Increasing uptake of live attenuated influenza vaccine among children in the United States, 2008–2014

The Advisory Committee on Immunization Practices (ACIP) recommends annual influenza vaccination for all persons in the United States aged ≥6 months. On June 25, 2014, ACIP preferentially recommended live attenuated influenza vaccine (LAIV) for healthy children aged 2–8 years [1]. Little is known about national LAIV uptake. To determine uptake of LAIV relative to inactivated influenza vaccine, we analyzed vaccination records from six immunization information system sentinel sites (approximately 10% of US population). LAIV usage increased over time in all sites. Among children 2–8 years of age vaccinated for influenza, exclusive LAIV usage in the collective sentinel site area increased from 20.1% (2008–09 season) to 38.0% (2013–14). During 2013–14, at least half of vaccinated children received LAIV in Minnesota (50.0%) and North Dakota (55.5%). Increasing LAIV usage suggests formulation acceptability, and this preexisting trend offers a favorable context for implementation of ACIP's preferential recommendation.     

Usage of quadrivalent influenza vaccine among children in the United States, 2013–14

Annual influenza vaccination is recommended for everyone ≥6 months in the U.S. During the 2013–14 influenza season, in addition to trivalent influenza vaccines, quadrivalent vaccines were available, protecting against two influenza A and two influenza B viruses. We analyzed 1,976,443 immunization records from six sentinel sites to compare influenza vaccine usage among children age 6 months–18 years. A total of 983,401 (49.8%) influenza vaccine doses administered were trivalent and 920,333 (46.6%) were quadrivalent (unknown type: 72,709). Quadrivalent vaccine administration varied by age and was least frequent among those <2 years of age.     

Place of influenza vaccination among children—United States, 2010–11 through 2013–14 influenza seasons

BackgroundStudies are published on settings adults receive influenza vaccination but few have reported on settings children are vaccinated and how this might be changing over time or vary by socio-demographics.MethodsData from the National Immunization Survey-Flu were analyzed to assess place of influenza vaccination among vaccinated children 6 months–17 years during the 2010–11, 2011–12, 2012–13, and 2013–14 influenza seasons. The percentage of children vaccinated at each place was calculated overall and by age, race/ethnicity, income, and Metropolitan Statistical Area (MSA).ResultsThe places children received influenza vaccination varied little over four recent influenza seasons. From the 2010–11 through 2013–14 influenza seasons the percentage of vaccinated children receiving influenza vaccination at a doctor's office was 64.1%, 65.1%, 65.3%, and 65.3%, respectively with no differences from one season to the next. Likewise, for vaccination at clinics or health centers (17.8%, 17.5%, 17.0%. 18.0%), health departments (3.2%, 3.6%, 3.0%, 2.8%), and other non-medical places (1.6%, 1.4%, 1.2%, 1.1%), there were no differences from one season to the next. There were some differences for vaccinations at hospitals, pharmacies, and schools. There was considerable variability in the place of influenza vaccination by age, race/ethnicity, income, and MSA. Fewer Hispanic children were vaccinated at a doctor's office than black, white, and other or multiple race children and fewer black children and children of other or multiple races were vaccinated at a doctor's office than white children. More children at or below the poverty level were vaccinated at a clinic or health center than all of the other income groups.ConclusionMost vaccinated children receive their influenza vaccination at a doctor's office. Place of vaccination changed little over four recent influenza seasons. Large variability in place of vaccination exists by age, race/ethnicity, income, and MSA. Monitoring place of vaccination can help shape future immunization programs.     

High-dose influenza vaccine use among patients receiving hemodialysis in the United States, 2010–2013

BackgroundStandard influenza vaccines may be of limited benefit to patients with end-stage renal disease (ESRD). These patients may benefit from high-dose influenza vaccine, currently indicated for patients aged ≥65 years. Studies in other populations have demonstrated that high-dose vaccine elicits a stronger immunological response. We compared vaccine uptake in the United States and predictors of receipt for high-dose and standard influenza vaccines.MethodsUsing data from the United States Renal Data System (2010–2013), we conducted a cohort study of 421,482 adult patients on hemodialysis. We examined temporal trends in uptake of high-dose or standard trivalent influenza vaccine each influenza season, and used multivariate logistic regression to assess the association between individual-level variables (e.g., demographics, comorbidities) and facility-level variables (e.g., facility size and type) with vaccine receipt.ResultsThe proportion of patients with ESRD who were vaccinated with any influenza vaccine increased from 68.3% in 2010 to 72.4% in 2013. High-dose vaccines were administered to 0.9% of patients during the study period, and 16.7% of high-dose vaccines were administered to patients <65 years of age. Among patients aged ≥65 years, older patients (>79 vs. 65–69 years: OR, 1.29; 95% CI, 1.19–1.41) and patients at hospital-based versus free-standing dialysis facilities (OR, 2.31; 95% CI, 2.13–2.45) were more likely to receive high-dose vaccine, while blacks (vs. whites [OR, 0.66; 95% CI, 0.61–0.71]) and patients with longer duration of ESRD (>9 vs. 0 years: OR, 0.66; 95% CI, 0.55–0.78) were less likely to receive the high-dose vaccine.ConclusionsWhile the overall influenza vaccination rate has increased, use of high-dose vaccine among patients with ESRD was very low. Being an older patient, living in the Midwest, and receiving care at hospital-based facilities were the strongest predictors of receiving high-dose vaccine.     

Safety of quadrivalent live attenuated influenza vaccine in subjects aged 2–49 years

BackgroundQuadrivalent live attenuated influenza vaccine (Q/LAIV) was licensed in 2012 and replaced trivalent live attenuated influenza vaccine in the United States during the 2013–2014 influenza season. This study assessed the safety of Q/LAIV in children and adults aged 2–49 years.MethodsThis was a prospective observational cohort study using data collected from Kaiser Permanente Northern California. Post-vaccination events of interest were any hospitalization, hospitalization for lower respiratory tract infection, and the following medically attended events: hypersensitivity, seizures/convulsions, lower respiratory tract infection, wheezing, Guillain-Barré syndrome, Bell’s palsy, encephalitis, neuritis, vasculitis, and narcolepsy/cataplexy. The rates of these events during the risk interval post-vaccination were compared with rates observed during reference periods later in the follow-up (within-cohort analysis) and with rates observed in frequency-matched unvaccinated controls and inactivated influenza vaccine (IIV) recipients.ResultsA total of 62,040 eligible Q/LAIV recipients were identified during the 2013–2014 influenza season. Within-cohort comparisons of all Q/LAIV recipients as well as comparisons between Q/LAIV recipients and unvaccinated controls or IIV recipients did not show any significantly higher risk of hospitalizations or medically attended events following administration of Q/LAIV. Additional analyses by setting (clinic visits, emergency department visits, and hospital admissions) and age group (2–4, 5–8, 9–17, and 18–49 years) also did not reveal clinically consistent findings that suggested any increased risk after administration of Q/LAIV.ConclusionIn this large population study of individuals aged 2–49 years, no safety signals associated with the administration of Q/LAIV were observed. A much larger study population would be needed to confidently reject any association between Q/LAIV and very rare events, specifically those with an incidence of <1 event/10,000 person-years.Trial registration: ClinicalTrials.gov NCT01985997     

Influenza vaccination type,live, attenuated influenza vaccine (LAIV) versus inactivated influenza vaccine (IIV), received by children,United States, 2011−12 through 2013−14 influenza seasons

BackgroundInfluenza vaccines available for children in the United States include inactivated influenza vaccine (IIV) and live, attenuated influenza vaccine (LAIV). Objectives of this study were to quantify proportions of IIV and LAIV received by vaccinated children, and examine associations between vaccine type received and demographic characteristics.MethodsNational Immunization Survey-Flu (NIS-Flu) parental reported data for the 2011−12 through 2013−14 influenza seasons were used to estimate proportions of vaccinated children 2−17 years who received IIV and LAIV. Tests of association between vaccination type and demographic variables were conducted using Wald chi-square tests and pair-wise comparison t-tests. Multivariable logistic regression was used to determine variables independently associated with receipt of LAIV versus IIV.ResultsIn the 2013−14 season, 33.3% of vaccinated children received LAIV, similar to the proportion in the 2011−12 (32.2%) and 2012−13 (32.1%) seasons. Across all seasons studied, the strongest observed association was between vaccination type and child's age, with children 2−8 years (Adjusted Prevalence Ratio (95% confidence interval) [APR(95% CI)] 1.41(1.27−1.56), 1.46(1.34−1.59), and 1.50(1.38−1.63) for 2011−12, 2012−13, and 2013−14) and 9−12 years (APR(95% CI) 1.37(1.23−1.54), 1.38(1.26−1.51), and 1.50(1.38−1.63) for 2011−12, 2012−13, and 2013−14) being more likely to have received LAIV than children 13−17 years. Among those vaccinated, whites were more likely to have received LAIV compared with blacks (APR(95% CI) 1.19(1.05−1.35), 1.24(1.10−1.39), and 1.22(1.11−1.34) for 2011−12, 2012−13, and 2013−14), and children living above poverty (annual income >$75,000) were more likely to have received LAIV than those living at or below poverty (APR(95% CI) 1.43(1.23−1.67), 1.13(1.02−1.26), and 1.16(1.06−1.28) for 2011−12, 2012−13, and 2013−14).ConclusionsThis study provides a baseline of the extent and patterns of LAIV uptake that can be used to measure the impact of relevant public health policy. Additional research is needed to investigate parental and provider preferences and barriers regarding LAIV.     

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

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

National and state-specific estimates of place of influenza vaccination among adult populations – United States, 2011–12 influenza season

Background

Annual influenza vaccination has been recommended for all persons ≥6 months since the 2010–11 season. New partnerships between public health agencies and medical and nonmedical vaccination providers have increased the number of vaccination providers and locations where vaccination services are delivered.

Methods

Data from the 2011–12 Behavioral Risk Factor Surveillance System (BRFSS) were analyzed. Point estimates of place of vaccination and 95% confidence intervals were calculated. Multivariable logistic regression and predictive marginal modeling were conducted to identify factors associated with vaccination settings.

Results

Among adults vaccinated during the 2011–12 influenza season, a doctor's office was the most common place (38.4%) for receipt of influenza vaccination, with stores (e.g., supermarkets or drug stores) (20.1%) the next common, and workplaces (17.6%) the third common. Overall, reported vaccination in nonmedical settings by state ranged from 32.2% in California to 60.4% in Nevada, with a median of 45.8%. Characteristics significantly associated with an increased likelihood of receipt of vaccination in nonmedical settings were higher education, not having certain identified high-risk conditions, not having had a routine checkup in the previous 12 months, and not having a primary doctor for health care. Being a member of a racial/ethnic minority group, unemployed or not in the work force were significantly associated with a decreased likelihood of receipt of vaccination in nonmedical settings.

Conclusion

Doctor's offices were the most common medical setting for adult influenza vaccination; workplaces and stores were important nonmedical settings. Increasing access to vaccination services in medical and nonmedical settings should be considered as important strategies for improving vaccination coverage. These results also can help guide development of strategies for achieving Healthy People 2020 objectives for influenza vaccination of adult populations.     

Post-licensure surveillance of quadrivalent live attenuated influenza vaccine United States,Vaccine Adverse Event Reporting System (VAERS), July 2013–June 2014

BackgroundQuadrivalent live attenuated influenza vaccine (LAIV4) was approved in 2012 for healthy persons aged 2–49 years. Beginning with the 2013–2014 influenza season, LAIV4 replaced trivalent live attenuated influenza vaccine (LAIV3).MethodsWe analyzed LAIV4 reports to VAERS, a national spontaneous reporting system. LAIV4 reports in 2013–2014 were compared to LAIV3 reports from the previous three influenza seasons. Medical records were reviewed for non-manufacturer serious reports (i.e., death, hospitalization, prolonged hospitalization, life-threatening illness, permanent disability) and reports of selected conditions of interest. We conducted Empirical Bayesian data mining to identify disproportional reporting for LAIV4.ResultsIn 2013–2014, 12.7 million doses of LAIV4 were distributed and VAERS received 779 reports in individuals aged 2–49 years; 95% were non-serious. Expired drug administered (42%), fever (13%) and cough (8%) were most commonly reported in children aged 2–17 years when LAIV4 was administered alone, while headache (18%), expired drug administered (15%) and exposure during pregnancy (12%) were most common in adults aged 18–49 years. We identified one death report in a child who died from complications of cerebellar vascular tumors. Among non-death serious reports, neurologic conditions were common in children and adults. In children, seizures (3) and Guillain-Barré syndrome (2) were the most common serious neurologic outcomes. We identified three serious reports of asthma/wheezing following LAIV4 in children. Data mining detected disproportional reporting for vaccine administration errors and for influenza illness in children.ConclusionsOur analysis of VAERS reports for LAIV4 did not identify any concerning patterns. The data mining finding for reports of influenza illness is consistent with low LAIV4 vaccine effectiveness observed for influenza A disease in children in 2013–2014. Reports of LAIV4 administration to persons in whom the vaccine is not recommended (e.g., pregnant women) indicate the need for education, training and screening regarding indications.     

Recommendations and offers for adult influenza vaccination, 2011–2012 season,United States

BackgroundProvider recommendations and offers for influenza vaccination improve adult influenza vaccination coverage. Analysis was performed to describe receipt of influenza vaccination recommendations and offers among adults who visited a healthcare provider (HCP) during the 2011–2012 influenza season and describe differences between those receiving and not receiving recommendations and offers for influenza vaccination. Associations between influenza vaccination and receipt of recommendations and offers were examined.MethodsRespondents to a random digit dial telephone survey who had visited a HCP since July 1, 2011 were asked if they had received a recommendation for influenza vaccination. Those receiving a recommendation were asked if they received an offer for vaccination. Participants were characterized by demographic and access to health care variables. Logistic regression was used to examine the relationships between participant characteristics and recommendation alone, between participant characteristics and recommendation and offer, and between influenza vaccination and recommendation and offer.ResultsOf those who reported visiting a HCP, 43.8% reported receiving a recommendation for influenza vaccination. Of those who reported receiving a recommendation, 76.6% reported receiving an offer for influenza vaccination. Persons with high-risk conditions and persons over 65 years were more likely to receive recommendations for influenza vaccination when compared to those without high-risk conditions and 18–49 year olds, respectively. Those reporting receipt of a recommendation and offer for influenza vaccination were 1.76 times more likely and those reporting receipt of a recommendation but no offer were 1.72 times more likely to report being vaccinated for influenza controlling for all patient characteristics.ConclusionsLess than half of respondents reported receipt of recommendations and offers of influenza vaccination during the 2011–2012 influenza season and disparities exist between groups. All healthcare providers seeing adults should recommend or offer influenza vaccination for all patients at every visit during the influenza season.     

Trends in vaccination coverage disparities among children,United States, 2001–2010

Introduction

One of two overarching goals of the Healthy People 2010 initiative was to eliminate health disparities. We evaluate trends in children vaccination coverage disparities by socio-demographic characteristics in the United States from 2001 through 2010.

Methods

Disparities in vaccination coverage for the 4:3:1:3:3:1 vaccine series was assessed with National Immunization Survey (NIS) 2001–2010 data. The disparities between two categories of population were independently evaluated yearly from 2001 through 2010.

Results

In 2001, 10 out of 12 disparities were significant (P-value <0.05). Six disparities were reduced from statistically significant in 2001 to not significant in 2010. Across 2001–2010, 8 disparities narrowed significantly; the average change in disparities per year were negative and ranged from −0.30% to −0.64% (P-value <0.05).

Conclusions

Significant success has been achieved in reducing disparities in vaccination coverage for young children among most of the major socio-demographic subpopulations in the United States by 2010.     

Assessment of influenza vaccine effectiveness in a sentinel surveillance network 2010–13, United States

BackgroundInfluenza vaccines are now widely used to reduce the burden of annual epidemics of influenza virus infections. Influenza vaccine effectiveness (VE) is monitored annually to determine VE against each season's circulating influenza strains in different groups such as children, adults and the elderly. Few prospective surveillance programs are available to evaluate influenza VE against medically attended illness for patients of all ages in the United States.MethodsWe conducted surveillance of patients with acute respiratory illnesses in 101 clinics across the US during three consecutive influenza seasons. We analyzed laboratory testing results for influenza virus, self-reported vaccine history, and patient characteristics, defining cases as patients who tested positive for influenza virus and controls as patients who tested negative for influenza virus. Comparison of influenza vaccination coverage among cases versus controls, adjusted for potential confounders, was used to estimate VE as one minus the adjusted odds ratio multiplied by 100%.ResultsWe included 10,650 patients during three influenza seasons from August 2010 through December 2013, and estimated influenza VE in children 6m–5y of age (58%; 95% CI: 49%–66%), children 6–17y (45%; 95% CI: 34%–53%), adults 18–49y (36%; 95% CI: 24%, 46%), and adults ≥50y (34%, 95% CI: 13%, 51%). VE was higher against influenza A(H1N1) compared to A(H3N2) and B.ConclusionsOur estimates of moderate influenza VE confirm the important role of vaccination in protecting against medically attended influenza virus infection.     

Hepatitis B vaccination among adolescents 13–17 years,United States, 2006–2012

BackgroundHepatitis B (HepB) vaccination is the most effective measure to prevent HBV infection. Routine HepB vaccination was recommended for infants in 1991 and catch-up vaccination has been recommended for adolescents since in 1995. The purpose of this study is to assess HepB vaccination among adolescents 13–17 years.MethodsThe 2006–2012 NIS-Teen were analyzed. Vaccination trends and coverage by birth cohort among adolescents were evaluated. Multivariable logistic regression and predictive marginal models are used to identify factors independently associated with HepB vaccination.ResultsHepB vaccination coverage increased from 81.3% in 2006 to 92.8% in 2012. Coverage varied by birth cohort and 79–83% received vaccination before 2 years of age for those who were born during 1995 and 1999. Among those who had not received vaccination by 11 years of age, for the 1993–1995 birth cohorts, 9–15% were vaccinated during ages 11–12 years, and 27–37% had been vaccinated through age 16 years. Coverage among adolescents 13–17 years in 2012 ranged by state from 84.4% in West Virginia to 98.7% in Florida (median 93.3%). Characteristics independently associated with a higher likelihood of HepB vaccination included living more than 5 times above poverty level, living in Northeastern or Southern region of the United States, and having a mixed facility as their vaccination provider. Those with a hospital listed as their vaccination provider and those who did not have a well-child visit at age 11–12 years were independently associated with a lower likelihood of HepB vaccination.ConclusionsEfforts focused on groups with lower coverage may reduce disparities in coverage and prevent hepatitis B infection. Parents and providers should routinely review adolescent immunizations. Routine reminder/recall, expanded access in health care settings, and standing order programs should be incorporated into routine clinical care of adolescents.     

Factors associated with perceptions of influenza vaccine safety and effectiveness among adults,United States, 2017–2018

BackgroundAnnual vaccination against seasonal influenza is widely recognized as the primary intervention method in preventing morbidity and mortality from influenza, but coverage among adults is suboptimal in the United States. Safety and effectiveness perceptions regarding vaccines are consistently cited as factors that influence adults’ decisions to accept or reject vaccination. Therefore, we conducted this analysis in order to understand sociodemographic, attitude, and knowledge factors associated with these perceptions for influenza vaccine among adults in three different age groups.MethodsProbability-based Internet panel surveys using nationally representative samples of adults aged ≥19 years in the United States were conducted during February–March of 2017 and 2018. We asked respondents if they believed the influenza vaccine was safe and effective. We calculated prevalence ratios using chi-square and pairwise t-tests to determine associations between safety and effectiveness beliefs and sociodemographic variables for adults aged 19–49, 50–64, and ≥65 years.ResultsSurvey completion rates were 58.2% (2017) and 57.2% (2018); we analyzed 4597 combined responses. Overall, most adults reported the influenza vaccine was safe (86.3%) and effective (73.0%). However, fewer younger adults reported positive perceptions compared with older age groups. Respondents who believed the vaccine was safe also reported it was effective.ConclusionsGenerally, adults perceived the influenza vaccine as safe and effective. Considering this, any improvements to these perceptions would likely be minor and have a limited effect on coverage. Future research to understand why, despite positive perceptions, adults are still choosing to forego the vaccine may be informative.     

Seasonal influenza vaccine coverage among high-risk populations in Thailand, 2010–2012

BackgroundThe Advisory Committee on Immunization Practice of Thailand prioritizes seasonal influenza vaccinations for populations who are at highest risk for serious complications (pregnant women, children 6 months–2 years, persons ≥65 years, persons with chronic diseases, obese persons), and healthcare personnel and poultry cullers. The Thailand government purchases seasonal influenza vaccine for these groups. We assessed vaccination coverage among high-risk groups in Thailand from 2010 to 2012.MethodsNational records on persons who received publicly purchased vaccines from 2010 to 2012 were analyzed by high-risk category. Denominator data from multiple sources were compared to calculate coverage. Vaccine coverage was defined as the proportion of individuals in each category who received the vaccine. Vaccine wastage was defined as the proportion of publicly purchased vaccines that were not used.ResultsFrom 2010 to 2012, 8.18 million influenza vaccines were publicly purchased (range, 2.37–3.29 million doses/year), and vaccine purchases increased 39% over these years. Vaccine wastage was 9.5%. Approximately 5.7 million (77%) vaccine doses were administered to persons ≥65 years and persons with chronic diseases, 1.4 million (19%) to healthcare personnel/poultry cullers, 82,570 (1.1%) to children 6 months–2 years, 78,885 (1.1%) to obese persons, 26,481 (0.4%) to mentally disabled persons, and 17,787 (0.2%) to pregnant women. Between 2010 and 2012, coverage increased among persons with chronic diseases (8.6% versus 14%; p < 0.01) and persons ≥65 years (12%, versus 20%; p < 0.01); however, coverage decreased for mentally disabled persons (6.1% versus 4.9%; p < 0.01), children 6 months–2 years (2.3% versus 0.9%; p < 0.01), pregnant women (1.1% versus 0.9%; p < 0.01), and obese persons (0.2% versus 0.1%; p < 0.01).ConclusionsFrom 2010 to 2012, the availability of publicly purchased vaccines increased. While coverage remained low for all target groups, coverage was highest among persons ≥65 years and persons with chronic diseases. Annual coverage assessments are necessary to promote higher coverage among high-risk groups in Thailand.     

Influenza vaccine effectiveness among patients with high-risk medical conditions in the United States, 2012–2016

BackgroundAnnual influenza vaccination has been recommended for persons with high-risk conditions since the 1960s. However, few estimates of influenza vaccine effectiveness (VE) for persons with high-risk conditions are available.MethodsData from the U.S. Influenza Vaccine Effectiveness Network from 2012 to 2016 were analyzed to compare VE of standard-dose inactivated vaccines against medically-attended influenza among patients aged ≥6 months with and without high-risk medical conditions. Patients with acute respiratory illness were tested for influenza by RT-PCR. Presence of high-risk conditions and vaccination status were obtained from medical records. VE by influenza virus type/subtype and age group was calculated for patients with and without high-risk conditions using the test-negative design. Interaction terms were used to test for differences in VE by high-risk conditions.ResultsOverall, 9643 (38%) of 25,369 patients enrolled during four influenza seasons had high-risk conditions; 2213 (23%) tested positive for influenza infection. For all ages, VE against any influenza was lower among patients with high-risk conditions (41%, 95% CI: 35–47%) than those without (48%, 95% CI: 43–52%; P-for-interaction = 0.02). For children aged <18 years, VE against any influenza was 51% (95% CI: 39–61%) and 52% (95% CI: 39–61%) among those with and without high-risk conditions, respectively (P-for-interaction = 0.54). For adults aged ≥18 years, VE against any influenza was 38% (95% CI: 30–45%) and 44% (95% CI: 38–50%) among those with and without high-risk conditions, respectively (P-for-interaction = 0.21). For both children aged <18 and adults aged ≥18 years, VEs against illness related to influenza A(H3N2), A(H1N1)pdm09, and influenza B virus infection were similar among those with and without high-risk conditions.ConclusionsInfluenza vaccination provided protection against medically-attended influenza among patients with high-risk conditions, at levels approaching those observed among patients without high-risk conditions. Results from our analysis support recommendations of annual vaccination for patients with high-risk conditions.     

Reasons given for not receiving an influenza vaccination, 2011–12 influenza season,United States

BackgroundInfluenza vaccination coverage in the United States remains below national targets and racial/ethnic differences persist.ObjectivesTo gain insights into potential strategies for improving influenza vaccination by examining reasons given for not receiving an influenza vaccination during the 2011–12 influenza season.MethodsData from the National Flu Survey were analyzed for the 2011–12 influenza season.Tests of association between reasons for non-vaccination and demographic variables were conducted using Wald chi-square tests. Multivariable logistic regression analyses were used to determine variables independently associated with each reason for non-vaccination.ResultsFor adults and children, there were no racial/ethnic differences in the overall most frequent reason for non-vaccination: “unlikely to get very sick from the flu”. Regarding adults, there were racial/ethnic differences in seven of the twelve reasons for non-vaccination in bivariate analyses, but only three remained significant in the multivariable models. Most notable of these was that blacks (40.9%) were more likely than Hispanics (27.0%), whites (25.2%), and adults of other/multiple races (21.2%) to report concerns about getting the flu from the vaccination and blacks (39.8%) were more likely than whites (28.4%) and adults of other/multiple races (29.3%) to report concerns about side effects from the vaccine. Regarding children, there were racial/ethnic differences for three of the reasons for non-vaccination, and these remained significant in the multivariable models. The most noteworthy of these was that more black (44.4%) than white (24.0%) and other/multiple race (19.0%) parents had concerns about their child getting the flu from the vaccination. Other demographic variables (age, gender income, MSA for adults and age and income for children) were also associated with reasons for non-vaccination based on the multivariable models.ConclusionsThere are racial/ethnic group differences in reasons for not receiving an influenza vaccination; recognition of these differences should guide the choice of interventions to increase vaccination rates.