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.     

Effects of prior influenza virus vaccination on maternal antibody responses: Implications for achieving protection in the newborns

BackgroundIn the US, influenza vaccination is recommended annually to everyone ≥6 months. Prior receipt of influenza vaccine can dampen antibody responses to subsequent vaccination. This may have implications for pregnant women and their newborns, groups at high risk for complications from influenza infection.ObjectiveThis study examined effects of prior vaccination on maternal and cord blood antibody levels in a cohort of pregnant women in the US.Study designInfluenza antibody titers were measured in 141 pregnant women via the hemagglutination inhibition (HAI) assay prior to receipt of quadrivalent influenza vaccine, 30 days post-vaccination, and at delivery (maternal and cord blood). Logistic regression analyses adjusting for age, BMI, parity, gestational age at vaccination, and year of vaccination compared HAI titers, seroprotection, and seroconversion in women with versus without vaccination in the prior year.ResultsCompared to those without vaccination in the previous year (n = 50), women with prior vaccination (n = 91) exhibited higher baseline antibody titers and/or seroprotection rates against all four strains after controlling for covariates. Prior vaccination also predicted lower antibody responses and seroconversion rates at one month post-vaccination. However, at delivery, there were no significant differences in antibody titers or seroprotection rates in women or newborns, and no meaningful differences in the efficiency of antibody transfer, as indicated by the ratio of cord blood to maternal antibody titers at the time of delivery.ConclusionIn this cohort of pregnant women, receipt of influenza vaccine the previous year predicted higher baseline antibody titers and decreased antibody responses at one month post-vaccination against all influenza strains. However, prior maternal vaccination did not significantly affect either maternal antibody levels at delivery or antibody levels transferred to the neonate. This study is registered with the NIH as a clinical trial (NCT02148874).     

Increasing seasonal influenza vaccination among high risk groups in China: Do community healthcare workers have a role to play?

BackgroundSeasonal influenza vaccine uptake in China is low. This study aims to assess the role of community healthcare workers (HCWs) in increasing vaccination among high risk groups in China.MethodsWe analyzed data from four knowledge, attitude and practice (KAP) studies on seasonal influenza vaccination in China targeting guardians of young children, pregnant women, adults aged ≥60 years, and HCWs from 2012 to 2014.ResultsThirty-one percent of pregnant women and 78% adults aged ≥60 years reported willingness to follow HCWs’ recommendations for influenza vaccination. Guardians were more likely to vaccinate their children if they received HCWs’ recommendations (35% vs. 17%, p < 0.001). Community HCWs were more likely to recommend seasonal influenza vaccination than hospital HCWs (58% vs. 28%, p < 0.001).ConclusionStudy results suggest the value of incorporating community HCWs’ recommendation for seasonal influenza vaccination into existing primary public health programs to increase vaccination coverage among high risk groups in China.     

Brief education to promote maternal influenza vaccine uptake: A randomized controlled trial

BackgroundAlthough pregnant women are the highest priority group for seasonal influenza vaccination, maternal influenza vaccination rates remain suboptimal. The purpose of this study was to evaluate the effect of a brief education intervention on maternal influenza vaccine uptake.MethodsDuring the 2013–14 and 2014–15 influenza seasons, we recruited 321 pregnant women from the antenatal clinics of 4 out of 8 public hospitals in Hong Kong with obstetric services. Hospitals were geographically dispersed and provided services to pregnant women with variable socioeconomic backgrounds. Participants were randomized to receive either standard antenatal care or brief one-to-one education. Participants received telephone follow-up at 2 weeks postpartum. The primary study outcome was self-reported receipt of influenza vaccination during pregnancy. The secondary outcomes were the proportion of participants who initiated discussion about influenza vaccination with a health care professional and the proportion of participants who attempted to get vaccinated.ResultsCompared with participants who received standard care, the vaccination rate was higher among participants who received brief education (21.1% vs. 10%; p = 0.006). More participants in the education group initiated discussion about influenza vaccination with their HCP (19.9% vs. 13.1%; p = 0.10), but the difference was not statistically significant. Of participants who did not receive the influenza vaccine (n = 271), 45 attempted to get vaccinated. A significantly higher proportion of participants who attempted to get vaccinated were in the intervention group (82.2% vs. 17.8%; p < 0.001). If participants who had attempted vaccination had received the vaccine, vaccination rates would have been substantially higher (44.1% vs. 15%; p < 0.001). Twenty-six participants were advised against influenza vaccination by a healthcare professional, including general practitioners, obstetricians, and nurses.ConclusionAlthough brief education was effective in improving vaccination uptake among pregnant women, overall vaccination rates remain suboptimal. Multicomponent approaches, including positive vaccination recommendations by healthcare professionals, are needed to promote maternal influenza vaccination.Clinical Trial Registration: www.clinicaltrials.gov (NCT01772901).     

Birth outcomes for Australian mother-infant pairs who received an influenza vaccine during pregnancy, 2012–2014: The FluMum study

IntroductionIn Australia, influenza vaccination is recommended for all women who will be pregnant during the influenza season. Vaccine safety and effectiveness are key concerns and influencers of uptake for both vaccine providers and families. We assessed the safety of receiving an influenza vaccination during any trimester of pregnancy with respect to preterm births and infant birthweight.MethodsWe conducted a nested retrospective cohort study of ‘FluMum’ participants (2012–2014). Our primary exposure of interest was influenza vaccination during pregnancy. The primary outcomes of interest were infant birthweight and weeks’ gestation at birth for live singleton infants. Analyses included comparisons of these birth outcomes by vaccination status and trimester of pregnancy an influenza vaccine was given. We calculated means, proportions, and relative risks and performed multivariable logistic regression for potential confounding factors.ResultsIn the 7126 mother-infant pairs enrolled in this study, mean maternal age at infant birth was 31.7 years. Influenza vaccine uptake in pregnancy was 34%. Most mothers with a known date of vaccination received a vaccine in the second trimester (51%). Those mothers with a co-morbidity or risk factor were 13% more likely to have influenza vaccine during pregnancy compared to other mothers (RR 1.13, 95% CI 1.04–1.24, p = 0.007). Mean weeks’ gestation at birth was 38.7 for the vaccinated and 38.8 for the unvaccinated group (p = 0.051). Infants in the vaccinated group weighed 15 g less in birthweight compared to the unvaccinated infants (95% CI −12.8 to 42.2, p = 0.29).ConclusionResults arising from this large Australian cohort study are reassuring with respect to two critical safety outcomes; preterm births and low infant birthweights. Studies examining a broader range of birth outcomes following influenza vaccination during pregnancy are required, particularly now that maternal vaccination in pregnancy has expanded to include pertussis as well as influenza.     

Predictors of reported influenza vaccination in HIV-infected women in the United States, 2006–2007 and 2007–2008 seasons

ObjectiveTo estimate the cumulative incidence of self-reported influenza vaccination (“vaccination coverage”) and investigate predictors in HIV-infected women.MethodsIn an ongoing cohort study of HIV-infected women in five US cities, data from two influenza seasons (2006–2007 n = 1209 and 2007–2008 n = 1161) were used to estimate crude and adjusted prevalence ratios (aPR) and 95% confidence intervals ([,]) from Poisson regression with robust variance models using generalized estimating equations (GEE).ResultsIn our study, 55% and 57% of HIV-infected women reported vaccination during the 2006–2007 and 2007–2008 seasons, respectively. Using data from both seasons, older age, non-smoking status, CD4 T-lymphocyte (CD4) count ≥ 200 cells/mm³, and reporting at least one recent healthcare visit was associated with increased vaccination coverage. In the 2007–2008 season, a belief in the protection of the vaccine (aPR = 1.38 [1.18, 1.61]) and influenza vaccination in the previous season (aPR = 1.66 [1.44, 1.91]) most strongly predicted vaccination status.ConclusionInterventions to reach unvaccinated HIV-infected women should focus on changing beliefs about the effectiveness of influenza vaccination and target younger women, current smokers, those without recent healthcare visits, or a CD4 count < 200 cells/mm³.     

Evaluación de una intervención comunitaria para incrementar la cobertura vacunal de la gripe en mujeres embarazadas

ObjectiveTo know the impact of the educational intervention carried out on the professionals of a basic health area and their community participation group, which make up the intervention group (IG), and to analyze its repercussion on the vaccination coverage achieved for influenza in the risk group (pregnant and puerperal women) comparing it with its neighboring basic zone, which makes up the control group (CG), during the 2019/20 vaccination season.DesignQuasi-experimental study of community intervention.SiteTwo basic health zones belonging to the Elche-Crevillente health department, Spain.ParticipantsPregnant and postpartum women from 2 basic health areas and the community participation group. Health professionals directly related to the flu vaccination campaign.InterventionsTraining session for the IG prior to the 2019/20 flu campaign.Main measurementsAttitudes towards influenza vaccination in health professionals through the validated CAPSVA questionnaire and the vaccination coverage of pregnant and postpartum women through the Nominal Vaccine Registry and their acceptance of the vaccine in the midwife's office.ResultsThe influenza vaccination coverage data recorded in Nominal Vaccine Registry for pregnant and puerperal women was 26.4% (n = 207) in the IG and 19.7% (n = 144) in the CG (p = 0.001), with an incidence ratio of 1.34, thus achieving 34% more vaccination in the IG. Acceptance for vaccination in the midwife's office was also high, with 96.5% immunization in IG vs. 89.0% in CG, with a RR = 1.09 (95% CI 1.01-1.62).ConclusionsJoint training strategies for professionals and community assets improve the results of vaccination coverage.     

Trends in reasons for non-receipt of influenza vaccination during pregnancy in Georgia, 2004–2011

BackgroundConsiderable research has identified barriers to antenatal influenza vaccination, yet no research has explored temporal trends in reasons for non-receipt.PurposeTo examine trends in reasons for non-receipt of influenza vaccination during pregnancy.MethodsSerial cross-sectional analyses using 8 years of Georgia Pregnancy Risk Assessment Monitoring Survey (PRAMS) data were conducted. Weighted logistic regression was used to examine trends in the prevalence of citing reasons for non-receipt over time.ResultsBetween 2004 and 2011, 8300 women reported no influenza vaccination during or immediately before pregnancy. Proportions of women citing “doctor didn’t mention vaccination,” “in first trimester during influenza season,” and “not pregnant during influenza season” decreased significantly over time (Doctor didn’t mention: 48.0% vs. 27.1%, test for trend p < 0.001; in first trimester: 26.8% vs. 16.3%, test for trend p < 0.001; not influenza season: 24.2% vs. 12.7%, test for trend p = 0.001). Safety concerns increased over 2004 proportions in 2010 (concern about side effects for me: 40.2% vs. 28.5%, prevalence ratio (PR): 1.41, 95% confidence interval (CI): 1.16, 1.71; concern about harming my baby: 38.9% vs. 31.0%, PR = 1.26, 95% CI: 1.04, 1.53) and 2011 (concern about side effects for me: 39.0% vs. 28.5%, PR = 1.37, 95% CI: 1.13, 1.65; concern about harming my baby: 38.8% vs. 31.0%, PR = 1.25, 95% CI: 1.04, 1.50). Following the 2009/2010 H1N1 pandemic, more Hispanic women cited concern about vaccination harming their baby than other women; in 2011, their concern remained elevated relative to non-Hispanic white women (63% vs. 35%; adjusted PR = 1.79, 95% CI: 1.23, 2.61).ConclusionExamining trends in reasons for non-receipt of antenatal influenza vaccination can reflect successes related to vaccine promotion and areas for improvement. By highlighting differential impacts of the 2009/2010 H1N1 pandemic, we reveal opportunities for additional research on tailoring vaccine promotion efforts to specific types of women.     

Influenza during pregnancy: Incidence,vaccination coverage and attitudes toward vaccination in the French web-based cohort G-GrippeNet

IntroductionPregnancy is a risk factor for severe influenza. However, data on influenza incidence during pregnancy are scarce. Likewise, no data are available on influenza vaccine coverage in France since national recommendation in 2012. We aimed to assess these points using a novel nationwide web-based surveillance system, G-GrippeNet.MethodsDuring the 2014/2015 influenza season, pregnant women living in metropolitan France were enrolled through a web platform (https://www.grippenet.fr/). Throughout the season, participants were asked to report, on a weekly basis, if they had experienced symptoms of influenza-like-illness (ILI). ILI episodes reported were used to calculate incidence density rates based on period of participation from each participant. Vaccination coverage was estimated after weighing on age and education level from national data on pregnant women. Factors associated with higher vaccination coverage were obtained through a logistic regression with Odds Ratio (OR) corrected with the Zhang and Yu method.ResultsA total of 153 women were enrolled. ILI incidence density rate was 1.8 per 100 person-week (95%CI, 1.5–2.1). This rate was higher in women older than 40 years (RR = 3.0, 95%CI [1.1–8.3], p = 0.03) and during first/second trimesters compared to third trimester (RR = 4.0, 95%CI [1.4–12.0], p = 0.01). Crude vaccination coverage was 39% (95%CI, 31–47) and weighted vaccination coverage was estimated at 26% (95%CI, 20–34). Health care provider recommendation for vaccination (corrected OR = 7.8; 95%CI [3.0–17.1]) and non-smoking status (cOR = 2.1; 95%CI [1.2–6.9]) were associated with higher vaccine uptake.ConclusionThis original web based longitudinal surveillance study design proved feasible in pregnant women population. First results are of interest and underline that public health policies should emphasize the vaccination promotion through health care providers.     

Influenza vaccine acceptance among pregnant women in urban slum areas,Karachi, Pakistan

BackgroundFacilitators and barriers to influenza vaccination among pregnant women in the developing world are poorly understood, particularly in South Asia. We assessed intention to accept influenza vaccine among ethnically diverse low-income pregnant women in Pakistan.MethodsFrom May to August 2013, we conducted a cross-sectional survey of pregnant women who visited health centers in urban slums in Karachi city. We assessed intention to accept influenza vaccine against socio-demographic factors, vaccination history, vaccine recommendation sources, and other factors.ResultsIn an unvaccinated study population of 283 respondents, 87% were willing to accept the vaccine, if offered. All except two participants were aware of symptoms typically associated with influenza. Perceived vaccine safety, efficacy, and disease susceptibility were significantly associated with intention to accept influenza vaccine (p < 0.05). Regardless of intention to accept influenza vaccine, 96% rated healthcare providers as highly reliable source of vaccine information. While a recommendation from a physician was critical for influenza vaccine acceptance, parents-in-law and husbands were often considered the primary decision-makers for pregnant women seeking healthcare including vaccination.ConclusionsMaternal influenza vaccination initiatives in South Asia should strongly consider counseling of key familial decision-makers and inclusion of healthcare providers to help implement new vaccination programs.     

Efficacy and safety of high-dose influenza vaccine in elderly adults: A systematic review and meta-analysis

IntroductionOlder adults are prioritized for influenza vaccination but also have lowered antibody responses to the vaccine. Higher-doses of influenza antigen may increase immune response and thus be more effective. Our objectives were to compare the efficacy and safety of the high-dose influenza vaccine to the standard-dose influenza vaccine in the elderly (age > 65).MethodsData sources: Randomized trials (RCTs) from Medline (Ovid), EMBASE (Ovid), Cochrane Library (Wiley), ClinicalTrials.gov, reference lists of relevant articles, and gray literature.Study selection: Two reviewers independently identified RCTs comparing high-dose influenza vaccine (60 μg of hemagglutinin per strain) to standard-dose influenza vaccine (15 μg of hemagglutinin per strain) in adults over the age of 65 years.Data extraction: Two reviewers independently extracted trial-level data including population characteristics, interventions, outcomes, and funding sources. Risk of bias was assessed using the Cochrane Risk of Bias tool.ResultsWe included seven eligible trials; all were categorized as having a low (n = 3) or unclear (n = 4) risk of bias. Patients receiving the high-dose vaccine had significantly less risk of developing laboratory-confirmed influenza infections (Relative Risk 0.76, 95%CI 0.65 to 0.90; I² 0%, 2 trials, 41,141 patients). Post-vaccination geometric mean titres and seroprotection rates were also higher in high-dose vaccine recipients. There were no protocol-defined serious adverse events in the included trials in either group.ConclusionsIn elderly adults, the high-dose influenza vaccine was well-tolerated, more immunogenic, and more efficacious in preventing influenza infections than the standard-dose vaccine. Further pragmatic trials are needed to determine if the higher efficacy translates into higher vaccine effectiveness in adults over the age of 65.     

Maternal pertussis and influenza immunization coverage and attitude of health care workers towards these recommendations in Flanders,Belgium

In Belgium, pertussis vaccination is recommended for all pregnant women in every pregnancy. Adults in close contact with young infants are equally advised to receive a pertussis containing booster dose. Maternal influenza vaccination is likewise recommended in Belgium in the second or third trimester of pregnancy, within the influenza season.A quantitative multicenter survey study has been performed between October 2014 and May 2015 in both postpartum women (N = 823, response rate = 89.2%) and health care workers (HCWs) (N = 261) to assess the coverage of both vaccines during pregnancy along with the coverage of the pertussis cocoon strategy, and to evaluate the knowledge and recommending attitude of HCWs towards the maternal vaccination strategies and the cocoon strategy among surveyed women and HCWs.Overall coverage of pertussis vaccination during pregnancy was 64.0%. Most women were vaccinated by their general practitioner (GP) (82.4%), and most often in the third trimester (74.0%) of pregnancy. Overall coverage of influenza vaccination during pregnancy was 45.0%. Again the GP administered most vaccines (67.6%); vaccines were equally administered in the second or third trimester of pregnancy. Educational level had a significant influence on both the pertussis and influenza vaccination coverage during pregnancy while working situation and parity had only an influence on the maternal pertussis vaccination coverage and country of birth only on the maternal influenza vaccination coverage.Overall, 78.4% of gynecologists and GPs recommends both maternal pertussis and influenza vaccination and 67.0% recommends both maternal vaccination strategies and the cocoon strategy. Within the group of the midwives, only 23.7% recommends both maternal pertussis and influenza vaccination and 10.5% recommends both maternal vaccination strategies and the cocoon strategy.High coverage is reached among pregnant women for pertussis and influenza vaccination. Several underserved populations of pregnant women regarding maternal immunization, are identified.     

Text messages for influenza vaccination among pregnant women: A randomized controlled trial

ObjectiveTo evaluate if text message reminders increase the likelihood of receiving the influenza vaccine among pregnant women.MethodsPregnant women were randomized to either receive or not receive weekly text messages. Women were told the messages would be about health-related behavior in pregnancy. Those randomized to the intervention group received two messages weekly for four consecutive weeks reinforcing that the influenza vaccine is recommended for all pregnant women and safe during pregnancy and breastfeeding. Women were contacted six weeks postpartum to determine if they had received the vaccine. Sample size calculation determined that 108 women were required in both groups to see a 75% increase in vaccination rates over baseline in the text message group compared to the control group.ResultsRecruitment began November 4, 2013, and 317 women were randomized. The mean gestational age at recruitment was 22 weeks. There were 40/129 (31%) women in the text message group and 41/152 (27%) women in the control group who received the vaccine (p = 0.51). Significant predictors of vaccine acceptance were being married compared to single (95% vs. 67%, p < 0.001), having higher household income (55% vs. 39%, p = 0.03) and having received the vaccine before (77% vs. 36%, p < 0.001). Among women receiving text messages, the majority were satisfied, with only 15/129 (12%) reporting that they did not like receiving the messages, and 24/129 (19%) stating that the information in the messages was not helpful.ConclusionWeekly text messages reinforcing the recommendation for and safety of the influenza vaccine in pregnancy did not increase the likelihood of actually receiving the vaccine among pregnant women. Overall vaccination rates were low, highlighting the need for patient education and innovative techniques to improve vaccine acceptance.Registered with ClinicalTrials.gov at http://www.clinicaltrials.gov, registration number NCT 02428738.     

Factors associated with influenza vaccination in middle and older aged Australian adults according to eligibility for the national vaccination program

BackgroundIn Australia, influenza vaccination is recommended and provided free of charge for all adults aged ≥65 years and those aged <65 years with specific risk factors. Other than age, there is limited information on characteristics associated with vaccine uptake.MethodsWe used the 45 and Up Study, a large cohort of adults aged ≥45 years, who completed a questionnaire in 2012 asking about influenza vaccination. We compared characteristics of those reporting influenza vaccination in those aged <65 and ≥65 years using a log binomial model to estimate relative rates (RRs), adjusted for age and other factors.ResultsAmong 27,036 participants, the proportion reporting influenza vaccination in the last year increased steadily with age from 24.6% in those <54 years to 67.2% in those 75–79 years; of those eligible for universal free vaccine, (≥65 years) 57.3% had an influenza vaccination in the previous year. Many characteristics associated with higher vaccination rates in adults aged <65 years (mean 60.7) and those ≥65 years (mean 73.7) were similar. These included sex (women versus men: <65 years, aRR = 1.14[95% CI 1.08–1.20]; ≥65 years, aRR = 1.04[1.02–1.07]), higher BMI (≥30 kg/m² versus >18.5 to <25 kg/m²: <65 years, aRR = 1.16[1.09–1.24]; ≥65 years, aRR = 1.06[1.03–1.09]), requiring assistance with daily tasks versus not (<65 years, aRR = 1.27[1.15–1.40]; ≥65 years, aRR = 1.05[1.02–1.09]) and reporting versus not reporting specific chronic illnesses (<65 years, aRR = 1.55 [1.48–1.63]; ≥65 years, aRR = 1.08[1.06–1.10]). Current smokers had lower vaccination rates (<65 years, aRR = 0.78[0.69–0.90]; ≥65 years, aRR = 0.91[0.84–0.99]). Among those aged <65 years only, being a carer, higher income, and education were associated with influenza vaccination (aRR = 1.32[1.19–1.47], 1.17[1.10–1.24] and 1.12[1.10–1.22] respectively). Non-English speaking country of birth was associated with lower vaccination rates in ≥65 years (aRR 0.86[0.81–0.92]).ConclusionsFactors most strongly associated with vaccination were age and among those aged <65 years, having a medical indication recommended for influenza vaccination, suggesting higher uptake among those who can access free vaccine. Among those eligible for free vaccination, interventions could be targeted towards men, smokers, those from non-English speaking backgrounds and those <65 years with a medical indication.     

Validity of the estimates of oral cholera vaccine effectiveness derived from the test-negative design

BackgroundThe test-negative design (TND) has emerged as a simple method for evaluating vaccine effectiveness (VE). Its utility for evaluating oral cholera vaccine (OCV) effectiveness is unknown. We examined this method's validity in assessing OCV effectiveness by comparing the results of TND analyses with those of conventional cohort analyses.MethodsRandomized controlled trials of OCV were conducted in Matlab (Bangladesh) and Kolkata (India), and an observational cohort design was used in Zanzibar (Tanzania). For all three studies, VE using the TND was estimated from the odds ratio (OR) relating vaccination status to fecal test status (Vibrio cholerae O1 positive or negative) among diarrheal patients enrolled during surveillance (VE =  (1 − OR)×100%). In cohort analyses of these studies, we employed the Cox proportional hazard model for estimating VE (=1 − hazard ratio)×100%).ResultsOCV effectiveness estimates obtained using the TND (Matlab: 51%, 95% CI:37–62%; Kolkata: 67%, 95% CI:57–75%) were similar to the cohort analyses of these RCTs (Matlab: 52%, 95% CI:43–60% and Kolkata: 66%, 95% CI:55–74%). The TND VE estimate for the Zanzibar data was 94% (95% CI:84–98%) compared with 82% (95% CI:58–93%) in the cohort analysis. After adjusting for residual confounding in the cohort analysis of the Zanzibar study, using a bias indicator condition, we observed almost no difference in the two estimates.ConclusionOur findings suggest that the TND is a valid approach for evaluating OCV effectiveness in routine vaccination programs.     

Comparing the rubella seronegativity in pregnant women who received one dose of rubella vaccine at different ages in Taiwan

IntroductionVaccination is the best strategy to prevent rubella and congenital rubella. The aim of our study was to assess the immunity to rubella and determine rubella virus antibody titers in pregnant women who were offered a single dose of rubella vaccine at different ages of their lives.MethodsA total 15,067 rubella IgG antibody test results for Taiwanese pregnant women who received routine prenatal checkup at Fooyin University Hospital from 1999 to 2014 were analyzed in this study. The women were divided into five birth cohorts in order to compare their rubella seronegativities and antibody titers according to the different period of rubella vaccination policy in Taiwan.ResultsThe total rubella seronegativity rate was 11.2% (95% CI: 10.7–11.7%) and the mean rubella antibody titers was 51.0 IU/mL (SD = 54.7 IU/mL). The junior school cohort has the lowest rubella seronegativity of 7.6% (95% CI: 6.9–8.2%). The seronegativities were significantly high in the preschool cohort and in the 15-month-old cohort, 14.9% (95% CI: 13.2–16.6%) and 14.8% (95% CI: 11.5–18.1%), respectively. The OR values were 2.1 (95% CI: 1.8–2.5, p < 0.001) in the preschool cohort and 2.2 (95% CI: 1.6–2.8, p < 0.001) in the 15-month-old cohort, respectively, against the junior school cohort. Women in the 15-month-old cohort have lowest average rubella IgG titer, 25.4 IU/mL.ConclusionThe total rubella seronegativity rate was 11.2% in all native pregnant women. Women who received one dose rubella vaccine at preschool and 15-month-old have highest seronegativities. The 15-month-old cohort has the lowest average rubella IgG titer. We recommend a revised catch-up immunization policy to women who received one dose rubella vaccine at a younger age.     

No association between influenza vaccination during pregnancy and adverse birth outcomes

BackgroundPregnant women are recommended to receive inactivated influenza vaccination anytime during pregnancy. Studies have investigated the impact of influenza vaccination during pregnancy on birth outcomes and results on preterm birth have been inconsistent.MethodsWe conducted a retrospective cohort study among children born at a gestational age ≥ 24 weeks from January 1, 2010 to December 31, 2015 at Kaiser Permanente Northern California facilities (KPNC). We evaluated the association between maternal influenza vaccination during pregnancy and risk of preterm birth, small and large for gestational age, admission to the neonatal intensive care unit (NICU), respiratory distress syndrome, low birth weight, and low Apgar score. We ascertained the dates of maternal influenza vaccination, conception, and delivery, as well as birth outcomes from KPNC inpatient and outpatient databases. Conditional multivariate Cox regression and logistic regression analyses were used to determine the association between maternal vaccination during pregnancy and risk of each birth outcome.ResultsThe study included 145,869 children. Maternal influenza vaccination during pregnancy was not associated with risk of small or large for gestational age births, preterm birth, need for mechanical ventilation at birth, respiratory distress syndrome, admission to the NICU, low birth weight, or low Apgar score. However, when we did not control for immortal time bias, the risk of preterm birth (odds ratio [OR] = 0.69, 95% confidence interval [CI] 0.66–0.72) was lower among infants of vaccinated mothers.ConclusionWe found no association between maternal influenza vaccination during pregnancy and adverse birth outcomes. When investigating preterm birth outcome in association with vaccination during pregnancy, immortal time bias should be taken into account in the analysis.     

Response to the influenza vaccine based on estradiol use in menopausal women

ObjectiveTo assess the impact of 17β-estradiol in modulating the response to the influenza vaccine in postmenopausal women.MethodsA prospective cohort study was conducted with 46 healthy postmenopausal women aged 41–62 years without previous vaccination against the influenza virus. Evaluation of serum antibodies using hemagglutination inhibition and single radial hemolysis was performed at the Virology Laboratory of the Butantan Institute, São Paulo, Brazil, using serum samples collected at two time points: immediately before and one month after vaccination.ResultsIn non-estradiol users (n = 25), the median number of hemagglutination-inhibiting units (Log₂) increased from 5.32 to 6.82 (p = 0.003). In estradiol users (n = 21), the median number of hemagglutination-inhibiting units (Log₂) increased from 5.32 to 5.82 (p = 0.149). The median hemolytic areas produced with the single radial hemolysis assay before and after the vaccine were 11 mm in both groups.ConclusionIn postmenopausal women, estrogen therapy did not have a positive influence on the production of antibodies against the influenza virus after vaccination, at least based on the formulation, time period, and methods used for quantifying these antibodies in the present study.     

Annual influenza vaccination reduces total hospitalization in patients with chronic hepatitis B virus infection: A population-based analysis

BackgroundThis study evaluated hospitalization and mortality in patients with chronic hepatitis B virus infection (HBV (+)) and matched comparison patients after stratifying the patients according to annual influenza vaccination (Vaccine (+)).MethodsData from Taiwan's National Health Insurance program from 2000 to 2009 were used to identify HBV(+)/vaccine(+) (n = 4434), HBV(+)/Vaccine(−) (n = 3646), HBV(−)/Vaccine(+) (n = 8868), and HBV(−)/Vaccine(−) (n = 8868) cohorts. The risk of pneumonia/influenza, respiratory failure, intensive care, hospitalization, and mortality in the four cohorts was evaluated.ResultsThe total hospitalization rate was significantly lower in patients with chronic HBV infection who received an annual influenza vaccination than in chronic HBV-infected patients who did not receive an influenza vaccination (16.29 vs. 24.02 per 100 person-years), contributing to an adjusted hazard ratio (HR) of 0.56 (95% confidence interval (CI) = 0.50–0.62). The HBV(+)/Vaccine(+) cohort also had lower risks than the HBV(+)/Vaccine(−) cohort for pneumonia and influenza (adjusted HR = 0.79, 95% CI = 0.67–0.92), intensive care unit admission (adjusted HR = 0.33, 95% CI = 0.25–0.43), and mortality (adjusted HR = 0.19, 95% CI = 0.15–0.24).ConclusionsOur results suggest that annual influenza vaccination can reduce the risk of hospitalization and mortality in patients with chronic HBV infection.     

Knowledge of influenza vaccination recommendation and early vaccination uptake during the 2015–16 season among adults aged ≥18 years – United States

BackgroundSince 2010, the Advisory Committee on Immunization Practices (ACIP) has recommended that all persons aged ≥6 months receive annual influenza vaccination.MethodsWe analyzed data from the 2015 National Internet Flu Survey (NIFS), to assess knowledge and awareness of the influenza vaccination recommendation and early influenza vaccination coverage during the 2015–16 season among adults. Predictive marginals from a multivariable logistic regression model were used to identify factors independently associated with adults’ knowledge and awareness of the vaccination recommendation and early vaccine uptake during the 2015–16 influenza season.ResultsAmong the 3301 respondents aged ≥18 years, 19.6% indicated knowing that influenza vaccination is recommended for all persons aged ≥6 months. Of respondents, 62.3% indicated awareness that there was a recommendation for influenza vaccination, but did not indicate correct knowledge of the recommended age group. Overall, 39.9% of adults aged ≥18 years reported having an influenza vaccination. Age 65 years and older, being female, having a college or higher education, not being in work force, having annual household income ≥$75,000, reporting having received an influenza vaccination early in the 2015–16 season, having children aged ≤17 years in the household, and having high-risk conditions were independently associated with a higher correct knowledge of the influenza vaccination recommendation.ConclusionsApproximately 1 in 5 had correct knowledge of the recommendation that all persons aged ≥6 months should receive an influenza vaccination annually, with some socio-economic groups being even less aware. Clinic based education in combination with strategies known to increase uptake of recommended vaccines, such as patient reminder/recall systems and other healthcare system-based interventions are needed to improve vaccination, which could also improve awareness.