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.     

Comparison of vaccine effectiveness against influenza hospitalization of cell-based and egg-based influenza vaccines, 2017–2018

Egg-based influenza vaccines could be less effective than cell-based vaccine due to adaptive mutations acquired for growth. We conducted a test-negative case-control study at Kaiser Permanente Southern California to assess vaccine effectiveness (VE) against hospitalization for laboratory-confirmed influenza during 2017–2018. Among the 1186 cases and 6946 controls, 74% and 59%, respectively, were ages ≥ 65 years. For any influenza, the adjusted relative VE of cell-based vaccine versus egg-based vaccines was 43% (95% CI: −45% to 77%) for patients ages < 65 years and 6% (95% CI: −46% to 39%) for patients ages ≥ 65 years. For influenza A(H3N2), the adjusted relative VE was 61% (95% CI: −63% to 91%) for patients ages < 65 years and −4% (95% CI: −70% to 37%) for patients ages ≥ 65 years. Statistically significant protection against influenza hospitalization of cell-based vaccine compared to egg-based vaccines was not observed, but further studies in additional influenza seasons are warranted.     

Reasons for low influenza vaccination coverage among adults in Puerto Rico,influenza season 2013–2014

BackgroundInfluenza vaccination is recommended annually for all persons 6 months and older. Reports of increased influenza-related morbidity and mortality during the 2013–2014 influenza season raised concerns about low adult influenza immunization rates in Puerto Rico. In order to inform public health actions to increase vaccination rates, we surveyed adults in Puerto Rico regarding influenza vaccination-related attitudes and barriers.MethodsA random-digit-dialing telephone survey (50% landline: 50% cellphone) regarding influenza vaccination, attitudes, practices and barriers was conducted November 19–25, 2013 among adults in Puerto Rico. Survey results were weighted to reflect sampling design and adjustments for non-response.ResultsAmong 439 surveyed, 229 completed the survey with a 52% response rate. Respondents’ median age was 55 years; 18% reported receiving 2013–2014 influenza vaccination. Among 180 unvaccinated respondents, 38% reported barriers associated with limited access to vaccination, 24% reported they did not want or need influenza vaccination, and 20% reported safety concerns. Vaccinated respondents were more likely to know if they were recommended for influenza vaccination, to report greater perceived risk of influenza illness, and to report being less concerned about influenza vaccine safety (p-value < 0.05). Of the 175 respondents who saw a healthcare provider (HCP) since July 1, 2013, 38% reported their HCP recommended influenza vaccination and 17% were offered vaccination. Vaccination rates were higher among adults who received a recommendation and/or offer of influenza vaccination (43% vs. 14%; p-value < 0.01).ConclusionsFailure of HCP to recommend and/or offer influenza vaccination and patient attitudes (low perceived risk of influenza virus infection) may have contributed to low vaccination rates during the 2013–2014 season. HCP and public health practitioners should strongly recommend influenza vaccination and provide vaccinations during clinical encounters or refer patients for vaccination.     

Three-season effectiveness of inactivated influenza vaccine in preventing influenza illness and hospitalization in children in Japan, 2013–2016

ObjectivesWe assessed the vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) in children 6 months to 15 years of age in 2015/16 season. In addition, based on the data obtained during the three seasons from 2013 to 2016, we estimated the three-season VE in preventing influenza illness and hospitalization.MethodsOur study was conducted according to a test-negative case-control design (TNCC) and as a case-control study based on influenza rapid diagnostic test results.ResultsDuring 2015/16 season, the quadrivalent IIV was first used in Japan. The adjusted VE in preventing influenza illness was 49% (95% confidence interval [CI]: 42–55%) against any type of influenza, 57% (95% CI: 50–63%) against influenza A and 34% (95% CI: 23–44%) against influenza B. The 3-season adjusted VE was 45% (95% CI: 41–49%) against influenza virus infection overall (N = 12,888), 51% (95% CI: 47–55%) against influenza A (N = 10,410), and 32% (95% CI: 24–38%) against influenza B (N = 9232). An analysis by age groups showed low or no significant VE in infants or adolescents. By contrast, VE was highest in the young group (1–5 years old) and declined with age thereafter. The 3-season adjusted VE in preventing hospitalization as determined in a case-control study was 52% (95% CI: 42–60%) for influenza A and 28% (95% CI: 4–46%) for influenza B, and by TNCC design, it was 54% (95% CI: 41–65%) for influenza A and 34% (95% CI: 6–54%) for influenza B.ConclusionWe demonstrated not only VE in preventing illness, but also VE in preventing hospitalization based on much larger numbers of children than previous studies.     

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.     

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.     

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.     

Estimated influenza illnesses and hospitalizations averted by influenza vaccination among children aged 6–59 months in Suzhou,China, 2011/12 to 2015/16 influenza seasons

BackgroundThere are few estimates of vaccination-averted influenza-associated illnesses in China.MethodsWe used a mathematical model and Monte Carlo algorithm to estimate numbers and 95% confidence intervals (CI) of influenza-associated outcomes (hospitalization, illness, and medically-attended (MA) illness) averted by vaccination among children aged 6–59 months in Suzhou from October 2011–September 2016. Influenza illnesses included non-hospitalized MA influenza illnesses and non-MA influenza illnesses. The numbers of influenza-associated outcomes averted by vaccination were the difference between the expected burden if there were no vaccination given and the observed burden with vaccination. The model incorporated the disease burden estimated based on surveillance data from Suzhou University Affiliated Children’s Hospital (SCH) and data from health utilization surveys conducted in the catchment area of SCH, age-specific estimates of influenza vaccination coverage in Suzhou from the Expanded Program on Immunization database, and influenza vaccine effectiveness estimates from previous publications. Averted influenza estimations were presented as absolute numbers and in terms of the prevented fraction (PF). A hypothetical scenario with 50% coverage (but identical vaccine effectiveness) over the study period was also modeled.ResultsIn ~250,000 children, influenza vaccination prevented an estimated 731 (CI: 549–960) influenza hospitalizations (PF: 6.2% of expected, CI: 5.8–6.6%) and 10,024 (7593–12,937) influenza illnesses (PF: 6.5%, 6.4–6.7%), of which 8342 (6338–10,768) were MA (PF: 6.6%, 6.4–6.7%) from 2011 to 2016. The PFs declined each year along with decreasing influenza vaccination coverage. If 50% of the study population had been vaccinated over time, the estimated numbers of averted cases during the study period would have been 4059 (3120–5762) influenza hospitalizations (PF: 27.2%, 26.4–27.9%) and 56,215 (42,925–78,849) influenza illnesses (PF: 28.5%, 28.3–28.7%), of which 46,596 (35,662–65,234) would be MA (PF: 28.5%, 28.3–28.7%).ConclusionInfluenza vaccination is estimated to have averted influenza-associated illness outcomes even with low coverage in children aged 6–59 months in Suzhou. Increasing influenza vaccination coverage in this population could further reduce illnesses and hospitalizations.     

A multi-country investigation of influenza vaccine coverage in pregnant individuals, 2010–2016

BackgroundMany countries recommend influenza vaccination during pregnancy. Despite this recommendation, influenza vaccine among pregnant individuals remains under-utilized and uptake varies by country. Factors associated with influenza vaccine uptake during pregnancy may also vary across countries.MethodsAs members of the Pregnancy Influenza Vaccine Effectiveness Network (PREVENT), five sites from four countries (Australia, Canada, Israel, and the United States) retrospectively identified cohorts of individuals aged 18–50 years who were pregnant during pre-defined influenza seasons. Influenza vaccine coverage estimates were calculated for the 2010–11 through 2015–16 northern hemisphere and the 2012 through 2015 southern hemisphere influenza seasons, by site. Sites used electronic health records, administrative data, and immunization registries to collect information on pregnancy, health history, demographics, and vaccination status. Each season, vaccination coverage was calculated as the percentage of individuals who received influenza vaccine among the individuals in the cohort that season. Characteristics were compared between those vaccinated and unvaccinated, by site.ResultsMore than two million pregnancies were identified over the study period. Influenza vaccination coverage ranged from 5% to 58% across sites and seasons. Coverage increased consistently over the study period at three of the five sites (Western Australia, Alberta, and Israel), and was highest in all seasons at the United States study site (39–58%). Associations with vaccination varied by country and across seasons; where available, parity >0, presence of a high-risk medical condition, and urban residence were consistently associated with increased likelihood of vaccination.ConclusionsThough increasing, uptake of influenza vaccine among pregnant individuals remains lower than recommended. Coverage varied substantially by country, suggesting an ongoing need for targeted strategies to improve influenza vaccine uptake in this population.     

Effectiveness of inactivated influenza vaccine in children by vaccine dose, 2013–18

ObjectivesWe assessed the vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) by vaccine dose in children aged 6 months to 12 years for whom two doses are recommended in Japan to ascertain the appropriate vaccine doses.MethodsVE was assessed according to a test-negative case-control design based on rapid influenza diagnostic test (RIDT) results. Children aged 6 months to 12 years with a fever ≥38 °C who had received an RIDT in outpatient clinics of 24 hospitals were enrolled for all five seasons since 2013/14. VE by vaccine dose (none vs. once or twice, and once vs. twice) was analyzed.ResultsIn the dose analysis, 20,033 children were enrolled. Both one- and two-dose regimens significantly reduced cases in preventing any influenza, influenza A, and influenza B, but there was no significant difference in adjusted VE between one- and two-dose regimens overall (adjusted OR, 0.560 [95% CI, 0.505–0.621], 0.550 [95% CI, 0.516–0.586]), 0.549 [95% CI, 0.517–0.583], and 1.014 [95% CI, 0.907–1.135], for none vs. once, none vs. twice, none vs. once or twice, and once vs. twice for any influenza, respectively). Both one- and two-dose regimens significantly reduced cases with any influenza and influenza A every season. Also, both regimens significantly reduced cases of any influenza, influenza A, and influenza B among children aged 1–12 years, especially among those aged 1–5 years. In the 2013/14, 2015/16, and 2016/17 seasons, however, only the two-dose regimen was significantly effective in preventing influenza B. Both one- and two-dose regimens significantly reduced cases involving hospitalization due to any influenza and influenza A.ConclusionsBoth one- and two-doses regimens of IIV were effective in preventing influenza for children aged 6 months to 12 years. The two-dose regimen was more effective against influenza B in some seasons.     

Seasonal influenza vaccine supply and target vaccinated population in China, 2004–2009

To better understand the gap between limited influenza vaccine supply and the target population for vaccination in China, we conducted a retrospective survey to quantify the production capacity, supply and sale of seasonal trivalent inactive vaccine (TIV) from the 2004–2005 through the 2008–2009 season, and estimated the target population who should receive annual influenza vaccine. The maximum domestic capacity to produce TIV was 126 million doses in 2009. A total of 32.5 million doses of TIV were supplied in 2008–2009, with an average annual increase rate of 18% from 16.9 million in 2004–2005. This represents an amount sufficient to vaccinate 1.9% of Chinese population. The average number of doses of TIV for sale by province ranged from <5 to 108 per 1000 people. The differences are explained in part by level of economic development but also influenced by local reimbursement policies in some provinces. Based on national recommendations, we estimated a target population of 570.6 million or 43% of the total population. Supply and domestic production capacity for influenza vaccine is currently insufficient to vaccinate the estimated target population in China. The Government of China should consider measures to improve domestic production capacity of influenza vaccine, expand successful promotional campaigns, and add cost subsidies in high risk groups to further encourage influenza vaccine usage.     

Seasonal influenza vaccine effectiveness against influenza in 2012–2013: A hospital-based case-control study in Lithuania

Background

Due to scarce information on seasonal influenza vaccine effectiveness (SIVE) against severe clinical influenza outcomes in risk populations, we conducted a case-control study to assess its effects against laboratory-confirmed influenza in hospitalized patients during the 2012–2013 influenza season.

Methods

We conducted a test-negative case-control study among ≥18 years old patients with influenza-like illness (ILI) hospitalized in two Lithuanian hospitals. Cases were influenza A(H1N1), A(H3) or influenza B positive by RT-PCR, and controls were influenza negative. Additional demographic and clinical data to assess the role of confounding were collected. SIVE and its confidence intervals (95% CI) were estimated by using multivariate logistic regression as (1 − OR) × 100%.

Results

The sample consisted of 185 subjects. Seasonal influenza vaccine uptake was 5%. Among 111 (60%) influenza positive cases, 24.3% were A(H1N1), 10.8% were A(H3) and 24.3% were influenza B cases. Unadjusted SIVE was 79% (95% CI −6% to 96%) and after the adjustment it increased to 86% (95% CI 19% to 97%).

Conclusions

Seasonal influenza vaccination in 2012–2013 was associated with reduced occurrence of laboratory-confirmed influenza, but due to low sample size the estimate of SIVE is imprecise. Given high prevalence of influenza in hospitalized ILI cases and low influenza vaccination coverage, there is a need to increase influenza vaccination rates.     

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.     

A study of excess mortality during influenza epidemics in the Czech Republic, 1982–2000

Influenza related mortality rates have been established in many countries; nevertheless, studies focusing on the Central European population have been rare to date. We assess mortality attributable to influenza by comparing all cause mortality and mortality due to diseases of the circulatory system during influenza epidemic and non-epidemic periods, as defined by acute respiratory infection surveillance data. Data on total mortality, mortality due to diseases of the circulatory system and surveillance data for influenza and other respiratory infections were used in a general linear model with a logarithmic link for dependence of left censored mortality data over time, and week as a categorical factor. Results of the analysis show statistically significant (p <0.001) differences in excess mortality rates between influenza epidemic and non-epidemic periods in the Czech Republic between 1982 and 2000. We estimate that 2.17% of all cause mortality, and 2.57% of mortality due to diseases of the circulatory system throughout the study period was attributable to influenza, with an estimated annual average of 2661 and 1752 deaths respectively. The highest numbers of deaths were reported during seasons when influenza A/H3N2 was the predominant circulating strain. Improving vaccination coverage against influenza is considered to be the primary strategy for prevention of influenza associated mortality.     

The 2015–2016 influenza epidemic in Beijing,China: Unlike elsewhere,circulation of influenza A(H3N2) with moderate vaccine effectiveness

BackgroundWhile the 2015–2016 influenza season in the northern hemisphere was dominated by A(H1N1)pdm09 and B/Victoria viruses, in Beijing, China, there was also significant circulation of influenza A(H3N2) virus. In this report we estimate vaccine effectiveness (VE) against influenza A(H3N2) and other circulating viruses, and describe further characteristics of the 2015–2016 influenza season in Beijing.MethodsWe estimated VE of the 2015–2016 trivalent inactivated vaccine (TIV) against laboratory-confirmed influenza virus infection using the test-negative study design. The effect of prior vaccination on current VE was also examined.ResultsOf 11,000 eligible patients included in the study, 2969 (27.0%) were influenza positive. Vaccination coverage was 4.2% in both cases and controls. Adjusted VE against all influenza was 8% (95% CI: −16% to 27%): 18% (95% CI: −38% to 52%) for influenza A(H1N1)pdm09, 54% (95% CI: 16% to 74%) for influenza A(H3N2), and −8% (95% CI: −40% to 18%) for influenza B/Victoria. The overall VE for receipt of 2015–2016 vaccination only, 2014–2015 vaccination only, and vaccinations in both seasons was −15% (95% CI: −63% to 19%), −25% (95% CI: −78% to 13%), and 18% (95% CI: −11% to 40%), respectively.ConclusionsOverall the 2015–2016 TIV was protective against influenza infection in Beijing, with higher VE against the A(H3N2) viruses compared to A(H1N1)pdm09 and B viruses.     

Excess mortality patterns during 1918–1921 influenza pandemic in the state of Arizona,USA

Purpose

Our understanding of the temporal dynamics and age-specific mortality patterns of the 1918–1921 influenza pandemic remains scarce due to lack of detailed respiratory mortality datasets in the United States and abroad.

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.     

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.