Survey of influenza vaccine knowledge,attitudes, and beliefs among pregnant women in the 2016–17 season

ObjectivesInfluenza vaccination coverage among pregnant women in the United States is suboptimal. We surveyed women who were pregnant during the 2016–17 influenza season to assess knowledge and attitudes regarding influenza vaccination.MethodsWe identified and sampled pregnant women to include approximately equal numbers of vaccinated and unvaccinated women from strata defined by vaccination status and trimester from four integrated health systems in the Vaccine Safety Datalink (VSD). Potential participants were contacted via mail and telephone to complete a standardized survey. Characteristics and responses of women vaccinated and unvaccinated during pregnancy were compared.ResultsThe survey was completed by 510 (48%) of 1062 contacted women; 500 were included in the analysis. Vaccine receipt while pregnant was associated with primigravida status (p = 0.02), college degree (p = 0.01), employment in health care (p < 0.01), and history of routine annual influenza vaccination (p < 0.01). Among 330 vaccinated women, the primary reasons for vaccination included protection of self and baby from influenza (n = 233, 71%), and medical professional recommendation (n = 46, 14%). Multiple reasons were given for nonvaccination, but concern about ‘negative effects’ was cited most often (n = 44, 29%). Vaccinated women were significantly more likely to believe that influenza vaccines are safe and effective, and to recognize the potential for harm from influenza infection. Nearly all women reported receiving at least one influenza vaccination recommendation from a healthcare provider.ConclusionsVaccinated pregnant women were more likely to receive routine annual influenza vaccine compared to those not vaccinated. Recommendations by obstetric providers should be supplemented with efforts to encourage women of childbearing age to receive annual vaccination.     

Does influenza vaccination attenuate the severity of breakthrough infections? A narrative review and recommendations for further research

The effect of influenza vaccination on influenza severity remains uncertain. We reviewed the literature for evidence to inform the question of whether influenza illness is less severe among individuals who received influenza vaccination compared with individuals with influenza illness who were unvaccinated prior to their illnesses. We conducted a narrative review to identify published findings comparing severity of influenza outcomes by vaccination status among community-dwelling adults and children ≥ 6 months of age with laboratory-confirmed influenza illness. When at least four effect estimates of the same type (e.g., odds ratio) were available for a specific outcome and age category (children versus adults), data were pooled with meta-analysis to generate a summary effect estimate. We identified 38 published articles reporting ≥ 1 association between influenza vaccination status and one of 21 indicators of severity of influenza illness among individuals with laboratory-confirmed influenza. Study methodologies and effect estimates were highly heterogenous, with only five severity indicators meeting criteria for calculating a combined effect. Among eight studies, influenza vaccination was associated with 26% reduction in odds of ICU admission among adults with influenza-associated hospitalization (OR = 0.74, 95% CI 0.58, 0.93). Among five studies of adults with influenza-associated hospitalization, vaccinated patients had 31% reduced risk of death compared with unvaccinated patients (OR = 0.69, 95% CI 0.52, 0.92). Among four studies of children with influenza virus infection, vaccination was associated with an estimated 45% reduction in the odds of manifesting fever (OR = 0.55, 95% CI 0.42, 0.71). Vaccination was not significantly associated with receiving a clinical diagnosis of pneumonia among adults hospitalized with influenza (OR = 0.92, 95% CI 0.82, 1.04) or with risk of hospitalization following outpatient influenza illness among adults (OR = 0.60, 95% CI 0.28, 1.28). Overall, our findings support the hypothesis that influenza vaccination may attenuate the course of disease among individuals with breakthrough influenza virus infection.     

Factors affecting repeated influenza vaccination among older people in Taiwan

Objective

This study identifies factors that influence repeated influenza vaccination among people aged 65 years and older in Taiwan.

Methods

Data of this retrospective cohort study were drawn from the 2005 National Health Interview Survey and the 2005–2007 National Health Insurance claims data; a sample of 1384 older people was analyzed. The pattern of repeated influenza vaccination was divided into 3 groups: unvaccinated all 3 years, vaccinated 1–2 times over 3 years, and vaccinated all 3 years. Multinomial logistic regression analyses were performed.

Results

Only 20.6% of older people were vaccinated all 3 years. Those 70–74 years of age (odds ratio [OR] = 1.81), living in rural areas (OR = 2.47), having one (OR = 2.07) or more (OR = 2.41) chronic conditions, frequent outpatient visits (OR = 1.48), and undergoing preventive health examinations (OR = 2.22) were more likely to have repeated vaccinations. However, those with difficulties performing one or more activities of daily living (ADL difficulty) (OR = 0.41) and seeking care from alternative medicine (OR = 0.48) were less likely to undergo regular vaccinations.

Conclusion

The repeated influenza vaccination rates in our Taiwan sample were far from optimal. Factors identified in this analysis may help to improving influenza vaccination programs.     

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.     

COVID-19 vaccination coverage in patients with chronic obstructive pulmonary disease – A cross-sectional study in Hungary

IntroductionCoronavirus infection is a particular risk for patients with chronic obstructive pulmonary disease (COPD), because they are much more likely to become severely ill due to oxygen supply problems. Primary prevention, including COVID-19 vaccination is of paramount importance in this disease group. The aim of our study was to assess COVID-19 vaccination coverage in COPD patients during the first vaccination campaign of the COVID-19 pandemic.MethodsA cross-sectional observational study (CHANCE) has been conducted in COPD patients in the eastern, western and central regions of Hungary from 15th November 2021. The anthropometric, respiratory function test results and vaccination status of 1,511 randomly selected patients were recorded who were aged 35 years and older.ResultsThe median age was 67 (61–72) years, for men: 67 (62–73) and for women: 66 (60–72) years, with 47.98 % men and 52.02 % women in our sample. The prevalence of vaccination coverage for the first COVID-19 vaccine dose was 88.62 %, whereas 86.57 % of the patients received the second vaccine dose. When unvaccinated (n = 172) and double vaccinated (n = 1308) patients were compared, the difference was significant both in quality of life (CAT: 17 (12–23) vs 14 (10–19); p < 0.001) and severity of dyspnea (mMRC: 2 (2–2) vs 2 (1–2); p = 0.048). The COVID-19 infection rate between double vaccinated and unvaccinated patients was 1.61 % vs 22.67 %; p < 0.001 six months after vaccination. The difference between unvaccinated and vaccinated patients was significant (8.14 % vs 0.08 %; p < 0.001) among those with acute COVID-19 infection hospitalized. In terms of post-COVID symptoms, single or double vaccinated patients had significantly fewer outpatient hospital admissions than unvaccinated patients (7.56 vs 0 %; p < 0.001).ConclusionThe COVID-19 vaccination coverage was satisfactory in our sample. The uptake of COVID-19 vaccines by patients with COPD is of utmost importance because they are much more likely to develop severe complications.     

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.     

Longitudinal,population-based cohort study of prenatal influenza vaccination and influenza infection in childhood

BackgroundInfluenza vaccination is recommended to protect mothers and their infants from influenza infection. Few studies have evaluated the health impacts of in utero exposure to influenza vaccine among children more than six months of age.MethodsWe used probabilistically linked administrative health records to establish a mother–child cohort to evaluate the risk of influenza and acute respiratory infections associated with maternal influenza vaccination. Outcomes were laboratory-confirmed influenza (LCI) and hospitalization for influenza or acute respiratory infection (ARI). Adjusted hazard ratios (aHRs) accounted for child’s Aboriginal status and were weighted by the inverse-probability of treatment.Results14,396 (11.5%) children were born to vaccinated mothers. Maternally vaccinated infants aged < 6 months had lower risk of LCI (aHR: 0.33; 95% CI: 0.13, 0.85), influenza-associated hospitalization (aHR: 0.39; 95% CI: 0.16, 0.94) and ARI-associated hospitalization (aHR: 0.85; 95% CI: 0.77, 0.94) compared to maternally unvaccinated infants. With the exception of an increased risk of LCI among children aged 6 months to < 2 years old following first trimester vaccination (aHR: 2.28; 95% CI: 1.41, 3.69), there were no other differences in the risk of LCI, influenza-associated hospitalization or ARI-associated hospitalization among children aged > 6 months.ConclusionStudy results show that maternal influenza vaccination is effective in preventing influenza in the first six months and had no impact on respiratory infections after two years of age.     

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.     

Duration of influenza vaccine effectiveness in the elderly in Japan: A retrospective cohort study using large-scale population-based registry data

BackgroundThe immune response to influenza vaccination in the elderly is likely to be lower than that in young adults. Clinical protection may not persist year-round in the elderly. However, the effectiveness of influenza vaccine in the elderly has not been adequately studied, especially in terms of the duration of effectiveness.MethodsWe used a linked database of healthcare administrative claims data and vaccination records maintained by the municipality of a city in Kanto region of Japan. We studied individuals who were aged 65 years or older at baseline and were followed up between April 1, 2014 to March 31, 2020. The duration of influenza vaccine effectiveness by age category was analyzed using a time-dependent piecewise Cox proportional hazard model with time-dependent vaccine status, prior season vaccination and covariates confirmed in the baseline period (age, sex, cancer, diabetes, chronic obstructive pulmonary diseases, asthma, chronic kidney diseases, and cardiovascular diseases).ResultsWe identified an analysis population of 83,146 individuals, of which 7,401 (8.9%) had experienced influenza and 270 (0.32%) underwent influenza-related hospitalization. Individuals who were vaccinated during the first season (n = 47,338) were older than non-vaccinated individuals (n = 35,808) (average age, 75.8 vs. 74.1 years, respectively). The multivariable analysis showed a lower incidence of influenza in vaccinated individuals (hazard ratio [HR], 0.47; 95% confidence interval [CI], 0.43–0.51; P < 0.001), while the incidence of hospitalization for influenza did not differ significantly by vaccination status (HR, 0.79; 95% CI, 0.53–1.18; P = 0.249). Protective effectiveness against incidence was maintained for 4 or 5 months after vaccination in those aged 65–69 and 80-years, 5 months in 70–79 years.ConclusionsOur study identified moderate vaccine effectiveness in preventing the incidence of influenza in the Japanese elderly. Vaccine effectiveness showed a trend of gradual attenuation. Clinicians should suspect influenza infection even in those vaccinated, especially in elderly individuals who had received vaccination more than 4 or 5 months previously.     

Predictors of herpes zoster vaccination among Australian adults aged 65 and over

Objective(s)To estimate HZ vaccine coverage in Australia among older Australians and to identify potential barriers to vaccination.DesignAnalysis of data from three cross-sectional surveys administered online between 2019 and 2020.Setting and participantsAdults aged 65 and over residing in Australia.Main outcome measuresSelf-reported herpes zoster vaccination.ResultsAmong the 744 adults aged 65 and over in this sample, 32% reported being vaccinated for HZ, including 23% of participants aged 65–74, 55% of participants aged 75–84, and 0% for participants aged 85 and above. Those who are vaccinated with other immunisations are more likely to have received HZ vaccine, including seasonal influenza (OR = 4.41, 95 % CI: 2.44–7.98) and pneumococcal vaccines (OR = 4.43, 95 % CI: 2.92 – 6.75). Participants with a history of certain conditions, such as stroke (OR = 2.26, 95 % CI: 1.13–4.49), were more likely to be vaccinated against HZ. Participants that reported smoking tobacco daily were less likely to be vaccinated against HZ (OR = 0.48, 95 % CI: 0.26–0.89). Participants were less likely to be vaccinated against HZ if they preferred to develop immunity ‘naturally’ (OR = 0.29, 95 % CI: 0.15 – 0.57) or expressed distrust of vaccines (OR = 0.34, 95 % CI: 0.13–0.91).Conclusion(s)Further research is required to understand the barriers to HZ vaccine uptake. Increasing the funding eligibility for those who are at risk of complications from shingles, or lowering the age of eligibility, may increase vaccine coverage.     

Lifestyle,socioeconomic characteristics,and medical history of elderly persons who receive seasonal influenza vaccination in a tax-supported healthcare system

BackgroundObservational studies on effectiveness of influenza vaccination in the elderly are thought to be biased by healthier lifestyles and higher socioeconomic status among vaccinated vs. unvaccinated persons. We examined this hypothesis in a uniform tax-supported health care system with free-of-charge influenza vaccination to the elderly.MethodsWe conducted a cross-sectional study among Danes aged 65–79 years participating in a survey. We compared elderly persons with and without a recent (within six months) influenza vaccination in terms of (i) lifestyle and socioeconomic characteristics obtained from the survey and (ii) health factors including medical history provided by Danish registries. We compared the prevalence of study variables among vaccinated and unvaccinated persons using age- and sex-adjusted prevalence ratios (aPRs) with 95% confidence intervals (CIs).ResultsAmong the 4237 elderly persons completing the survey, 1718 (41%) had received an influenza vaccination. Vaccinated persons had more comorbidity than unvaccinated persons (aPR for high comorbidity level: 1.51 95% CI 1.24–1.84), were less likely to never have smoked (aPR: 0.88, 95% CI 0.80–0.97), and had a higher prevalence of physical inactivity (aPR: 1.08, 95% CI 1.03–1.13). Levels of education and income were similar in the two groups. Vaccinated persons had a higher prevalence of major physical limitations (aPR: 1.40, 95% CI 1.17–1.66) and need for assistance with activities of daily living (aPR: 1.29, 95% CI 1.13–1.47).ConclusionElderly influenza vaccinated persons were not healthier in terms of lifestyle and burden of disease, did not have a higher socioeconomic status, and were more frail than unvaccinated persons.     

Social and demographic patterns of influenza vaccination coverage in Norway,influenza seasons 2014/15 to 2020/21

AimsTo examine influenza vaccination coverage among risk groups (RG) and health care workers (HCW), and study social and demographic patterns of vaccination coverage over time.MethodsVaccination coverage was estimated by self-report in a nationally representative telephone survey among 14 919 individuals aged 18–79 years over seven influenza seasons from 2014/15 to 2020/21. We explored whether belonging to an influenza RG (being >=65 years of age and/or having >=1 medical risk factor), being a HCW or educational attainment was associated with vaccination status using logistic regression.ResultsVaccination coverage increased from 27 % to 66 % among individuals 65–79 years, from 13 % to 33 % among individuals 18–64 years with >=1 risk factor, and from 9 % to 51 % among HCWs during the study period. Being older, having a risk factor or being a HCW were significantly associated with higher coverage in all multivariable logistic regression analyses. Higher education was also consistently associated with higher coverage, but the difference did not reach significance in all influenza seasons. Educational attainment was not significantly associated with coverage while coverage was at its lowest (2014/15–2017/18), but as coverage increased, so did the differences. Individuals with intermediate or lower education were less likely to report vaccination than those with higher education in season 2018/19, OR = 0.61 (95 % CI 0.46–0.80) and OR = 0.58 (95 % CI 0.41–0.83), respectively, and in season 2019/20, OR = 0.69 (95 % CI 0.55–0.88) and OR = 0.71 (95 % CI 0.53–0.95), respectively. When the vaccine was funded in the COVID-19 pandemic winter of 2020/21, educational differences diminished again and were no longer significant.ConclusionsWe observed widening educational differences in influenza vaccination coverage as coverage increased from 2014/15 to 2019/20. When influenza vaccination was funded in 2020/21, differences in coverage by educational attainment diminished. These findings indicate that economic barriers influence influenza vaccination decisions among risk groups in Norway.     

Veteran influenza vaccination acceptance rates after completion of the COVID-19 vaccination series among historical influenza vaccine refusers

BackgroundVaccine hesitancy remains an obstacle in disease prevention. The recent COVID-19 pandemic highlighted this issue and may influence acceptance of other recommended immunizations. The objective of this study was to determine the association between receiving the COVID-19 vaccination and the subsequent acceptance of the influenza vaccination in a Veteran population that historically declined influenza vaccination.MethodsInfluenza vaccination acceptance rates for the 2021–2022 influenza season were compared in patients who historically declined the influenza vaccine and either received or declined COVID-19 vaccinations. Logistic regression analysis was used to analyze factors associated with receiving influenza vaccination among vaccine hesitant individuals.ResultsA higher proportion of patients who had received the COVID-19 vaccination(s) subsequently accepted the influenza vaccination compared to the control group (37% vs. 11%, OR = 5.03; CI 3.15–8.26; p = 0.0001).ConclusionAmong previous influenza vaccine decliners, those who received COVID-19 vaccination had significantly higher odds of receiving subsequent influenza vaccination.     

Knowledge and attitudes towards influenza and influenza vaccination among pregnant women in Kenya

BackgroundInfluenza vaccination during pregnancy benefits mothers and children. Kenya and other low- and middle-income countries have no official influenza vaccination policies to date but are moving towards issuing such policies. Understanding determinants of influenza vaccine uptake during pregnancy in these settings is important to inform policy decisions and vaccination rollout.MethodsWe interviewed a convenience sample of women at antenatal care facilities in four counties (Nairobi, Mombasa, Marsabit, Siaya) in Kenya. We described knowledge and attitudes regarding influenza vaccination and assessed factors associated with willingness to receive influenza vaccine.ResultsWe enrolled 507 pregnant women, median age was 26 years (range 15–43). Almost half (n = 240) had primary or no education. Overall, 369 (72.8%) women had heard of influenza. Among those, 288 (78.1%) believed that a pregnant woman would be protected if vaccinated, 252 (68.3%) thought it was safe to receive a vaccine while pregnant, and 223 (60.4%) believed a baby would be protected if mother was vaccinated. If given opportunity, 309 (83.7%) pregnant women were willing to receive the vaccine. Factors associated with willingness to receive influenza vaccine were mothers’ belief in protective effect (OR 3.87; 95% CI 1.56, 9.59) and safety (OR 5.32; 95% CI 2.35, 12.01) of influenza vaccines during pregnancy.ConclusionApproximately one third of pregnant women interviewed had never heard of influenza. Willingness to receive influenza vaccine was high among women who had heard about influenza. If the Kenyan government recommends influenza vaccine for pregnant women, mitigation of safety concerns and education on the benefits of vaccination could be the most effective strategies to improve vaccine acceptance.     

Effectiveness of the current and prior influenza vaccinations in Northern Spain, 2018–2019

BackgroundThe population targeted for influenza vaccination can be repeatedly vaccinated over successive seasons, and vaccines received in previous seasons may retain preventive effect. This study aims to estimate the effectiveness of inactivated influenza vaccines received in the current and prior seasons in the 2018–2019 season.MethodsInfluenza-like illness patients attended by sentinel general practitioners or admitted to hospitals in Navarre, Spain, were tested for influenza. Vaccination status in the current and three prior seasons was obtained from the vaccination registry. The test-negative design was used to estimate the vaccine effectiveness.ResultsA total of 381 influenza A(H1N1)pdm09 cases, 341 A(H3N2) cases and 1222 controls were analysed. As compared to individuals unvaccinated in the current and three prior seasons, the influenza vaccine effectiveness against A(H1N1)pdm09 was 57% (95% confidence interval [CI]: 40%, 70%) for current season vaccination regardless of prior doses and 48% (95%CI: 14%, 68%) for vaccination in prior seasons but not in the current season. These estimates were 12% (95%CI: −23%, 37%) and 27% (95%CI: −22%, 56%), respectively, against influenza A(H3N2). Individuals vaccinated with the two A(H1N1)pdm09 strains in influenza vaccines since 2009, A/Michigan/45/2015 and A/California/07/2009, had higher protection (68%; 95%CI: 53%, 77%) than those vaccinated with A/Michigan/45/2015 only (29%, p = 0.020) or with A/California/07/2009 only (34%, p = 0.005).ConclusionThese results suggest moderate effectiveness of influenza vaccination against A(H1N1)pdm09 and low effectiveness against A(H3N2) influenza in the 2018–2019 season. Vaccination in prior seasons maintained a notable protective effect. Strains included in previous vaccines were as effective as the current vaccine strain, and both added their effects against influenza A(H1N1)pdm09.     

Factors associated to repeated influenza vaccination in the Portuguese adults with chronic conditions

Annual influenza vaccination is recommended to people with chronic conditions. This study aimed to estimate the proportion of chronically ill adults vaccinated against influenza in consecutive seasons and to identify associated factors.We used data from the first National Health Examination Survey (INSEF), a cross-sectional study conducted in 2015 on a probabilistic sample of individuals aged 25–74 years. The population was restricted to individuals who self-reported diabetes, a respiratory, cardiovascular, liver or kidney disease. Self-reported vaccination in 4 consecutive seasons was categorized in 3 levels: unvaccinated, occasionally (vaccinated 1–3 seasons) and repeatedly vaccinated (in all 4 seasons). A multinomial logistic regression was applied to estimate odds-ratio (OR) of influenza vaccination according to sociodemographic factors, chronic condition, health care use and status.In the target population, the 2014/15 influenza vaccine coverage was 33.8% (95% CI: 29.8–38.1). The higher coverage was found in individuals reporting renal disease (66.7%) and diabetes (43.8%). The coverage decreased to 32.6%, 26.0% and 20.8% for individuals with respiratory, cardiovascular and liver diseases, respectively. The probability of being repeatedly vaccinated, compared to unvaccinated, was higher in males (OR = 2.14: 95% CI: 1.31–3.52); aged 65 and 74 (OR = 4.39; 95% CI: 1.99–9.69); whom had an appointment with a general practitioner (OR = 2.77; 95% CI: 1.00–7.66) or other physician (OR = 3.95: 95% CI: 2.53–6.16); with no smoking habits (OR = 1.58; 95% I: 1.02–2.46) and reporting diabetes (OR = 2.13; 95% CI: 1.02–4.45). Finally, having a self-reported cardiovascular condition decreased the likelihood of being occasionally (OR = 0.38; 95% CI = 0.22–0.65) vaccinated against influenza.Younger individuals, females and the ones with a self-reported cardiovascular condition were identified as more likely of non-compliance to the vaccine uptake recommendation. Future vaccination strategies should focus on the previous identified population subgroups. Also, the medical recommendation of the influenza vaccine uptake should continue and be reinforced particularly in individuals with a cardiovascular condition.     

Factors associated with vaccination status among Korean submariners who are eligible for free non-mandatory influenza vaccination

IntroductionSubmarine crews live in a confined setting and are vulnerable to influenza. Thus, it would be useful to identify factors that are associated with influenza vaccination. In this study, we investigated the influenza vaccination rate and the influence of health beliefs on the vaccination rate among submariners who were eligible for a free but non-mandatory vaccination program.MethodsA total of 487 Korean submariners participated in this study after the closing of a free influenza vaccination program in 2015. Data regarding the participants’ general characteristics and health beliefs (based on the health belief model [HBM]) were collected using a self-administered questionnaire, and their vaccination status was determined using their medical records. Multiple logistic regression analysis were performed to evaluate the associations of the HBM components with influenza vaccination.ResultsThe overall vaccination rate was 78% (921/1183). The unvaccinated and vaccinated respondents exhibited similar characteristics, although the vaccinated group was significantly more likely to have high-risk family members (chronic disease, age of <2 years, or age of ⩾65 years; p = 0.025). Among the HBM components, perceived severity (odds ratio: 1.38, p = 0.019) and cue to action (odds ratio: 1.74, p = 0.002) were significantly associated with a higher likelihood of influenza vaccination.ConclusionVaccination policies that emphasize the severity of influenza and prompt individuals to undergo vaccination are needed to increase the vaccination rate among people who live in confined environments or institutions with non-mandatory vaccination programs.     

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.     

What Parents and Adolescent Boys Want in School Vaccination Programs in the United States

PurposeSchools are increasingly a part of vaccine provision, because of laws mandating provision of information by schools about vaccination, school entry requirements, and mass vaccination campaigns. We examined preferences for programmatic aspects of voluntary school mass vaccination programs (i.e., “vaccination days”).MethodsWe analyzed data from a national sample of United States parents of adolescent males ages 11–19 years (n = 308) and their sons (n = 216), who completed an online survey in November 2011.ResultsSons believed that adolescents should be able to get vaccinated without parental consent at a younger age than parents did (p < .001) and were more willing to participate in vaccination days without a parent present (p = .04). Parents perceived school vaccination days to be a more convenient way to get their sons recommended vaccines if they were younger parents, had older adolescent sons, supported laws letting schools share vaccination records with health care providers, or had sons who were previously immunized at school (all p < .05). Parents of older sons were less likely to want their sons' vaccination records sent home (odds ratio [OR] = .47; 95% confidence interval [CI], .29–.77) or to their sons' physicians (OR = .61; 95% CI, .37–.98) compared with parents of younger sons, but more likely to prefer their sons' records be entered in an immunization registry (OR = 1.66; 95% CI, 1.05–2.63).ConclusionsSons' age had an important role in support for vaccination days and preferences for sharing vaccination information with health care professionals. Parents and sons had similar beliefs about vaccination in schools, but the sons' responses suggested an interest in greater autonomy.