Universal tetanus,diphtheria, acellular pertussis (Tdap) vaccination of adults: What the Canadian public knows and wants to know

Tetanus, diphtheria, and acellular pertussis vaccine (Tdap) is recommended for all adults in Canada but uptake is low. This study measured the knowledge, attitudes, beliefs, and behaviors of Canadian adults to identify potential barriers and facilitators to Tdap uptake. A survey was undertaken on a geographically representative sample of Canadian adults (n = 4023) and 8 focus groups (62 participants) were conducted nationwide. The survey revealed that knowledge about pertussis and Tdap was low (38.3% correct answers). Only 36.0% of respondents reported being aware that all adults were recommended to receive Tdap and only 10.7% reported being immunized; 36.7% did not know whether they had received Tdap. Respondents who were aware of the immunization recommendations were twice as likely to be immunized (16.6% vs. 8.3%; p < 0.001). Only 9.3% believed that their health care provider thought that Tdap was important for adults. The focus group data supported the survey results. Participants wanted information about pertussis and Tdap communicated through multiple modalities, but a recommendation by their family physician was most important to their decision to be immunized or not. This study demonstrates that current recommendations for universal adult vaccination with Tdap are not reaching the general public in Canada and an alternative strategy will be required to improve Tdap vaccine uptake.     

Vaccine effectiveness of tetanus toxoid,reduced diphtheria toxoid,and acellular pertussis vaccine during a pertussis outbreak in Maine

BackgroundMultiple school-associated pertussis outbreaks were reported in Maine from 2010 to 2011. These outbreaks were associated with an overall increase in pertussis cases statewide. Waning of protection in students recently vaccinated with tetanus, diphtheria, and acellular pertussis (Tdap) has been implicated in the increase in reported rates of pertussis nationally.MethodsWe conducted a retrospective cohort study to evaluate Tdap vaccine effectiveness (VE) among students aged 11–19 years in two schools reporting outbreaks in 2011. All pertussis cases reported from August through November, 2011 at the two schools were included. Vaccination history was verified using provider information, state vaccine registry data, and parental verification. Attack rates (AR) were calculated. VE and duration of protection was calculated as VE = 1 − (AR_vaccinated/AR_unvaccinated) × 100% using a log binomial regression model.ResultsOf 416 students enrolled, 314 were included in the analyses. Twenty-nine cases collectively in Schools A and B. Tdap coverage was 65% at School A and 42% at School B before the start of the outbreak. Among students enrolled in the study, attack rates were 11.9% and 7.7% at Schools A and B, respectively. Overall VE was 68.5% (95% confidence interval (CI) 37.7–86.2). VE was 70.4% (95% CI 17.5–89.4) for School A and 65.2% (95% CI −19.2 to 89.9) for School B. VE <2 years versus ≥2 years from outbreak onset was not significantly different.ConclusionsTdap was moderately effective in preventing disease among vaccinated students. Vaccine coverage of 65% or less was suboptimal and might contribute to outbreaks. Waning VE was not demonstrated. Increased vaccination coverage rates as well as further evaluation of the role of acellular vaccine on VE is needed.     

Intention to accept pertussis vaccine among pregnant women in Karachi,Pakistan

BackgroundMaternal immunization against pertussis is a potential strategy to protect young infants from severe disease. We assessed factors associated with intention to accept pertussis vaccination among pregnant women in Karachi, Pakistan.MethodsWe conducted a cross-sectional survey between May and August 2013 in pregnant women who visited healthcare centers in urban slums of Karachi city. Women completed a survey examining socio-demographic factors, vaccination history, knowledge on pertussis disease, perception of vaccine recommendation sources, and potential influences on vaccine decision-making.ResultsOf the 283 participants, 259 (92%) provided their intention to either accept or decline pertussis vaccination. Eighty-three percent women were willing to accept the pertussis vaccine if offered during pregnancy. About half (53%) of the participants had ever heard of pertussis disease. Perceptions of pertussis vaccine efficacy, safety, and disease susceptibility were strongly associated with intention to accept pertussis vaccine (p < 0.01). Healthcare providers, Ministry of Health, and mass media were considered as highly reliable sources of vaccine recommendation and associated with intention to accept antenatal pertussis vaccination (p < 0.001). Healthcare provider recommendation was a common reason cited by respondents for pregnant women to accept antenatal pertussis vaccination (p = 0.0005). However, opinion of primary decision-makers in the family (husbands and in-laws) was a crucial reason cited by respondents for pregnant women to reject pertussis vaccination in pregnancy (p = 0.003).ConclusionAntenatal pertussis vaccination initiatives in South Asia should strongly consider inclusion of family members, healthcare providers, national health ministries, and mass media to help implement new vaccination programs.     

Improving influenza and Tdap vaccination during pregnancy: A cluster-randomized trial of a multi-component antenatal vaccine promotion package in late influenza season

BackgroundEvidence-based interventions to improve influenza vaccine coverage among pregnant women are needed, particularly among those who remain unvaccinated late into the influenza season. Improving rates of antenatal tetanus, diphtheria and acellular pertussis (Tdap) vaccination is also needed.PurposeTo test the effectiveness of a practice-, provider-, and patient-focused influenza and Tdap vaccine promotion package on improving antenatal influenza and Tdap vaccination in the obstetric setting.MethodsA cluster-randomized trial among 11 obstetric practices in Georgia was conducted in 2012–2013. Intervention practices adopted the intervention package that included identification of a vaccine champion, provider-to-patient talking points, educational brochures, posters, lapel buttons, and iPads loaded with a patient-centered tutorial. Participants were recruited from December 2012–April 2013 and included 325 unvaccinated pregnant women in Georgia. Random effects regression models were used to evaluate primary and secondary outcomes.ResultsData on antenatal influenza and Tdap vaccine receipt were obtained for 300 (92.3%) and 291 (89.5%) women, respectively. Although antenatal influenza and Tdap vaccination rates were higher in the intervention group than the control group, improvements were not significant (For influenza: risk difference (RD) = 3.6%, 95% confidence interval (CI): −4.0%, 11.2%; for Tdap: RD = 1.3%, 95% CI: −10.7%, 13.2%). While the majority of intervention package components were positively associated with antenatal vaccine receipt, a provider's recommendation was the factor most strongly associated with actual receipt, regardless of study group or vaccine.ConclusionsThe intervention package did not significantly improve antenatal influenza or Tdap vaccine coverage. More research is needed to determine what motivates women remaining unvaccinated against influenza late into the influenza season to get vaccinated. Future research should quantify the extent to which clinical interventions can bolster a provider's recommendation for vaccination. This study is registered with clinicaltrials.gov, study ID NCT01761799.     

Increasing postpartum rate of vaccination with tetanus,diphtheria, and acellular pertussis vaccine by incorporating pertussis cocooning information into prenatal education for group B streptococcus prevention

BackgroundTo evaluate whether incorporating pertussis cocooning information into prenatal education for group B streptococcus (GBS) prevention increased postpartum rate of vaccination with tetanus, diphtheria, and acellular pertussis (Tdap) vaccine.MethodsWe performed a retrospective pre-intervention/post-intervention study of postpartum women at a teaching hospital in Taiwan. We compared the frequency of Tdap vaccination during the pre-intervention (May 1, 2009 to December 31, 2010) and post-intervention (March 1, 2011–March 31, 2012) time periods. The clinical intervention was incorporation of pertussis cocooning information into prenatal education for GBS prevention to pregnant women presented during a prenatal visit at 35–37 weeks of gestation. Postpartum Tdap vaccination rate during the pre-intervention and post-intervention periods was compared. We also specifically examined group differences in the percentage of women who received postpartum Tdap vaccination to explore factors that influenced their decision regarding Tdap vaccine.ResultsTdap vaccination was more likely during the post-intervention period compared with the pre-intervention period (2268 of 3186 [71.2%] compared with 2556 of 5030 [55.6%]; p < .001). Comparisons between each subgroup of pre-intervention and post-intervention women showed that incorporating pertussis information into prenatal education for GBS prevention was beneficial except for women of maternal age 30–34 years and women living in rural areas.ConclusionsPrenatal GBS screening activities represent an opportunity for healthcare providers to offer pertussis cocooning information to eligible pregnant women to improve rates of postpartum Tdap vaccination.     

Impact of a maternal immunization program against pertussis in a developing country

BackgroundPertussis disease is a growing concern for developing countries. In Argentina, rates of illness and death peaked in 2011. More than 50% of fatalities due to pertussis occurred in infants younger than two months of age, too young for vaccination. In 2012, the government offered immunization with a vaccine containing Tdap to all pregnant women after 20 weeks of gestation with the intent of reducing morbidity and mortality in young infants.MethodsMaternal acellular pertussis vaccine impact on reducing infant disease burden was estimated based on data from the Argentinean Health Surveillance System. We divided Argentinean states in two groups experiencing high (>50) and low (⩽50) Tdap vaccine coverage and compared these two groups using a Bayesian structural time-series model. Low coverage regions were used as a control group, and the time series were compared before and after the implementation of the Tdap program.FindingsWe observed a relative reduction of 51% (95% CI [−67%, −35%]; p = 0.001) in pertussis cases in high coverage states in comparison with the low coverage areas. Analysis of infants between two and six months showed a 44% (95% CI [−66%, −24%]; p = 0.001) reduction in illness. Number of deaths was highest in 2011 with 76 fatalities, for an incidence rate of 2.9 per 100,000. Comparing with 2011, rates decreased by 87% to 10 subjects, or 0.9 per 100,000 in 2013.InterpretationWe show an age-dependent protective effect of maternal Tdap immunization in a developing country for infants younger than six months.     

Implementation of pertussis immunization in health-care personnel

Background and aimInfection with Bordetella pertussis is most severe in young infants who frequently acquire it from adults. Pertussis immunization in adults 25–29 years of age and all adults in close contact with infants <6 months was introduced in Switzerland in 2012. We immediately implemented this new recommendation in our hospital with a vaccination campaign.MethodsBetween April 2012 and March 2013 we provided information about the campaign to our staff through several channels and offered appointments for counseling and immunization. After checking indications and contraindications of responding health-care personnel (HCP), informed consent for tetanus–diphtheria–acellular pertussis component (Tdap) immunization was obtained. Specific adverse events (AE) were self-assessed by standardized diaries for 7 days. Statistical analyses were performed using a t-test and Mann–Whitney U-tests SPSS (V21).ResultsOf 852 HCP eligible for pertussis immunization, 427 (51%) responded. Of these, 72 (17%) had already received Tdap <10 years ago, 304 (71%) received Tdap now, 38 (9%) were scheduled for vaccination and 12 (3%) declined. Diaries were returned by 272 (89%) of 304 vaccinees; 56 HCP reported ≥1 local AE, most frequently local swelling (8%), redness (2%), redness and swelling (7%), and fever (5 = 2%); no serious AE occurred.ConclusionsComprehensive efforts were needed to achieve pertussis immunization coverage of ≥49% among all HCP in our institution. Good tolerability of the vaccine and continuous and individual information to HCP about the rationale and benefits of pertussis immunization contributed to this partial success, but increased efforts are needed to mobilize non-responding HCP.     

What predicts postpartum pertussis booster vaccination? A controlled intervention trial

Background‘Cocooning’ aims to protect susceptible infants from pertussis via caregiver vaccination. Control trials evaluating educational interventions to promote cocooning are lacking. We evaluated the role of message-framing vs. standard health information in promoting pertussis vaccination.MethodsWe recruited postpartum women from a maternity hospital in Sydney, Australia (November 2010–July 2012). Participants self-completed a pertussis knowledge and attitudes questionnaire. We then assigned pertussis-susceptible (no pertussis vaccine ≤10 years) participants to receive a gain-framed, loss-framed pamphlet or control (Government Pertussis factsheet) using weekly sequential block allocation. Next, participants were offered a pertussis vaccine (dTpa) and completed a post-questionnaire on discharge.ResultsA baseline questionnaire was completed for 96.4% (1433/1486) of postpartum women approached. Missing data was excluded (n = 29). Next, participants (1404) were screened for vaccine status: 324 (23%) reported prior pertussis booster vaccine receipt, leaving 1080 participants requiring vaccination. Among susceptible mothers, 70% (754/1080) were vaccinated post-intervention. Rates were similar between ‘gain’, ‘loss’ or ‘control’ pamphlets (69.1% vs. 71.8% vs. 68.8%; p = 0.62). Intention to be vaccinated (OR 2.46, p < 0.001; 95% CI: 1.69–3.58), perceived vaccine benefits (OR: 1.61, p < 0.001; 95% CI: 1.25–2.15) and having received a vaccine recommendation (OR 1.68; p = 0.025; 95% CI: 1.07–2.65) were independent predictors of vaccine uptake. At discharge, overall pertussis vaccine coverage had increased from 23% to 77% among women screened (1078/1404).ConclusionA cocooning strategy for pertussis vaccination can be highly effective when partially implemented within maternity hospitals, with information accompanied by a funded vaccine. Mothers were highly receptive to vaccination in the postnatal ward: facts about pertussis were as effective as message-framing in promoting a high uptake of 70%. Perceived vaccine benefits, intentions and vaccine recommendation were important predictors of uptake. Our intervention trial increased the existing pertussis vaccine coverage of 23–77%.     

Evaluation of two vaccine education interventions to improve pertussis vaccination among pregnant African American women: A randomized controlled trial

BackgroundVaccination coverage with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine in pregnancy or immediately postpartum has been low. Limited data exist on rigorously evaluated interventions to increase maternal vaccination, including Tdap. Tailored messaging based on the Elaboration Likelihood Model (ELM) framework has been successful in improving uptake of some public health interventions. We evaluated the effect of two ELM-based vaccine educational interventions on Tdap vaccination among pregnant African American women, a group of women who tend to have lower vaccine uptake compared with other groups.MethodsWe conducted a prospective randomized controlled trial to pilot test two interventions – an affective messaging video and a cognitive messaging iBook – among pregnant African American women recruited during routine prenatal care visits. We measured Tdap vaccination during the perinatal period (during pregnancy and immediately postpartum), reasons for non-vaccination, and intention to receive Tdap in the next pregnancy.ResultsAmong the enrolled women (n = 106), 90% completed follow-up. Tdap vaccination in the perinatal period was 18% in the control group; 50% in the iBook group (Risk Ratio [vs. control group]: 2.83; 95% CI, 1.26–6.37), and 29% in the video group (RR: 1.65; 95% CI, 0.66–4.09). From baseline to follow-up, women’s reported intention to receive Tdap during the next pregnancy improved in all three groups. Among unvaccinated women, the most common reason reported for non-vaccination was lack of a recommendation for Tdap by the woman’s physician.ConclusionsEducation interventions that provide targeted information for pregnant women in an interactive manner may be useful to improve Tdap vaccination during the perinatal period. However, larger studies including multiple racial and ethnic groups are needed to evaluate robustness of our findings.Trial Registration: clinicaltrials.gov Identifier: NCT01740310.     

Promoting Tdap immunization in pregnancy: Associations between maternal perceptions and vaccination rates

ObjectiveTdap vaccine uptake among US pregnant women is low despite current recommendations. This study evaluated if a Tdap vaccine information statement (VIS) affected overall perception, vaccination intention, and components of a health behavior model associated with Tdap vaccination rates.MethodsA randomized, prospective study was conducted among pregnant women receiving care at two women's clinics in May–August 2014. Verbally consented participants were randomized to receive either the standard CDC Tdap VIS (sVIS) or a modified version (mVIS) before completing the first multi-part survey (T1). After T1, participants read their assigned VIS then completed the second part (T2). A 2015 chart review identified vaccinated participants. A health behavior model was hypothesized using the Reasoned Action Approach and Health Belief Model. Logistic regression, path analysis, and chi-square tests were used in the analysis.Results279 surveys were analyzed. Average age of the participants was 26.4 years (SD = 5.7) with average gestational age of 25.9 weeks (SD = 9.2). 13% self-reported receiving Tdap vaccine prior to the survey. Overall perception scores significantly increased (3.1–3.4, p < 0.001) after VIS review. A chart review showed that 131 (47%) received the vaccine post study. There was no significant difference in vaccination rates between the sVIS and mVIS groups (45% vs. 49%). Perceived benefits (B = 0.315) and self-efficacy (B = 0.197) were positively associated with the overall perception (T1), while perceived barriers (B = −0.191) were negatively associated with the overall perception (T1). Social norms (B = 0.230), self-efficacy (B = 0.213), and perceived benefits (B = 0.117) were positively associated with vaccination intention (T1). The vaccination intention (T2) was positively associated with participants’ decision to receive Tdap vaccine (B = 0.223).ConclusionA VIS improved overall perception of the Tdap vaccine. Vaccination intention was a predictor of Tdap vaccination. It is crucial to provide information about immunization benefits to promote maternal Tdap vaccination.     

Community awareness and predictors of uptake of pertussis booster vaccine in South Australian adults

ObjectivePertussis is a highly virulent vaccine preventable disease that remains a global challenge. This study aimed to assess community knowledge of pertussis infection as well as awareness and uptake of adult pertussis booster vaccine.MethodsA cross-sectional survey was conducted of randomly selected households in South Australia by Computer Assisted Telephone Interviews in 2011. Survey data were weighted to the age, gender and geographical area profile of the population.ResultsFrom 3124 randomly sampled contactable households, 1967 interviews were conducted (participation rate 63%) with individuals aged 18–93 years, including 608 parents of children aged <18 years. The majority of respondents (97%) had heard of pertussis (whooping cough) and 18% reported that a household member had previously contracted whooping cough infection. Most respondents considered whooping cough to be highly contagious (73%) and severe for infants (89%). Over half (51%) of those surveyed were aware that family members commonly transmit pertussis to infants. Despite high knowledge, pertussis vaccine uptake was low, with only 10% of respondents reporting pertussis vaccination in the previous five years. Whilst 61% of respondents were aware of the availability of an adult pertussis booster vaccine, only 8% (n = 154) reported their Family Physician had discussed it with them. If provided free, 77% agreed that they would be more likely to accept a booster pertussis vaccination. Independent predictors of recent pertussis vaccination included higher education, larger household size, perception of greater disease severity for infants and discussion with a Family Physician about pertussis vaccination.ConclusionsWhilst knowledge regarding transmission and severity of Bordetella pertussis was high, uptake of pertussis vaccination for adults is remarkably low amongst the South Australian community. Improved awareness regarding the availability of a booster pertussis vaccine through Family Physicians and/or provision of funded pertussis vaccination for adults has the potential to improve pertussis vaccine coverage.     

Comparison of whole-cell versus acellular pertussis vaccine effectiveness in school clusters of pertussis,France, 2013

Objectives and methodWe conducted a prospective study in 2013 to compare the whole-cell versus acellular pertussis vaccines effectiveness and duration of protection, following the occurrence of pertussis clusters.ResultsDuring seven school outbreaks, we identified 102 clinical pertussis cases, including 10 cases biologically confirmed by Bordetella pertussis specific PCR, among a cohort of 305 children in 2nd to 6th grade. The risk of pertussis when vaccinated with an acellular vaccine alone was 1.6 (RR = 1.6; 95% CI = 1.1–2.5) times higher than when vaccinated with a whole-cell vaccine or using a combined schedule.ConclusionsThe limited duration of protection conferred by the acellular vaccine reinforces the 2013 introduction of the pertussis booster at six years old.     

Estimates of pertussis vaccine effectiveness in United States air force pediatric dependents

BackgroundPertussis vaccination compliance is critical for reduction in the prevalence of disease; however, the current acellular pertussis vaccine may not provide sufficient protection from infection. This study examined acellular pertussis vaccine effectiveness (VE) for Air Force dependents less than 12 years of age.MethodsWe conducted a case-control study among Air Force pediatric dependents from 2011 to 2013, comparing cases with positive pertussis test results to controls who received the same lab tests with a negative result. Our study population was categorized by age group and vaccination status based on the Centers for Disease Control and Prevention recommended pertussis vaccination schedule. VE was calculated with respect to vaccination status and pertussis lab results.ResultsWe compared 27 pertussis laboratory positive cases with 974 pertussis laboratory negative controls, 2 months to <12 years old. Comparing completely vaccinated to non-vaccinated patients, the overall VE was 78.3% (95% confidence interval (CI): 48.6, 90.8; p < 0.001). VE was highest among those 15 months to <6 years old: 97.6% (95% CI: 78.5, 99.7; p < 0.001). Children 6 to <12 years old had the lowest VE: 48.5% (95% CI: −74.0, 84.7; p = 0.28). Comparing partially vaccinated patients to nonvaccinated patients yielded 64.2% (95% CI: −7.2, 88.1; p = 0.06) overall VE.ConclusionsAcellular pertussis vaccination was effective at preventing laboratory confirmed pertussis among our Air Force pediatric dependent population, with highest protection among completely vaccinated, young children. Older children received the lowest amount of protection. Partial vaccination had near significant protection. Our overall calculated pertussis VE corroborates other pertussis VE studies looking at similar age groups.     

Age-specific effectiveness following each dose of acellular pertussis vaccine among infants and children in New Zealand

BackgroundThough it is believed the switch from whole cell to acellular pertussis vaccine has contributed to the resurgence of pertussis disease, few studies have evaluated vaccine effectiveness (VE) and duration of protection provided by an acellular vaccine schedule including three primary doses but no toddler-age dose. We assessed this schedule in New Zealand (NZ), a setting with historically high rates of pertussis disease, and low but recently improved immunisation coverage. We further evaluated protection following the preschool-age booster dose.MethodsWe performed a nested case-control study using national-level healthcare data. Hospitalised and non-hospitalised pertussis was detected among children 6 weeks to 7 years of age between January 2006 and December 2013. The NZ National Immunisation Register provided vaccination status for cases and controls. Conditional logistic regression was used to calculate dose-specific VE with duration of immunity examined by stratifying VE into ages aligned with the immunisation schedule.ResultsVE against pertussis hospitalisation was 93% (95% confidence interval [CI]: 87, 96) following three doses among infants aged 5–11 months who received three compared to zero doses. This protection was sustained through children’s fourth birthdays (VE ⩾ 91%). VE against non-hospitalised pertussis was also sustained after three doses, from 86% (95% CI: 80, 90) among 5–11 month olds to 84% (95% CI: 80, 88) among 3-year-olds. Following the first booster dose at 4 years of age, the protective VE of 93% (95% CI: 90, 95) among 4-year-olds continued through 7 years of age (VE ⩾ 91%).ConclusionsWe found a high level of protection with no reduction in VE following both the primary course and the first booster dose. These findings support a 3-dose primary course of acellular vaccine with no booster dose until 4 years of age.     

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

BackgroundThe Centers for Disease Control and Prevention recommend tetanus–diphteria–acellular pertussis (Tdap) immunization during pregnancy, preferably at 27–36 weeks gestation.AimsFirst, 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.MethodsRAI of IgG to PT was assessed via an adapted ELISA using NH₄SCN as a dissociating agent.ResultsWe 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.ConclusionGestational 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.     

Estimated and reported incidence of pertussis in Estonian adults: A seroepidemiological study

ObjectivesRates of pertussis immunisation among children in Estonia are high (∼95%), but pertussis is still the most common vaccine preventable childhood disease. Adults are suspected to be sources of pertussis in children. We aimed to measure pertussis toxin (PT) IgG in adults to estimate pertussis infection activity and compare estimated and reported pertussis incidences.MethodsIn a cross-sectional serosurvey, consecutive leftover blood sera (n = 3327) from subjects aged 20–99 years old were collected at Quattromed HTI laboratories between the 7th January and 27th February 2013. Anti-PT IgG concentration was measured by ELISA (Euroimmun, Lübeck, Germany). Estimated annual pertussis incidence was calculated for 10-year age classes using de Melker et al. (2006. J Infect. 53(2):106–13) formula.ResultsThe mean number of samples in each 10-year age class was 466 (SD 20.5), except for 90–99 year olds which contained 65 samples.More than half of all subjects (58.1%) had anti-PT IgG <5.0 IU/mL, 2.7% had 62.5 to <125 IU/mL and 0.6% ≥125 IU/mL; no differences occurred between 10-year age classes.Estimated incidence of pertussis infection was 5.8% (95% CI 4.8–7.0) in 2012, with peaks observed in 20–29 year olds (11.0%; 95% CI 7.4–15.6) and 90–99 year olds (10.8%; 95% CI 3.0–26.2). Estimated pertussis incidence rate was 915 times higher than reported.Of 80 subjects with anti-PT IgG ≥62.5 IU/mL, 25 (31.3%) had complained of coughing to their GP during the previous six months.ConclusionThe frequency of pertussis infection was similar for all ages, suggesting similar Bordetella pertussis activity in adults and children. The wide gap between reported and estimated incidence indicates poor recognition of pertussis, likely owing to it being an asymptomatic or mild disease.     

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

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

Whooping cough surveillance in France in pediatric private practice in 2006–2015

BackgroundIncreasing incidence of whooping cough (pertussis) has been reported in many countries, attributed to a switch from whole-cell pertussis-containing vaccine (wPV) to acellular PV (aPV) and circulation of the pertactin non-producing Bordetella pertussis. The present study aimed to estimate the duration of immunity conferred by PVs in children in France with data from an ongoing pediatric ambulatory surveillance of pertussis.MethodsA total of 64 pediatricians throughout France enrolled children with suspected pertussis. A standardized data form was used to collect data on age sex, vaccination status, brand of wPV or aPV and source of infection. Confirmed cases were positive on culture and/or real-time Polymerase Chain Reaction (for B.-non-classified or B. pertussis or B. parapertussis) and/or pertussis serology.ResultsBetween October 2006 and December 2015, 149 cases of confirmed Bordetella infections were reported, 86 infected with B. pertussis and 55 B. non-classified. Fifteen children (10.1%) were not vaccinated, and 26 (17.4%) were partially vaccinated. The mean age was greater for children who received 4 doses of wPV (11.3 ± 2.2, p < 0.001) or a combination of wPV and aPV (10.5 ± 3.3, p < 0.001) than only aPV (7.2 ± 2.4 years). The mean duration of cough before a visit to a pediatrician was longer for children with wPV or a combination of wPV and aPV than only aPV (23.8 ± 10.1 and 25.0 ± 25.6 vs 13.6 ± 10.0 days).ConclusionDespite the use of a more sensitive diagnostic method and emergence of pertactin non producing B. pertussis, in France context, aPV-induced immunity still protects against pertussis; however, the mean duration of immunity is about 6 to 7 years, compared to 9 years for wPV vaccine, after the primary vaccination and one booster (3 + 1 doses).     

Physician communication about adolescent vaccination: How is human papillomavirus vaccine different?

BackgroundLow human papillomavirus (HPV) vaccination coverage stands in stark contrast to our success in delivering other adolescent vaccines. To identify opportunities for improving physicians' recommendations for HPV vaccination, we sought to understand how the communication context surrounding adolescent vaccination varies by vaccine type.MethodsA national sample of 776 U.S. physicians (53% pediatricians, 47% family medicine physicians) completed our online survey in 2014. We assessed physicians' perceptions and communication practices related to recommending adolescent vaccines for 11- and 12-year-old patients.ResultsAbout three-quarters of physicians (73%) reported recommending HPV vaccine as highly important for patients, ages 11–12. More physicians recommended tetanus, diphtheria, and acellular pertussis (Tdap) (95%) and meningococcal vaccines (87%, both p < 0.001) as highly important for this age group. Only 13% of physicians perceived HPV vaccine as being highly important to parents, which was far fewer than perceived parental support for Tdap (74%) and meningococcal vaccines (62%, both p < 0.001). Physicians reported that discussing HPV vaccine took almost twice as long as discussing Tdap. Among physicians with a preferred order for discussing adolescent vaccines, most (70%) discussed HPV vaccine last.ConclusionsOur findings suggest that primary care physicians perceived HPV vaccine discussions to be burdensome, requiring more time and engendering less parental support than other adolescent vaccines. Perhaps for this reason, physicians in our national study recommended HPV vaccine less strongly than other adolescent vaccines, and often chose to discuss it last. Communication strategies are needed to support physicians in recommending HPV vaccine with greater confidence and efficiency.     

Effect of multiple,simultaneous vaccines on polio seroresponse and associated health outcomes

BackgroundAdministration of multiple simultaneous vaccines to infants, children, and military recruits is not uncommon. However, little research exists to examine associated serological and health effects, especially in adults.MethodWe retrospectively examined 416 paired serum specimens from U.S. military subjects who had received the inactivated polio vaccine (IPV) alone or in combination with either 1 other vaccine (<3 group) or 4 other vaccines (>4 group). Each of the 2 groups was subdivided into 2 subgroups in which Tdap was present or absent.ResultsThe >4 group was associated with a higher proportion of polio seroconversions than the <3 group (95% vs. 58%, respectively, p < 0.01). Analysis of the <3 subgroup that excluded Tdap vs. the >4 subgroup that excluded Tdap showed no difference between them (p > 0.1). However, the >4 subgroup that included Tdap had significantly more seroconversions than either the <3 subgroup that excluded Tdap or the >4 subgroup that excluded Tdap (p < 0.01). Overall, at least 98% of subjects were at or above the putative level of seroprotection both pre- and post-vaccination, yet at least 81% of subjects seroconverted. In an analysis of 400 of the subjects in which clinic in- and outpatient encounters were counted over the course of 1 year following vaccinations, there was no significant difference between the 2 groups (p > 0.1).ConclusionA combination of >4 vaccines including IPV appeared to have an immunopotentiation effect on polio seroconversion, and Tdap in particular was a strong candidate for an important role. The dose of IPV we studied in our subjects, who already had a high level of seroprotection, acted as a booster. In addition, there appear to be no negative health consequences from receiving few versus more multiple simultaneous vaccinations.