (anti-PT IgG) among HCPs. Secondary objectives were to evaluate Tdap vaccination coverage, to assess predictive factors associated with anti-PT IgG, and to estimate the decay of anti-PT IgG and time to Tdap vaccination. METHODS: Observational cross-sectional serological study in 352 HCPs who worked at São Paulo Hospital - Federal University of São Paulo (UNIFESP) in 2020, approved by UNIFESP Ethics Committee. Data collected included sociodemographics, knowledge about Tdap, and vaccination status. Anti-PT IgG were quantified by ELISA: <10 IU/mL seronegative and ≥ 10-1000 IU/mL seropositive. Titers ≥ 10-50 IU/mL were classified low positivity, indicating no recent B. pertussis infection or Tdap vaccination; >50 IU/mL high positivity, indicating recent B. pertussis infection or Tdap vaccination, and > 100 IU/mL as acute B. pertussis infection or Tdap vaccination in the previous year. Comparisons were done by Chi-square test, multivariable logistic regression, and Pearsons correlation, at 5% p-level. RESULTS: 331/352 HCPs were not aware the Brazilian National Immunization Program recommends Tdap for all HCPs and pregnant women. 68/339 HCPs received Tdap (mean 3.1 ± 2.0 years). 55/352 were seronegative for pertussis, all unvaccinated. 56/271 with no history of Tdap vaccination had high positivity. The probability of anti-PT IgG > 50 IU/mL was 11.5 times higher in Tdap vaccinated HCPs than in non-vaccinated (p < 0.001). There was a weak but significant correlation between anti-PT IgG and interval of Tdap vaccination (r = 0.404; p = 0.001). Anti-PT IgG dropped 5 IU/mL/year (p = 0.001). CONCLUSION: Better education of HCPs on needs and benefits of Tdap vaccination is critical. Goals must be to improve HCPs vaccination coverage.

Association between acceptance of routine pregnancy vaccinations and COVID-19 vaccine uptake in pregnant patients.

OBJECTIVE: COVID-19 vaccination is a key approach to reduce morbidity and mortality in pregnant patients and their newborns. Anti-vaccine sentiment has recently increased with unclear impact on pregnant patients. We examined the association between acceptance of tetanus-diphtheria-acellular pertussis (Tdap) and influenza vaccines, considered to be routine pregnancy vaccines, and COVID-19 vaccine acceptance. Secondarily, we identified other predictors of COVID-19 vaccine uptake and described pregnancy outcomes in patients who were and were not vaccinated during pregnancy. METHODS: A retrospective cohort study of all patients who delivered at a single site from December 2020 - March 2022. Demographic, pregnancy, neonatal, and vaccination data were abstracted from the electronic medical record, which imports vaccine history from the California Immunization Registry. The relationship between influenza and Tdap vaccine acceptance, other baseline characteristics, and COVID-19 vaccine uptake was assessed using univariable and multivariable regression analysis. RESULTS: Of the 7857 patients who delivered during the study period, 4410 (56.1%) accepted the COVID-19 vaccine. Of those who received the COVID-19 vaccine, 3363 (97.6%) and 3049 (88.5%) received influenza and Tdap vaccines, respectively. Patients were more likely to receive the COVID-19 vaccine if they had advanced maternal age, obesity, Asian race, and private insurance. After adjustment for baseline differences, COVID vaccine acceptance was associated with receipt of Tdap (aOR 2.10, 95% CI 1.90-2.33) and influenza vaccines (aOR 2.83, 95% CI 2.55-3.14). There were no differences in preterm birth, low birthweight, and NICU admission between patients who received and did not receive the COVID-19 vaccine. CONCLUSION: Patients were more likely to accept COVID-19 vaccination if they received Tdap or influenza vaccinations. Older age, obesity, Asian race, and private insurance were independent predictors of vaccine uptake. Disparities in COVID-19 vaccination uptake bear further exploration to guide efforts in equitable and widespread vaccine distribution.

The Healthy, Immunized Communities Study: A pilot intervention to increase parents' intentions to get vaccines for their middle school children.

Pennsylvania shortened the provisional period for student vaccine compliance in 2018. We pilot tested a school-based health education intervention, The Healthy, Immunized Communities Study, to improve parents' intentions to get school-required (tetanus, diphtheria, acellular pertussis [Tdap]; and meningococcal conjugate [MCV]) and recommended (human papillomavirus [HPV]) vaccines for their children. In Phase 1, we partnered with the School District of Lancaster (SDL) to conduct four focus groups with stakeholders (local clinicians, school staff, school nurses, and parents) to inform the development of the intervention. In Phase 2, we randomized four middle schools in SDL to either the intervention (six email communications and school-community educational event) or control group. Seventy-eight parents took part in the intervention and 70 joined the control group. Vaccine intentions were compared within and between groups from baseline to 6-month follow-up with generalized estimating equations (GEE) models. Compared to the control, the intervention did not increase parents' vaccine intentions for Tdap (RR = 1.18; 95 % CI:0.98-1.41), MCV (RR = 1.10; 95 % CI:0.89-1.35), or HPV (RR = 0.96; 95 % CI:0.86-1.07). Among intervention participants, only 37 % opened ≥ 3 email communications and 23 % attended the event. Intervention participants reported high satisfaction with email communications (e.g., informative = 71 %) and felt that the school-community event met their educational objectives on key topics (e.g., immune system = 89 %). In conclusion, although we observed no intervention effect, our data suggest that this could be a result of the low uptake of intervention components. Further research is needed to understand how school-based vaccination-focused interventions can be successfully implemented with high fidelity among parents.

Association between social vulnerability and influenza and tetanus-diphtheria-acellular pertussis vaccination in pregnant and postpartum individuals.

BACKGROUND: Despite current guidelines recommending universal vaccination, the frequency of vaccination in pregnancy for influenza and tetanus-diphtheria-acellular pertussis remains low. OBJECTIVE: This study aimed to evaluate the association between community-level social vulnerability and influenza and anticipated tetanus-diphtheria-acellular pertussis vaccinations among pregnant and postpartum individuals. STUDY DESIGN: We conducted a cross-sectional survey of vaccine hesitancy in the peripartum period among pregnant and postpartum participants enrolled in prenatal care at a single tertiary care center from March 22, 2021, to April 02, 2021. Participant addresses were geocoded using ArcGIS and linked at the census tract level. The primary exposure was community-level social vulnerability as measured by the US Centers for Disease Control and Prevention's Social Vulnerability Index. This index incorporates 15 census variables to produce a composite score and subscores across 4 major thematic domains (socioeconomic status, household composition and disability, minority status and language, and housing type and transportation). The scores range from 0 to 1, with higher values indicating greater social vulnerability. The primary outcomes were self-reported influenza vaccination during the current influenza season and having received or planning to receive the tetanus-diphtheria-acellular pertussis vaccination in pregnancy. We used multivariable logistic regression and adjusted for age, self-reported race and ethnicity, parity, trimester of pregnancy, and chronic comorbid conditions. RESULTS: Of 456 assessed individuals (95% pregnant individuals and 5% postpartum individuals), the frequency of influenza vaccination was 58% (95% confidence interval, 53-62), and the anticipated tetanus-diphtheria-acellular pertussis vaccination was 72% (95% confidence interval, 68-76). Individuals from communities with a higher Social Vulnerability Index were less likely to report vaccination in pregnancy than those from communities with a lower Social Vulnerability Index. Specifically, for each 0.1-unit increase in the Social Vulnerability Index, the odds of influenza vaccination (adjusted odds ratio, 0.23; 95% confidence interval, 0.11-0.46) and anticipated tetanus-diphtheria-acellular pertussis vaccination (adjusted odds ratio, 0.24; 95% confidence interval, 0.11-0.53) decreased by >70%. By domain, the Social Vulnerability Index subscores of socioeconomic status (influenza adjusted odds ratio, 0.20 [95% confidence interval, 0.10-0.40]; tetanus-diphtheria-acellular pertussis adjusted odds ratio, 0.25 [95% confidence interval, 0.12-0.53]) and housing type and transportation (influenza adjusted odds ratio, 0.41 [95% confidence interval, 0.19-0.84; tetanus-diphtheria-acellular pertussis adjusted odds ratio, 0.39 [95% confidence interval, 0.18-0.87) were inversely associated with a lower odds of influenza and tetanus-diphtheria-acellular pertussis vaccinations. CONCLUSION: Pregnant and postpartum individuals living in areas with higher social vulnerability were less likely to report influenza and anticipated tetanus-diphtheria-acellular pertussis vaccinations in pregnancy. The Social Vulnerability Index could be used as a tool to improve vaccine equity and address disparities in vaccination in pregnancy.

Factors associated with human papillomavirus and meningococcal vaccination among adolescents living in rural and urban areas.

Background: Studies have shown that adolescent vaccination rates with human papillomavirus (HPV) and quadrivalent meningococcal conjugate (MenACWY) vaccines are lower in rural areas of the U.S. than in urban areas. We sought to determine factors associated with vaccine acceptance in these two settings. Methods: We conducted a cross-sectional survey of 536 parents or guardians of teens age 13 through 15 years in select rural and urban counties of Minnesota and Wisconsin. We collected information on demographic variables, receipt of adolescent vaccines, and attitudes toward HPV vaccine in particular. Multivariable logistic regression models were used to assess associations between covariates and outcomes of interest (HPV vaccine receipt and MenACWY receipt). Results: Of the 536 respondents, 267 (50%) resided in a rural county. Most respondents were female (78%) and non-Hispanic White (88%). About half (52%) of teens of the surveyed parents received the three vaccines recommended specifically for adolescents: 90% received tetanus-diphtheria-acellular pertussis (Tdap), 84% received MenACWY, and 60% received one or more doses of HPV vaccine. Rural and urban parents surveyed differed on several covariates relating to teen's health services, parent's demographics, and household characteristics. Parent's perception of the importance that their healthcare providers placed on vaccination with HPV and MenACWY were independently associated with receipt of each of those vaccines (odds ratio [OR] 6.37, 95% confidence interval [CI] 2.90-13.96 and OR 2.15, 95% CI 1.07-4.31, respectively). Parents of vaccinated teens were less likely to report concerns about potential harm from the HPV vaccine or having heard stories about health problems caused by the HPV vaccine. Conclusion: Teen receipt of HPV vaccine and MenACWY appears to be influenced by parents' perception of vaccine importance, provider recommendations, and concerns regarding potential harm from the HPV vaccine. Continued education of providers and parents of the importance of adolescent vaccinations is warranted.

Immunogenicity of a Quadrivalent Human Papillomavirus Vaccine When Co-Administered with Tetanus-Reduced Diphtheria-Acellular Pertussis and Quadrivalent Meningococcal Conjugate Vaccines in Healthy Adolescents: Results from a Randomized, Observer-Blind, Controlled Trial.

INTRODUCTION: Vaccines against human papillomavirus (HPV), tetanus, diphtheria, pertussis (Tdap) and Neisseria meningitidis are widely recommended in adolescents. A phase-4 observer-blind study was performed to investigate the impact of concomitant administration of a quadrivalent HPV (HPV4) and Tdap vaccine with a quadrivalent meningococcal CRM197-conjugate vaccine (MenACWY-CRM) in terms of immunogenicity against the different vaccine antigens and overall safety profile. Previous results showed that concomitant administration of the three vaccines did not impact the immunogenicity of Tdap and MenACWY, or safety. This article presents recently released HPV immunogenicity results. METHODS: Healthy adolescents aged 11-18 years (801) were randomized to receive either HPV4 + Tdap + MenACWY or HPV4 + Tdap + Placebo and two additional doses of HPV4 at 2 and 6 months after the first dose. Antibody responses to HPV types (HPV-6, -11, -16 and -18) were assessed at baseline and at 1 month post-full vaccination. RESULTS: Post-third HPV4 dose, non-inferiority of immune responses to HPV4 + Tdap + MenACWY vs. HPV4 + Tdap + Placebo was demonstrated; the lower limits of two-sided 95% CIs of the between-group differences in seroconversion rates were > - 5% (non-inferiority margin) against each HPV type tested. Seroconversion rates ranged between 98.0% (HPV-6) and 99.7% (HPV-11 and HPV-18) in group HPV4 + Tdap + MenACWY and from 99.0% (HPV-11 and HPV-16) to 99.7% (HPV-6 and HPV-18) in group HPV4 + Tdap + Placebo. CONCLUSION: Overall, these data support the concomitant administration of HPV4, Tdap and MenACWY-CRM in adolescents. FUNDING: Novartis Vaccines and Diagnostics Inc., now part of the GSK group of companies. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT01424644.

Coverage of recommended vaccines during pregnancy in Flanders, Belgium. Fairly good but can we do better?

BACKGROUND: In Flanders, Belgium, pertussis vaccination is recommended since 2013 and available free-of-charge in every pregnancy between 24 and 32 weeks of gestation. Influenza vaccination is recommended for more than 10 years with a co-payment system in the second or third trimester of pregnancy, when pregnancy coincides with the influenza season. This study aims to estimate the coverage of pertussis and influenza vaccination during pregnancy in 2016 and to determine predictors for missing vaccination. METHODS: Postpartum women were visited at home for a vaccination coverage survey using an Expanded Program on Immunization (EPI)-based two-stage cluster sampling design. Predictors for missed vaccination were identified using a multiple logistic regression model. RESULTS: Among 481 participating women, 69.3% were vaccinated against pertussis and 47.2% were vaccinated against influenza. Moreover, 65.3% of pertussis vaccine recipients and 96.9% of influenza vaccine recipients were vaccinated within the recommended gestational window. Surprisingly, among women who were completely informed (i.e. on disease-associated risks, maternal vaccination costs and recommendations), still 12.4% were unvaccinated against pertussis and 23.9% against influenza. In the final models, the only common predictor of missing maternal pertussis and influenza vaccination was multiparity. Significant predictors of maternal pertussis vaccination were family income (less likely if unknown or low (< €3000) than if moderate (€3001-€4000)) and hospital of delivery (less likely if >800 annual deliveries than <800). Significant predictors of maternal influenza vaccination, though with less straight-forward associations, were maternal ethnicity and educational level, involvement of a gynaecologist in pregnancy follow-up, and characteristics of the hospital of delivery. CONCLUSION: In Flanders, more than two-third of pregnant women receives pertussis vaccination but less than half of them receives the influenza vaccine. Further improvement for both maternal vaccination programs can be achieved by targeting the underserved populations and diminishing vaccination hurdles.

Patterns of Use of Human Papillomavirus and Other Adolescent Vaccines in the United States.

PURPOSE: The purpose of the study was to describe the patterns of use of universally recommended adolescent vaccines in the United States. METHODS: We identified 11-year-olds using the MarketScan insurance claims database (2009-2014). Human papillomavirus (HPV), tetanus-diphtheria-acellular pertussis (Tdap), and meningococcal (MenACWY) vaccination claims were identified using diagnosis and procedure codes. Generalized linear models estimated vaccination incidence rates and correlates of adolescent vaccination and timely vaccination. RESULTS: Among 1,691,223 adolescents, receipt of Tdap (52.1%) and MenACWY (45.8%) vaccinations exceeded receipt of HPV vaccination (18.4%). While both sexes had similar Tdap and MenACWY vaccination proportions, girls received HPV vaccination more frequently than boys (21.9% vs. 15.1%). Adolescents received HPV vaccination later (mean age: 11.8 years) than Tdap or MenACWY vaccination (mean age: 11.2 years for both). Half of vaccinated adolescents received Tdap and MenACWY vaccination only; however, coadministration with HPV vaccine increased with birth cohort. Western adolescents had the highest incidence rates of HPV vaccination, and Southern adolescents had the lowest. Rural adolescents were less likely than urban adolescents to receive each vaccination except in the Northeast, where they were more likely to receive HPV vaccination (incidence rate ratio: 1.09, 95% confidence interval: 1.2005-1.13). Timely HPV vaccination was associated with female sex, urbanicity, Western residence, and later birth cohort. CONCLUSIONS: HPV vaccination occurred later than Tdap or MenACWY vaccination and was less frequent in boys and rural adolescents. Girls, Western and urban residents, and younger birth cohorts were more likely to receive timely HPV vaccination. Vaccine coadministration increased over time and may encourage timely and complete vaccination coverage.

Tdap vaccine attitudes and utilization among pregnant women from a high-risk population.

Infants infected with Bordatella pertussis experience high morbidity and significant mortality. Vaccinating pregnant mothers with the tetanus-diphtheria-acellular pertussis (Tdap) vaccine is a recommended strategy for preventing infant pertussis. This is especially important for mothers living in poverty and from racial and ethnic minority populations as these groups are at increased risk of having a pertussis-affected infant. Using the Health Belief Model as a framework, we surveyed a convenience sample of pregnant mothers representing these high-risk populations to understand factors associated with Tdap vaccine uptake during their pregnancy. Among the 316 mothers surveyed, 82% had gotten or planned to get Tdap that same day even though 63% of the sample had concerns about the safety of the vaccine during pregnancy. Perceived benefits and norms were the Health Belief Model constructs most consistently associated with Tdap vaccination. Although 32% of women reported prior Tdap vaccine receipt, this factor was not associated with Tdap vaccination during the current pregnancy, contrasting studies of vaccination done in non-pregnant populations. Important variations in attitudes were apparent, with Spanish-speaking women significantly more likely to have concerns about the vaccine's safety and efficacy than English-speaking women. This study indicates that among this high-risk population acceptance of Tdap vaccine during pregnancy is high. However, our results suggest that it may be important to modify information conveyed about the safety and importance of Tdap during pregnancy based on individual level factors such as language or acculturation.

Knowledge attitude and practice toward pertussis vaccination during pregnancy among pregnant and postpartum Italian women.

In Italy, no specific recommendation toward maternal pertussis immunization during pregnancy has been issued. However, vaccination during pregnancy will be likely integrated in the Italian immunization program in the future. In order to identify barriers to achieving a sufficient vaccination coverage during pregnancy, we investigated knowledge, attitude and practice toward pertussis vaccination during pregnancy through a web-based survey. A total of 343 Italian pregnant women (N = 164) and women in the postpartum period (N = 183) completed the online questionnaire. More than a half of the study population was uncertain regarding the benefits of the vaccination during pregnancy. Only 1.7% of women in the postpartum had received the vaccination during pregnancy, and 21% of pregnant women declared the intention to be vaccinated in pregnancy. Only 34% would accept the vaccination in the current or in a future pregnancy, if recommended by a physician, and a half would remain uncertain. Perceiving the vaccine as harmful for the fetus' development is associated to a decreased willingness to be vaccinated if recommended by a HCP, both in pregnant women (OR 0.25 p = 0.010 95% CI 0.09-0.72) and in women in the postpartum period (OR 0.32 p = 0.006 95% CI 0.15-0.72). Our study suggests that the vaccination recommendation by physicians might not be sufficient to adequately raise vaccination coverage against pertussis among Italian pregnant women. A combination of educational interventions and tailored communi-cation campaigns could be implemented to promote maternal immunization.

Immunization of pregnant women against pertussis: the effect of timing on antibody avidity.

BACKGROUND: The Centers for Disease Control and Prevention recommend tetanus-diphteria-acellular pertussis (Tdap) immunization during pregnancy, preferably at 27-36 weeks gestation. AIMS: First, to assess the relative avidity index (RAI) of umbilical cord immunoglobulin G (IgG) to pertussis toxin (PT) for newborns of women immunized with Tdap during late pregnancy as compared to unimmunized women. Second, to assess whether there is a preferential period of gestational Tdap immunization that provides the highest RAI of umbilical cord IgG to PT. METHODS: RAI of IgG to PT was assessed via an adapted ELISA using NH4SCN as a dissociating agent. RESULTS: We found that newborns of women immunized with Tdap during late pregnancy (n=52) had higher mean RAI of umbilical cord IgG to PT than those of unimmunized women (n=8), 73.77%±12.08 (95% CI, 70.41-77.13) vs. 50.23%±21.32 (95% CI, 32.41-68.06), p<0.001. Further, the RAI of umbilical cord IgG to PT was significantly higher in newborns of women immunized at 27-30(+6) weeks gestation (n=20) when compared with newborns of women immunized at 31-36 weeks (n=22) and >36 weeks (n=7), 79.53%±5.61 (95% CI, 76.91-82.16) vs. 71.56%±12.58 (95% CI, 65.98-77.14) vs. 63.93%±17.98 (95% CI, 47.31-80.56), p<0.03. CONCLUSION: Gestational Tdap immunization between 27 and 30(+6) weeks resulted in the highest avidity of IgG to PT conveyed at delivery as compared with immunization beyond 31 weeks gestation. Future studies should be conducted to confirm our findings to optimize pertussis-controlling strategies.

The effect of timing of maternal tetanus, diphtheria, and acellular pertussis (Tdap) immunization during pregnancy on newborn pertussis antibody levels - a prospective study.

BACKGROUND: The Centers for Disease Control and Prevention recommend Tdap immunization during pregnancy, preferably at 27-36 weeks. AIM: To ascertain whether there is a preferential period of maternal Tdap immunization during pregnancy that provides the highest concentration of pertussis-specific antibodies to the newborn. METHODS: This prospective study measured pertussis-specific antibodies in paired maternal-cord sera of women immunized with Tdap after the 20th week of their pregnancy (n=61). RESULTS: The geometric mean concentrations (GMCs) of Immunoglobulin G (IgG) to pertussis toxin (PT) were higher in the newborns' cord sera when women were immunized at 27-30(+6) weeks (n=21) compared with 31-36 weeks (n=30) and >36 weeks (n=7), 46.04 international units/milliliter (IU/mL) (95% CI, 24.29-87.30) vs. 8.69IU/mL (95% CI, 3.66-20.63) and 21.12IU/mL (95% CI, 7.93-56.22), p<0.02, respectively. The umbilical cord GMCs of IgG to filamentous hemagglutinin (FHA) were higher in the newborns' cord sera when women were immunized at 27-30(+6) weeks compared with 31-36 weeks and >36 weeks, 225.86IU/mL (95% CI, 182.34-279.76) vs. 178.31IU/mL (95% CI, 134.59-237.03) and 138.03IU/mL (95% CI, 97.61-195.16), p<0.02, respectively. CONCLUSIONS: Immunization of pregnant women with Tdap between 27-30(+6) weeks was associated with the highest umbilical cord GMCs of IgG to PT and FHA compared with immunization beyond 31 weeks gestation. Further research should be conducted to reaffirm these finding in order to promote an optimal pertussis controlling policy.

The induction of breast milk pertussis specific antibodies following gestational tetanus-diphtheria-acellular pertussis vaccination.

BACKGROUND: Center for Disease Control and Prevention recommends vaccination of pregnant women with tetanus-diphtheria-acellular pertussis (Tdap). AIM: To measure pertussis specific antibodies, total protein and their ratio in breast milk following gestational Tdap vaccination. METHODS: Women who received Tdap after the 20th week of pregnancy were recruited and unvaccinated women served as controls. Breast milk total protein, immunoglobulin A (IgA) to pertussis toxin (PT), filamentous hemagglutinin (FHA) and immunoglobulin G (IgG) to PT, FHA and pertactin (PRN) were measured. To overcome the dilution that occurs in the transition from colostrum to mature breast milk, we calculated pertussis specific antibody to total protein ratio. RESULTS: Pertussis specific IgA was the predominant pertussis immunoglobulin in the colostrum of Tdap vaccinated women with the geometric mean concentrations (GMCs) of IgA to FHA higher than for IgA to PT, 24.12 ELISA units/milliliter (EU/mL) vs. 8.18EU/mL, respectively, p<0.004. There were differences between the vaccinated women and controls in the GMCs of IgA to FHA and IgG to PRN in the colostrum, 24.12EU/mL vs. 6.52EU/mL, p=0.01 and 2.46EU/mL vs. <0.6EU/mL, p=0.03, respectively. The GMCs of total protein showed significant decline over 8 weeks in the vaccinated women and controls, p<0.004. Among vaccinated women, there was significant decline in the GMCs of IgA to PT and FHA over 8 weeks, p<0.001. The geometric mean ratio of IgA to FHA to total protein also declined significantly over 8 weeks in the vaccinated women, p<0.01, demonstrating a true decrease, however, pertussis IgA was measurable at 8 weeks. CONCLUSIONS: Select colostrum pertussis antibody levels were significantly higher among women vaccinated with Tdap during pregnancy compared with unvaccinated women. Among vaccinated women, maximal levels of pertussis specific IgA were in the colostrum but still detected at 8 weeks. Lactation may augment infant's protection against pertussis.

Comprehensive efforts to increase healthcare personnel immunization.

Vaccination of healthcare personnel (HCP) is an important component of worker and patient safety, yet vaccination rates are lagging. The findings from Taddei et al.'s study of healthcare personnel immunization attitudes and practices in Florence, Italy provides further data of the importance of routine assessment of and recommendations for vaccines for HCP in order to improve coverage.