Parental perceptions of childhood seasonal influenza vaccination in Singapore: A cross-sectional survey

PurposeSeasonal influenza vaccination is recommended in children aged 6–59 months, but little is known about child vaccination coverage and determinants in Asian settings. We report the results of a survey of knowledge, attitudes, practices, and determinants of child influenza vaccination in Singapore.MethodsIn December 2015-March 2016, we conducted a survey of 332 parents of children aged 6 months to 5 years attending pre-schools. We assessed child influenza vaccine coverage and parental knowledge, attitudes, and practices of child influenza vaccination. We used multivariable regression and structural equation models to identify factors associated with child influenza vaccination.ResultsKnowledge about influenza, perceived benefit of vaccination, and willingness to vaccinate were high. However, only 32% of children had ever received influenza vaccine, and only 15% in the past year. Factors independently associated with child influenza vaccination included: being recommended influenza vaccine by a child’s doctor (prevalence ratio (PR) = 2.47, 95% CI: 1.75–3.48); receiving influenza vaccine information from a private general practitioner (PR = 1.47, 95% CI: 1.05–2.04); regularly receiving pre-travel influenza vaccine (PR = 1.64, 95% CI: 1.19–2.25); higher willingness to vaccinate (PR = 1.58, 95% CI:1.24–2.04 per unit increase in willingness score); and feeling well-informed about influenza vaccine (PR = 1.44, 95% CI: 1.04–1.99). Parents who obtained influenza vaccine information from television were less likely to have vaccinated their child (PR = 0.44, 95% CI: 0.23–0.85). Path analysis indicated that being recommended vaccination by a child's doctor increased willingness to vaccinate and self-efficacy (feeling well-informed about influenza vaccine). Median willingness-to-pay for a dose of influenza vaccine was SGD30 (interquartile range: SGD20-SGD50), and was higher in parents of vaccinated compared with unvaccinated children (SGD45 vs SGD30, p = 0.0012).ConclusionKnowledge and willingness to vaccinate was high in this parent population, but influenza vaccine uptake in children was low. Encouraging medical professionals to recommend vaccination of eligible children is key to improving uptake.     

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.     

Prevalence and associated factors of seasonal influenza vaccination among 24- to 59-month-old children in Hong Kong

BackgroundInfluenza results in severe complications among 24- to 59-month-old children, who are recommended by the WHO to take up influenza vaccination (IV) annually. Health promotion is warranted. Yet, there is a dearth of studies on IV prevalence and associated factors in this age group.MethodsA random population-based telephone survey interviewed 540 parents of Chinese children aged 24–59 months in Hong Kong during March through June, 2011. Constructs of the Health Belief Model (HBM) and subjective norm formed basis for assessing parental perceptions on influenza and IV. For data analysis, adjusted, and stepwise multiple logistic regression models were fit.ResultsThe prevalence of having taken up at least one dose and two doses of IV among children aged 24–59 months was 58.9 and 42.4%, respectively. Significant associated factors included family members’ IV experience (ORu = 5.37, 95% CI: 3.48, 8.29), variables related to the HBM constructs (except perceived severity) [perceived susceptibility of seasonal influenza (ORu = 2.03, 95% CI: 1.39, 2.95), perceived benefits of IV (ORu = 3.11, 95% CI: 2.05, 4.71), perceived barriers (ORu = 0.49, 95% CI: 0.25, 0.96) of IV, and cue to action (ORu = 4.79, 95% CI: 2.87, 7.99)], supportive subjective norm (ORu = 4.26, 95% CI: 2.91, 6.25), and level of fear felt during the H1N1 pandemic (ORu = 1.97, 95% CI: 1.01, 3.87). Adjusted for the child's age, the same significant factors were found. Exposure to related media messages was statistically non-significant.ConclusionThe reported IV prevalence was higher than that of 24- to 59-month-old children reported in other studies. There is room for improvement through health promotion, which should modify parental cognitions related to HBM (except perceived severity and self-efficacy) and involve family members to create subjective norm. Media campaigns may be inadequate for promotion of IV; use of the setting approach may be considered.     

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.     

The impacts of email reminder/recall on adolescent influenza vaccination

BackgroundWe sought to: (1) explore the feasibility of using email for seasonal influenza vaccination reminders to parents of adolescents and (2) assess influenza vaccination rates among adolescents whose parents were randomized to either receive or not receive email reminders.MethodsEmail addresses were obtained for parents of patients 10–18 years from 4 practices in Michigan. Addresses were randomized to either receive email reminders, or not. Reminder messages were sent during October 2012-March 2013 (Season 1) and October 2013-March 2014 (Season 2). Vaccination status was determined 60 days following the last email reminder for each season using the statewide Michigan Care Improvement Registry (MCIR); per protocol bivariate and multivariate logistic regression analyses were conducted to evaluate reminder notification.ResultsAfter email cleaning, testing, and matching with MCIR, approximately half of email addresses (2348 of 5312 in Season 1; 3457 of 6549 in Season 2) were randomized. Bivariate analyses found that influenza vaccination within 60 days after notification date was similar among those notified (34%) versus not notified (29%) in both Season 1 (p = 0.06) and Season 2 (39% vs. 37%, p = 0.20). However, multivariate models adjusted for season, site, and receipt of notification in two seasons found a higher likelihood of influenza vaccination among children that received notification (aOR = 1.28, 95% CI = 1.09, 1.51); in addition, differences in influenza vaccination were also observed between practice sites (range: p = 0.15 to p < 0.001).ConclusionsWe found that practice-based email influenza vaccine reminders to parents of adolescents are feasible, but not without complications. Our study demonstrates that email reminders from practices can yield increases in influenza vaccination rates among adolescents. Practices should consider email as an option for influenza reminders and establish business practices for collecting and maintaining patient email addresses.This study is registered at www.ClinicalTrials.gov id #NCT01732315.     

Immunogenicity and safety of a quadrivalent inactivated influenza virus vaccine compared with a comparator quadrivalent inactivated influenza vaccine in a pediatric population: A phase 3, randomized noninferiority study

BackgroundSeqirus 2010 Southern Hemisphere split-virion trivalent inactivated influenza vaccine (IIV3) was associated with increased febrile reactions in children. Studies in vitro concluded that increasing concentrations of splitting agent decreased residual lipids and attenuated proinflammatory cytokine signals associated with fever. We assessed immunogenicity and safety of a quadrivalent inactivated influenza vaccine (IIV4; produced using higher concentration of splitting agent) versus a United States-licensed comparator IIV4 in healthy children aged 5–17 years.MethodsParticipants (N = 2278) were randomized 3:1 and stratified by age (5–8 years; 9–17 years) to receive IIV4 (n = 1709) or comparator IIV4 (n = 569). Primary objective was to demonstrate noninferiority of IIV4 versus comparator IIV4 as assessed by hemagglutination inhibition (HI) geometric mean titer (GMT) ratio (upper bound of two-sided 95% confidence interval [CI] ≤ 1.5) and difference in seroconversion rate (upper bound of two-sided 95% CI ≤ 10%) for all four vaccine strains. HI antibody titers were assessed at baseline and 28 days postvaccination. Solicited and unsolicited adverse events were assessed during each 7- and 28-day postvaccination period, respectively.ResultsIIV4 met immunogenicity criteria for noninferiority. Adjusted GMT ratios (comparator IIV4/IIV4) for A/H1N1, A/H3N2, B/Yamagata, and B/Victoria strains were 1.01 (95% CI; 0.93, 1.09), 1.05 (0.96, 1.15), 0.89 (0.81, 0.98), and 0.92 (0.83, 1.02), respectively. Corresponding values for differences (95% CI) in seroconversion rates (comparator IIV4 minus IIV4) were −3.1 (−8.0, 1.8), 0.4 (−4.5, 5.3), −3.4 (−8.3, 1.5), and −2.0 (−6.9, 2.9). Fever rates were numerically higher, but not statistically different, with IIV4 versus comparator IIV4. No new safety signals were reported.ConclusionIIV4 demonstrated immunological noninferiority to the comparator IIV4 with a clinically acceptable safety profile in children aged 5–17 years. Increased levels of virus splitting agent seem to have reduced fever rates observed in children with Seqirus IIV3, particularly those aged 5–8 years.Funding: Seqirus Pty Ltd; Clinicaltrials.gov identifier: NCT02545543.     

Risk factors for severe outcomes among members of the United States military hospitalized with pneumonia and influenza, 2000–2012

BackgroundThe progression from hospitalization for a respiratory infection to requiring substantial supportive therapy is a key stage of the influenza severity pyramid. Respiratory infections are responsible for 300,000–400,000 medical encounters each year among US military personnel, some of which progress to severe acute respiratory infections.MethodsWe obtained data on 11,086 hospitalizations for pneumonia and influenza (P&I) among non-recruit US military service members during the period of 1 January 2000 through 31 December 2012. From these, we identified 512 P&I hospitalizations that progressed to severe episodes using standard case definitions. We evaluated the effect of demographic and occupational characteristics, co-morbid conditions, and history of influenza vaccination on the risk of a hospitalized P&I case becoming a severe case. We also evaluated the risk of a severe outcome and the length of time since influenza vaccination (within 180, 60, and 30 days).ResultsThe median age of subjects at the time of the P&I episode was 32 years (range, 28–40) and subjects were predominantly male (89.5%). In a univariate analysis, demographic risk factors for a severe episode included service in the US Air Force (RR = 1.6 relative to US Army, 95%CI 1.3–2.1), US Coast Guard (RR = 2.1, 1.2–3.7) or US Navy (RR = 1.4, 1.1–1.8). Being born in the US and recent influenza vaccination (within 180 days of episode) were protective against developing severe disease. Among co-morbid conditions, univariate risk factors for severe disease included chronic renal or liver disease (RR = 4.98, 95%CI 4.1–6.1), diseases of the circulatory system (RR = 3.1, 95%CI 2.6–3.7), diabetes mellitus (RR = 2.3, 95%CI 1.5–3.6), obesity (RR = 1.6, 95%CI 1.2–2.1), cancer (RR = 1.6, 95%CI 1.3–2.0), and chronic obstructive pulmonary disease (RR = 1.4, 95%CI 1.1–1.7). Although many of the risk factors found to be significant in univariate analysis were no longer significant under a multivariate analysis, receipt of any influenza vaccine within 180 days of episode remained protective (RR = 0.81, 95%CI 0.67–0.99), while serving in the US Coast Guard (RR = 1.9, 95%CI 1.1–3.4) or US Air Force (RR = 1. 5, 95%CI 1.2–2.0), presence of renal or liver disease (RR = 3.6, 95%CI 2.9–4.6), and diseases of the circulatory system (RR = 2.2, 95%CI 1.8–2.8), remained significantly associated with a higher risk of developing severe disease.ConclusionsIn a large cohort, after adjusting for many possible risk factors, influenza vaccination was protective against severe episodes among P&I hospitalizations. The service-specific (US Coast Guard or US Air Force) increased risk may represent some differences in data (e.g., coding or reporting practices) as opposed to genuine differences in physiological outcome. Our findings suggest that renal and liver disease as well as diseases of the circulatory system may contribute to influenza severity in this population independently of age and other potential comorbidities. These findings provide additional evidence for the prioritization of specific risk groups within the US military for influenza vaccination     

Hospitalizations within 14 days of vaccination among pediatric recipients of the live attenuated influenza vaccine,United States 2010–2012

BackgroundLive attenuated influenza vaccine (LAIV) is safe in healthy children ⩾2 years. The original clinical trials excluded individuals with underlying conditions; however, post-marketing data suggest LAIV may be safe for these populations.MethodsWe analyzed MarketScan Commercial Claims Databases from 2010 to 2012 to describe hospitalizations within 14 days of vaccination among LAIV recipients. We evaluated LAIV recipients aged 2–18 years and defined underlying conditions by presence of inpatient or outpatient ICD-9 code during the previous calendar year. We excluded asthma and immunocompromising conditions. We defined risk windows as 1–7 days and 8–14 days after vaccination; the control period was 12–4 days prior to and 15–23 days after vaccination. We conducted a self-controlled case series analysis using a conditional Poisson regression model to estimate incidence-rate ratios (IRR).Results1,216,123 children aged 2–18 years received LAIV from 2010 to 2012. 634 children met our inclusion criteria and were hospitalized during the observation period (12 days prior to vaccination to 23 days after vaccination). Of those hospitalized, 72 (11.4%) had non-asthma, non-immunocompromising underlying conditions. Children with non-asthma, non-immunocompromising underlying conditions had an all-cause hospitalization IRR of 1.1 (95% CI 0.6–2.0, p = 0.83) in the 1–7 day risk period and 0.9 (95% CI 0.4–1.7, p = 0.67) in the 8–14 day risk period. Children with no underlying conditions had an all-cause hospitalization IRR of 0.9 (0.8–1.2, p = 0.60) in the 1–7 day risk period and 1.1 (95% CI 0.9–1.3, p = 0.53) in the 8–14 day risk period. There were no differences in all-cause hospitalization risk in individuals with non-asthma, non-immunocompromising underlying conditions compared to those without underlying conditions in the 1–7 day (p = 0.88) or 8–14 day (p = 0.24) risk period.ConclusionsWe found no evidence of differences in post-LAIV hospitalization risk among children with non-asthma, non-immunocompromising underlying conditions compared to healthy children.     

The 23-valent pneumococcal polysaccharide vaccine is effective in elderly adults over 75 years old—Taiwan's PPV vaccination program

BackgroundPneumococcal infection is a serious cause of mortality and morbidity in the elderly. A nationwide pneumococcal polysaccharide vaccine (PPV) program for elderly adults aged 75 years and older was conducted in Taiwan in 2008. The efficacy of the PPV in this very elderly population was evaluated.MethodsThe data were analyzed using the Taiwan National Health Insurance Research Database (NHIRD), the cause-of-death registration database and the invasive pneumococcal disease (IPD) notification database of Taiwan's Ministry of Health and Welfare. The efficacy of PPV administration in this very elderly population was evaluated using multivariate logistic regression after propensity score matching (PSM). The rates of IPD, death from IPD, pneumonia hospitalization, death from pneumonia, and all-cause mortality were compared for those who did and did not receive the PPV.ResultsAmong the 1078,955 eligible people, 318,257 (29.5%) received the PPV, and 760,698 (70.5%) were not vaccinated. Using PSM to adjust for confounding factors, including age, gender, influenza vaccination status, associated chronic diseases and health care utilization, those who received the PPV had significantly lower odds ratios (ORs) for IPD (OR = 0.24, 95% CI = 0.123–0.461, p < 0.001), death from IPD (OR = 0.09, 95% CI = 0.011–0.704, p < 0.022, p < 0.001), pneumonia hospitalization (OR = 0.40, 95% CI = 0.395–0.415, p < 0.001), death from pneumonia (OR = 0.07, 95% CI = 0.059–0.082, p < 0.001), and all-cause mortality (OR = 0.07, 95% CI = 0.069–0.072, p < 0.001) compared with those who were not vaccinated.ConclusionsPPV vaccination in the previous year was associated with a 60% reduction in pneumonia hospitalization, a 76% reduction in IPD, and a greater than 90% reduction in death from pneumonia, IPD and all causes among people over 75 years old in Taiwan. Data from subsequent years in Taiwan and similar populations elsewhere are needed to evaluate the contribution of underlying variations in the mortality rate and the confounding effects of prior disease severity to these findings.     

Vaccine-associated reduction in symptom severity among patients with influenza A/H3N2 disease

BackgroundThe moderate level of protection conferred by influenza vaccines is well-known, but the vaccine's ability to attenuate symptom severity among vaccinated individuals (i.e., vaccine failures) has not been established.MethodsWe enrolled otherwise healthy adults who presented with influenza-like illness (ILI) at five US military hospitals between 2009 and 2014. Influenza was diagnosed and subtyped by PCR. Individual and composite severity scores were compared between those who had vs. had not received the seasonal influenza vaccine >14 days prior to enrollment.ResultsA total of 155 cases of influenza (A/H1N1, n = 69; A/H3N2, n = 66; A/untyped, n = 3; B, n = 17) were identified, of whom 111 (72%; A/H1N1, n = 44; A/H3N2, n = 52; A/untyped, n = 3; B, n = 12) had been vaccinated. Women were significantly less likely to be vaccinated than men (49% vs. 89%; p < 0.01). In multivariate analysis, vaccinated individuals were significantly less likely to report a fever >101 °F (OR 0.24; 95% CI [0.10, 0.62]) and more likely to report myalgias (OR 3.31; 95% CI [1.22, 8.97]) than vaccinated individuals. Among patients with A/H3N2 infection, upper respiratory and total symptom severity scores were significantly lower for vaccinated patients during the first 2 days of illness, and differences in total symptom severity persisted over 7 days (p < 0.05 for all comparisons). Differences across additional symptom categories (lower respiratory and systemic) were also observed throughout 7 days of illness in bivariate analyses. Differences in symptom severity were not observed between vaccinated and unvaccinated participants with A/H1N1 infection.ConclusionsAmong patients with A/H3N2 infection, receipt of seasonal influenza vaccine was associated with reduced symptom severity. Patient-centered discussion about the benefits of influenza vaccination should be expanded to include the possibility that the vaccine could attenuate symptoms.     

Knowledge,attitude and awareness among healthcare professionals about influenza vaccination in Peshawar,Pakistan

A cross-sectional study was carried out among HCPs in Northwest General Hospital & Research Centre, Hayatabad Peshawar, Pakistan. The purpose of this study was to investigate knowledge, awareness and attitude of HCPs towards influenza vaccination. A total of N = 170 questionnaires were distributed among the staff. There was a 97% response rate to this survey (n = 165). The median age of the respondents was 30 years and most of them, 98 (59.0%), were from age group of 24–30 years. The majority of the HCPs that participated in this study were male 106 (64.2%), and by profession, the majority were physicians 77 (46.7%), followed by pharmacists and nurses. A majority 114 (69.1%) believed that it was not compulsory for HCPs to get vaccinated for influenza. Top three identified barriers to vaccination were: not everyone is familiar with the availability of the influenza vaccination at their institution (Relative importance weight factors (RIWF) = 0.71), due to needle fear I do not like to get vaccinated (RIWF = 0.70) and it is not compulsory for healthcare professionals to get vaccinated for influenza (RIWF = 0.64). The logistic regression analysis has revealed association for job experience and profession with the most of the eleven knowledge item. However, when overall sum of eleven items were tested to identify the factors affecting the knowledge score, along with profession (−0.215 [−0.389 to 0.040]; p = 0.016) and job experience (0.823 [0.521–1.125]; p < 0.001) HCPs age (−0.409 [−0.755 to −0.064]; p = 0.020) was found to be another significant factor affecting the total knowledge score of HCPs. Overall, scoring of the correct responses revealed that nurses have better knowledge and understanding about influenza and the influenza vaccination (6.5 ± 0.8, p < 0.001*), followed by pharmacists (6.3 ± 1.14) and physicians. In spite of the published guidelines and recommendations, a very low percentage of the healthcare professionals in our hospital were vaccinated against influenza, and the barriers to vaccination were prevalent. Various strategies, including arranging seminars regarding awareness about vaccinations, are required to improve the knowledge and overall outcomes.     

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.     

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).     

Immunogenicity and safety of inactivated quadrivalent influenza vaccine in adults: A systematic review and meta-analysis of randomised controlled trials

BackgroundA quadrivalent influenza vaccine (QIV) includes two A strains (A/H1N1, A/H3N2) and two B lineages (B/Victoria, B/Yamagata). The presence of both B lineages eliminate potential B lineage mismatch of trivalent influenza vaccine (TIV) with the circulating strain.MethodsElectronic database searches of Medline, Embase, Cochrane Central Register of Controlled Trials (CCRCT), Scopus and Web of Science were conducted for articles published until June 30, 2015 inclusive. Articles were limited to randomised controlled trials (RCTs) in adults using inactivated intramuscular vaccine and published in English language only. Summary estimates of immunogenicity (by seroprotection and seroconversion rates) and adverse events outcomes were compared between QIV and TIV, using a risk ratio (RR). Studies were pooled using inverse variance weights with a random effect model and the I² statistic was used to estimate heterogeneity.ResultsA total of five RCTs were included in the meta-analysis. For immunogenicity outcomes, QIV had similar efficacy for the three common strains; A/H1N1, A/H3N2 and the B lineage included in the TIV. QIV also showed superior efficacy for the B lineage not included in the TIV; pooled seroprotection RR of 1.14 (95%CI: 1.03–1.25, p = 0.008) and seroconversion RR of 1.78 (95%CI: 1.24–2.55, p = 0.002) for B/Victoria, and pooled seroprotection RR of 1.12 (95%CI: 1.02–1.22, p = 0.01) and seroconversion RR of 2.11 (95%CI: 1.51–2.95, p < 0.001) for B/Yamagata, respectively. No significant differences were found between QIV and TIV for aggregated local and systemic adverse events within 7 days post-vaccination. There were no vaccine-related serious adverse events reported for either QIV or TIV. Compared to TIV, injection-site pain was more common for QIV, with a pooled RR of 1.18 (95%CI: 1.03–1.35, p = 0.02).ConclusionIn adults, inactivated QIV was as immunogenic as seasonal TIV, with equivalent efficacy against the shared three strains included in TIV, and a superior immunogenicity against the non-TIV B lineage.     

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.     

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.     

Relationship between Guillain–Barré syndrome,influenza-related hospitalizations,and influenza vaccine coverage

Some studies reported an increased risk of Guillain–Barré syndrome (GBS) within six weeks of influenza vaccination. It has also been suggested that this finding could have been confounded by influenza illnesses. We explored the complex relationship between influenza illness, influenza vaccination, and GBS, from an ecologic perspective using nationally representative data. We also studied seasonal patterns for GBS hospitalizations.Monthly hospitalization data (2000–2009) for GBS, and pneumonia and influenza (P&I) in the Nationwide Inpatient Sample were included. Seasonal influenza vaccination coverage for 2004–2005 through the 2008–2009 influenza seasons (August–May) was estimated from the National Health Interview Survey data. GBS seasonality was determined using Poisson regression. GBS and P&I temporal clusters were identified using scan statistics. The association between P&I and GBS hospitalizations in the same month (concurrent) or in the following month (lagged) were determined using negative binomial regression.Vaccine coverage increased over the years (from 19.7% during 2004–2005 to 35.5% during 2008–2009 season) but GBS hospitalization did not follow a similar pattern. Overall, a significant correlation between monthly P&I and GBS hospitalizations was observed (Spearman's correlation coefficient = 0.7016, p < 0.0001). A significant (p = 0.001) cluster of P&I hospitalizations during December 2004–March 2005 overlapped a significant (p = 0.001) cluster of GBS hospitalizations during January 2005–February 2005. After accounting for effects of monthly vaccine coverage and age, P&I hospitalization was significantly associated (p < 0.0001) with GBS hospitalization in the concurrent month but not with GBS hospitalization in the following month. Monthly vaccine coverage was not associated with GBS hospitalization in adjusted models (both concurrent and lagged). GBS hospitalizations demonstrated a seasonal pattern with winter months having higher rates compared to the month of June.P&I hospitalization rates were significantly correlated with hospitalization rates for GBS. Vaccine coverage did not significantly affect the rates of GBS hospitalization at the population level.     

Influenza vaccination rates in children decline when the live attenuated influenza vaccine is not recommended

BackgroundIn 2016 the Centers for Disease Control and Prevention (CDC) recommended against using the live attenuated influenza vaccine (LAIV) for the 2016–2017 influenza season. This recommendation is potentially important for vaccination rates because perceived effectiveness and ease of administration are among the primary determinants of families decisions to vaccinate their children. This investigation sought to determine whether rates of pediatric influenza vaccination changed in a season when the LAIV was not recommended.MethodsThis study used cohort and cross sectional data from an academic primary care pediatric center in central Pennsylvania that serves approximately 12,500 patients. Early season (prior to November 1) and end-of-season (prior to March 1) vaccination rates in the 2015–16 and 2016–17 influenza seasons were recorded for individuals 2–17 years old. Repeat vaccination rates (percentage of children receiving influenza vaccination in one season who were also vaccinated in the next season) were recorded for the 2015–16 into 2016–17 seasons. A logistic regression model adjusting for race, ethnicity, age, insurance type and type of vaccination received was employed to identify predictors of repeat vaccination.ResultsIn the absence of LAIV (2016–17) early vaccination rates were significantly higher (24.7% vs 22.8%, p = 0.004), but end-of-season rates were lower (50.4% vs 52.0%, p = 0.03) than when LAIV was offered (2015–16). After adjusting for covariates, those who had received IIV in the 2015–16 season had higher odds (OR 1.32, 95% CI, 1.15–1.52) of getting a repeat vaccination in the 2016–17 season, compared with those who had received LAIV in the 2015–16 season.ConclusionsEnd-of-season vaccination rates were lower in 2016–17 when LAIV was not recommended, particularly among children who received LAIV in the preceding year. Unavailability of LAIV in the 2016–17 season may have impacted influenza vaccination convenience and perceived effectiveness, two factors which could influence vaccine uptake in pediatric populations.     

Plasma cell and serum antibody responses to influenza vaccine in preterm and full-term infants

BackgroundPreterm (PT) infants are at greater risk for severe influenza infection and experience decrements in long-term antibody responses to vaccines. This may related to defects in antibody secreting cell (ASC) generation.ObjectiveTo investigate the relationships among the frequencies of influenza-specific antibody secreting cells, ASC numbers and subsets, and antibody responses to influenza vaccines (IV) among PT and full-term (FT) infants.Design/methodsWe enrolled 11 former PT (≤32 weeks′ gestation, ≤1500 g′ birth weight) and 11 FT infants, 6–17 months of age, receiving their first influenza immunizations. Infants received two doses of inactivated trivalent (T)IV or quadrivalent (Q)IV during the 2012–2013 and 2013–2014 influenza seasons, respectively, at 0 and 28 days, and blood was drawn at 0, 10, 35, and 56 days and 9 months. Vaccine-specific antibody was measured by hemagglutination inhibition (HAI) at 0 and 56 days and 9 months, vaccine-specific ASC numbers by enzyme linked immunospot (ELISPOT) at 10 and 35 days, and ASC subsets by flow cytometry at 0, 10 and 35 days.ResultsPT infants had post-vaccine HAI titers to all 4 vaccine strains at least equal to FT infants at 56 days and 9 months after beginning immunization. Influenza-specific ASC ELISPOT responses at 35 days were higher among PT than FT infants (median 100 v. 30 per 10⁶ PBMC, p = 0.04). ASC numbers at 35 days were positively correlated with serum HAI titers at 56 days (ρ = 0.50–0.80). There were no statistical differences between PT and FT infants in the frequency of five ASC subsets and no specific ASC subset correlated with durability of serum antibody titers.ConclusionsInfluenza-specific ASC numbers in both FT and PT infants correlated with peak antibody titers, but ASC subsets did not correlate with durability of antibody response.