Comparison of mRNA vaccine effectiveness against COVID-19-associated hospitalization by vaccination source: Immunization information systems,electronic medical records,and self-report—IVY Network,February 1–August 31, 2022

BackgroundAccurate determination of COVID-19 vaccination status is necessary to produce reliable COVID-19 vaccine effectiveness (VE) estimates. Data comparing differences in COVID-19 VE by vaccination sources (i.e., immunization information systems [IIS], electronic medical records [EMR], and self-report) are limited. We compared the number of mRNA COVID-19 vaccine doses identified by each of these sources to assess agreement as well as differences in VE estimates using vaccination data from each individual source and vaccination data adjudicated from all sources combined.MethodsAdults aged ≥18 years who were hospitalized with COVID-like illness at 21 hospitals in 18 U.S. states participating in the IVY Network during February 1–August 31, 2022, were enrolled. Numbers of COVID-19 vaccine doses identified by IIS, EMR, and self-report were compared in kappa agreement analyses. Effectiveness of mRNA COVID-19 vaccines against COVID-19-associated hospitalization was estimated using multivariable logistic regression models to compare the odds of COVID-19 vaccination between SARS-CoV-2-positive case-patients and SARS-CoV-2-negative control-patients. VE was estimated using each source of vaccination data separately and all sources combined.ResultsA total of 4499 patients were included. Patients with ≥1 mRNA COVID-19 vaccine dose were identified most frequently by self-report (n = 3570, 79 %), followed by IIS (n = 3272, 73 %) and EMR (n = 3057, 68 %). Agreement was highest between IIS and self-report for 4 doses with a kappa of 0.77 (95 % CI = 0.73–0.81). VE point estimates of 3 doses against COVID-19 hospitalization were substantially lower when using vaccination data from EMR only (VE = 31 %, 95 % CI = 16 %–43 %) than when using all sources combined (VE = 53 %, 95 % CI = 41 %–62%).ConclusionVaccination data from EMR only may substantially underestimate COVID-19 VE.     

Agreement between state registry,health record,and self-report of influenza vaccination

BackgroundDocumentation of influenza vaccination, including the specific product received, is critical to estimate annual vaccine effectiveness (VE).MethodsWe assessed performance of the Michigan Care Improvement Registry (MCIR) in defining influenza vaccination status relative to documentation by provider records or self-report among subjects enrolled in a study of influenza VE from 2011 through 2019.ResultsThe specificity and positive predictive value of MCIR were high; however, >10% of vaccinations were identified only by other sources each season. The proportion of records captured by MCIR increased from a low of 67% in 2013–2014 to a high of 89% in 2018–2019, largely driven by increased capture of vaccination among adults.ConclusionsState vaccine registries, such as MCIR, are important tools for documenting influenza vaccination, including the specific product received. However, incomplete capture suggests that documentation from other sources and self-report should be used in combination with registries to reduce misclassification.     

The continuum of influenza vaccine hesitancy among nursing professionals in Hong Kong

IntroductionInfluenza vaccine hesitancy among healthcare workers poses challenges to the achievement of herd immunity and causes infection risks to vulnerable patients. This study aimed to quantify the extent of influenza vaccine hesitancy among nurses in Hong Kong, to delineate its pattern, and to explore its socio-demographic, professional and personal correlates.MethodNurses in Hong Kong were recruited in a cross-sectional study involving the administration of an online questionnaire survey after the 2017/18 winter influenza season. Respondents’ influenza vaccination behaviours, attitudes and psychological antecedents were assessed, followed by their delineation into subgroups along the hesitancy continuum through a combination of multiple correspondence analysis and K-means cluster analysis. Socio-demographic, professional and personal correlations of subgrouping were investigated using generalised ordered logistic regression.ResultsThe overall vaccination coverage of nurses for the 2017/18 influenza season was 44%. Five clusters were differentiated by the level of influenza vaccine hesitancy: “Very high hesitancy-to-complete refusal” (n = 56; 7%) characterised by outright refusal of vaccination; “High hesitancy” (n = 171; 23%) distinguished by tendency of skipping vaccination and scepticism about safety of vaccine; “Moderate hesitancy” (n = 273; 36%) with uncertainties towards vaccination, mistrust of the government’s vaccine recommendations and priority concern on affordability of vaccine; “Low hesitancy” (n = 95; 13%) with cautious acceptance towards vaccination and “No-to-minimal hesitancy” (n = 158; 21%) with strong vaccine confidence and compliance greatly linked to convenience of vaccine access. Nurses having completed at least 3 years’ pre-registration professional training, having most family members vaccinated against influenza, and with influenza vaccination history during studentship were less vaccine hesitant.ConclusionWith more than half of the nurses in Hong Kong having moderate or higher level of influenza vaccine hesitancy, interventions customised to the needs of nurses as reflected from the characteristics of clusters along the vaccine hesitancy continuum could form an important strategy for improving vaccination uptake.     

Influenza vaccination hesitancy and its determinants among elderly in China: A national cross-sectional study

BackgroundThe Chinese elderly face a significant threat from seasonal influenza, owing to the consistently low vaccination coverage. This study investigated the prevalence and determinants of influenza vaccination hesitancy among the Chinese elderly.MethodsIn 2019, 3849 elderly individuals from 10 provinces in China were recruited in a cross-sectional survey. Multinomial logistic regression was applied to investigate the determinants of influenza vaccination hesitancy.ResultsAmong the elderly respondents, 37.18% expressed some degree of hesitancy towards influenza vaccination: 19.28% were hesitant, and 17.90% refused influenza vaccination, including 19.28% acceptors with doubts and 17.90% refusers. Only 39.10% of the respondents considered themselves as the priority group for influenza vaccination, and 13.93% reported receiving a recommendation for vaccination from healthcare workers. Respondents with higher education levels and from urban areas had significantly higher odds of vaccine hesitancy than their counterparts. Confidence in the safety of vaccines was negatively associated with vaccine hesitancy, but confidence in vaccine efficacy had no such association. Respondents who perceived themselves as highly susceptible to influenza (AOR = 0.85; 95 %CI = 0.77–0.93) and those aware of the elderly as a priority group for influenza vaccination (AOR = 0.51; 95 %CI = 0.41–0.64) had a significantly lower odds of being refusers.ConclusionThis study found a high prevalence of hesitancy towards influenza vaccination among the Chinese elderly, especially well-educated and urban-dwelling respondents. The government should address vaccine hesitancy through culturally appropriate communication, subsidies for vaccination, and actively promoting vaccines through primary care professionals.     

What influenza vaccination programmes are preferred by healthcare personnel? A discrete choice experiment

ObjectivesThis study examined the relative importance of factors relating to vaccine characteristics, social normative influence and convenience in access to vaccine for determining decision making for seasonal influenza vaccination (SIV) among healthcare personnel (HCP), aiming to optimize existing influenza vaccination programmes for HCP.MethodsA discrete choice experiment (DCE) was conducted in HCP working in public hospitals in Hong Kong. The DCE was designed to examine the relative importance of vaccine characteristics (vaccine efficacy and safety), social normative influence reflected by the proportion of HCP colleagues intending to take SIV, and convenience in access to vaccine indicated by vaccination programme duration, vaccination location, vaccination arrangement procedure and service hours in determining influenza vaccination choice among HCP. Mixed logit regression modelling was conducted to examine the preference weight (β) of factors included in the DCE for determining vaccination choice.ResultsVaccination probability increased with increase in vaccine efficacy (β = 0.02 for per 1% increase), vaccination location changing from “designated staff clinic” to “mobile station” (β = 0.37), vaccination arrangement procedure changing from “by appointment” to “by walk-in” (β = 0.99), but decreased with the increase in probability of mild reactions to vaccination (β = −0.05 for per 1% increase).ConclusionVaccine safety was judged to be more important than vaccine efficacy for determining vaccination choice. Arranging vaccination service by walk-in and implementing mobile vaccination station should be considered in future SIV programmes to compensate for the effect of perceived low vaccination efficacy and concerns about vaccine safety to promote SIV uptake among HCP.     

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.     

Acceptability of vaccination against human papillomavirus among women aged 20 to 45 in rural Hunan Province,China: A cross-sectional study

ObjectiveThis study aimed to examine the intentions of and barriers to vaccination against human papillomavirus (HPV) among women aged 20 to 45 in rural areas, and to determine the popular sources to getting information about HPV vaccine and vaccination.MethodsThis cross-sectional study was conducted in 2018 with a sample of women aged 20 to 45 from rural areas of Hunan Province in China. Anonymous self-administered questionnaires were used to collect sociodemographic information and characteristics related to reproductive health of participants, and intentions of and barriers to HPV vaccination. All statistical analysis methods were performed with SPSS 18.0.ResultsA total of 2101 women participated in the study, with 58.55% intended to vaccinate against HPV. Increased intention of HPV vaccination was associated with higher age (adjusted odds ratio [AOR] = 1.35 and 1.50, respectively) and education level (AOR = 1.13 and 1.47, respectively). Women who have heard of HPV vaccine (AOR = 2.67, 95% confidence interval [CI]: 1.20–5.98) and have been aware of that cervical cancer could be prevented (AOR = 2.01, 95%CI: 1.44–2.82) were more willing to vaccinate. Having never heard of HPV vaccine and worry about efficacy and safety of vaccines were the most commonly cited reasons to refuse vaccination. The preferred source to get the knowledge was medical personnel (58.45%), followed by WeChat or Microblog, TV programs, and Internet.ConclusionWe found the intention of HPV vaccination among women aged 20 to 45 in rural China is low. Findings highlighted the importance of knowledge and trust in HPV vaccine, and suggested strengthening educational interventions on HPV vaccine and vaccination through multiple sources, including HPV vaccine coverage in health insurance to increase access.     

Influenza vaccine acceptance and hesitancy among adults hospitalized with severe acute respiratory illnesses,United States 2019–2020

IntroductionUnderstanding patient factors associated with not being vaccinated is essential for successful implementation of influenza vaccination programs.MethodsWe enrolled adults hospitalized with severe acute respiratory illness at 10 United States (US) hospitals during the 2019–2020 influenza season. We interviewed patients to collect data about influenza vaccination, sociodemographic characteristics, and vaccine perceptions.ResultsAmong 679 participants, 264 (38.9%) reported not receiving influenza vaccination. Among those not vaccinated, 135 (51.1%) reported choosing not to receive a vaccine because of perceived ineffectiveness (36.7%) or risk (14.4%) of influenza vaccination. Sociodemographic factors associated with not being vaccinated included no medical insurance (aOR = 6.42; 95% CI: 2.52–16.38) and being non-White or Hispanic (aOR = 1.54, 95% CI: 1.02–2.32).ConclusionsOptimizing uptake of influenza vaccination in the US may be improved by educational programs regarding vaccine safety and effectiveness and enhancing vaccine access, particularly among non-White and Hispanic Americans and those without medical insurance.     

Attitudes towards influenza and uptake of the flu vaccine: A survey of pharmacy staff working in English hospitals

ObjectivesPharmacy staff working in hospitals are at risk of contracting and disseminating influenza. Previous research focuses on community pharmacists’ attitudes towards influenza and vaccination. This survey investigates the beliefs and attitudes of pharmacists and other pharmacy staff working in English Hospitals regarding influenza and the vaccine and how this relates to vaccine uptake.MethodsA self-administered survey was provided to pharmacy staff at three hospitals in the East Midlands of England. Job role, age and vaccination status (vaccinated, intended to be vaccinated, and not vaccinated) were collected alongside ratings of agreement with 20 statements regarding influenza and vaccination using a Likert scale.Results170 pharmacy staff responded; 50.6% had been vaccinated, 17.1% intended to be vaccinated and 32.4% were not vaccinated. Increasing age showed a significant (p = 0.017) positive correlation with increased vaccine uptake as did the beliefs that vaccination protects the individual from influenza (p = 0.049) and that vaccination should be mandatory for NHS staff (p = 0.006). Fear of needles and believing their immune system is strong enough to protect against influenza were negatively correlated with vaccine uptake (p = 0.016 and p = 0.010, respectively). Job role was also strongly correlated with vaccine uptake (p = 0.001), with those holding a pharmacy degree more likely to report being vaccinated or intending to be vaccinated compared to all other pharmacy staff groups.ConclusionsThis is the first survey to focus on vaccine behaviours of all pharmacy staff groups working in hospitals. Current uptake of the influenza vaccine may be increased through engagement of senior pharmacy colleagues and providing education on influenza, vaccines, and vaccination. Similar studies should be undertaken on a larger scale to fully interrogate the differences between pharmacy staff groups.     

Attitudes of parents towards influenza vaccine in the Eastern Mediterranean Region: A multilevel analysis

BackgroundSeasonal influenza vaccines (SIVs) can protect against influenza and substantially reduce the risk of influenza-related hospitalizations and fatalities in children. This study aimed to assess parental attitudes towards SIVs in the Eastern Mediterranean region (EMR).MethodsThrough an anonymous online survey conducted in 19 countries in the EMR, parents or caregivers over 18 years who had at least one child above 6 months filled out the Parent Attitudes about Childhood Vaccines questionnaire. As data had two levels; country and individual factors, we utilized multilevel binary logistic regression models.ResultsIn total, 6992 respondents filled out the questionnaire. Of them, 47.4 % were residents of middle-income countries, 72.4 % of the mothers were between 26 and 45 years old, 56.5 % had at least a university degree, and approximately 51.6 % were unemployed. Nearly 50.8 % of the respondents were hesitant to vaccinate their children against seasonal influenza. Parental attitudes towards seasonal influenza vaccination differed significantly between countries, p < 0.001. The main predictors of parental seasonal influenza vaccine hesitancy (VH) were parents vaccination (odds ratio (OR) = 0.42, 95 % CI = 0.32–0.55, p < 0.001)), the mother's education if mother educated vs. who did not receive any education (OR ranged from 0.48 to 0.64, p < 0.05), living in low-income countries (OR = 0.52, 95 % CI = 0.35–0.77, p < 0.01), mountain residence (0.69, 95 % CI = 0.49–0.99, p < 0.05), health workers as a source of information (OR = 0.70, 95 % CI = 0.58–0.85, p < 0.001), children vaccination against COVID-19 (OR = 0.52, 95 % CI = 0.41–0.65, p < 0.001), not receiving routine vaccinations (OR = 1.93, 95 % CI = 1.09–3.44, p = 0.025), and if parents respondents could not remember whether their child had suffered from seasonal influenza in the previous year (OR = 1.57, 95 % CI = 1.33–1.84, p < 0.001).ConclusionA high seasonal influenza VH rate was found in the EMR. Health authorities should implement different interventions targeting the identified modifiable risk factor to increase vaccine uptake among children, especially those at risk of complication from seasonal influenza infection.     

Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old

IntroductionIn Argentina respiratory disease is the third leading cause of death in children under 5 years. In 2011 influenza vaccination was included in the National Calendar for children between 6 and 24 months (two doses schedule). Influenza vaccine coverage for second dose was 46.1% in 2013. The aim was to determine the proportion of delayed schedules and missed opportunities, to assess the characteristics of missed opportunities for vaccination and to explore the perception of influenza disease and vaccination from the parents of children between 6 and 24 months in different regions of Argentina in 2013.MethodsAnalytical observational multicenter cross-sectional study. Structured surveys were carried out to the children's parents who were between 6 and 24 months of age during the influenza virus vaccination season (April–October 2013). Chi-Square test was used to assess association and differences between proportions and categorical variables. A logistic regression model was built to identify delay predictor variables in the vaccination schedules. Missed opportunities for vaccination were characterized through the estimation of proportions.Results1350 surveys were conducted in the three centers. We detected 65% (884/1340) of delayed influenza vaccination schedules, 97% of them associated with missed opportunities of vaccination. The independent protective factors associated with a decreases risk of delayed schedules were: (a) perception of the importance of influenza vaccination (OR = 0.42(0.18–0.94); p = 0.035), (b) having less than one year of age (OR = 0.75(0.59–0.96); p = 0.022), (c) to have received information in pediatric visits or in any media (OR = 0.71(0.56–0.90); p = 0.004). There was 38% of MOIV in 1st dose and 63.4% in 2nd dose. The main cause of MOIV in 1st dose was not detecting the need for vaccination (39%) and in 2nd dose the unknowledge of the vaccination schedule (35.3%). No cultural reasons were detected.ConclusionsHigh frequency of delayed vaccination schedules and missed opportunities were detected. Parents had little concern about the safety of influenza vaccine.     

Prospective associations of regional social media messages with attitudes and actual vaccination: A big data and survey study of the influenza vaccine in the United States

ObjectiveUsing longitudinal methods to assess regional associations between social media posts about vaccines and attitudes and actual vaccination against influenza in the US.MethodsGeolocated tweets from U.S. counties (N = 115,330) were analyzed using MALLET LDA (Latent Dirichlet allocation) topic modeling techniques to correlate with prospective individual survey data (N = 3005) about vaccine attitudes, actual vaccination, and real-life discussions about vaccines with family and friends during the 2018–2019 influenza season.ResultsTen topics were common across U.S. counties during the 2018–2019 influenza season. In the overall analyses, two of these topics (i.e., Vaccine Science Matters and Big Pharma) were associated with attitudes and behaviors. The topic concerning vaccine science in November-February was positively correlated with attitudes in February-March, r = 0.09, BF₁₀ = 3. Moreover, among respondents who did not discuss the influenza vaccine with family and friends, the topic about vaccine fraud and children in November-February was negatively correlated with attitudes in February-March and with vaccination in February-March, and April-May (rs = −0.18 to −0.25, BF₁₀ = 4–146). However, this was absent when participants had discussions about the influenza vaccine with family and friends.DiscussionRegional vaccine content correlated with prospective measures of vaccine attitudes and actual vaccination.ConclusionsSocial media have demonstrated strong associations with vaccination patterns. When the associations are negative, discussions with family and friends appear to eliminate them. Programs to promote vaccination should encourage real-life conversations about vaccines.     

A community-based survey on influenza and vaccination knowledge,perceptions and practices in Peru

BackgroundAlthough Peru provides safe and effective influenza vaccines free-of-charge, coverage among vaccine target groups like pregnant women and older adults remains low. To improve risk communication messages and vaccine uptake, we explored knowledge, perceptions and practices about influenza illness and vaccination.MethodsA cross-sectional, community-based survey with a three-stage cluster sampling design was conducted in three cities in Peru. We included mothers of young children, pregnant women and persons ≥65 years. Participants completed a questionnaire about knowledge, perceptions and practices about influenza illness and vaccination against influenza during the past year. Generalized linear models were used to explore factors associated with vaccination in the past year.Results624/645 (97%) mothers, 54/55 (98%) pregnant women and 622/673 (92%) older adults approached provided informed consent and were surveyed. While most mothers, pregnant women and older adults (94%, 96% and 91%, respectively) perceived influenza as a potentially serious illness, few pregnant women (13%) and older adults (34%) self-identified themselves as a target group for influenza vaccination. Only 28% of mothers, 19% pregnant women, and 27% older adults were vaccinated against influenza during the previous year. Among the participants that did not get vaccinated against influenza in the previous year, “being afraid of vaccination and its effects” was the most commonly cited barrier. Knowledge of the recommendation for annual vaccination was significantly associated with vaccination status among pregnant women (p = 0.048) and older adults (p = 0.004).ConclusionDespite a government subsidized vaccine program, vaccine utilization remained low among pregnant women and older adults, who seemed typically unaware of their status as high-risk groups targeted for vaccination. Those aware of the recommendations for annual vaccination were more likely to be vaccinated. Information campaigns addressing fears and highlighting populations at risk for severe influenza illness that are targeted for vaccination might increase vaccine coverage in Peru.     

Trends in compliance with two-dose influenza vaccine recommendations in children aged 6 months through 8 years, 2010–2015

BackgroundChildren aged 6 months through 8 years may require two doses of influenza vaccine for adequate immune response against the disease. However, poor two-dose compliance has been reported in the literature.MethodsWe analyzed data for >2.6 million children from six immunization information system (IIS) sentinel sites, and assessed full vaccination coverage and two-dose compliance in the 2010–2015 influenza vaccination seasons. Full vaccination was defined as having received at least the recommended number of influenza vaccine doses (one or two), based on recommendations from the Advisory Committee on Immunization Practices. Two-dose compliance was defined as the percentage of children during each season who received at least two doses of influenza vaccine among those who required two doses and initiated the series.ResultsAcross seasons, ⩾1-dose influenza vaccination coverage was mainly unchanged among 6–23 month olds (range: 60.9–66.6%), 2–4 year olds (range: 44.8–47.4%), and 5–8 year olds (range: 34.5–38.9%). However, full vaccination coverage showed increasing trends from 2010–11 season to 2014–15 season (6–23 months: 43.0–46.5%; 2–4 year olds: 26.3–39.7%; 5–8 year olds, 18.5–33.9%). Across seasons, two-dose compliance remained modest in children 6–23 months (range: 63.3–67.6%) and very low in older children (range: 11.6–18.7% in children 2–4 years and 6.8–13.3% in children 5–8 years). In the 2014–15 season, among children who required and received 2 doses, only half completed the two-dose series before influenza activity peaked.ConclusionsImproved messaging of the two-dose influenza vaccine recommendations is needed for providers and parents. Providers are encouraged to determine a child’s eligibility for two doses of influenza vaccine using the child’s vaccination history, and to vaccinate children early in the season so that two-dose series are completed before influenza peaks.     

Variation in influenza vaccine assessment,receipt, and refusal by the concentration of Medicare Advantage enrollees in U.S. nursing homes

BackgroundMore older adults enrolled in Medicare Advantage (MA) are entering nursing homes (NHs), and MA concentration could affect vaccination rates through shifts in resident characteristics and/or payer-related influences on preventive services use. We investigated whether rates of influenza vaccination and refusal differ across NHs with varying concentrations of MA-enrolled residents.MethodsWe analyzed 2014–2015 Medicare enrollment data and Minimum Data Set clinical assessments linked to NH-level characteristics, star ratings, and county-level MA penetration rates. The independent variable was the percentage of residents enrolled in MA at admission and categorized into three equally-sized groups. We examined three NH-level outcomes including the percentages of residents assessed and appropriately considered for influenza vaccination, received influenza vaccination, and refused influenza vaccination.ResultsThere were 936,513 long-stay residents in 12,384 NHs. Categories for the prevalence of MA enrollment in NHs were low (0% to 3.3%; n = 4131 NHs), moderate (3.4% to 18.6%; n = 4127 NHs) and high (>18.6%; n = 4126 NHs). Overall, 81.3% of long-stay residents received influenza vaccination and 14.3% refused the vaccine when offered. Adjusting for covariates, influenza vaccination rates among long-stay residents were higher in NHs with moderate (1.70 percentage points [pp], 95% confidence limits [CL]: 1.15 pp, 2.24 pp), or high (3.05 pp, 95% CL: 2.45 pp, 3.66 pp) MA versus the lowest prevalence of MA. Influenza vaccine refusal was lower in NHs with moderate (-3.10 pp, 95% CL: ?3.53 pp, ?2.68 pp), or high (-4.63 pp, 95% CL: ?5.11 pp, ?4.15 pp) MA compared with NHs with the lowest prevalence of MA.ConclusionA higher concentration of long-stay NH residents enrolled in MA was associated with greater influenza vaccine receipt and lower vaccine refusal. As MA becomes a larger share of the Medicare program, and more MA beneficiaries enter NHs, decisionmakers need to consider how managed care can be leveraged to improve the delivery of preventive services like influenza vaccinations in NH settings.     

Using classification and regression tree analysis to explore parental influenza vaccine decisions

Background and objectivesInfluenza poses a public health threat for children and adults. The CDC recommends annual influenza vaccination for children <18 years, yet vaccine uptake remains low for children (57.9%) and adults (37.1%). Given that parental decision-making is key in childhood vaccine uptake, there is a critical need to understand vaccine hesitancy among parents who decide not to vaccinate their children. This study aims to explore predictors of children’s influenza vaccine status given parental vaccination status and examine the factors that contribute to concordance or discordance between parental and children’s vaccine uptake.MethodsClassification and regression tree (CART) analyses were used to identify drivers of parental decisions to vaccinate their children against influenza. Hierarchy and interactions of these variables in predicting children’s vaccination status were explored.ResultsFrom a nationally representative sample of non-Hispanic Black and White parents who completed an online survey (n = 328), the main factors influencing parents’ decisions to vaccinate their children were vaccine behavior following physician recommendation, knowledge of influenza recommendations for children, influenza vaccine confidence and disease risk. Among unvaccinated parents, the greatest concordance was observed among parents who usually do not get vaccinated following physician recommendation and had lower knowledge of recommendations for influenza vaccination for children. The greatest discordance was observed among unvaccinated parents who had lower hesitancy about recommended vaccines.ConclusionsUnderstanding drivers of parental decisions to vaccinate themselves and their children can provide insights on health communication and provider approaches to increase influenza vaccine coverage and prevent influenza related mortality.     

Factors associated with parental acceptance of seasonal influenza vaccination for their children – A telephone survey in the adult population in Germany

IntroductionInfluenza vaccination of children with underlying chronic diseases is currently recommended in Germany, but targeting all children constitutes an alternative approach to control seasonal influenza. To inform the modelling of vaccination impact and possible communication activities, we aimed to assess among parents the acceptance of universal childhood vaccination against seasonal influenza and possible modifiers.MethodsWe conducted a telephone survey in households in Germany using random digit dialing. We interviewed parents with children aged <18 years by constructing three hypothetical scenarios in subsequent order: (1) hearing about the influenza vaccination recommendation through the media, (2) the vaccine being recommended by a physician, and (3) being informed about the availability of the vaccine as a nasal spray. We calculated the proportion of parents who would immunize their child and used univariable and multivariable logistic regression to identify factors associated with influenza vaccination intention.ResultsResponse was between 22 and 46%. Of 518 participants, 74% were female, mean age was 41.3 years. Participants had on average 1.6 children with a mean age of 8.9 years. In scenario 1, 52% of parents would immunize their child, compared to 64% in scenario 2 (p < 0.01) and to 45% in scenario 3 (p = 0.20). Factors independently associated with vaccination acceptance in scenario 1 were previous influenza vaccination of the child or parent (adjusted odds ratio [aOR] 4.5 and 8.6, respectively), perceived severity of influenza (aOR = 5.1) and living in eastern Germany (aOR = 2.4).ConclusionIf seasonal influenza vaccination was recommended for all children, more than half of the parents would potentially agree to immunize their child. Involving physicians in future information campaigns is essential to achieve high uptake. As intranasal vaccine administration is non-invasive and easily done, it remains unclear why scenario 3 was associated with low acceptance among parents, and the underlying reasons should be further explored.     

Effectiveness of Influenza Vaccination in Institutionalized Older Adults: A Systematic Review

IntroductionInfluenza infection is common among institutionalized older adults. Many nonrandomized observational studies on influenza vaccination suggested that it could reduce influenza-related hospitalizations and mortality in institutionalized older adults. Criticism regarding the effectiveness of influenza vaccine estimated by nonrandomized observational studies include the frailty selection bias and use of nonspecific outcome, such as all-cause mortality.MethodsWe conducted a systematic review of studies of influenza vaccination in institutionalized older adults to determine the effects on clinical outcomes. We searched for studies from 3 databases from 1946 to June 2013 assessing effectiveness against influenza infection. We selected studies with good comparability between vaccine group and control group. We expressed vaccine effectiveness (VE) as a proportion, using the formula VE = 1–relative risk or 1–odds ratio. We focused on the following outcomes: influenza-like illness (ILI), laboratory confirmed influenza, hospitalizations due to ILI, or pneumonia and death due to influenza or pneumonia. We did not include all-cause mortality.ResultsEleven studies that satisfied the inclusion criteria were identified, representing 11,262 institutionalized older adults. After meta-analysis, we found a significant reduction in pneumonia (VE: 37%, 95% confidence interval [CI]: 18%–53%, P = .001) and death due to pneumonia or influenza (VE: 34%, CI: 10%–53%, P = .01). There was no significant heterogeneity between studies. There was no significant publication bias.ConclusionInfluenza vaccination in institutionalized older adults could reduce pneumonia and death due to pneumonia or influenza. Influenza vaccination is recommended for institutionalized older adults.