Influenza vaccination coverage among children aged 6-23 months - six immunization information system sentinel sites, United States, 2005-06 influenza season

Beginning with the 2004-05 influenza season, the Advisory Committee on Immunization Practices (ACIP) recommended that all children aged 6-23 months receive influenza vaccinations annually. Other children recommended to receive influenza vaccinations include those aged 6 months-18 years who have certain high-risk medical conditions, those on chronic aspirin therapy, those who are household contacts of persons at high risk for influenza complications, and, since 2006, all children aged 24-59 months. Previously unvaccinated children aged <9 years need 2 doses administered at least 1 month apart to be considered fully vaccinated. This report assesses influenza vaccination coverage among children aged 6-23 months during the 2005-06 influenza season by using data from six immunization information system (IIS) sentinel sites. The findings demonstrate that vaccination coverage with 1 or more doses varied widely (range: 6.6% to 60.4%) among sites, with coverage increasing from the preceding influenza season in four of the six sites. However, <23% of children in five of the sites were fully vaccinated, underscoring the need for increased measures to improve the proportion of children who are fully vaccinated.     

Childhood influenza vaccination coverage--United States, 2004-05 influenza season

Children aged <2 years are at increased risk for influenza-related hospitalizations, and children aged 24-59 months are more likely than older children to visit a clinic, hospital, or emergency department with influenza-associated illness. In 2002, the Advisory Committee on Immunization Practices (ACIP) encouraged annual influenza vaccinations for children aged 6-23 months (and for household contacts of and out-of-home caregivers for children aged <2 years). For the 2004-05 influenza season, ACIP strengthened its encouragement to a full recommendation. For the upcoming 2006-07 influenza season, ACIP has further extended its recommendation to include all children aged 6-59 months (and their household contacts and out-of-home caregivers). Others recommended to receive influenza vaccination include children aged 6-18 years who have certain high-risk medical conditions, are on chronic aspirin therapy, or who are household contacts of persons at high risk for influenza complications. This report provides an assessment of influenza vaccination coverage among children aged 6-23 months during the 2004-05 influenza season. The findings demonstrate that vaccination coverage in that age group approximately doubled from the 2003-04 influenza season, with substantial variability among states and urban areas. However, the percentage of fully vaccinated children remained low, underscoring the need for increased measures to improve pediatric vaccination coverage and ongoing monitoring of coverage among young children and their close contacts.     

Influenza vaccination coverage among children aged 6-59 months--eight immunization information system sentinel sites, United States, 2007-08 influenza season

Vaccination is the most effective way to prevent influenza-associated morbidity and mortality. However, influenza vaccination coverage among children historically has been low. The Advisory Committee on Immunization Practices (ACIP) recommends annual vaccination with influenza vaccine for all children aged 6-59 months. Previously unvaccinated children and children who received only 1 vaccine dose for the first time in the previous influenza season are recommended to receive 2 influenza vaccine doses. To assess vaccination coverage among children aged 6-59 months during the 2007-08 influenza season, CDC analyzed data from the eight immunization information system (IIS) sentinel sites. For the eight sites, an average (unweighted) of 40.8% of children aged 6-23 months received 1 or more influenza vaccine doses, and an average of 22.1% were fully vaccinated. Among children aged 24-59 months, an average of 22.2% received 1 or more doses, and an average of 16.5% were fully vaccinated. These results indicate that influenza vaccination coverage among children remains low and highlight the need to identify additional barriers to influenza vaccination and to develop more effective interventions to promote vaccination of children aged 6--59 months who are at high risk for influenza-related morbidity and mortality.     

Influenza vaccination coverage among children aged 6-23 months--United States, 2005-06 influenza season

Children aged <2 years are at increased risk for influenza-related hospitalizations, and those aged <5 years have more influenza-related health-care visits than older children. In 2004, the Advisory Committee on Immunization Practices (ACIP) recommended annual influenza vaccination of children aged 6-23 months. Two doses, at least 4 weeks apart, were recommended to fully vaccinate children aged <9 years who were receiving influenza vaccination for the first time. To assess influenza vaccination coverage among children aged 6-23 months during the 2005-06 influenza season, data from the 2006 National Immunization Survey (NIS) were analyzed. This report describes the results of that analysis, which indicated that 31.9% of children in this age group received at least 1 dose of influenza vaccine and 20.6% were fully vaccinated according to ACIP recommendations; however, results varied substantially among states. The results underscore the need to continue to monitor influenza vaccination coverage among young children, develop systems to provide childhood influenza vaccination services more efficiently, and increase awareness among health-care providers and caregivers about the effectiveness of influenza vaccination among young children.     

Influenza vaccination coverage among children aged 6-23 months--United States, 2006-07 influenza season

Children aged <5 years have more influenza-related medical-care visits compared with older children, and those aged <2 years are at the greatest risk for influenza-related hospitalizations. In 2002, the Advisory Committee on Immunization Practices (ACIP) encouraged annual influenza vaccination of children aged 6-23 months and then, in 2004, recommended vaccination for this group. Two doses, spaced at least 4 weeks apart, are recommended to fully vaccinate children aged <9 years who are receiving influenza vaccination for the first time. This report, based on data from the 2007 National Immunization Survey (NIS), provides an assessment of influenza vaccination coverage among children aged 6-23 months during September-December of the 2006-07 influenza season. Nationally, 31.8% of children received 1 or more doses of influenza vaccine, and 21.3% were fully vaccinated, with substantial variability among states. The findings underscore the need to increase interest in and access to influenza vaccination for more children in the United States. Further study is needed to identify knowledge deficits or logistical barriers that might contribute to continued low influenza vaccination coverage among young children.     

Childhood influenza vaccination coverage--United States, 2003-04 influenza season

Children aged <2 years are at increased risk for influenza-related hospitalizations. Beginning in 2002, the Advisory Committee on Immunization Practices (ACIP) encouraged that, when feasible, children aged 6-23 months and household contacts and out-of-home caregivers for children aged <2 years receive influenza vaccinations each year. Beginning with the 2004-05 influenza season, ACIP strengthened the encouragement to a recommendation. Other children recommended to receive influenza vaccination include children aged 6 months-18 years who have certain high-risk medical conditions, are on chronic aspirin therapy, or who are household contacts of persons at high risk for influenza complications. This report provides an assessment of childhood influenza vaccination coverage for the 2003-04 influenza season, the second year of the ACIP encouragement for influenza vaccination of children aged 6-23 months. The findings demonstrate that vaccination coverage increased from the previous influenza season but remained low, with substantial variability among states and urban areas.     

Childhood influenza-vaccination coverage--United States, 2002-03 influenza season

Children aged <2 years are at increased risk for influenza-related hospitalizations. Beginning in 2002, the Advisory Committee on Immunization Practices (ACIP) encouraged that, when feasible, all children aged 6-23 months, as well as household contacts and out-of-home caregivers for children aged <2 years, receive influenza vaccinations each influenza season. Beginning with the 2004-05 influenza season, ACIP strengthened the encouragement to a recommendation. Other children recommended to receive influenza vaccine continue to include those aged 6 months--18 years with certain high-risk medical conditions and those aged 6 months-18 years who are household contacts of persons at high risk for influenza complications. This report on childhood influenza-vaccination coverage for the 2002-03 influenza season provides a baseline for the continuing assessment of coverage among children aged 6-23 months. The findings demonstrate that, during the first year of the ACIP encouragement to vaccinate children aged 6-23 months against influenza, vaccination coverage was low, with substantial variability among states and urban areas.     

Seasonal influenza vaccination coverage among children aged 6 months-18 years --- eight immunization information system sentinel sites, United States, 2009-10 influenza season

Annual influenza vaccination was first recommended for children aged 6-23 months and 2-4 years by the Advisory Committee on Immunization Practices (ACIP) in 2004 and 2006, respectively. In August 2008, ACIP expanded its seasonal influenza vaccination recommendations to also include all children aged 5-18 years no later than the 2009-10 season. To update previous estimates of seasonal influenza vaccination coverage among children aged 6 months-18 years, CDC analyzed data from the eight immunization information system (IIS) sentinel sites for the 2009-10 influenza season. Vaccination coverage with influenza A (H1N1) 2009 monovalent vaccine is not included in this report. Average (unweighted) vaccination coverage with ≥1 seasonal influenza vaccine doses was 26.3%, a 5.5 percentage point increase from the 2008-09 season (20.8%). Increases varied by age group, ranging from almost no increase among children aged 6-23 months (55.2% during the 2008-09 season to 55.7% during the 2009-10 season) to notable increases among children aged 2--4 years (from 33.0% to 38.4%), 5-12 years (19.0% to 27.1%), and 13-18 years (10.9% to 15.3%). Full vaccination coverage was low during the 2009-10 season, ranging from 34.7% among children aged 6-23 months to 15.3% among children aged 13-18 years. These findings highlight the need to identify varied strategies and venues for delivering influenza vaccine to different age groups of children to increase vaccination coverage.     

Characteristics associated with seasonal influenza vaccination of preschool children--Oregon, 2006-2008

Starting with the 2010-11 influenza season, the Advisory Committee on Immunization Practices (ACIP) recommended that all children aged ≥6 months be vaccinated against influenza annually, and that previously unvaccinated children aged ≤8 years be given 2 doses of vaccine. The American Academy of Pediatrics (AAP) also recommends influenza vaccinations for this population. Throughout influenza seasons, preschool children often have higher rates of influenza-related hospitalization than any other age group except older adults. To estimate influenza vaccination coverage and identify sociodemographic and health-care usage correlates of influenza vaccination status among children aged 2 years, data from the 2006-2008 Oregon Pregnancy Risk Assessment Monitoring Survey follow-back survey (Oregon PRAMS-2) were analyzed. This report summarizes the results. In Oregon, 37.7% of mothers reported that their children had received an influenza vaccination during the most recent influenza season. Factors positively associated with recent influenza vaccination in the multivariable-adjusted model were children's influenza vaccination in the previous year, children's receipt of all recommended immunizations, children's uninterrupted health insurance coverage, and mothers' unmarried status. The only factor negatively associated with vaccination was use of a family doctor rather than a pediatrician for well-child visits. The concern about vaccinations most commonly identified by mothers of children who had not received an influenza vaccination during the most recent influenza season (33.9%) was the opinion that too many shots are given at a time. This report highlights the need for health-care provider-based and community-based strategies to increase influenza vaccination coverage for children in Oregon.     

Estimates of influenza vaccination target population sizes in Spain for the 2006-2007 season

This study sought to estimate influenza vaccination target population sizes in Spain for the 2006-2007 season, based firstly on current vaccine recommendations, and secondly, on the hypothetical assumption that Advisory Committee on Immunization Practices (ACIP) recommendations were to be implemented. We estimate that under present Spanish guidelines, 41% of the population should be vaccinated against influenza in the 2006-2007 season. Of those eligible for vaccination, 41% are aged >or=65 years, 16% are aged <65 years and suffer from a chronic condition, and 36% are healthy household contacts aged <65 years. If the ACIP recommendations were implemented in Spain, the target population size would increase to 26,761,506 persons (61%), and of those eligible for vaccination, 57% would fall within the age-based recommendations (ages 6-59 months or >or=50 years), 29% would come under the healthy household contacts category, and only 5% would qualify due to suffering from a medical condition. We thus conclude that approximately 18 million persons, 41% of the Spanish population, should receive influenza vaccination in the 2006-2007 season under present Spanish guidelines. With the estimated number of doses to be distributed during this season (10 million), compliance with current recommendations would amount to only 56% at best. Extending universal vaccination to the 50-64 age group should be considered as an option for improving influenza vaccination coverage, particularly among high-risk patients, because a greater proportion of persons would receive the recommended dose by becoming eligible for the more effective age-based strategies.     

Influenza-associated pediatric deaths--United States, September 2010-August 2011

Influenza-associated pediatric mortality has been a nationally notifiable condition since October 2004. This report summarizes the 115 cases of influenza-associated pediatric mortality reported to CDC that occurred from September 1, 2010, through August 31, 2011. Deaths occurred in 33 states. Nearly half of the deaths (46%) occurred in children aged <5 years. Of the children who died, 49% had no known Advisory Committee on Immunization Practices (ACIP)-defined high-risk medical conditions, and 35% died at home or in the emergency department. Of the 74 children aged ≥6 months for whom vaccination data were available, 17 (23%) had been fully vaccinated. ACIP recommends that all children aged ≥6 months receive vaccination against influenza annually. These findings underscore the importance of vaccinating children to prevent influenza virus infection and its potentially severe complications. Health-care providers should develop a comprehensive strategy to increase vaccination coverage among children.     

Target groups for influenza vaccination

PURPOSE: To assess target groups for influenza vaccination. METHODS: The target groups for influenza vaccination specified in the recommendations of the US Advisory Committee on Immunization Practices (ACIP) were summarized and compared between 1997 and 2006. RESULTS: Principal changes after the 1997's recommendation are as follows: 1) all children aged 6-59 months became included into the high risk group for active vaccination; 2) recommendation for vaccination timing of pregnant women was extended from those at the second trimester or after to all women who are pregnant during the influenza season; 3) persons with neuro- or muscular-disorders and therefore prone to development of respiratory systems or aspiration pneumonia became included into the high risk group; 4) a category with increased risk to visit a clinic, hospital or emergency department due to influenza-related symptoms was newly established, covering children aged 24-59 months and persons aged 50-64 years; 5) healthy household contacts and caregivers of children aged 0-59 months were included into the group who can transmit influenza to persons in the high risk group; 6) people likely to transmit influenza to persons in the high risk group were classified into 3 categories (health-care providers, household contacts and caregivers, and those in close contact with children aged 0-59 months). CONCLUSION: The ACIP has gradually expanded the target populations for routine influenza vaccination. The most notable change during past 10 years seems to be the recommendation for inclusion of all children aged 6-59 months and people in close contact with babies for active vaccination.     

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.     

Rapid assessment of influenza vaccination coverage among HMO members--northern California influenza seasons, 2001-02 through 2004-05

The Vaccine Safety Datalink (VSD) is a collaborative project involving CDC and eight health maintenance organizations (HMOs) in the United States. Computerized data on vaccination, medical outcomes, and patient demographics are collected and linked under a standard protocol at multiple HMOs. Beginning with the 2003-04 influenza season, the VSD team and one of the HMOs, Kaiser Permanente Northern California (KPNC), established an automated system for rapid detection of potentially adverse events after vaccinations among its members. During the 2004-05 influenza season, in response to the influenza vaccine shortfall and resulting prioritization of vaccine distribution, this rapid analysis system also was used to assess influenza vaccination coverage weekly among KPNC members. The results indicated that KPNC followed Advisory Committee on Immunization Practices (ACIP) prioritization guidelines by targeting influenza vaccination to children aged 6-23 months and adults aged >/=65 years. For the 2005-06 influenza season, the rapid analysis system should be expanded to include data from additional HMOs and more detailed information on vaccinees (e.g., high risk for influenza complications) to better characterize influenza vaccination coverage during the 2005-06 influenza season on a weekly basis.     

State-specific influenza vaccination coverage among adults aged > or =18 years--United States, 2003-04 and 2005-06 influenza seasons

Influenza epidemics occur seasonally and result in substantial morbidity and mortality among adults in the United States. Adult groups included in the 2007 Advisory Committee on Immunization Practices (ACIP) recommendation for annual influenza vaccination are persons aged 18-49 years with high-risk conditions (i.e., conditions associated with an increased risk for complications from influenza), persons aged > or =50 years, health-care personnel, and others who are household contacts or caregivers of persons at high risk (e.g., persons with high-risk conditions or children aged < or =59 months). In addition, adults who want to reduce the risk for becoming ill with influenza or of transmitting influenza to others should be vaccinated. Healthy People 2010 (HP2010) objectives include increasing vaccination levels to 90% for adults aged > or =65 years (objective 14-29a) and 60% for persons aged 18-64 years who have one or more high-risk conditions (objective 14-29c). From the 1992-93 through 2003-04 influenza seasons, seasonal influenza vaccination coverage estimates (based on Behavioral Risk Factor Surveillance System [BRFSS] data) among adults aged > or =65 years trended upward, except for three seasons (1997-98, 1999-00, and 2000-01) when no increases occurred (Figure). To evaluate recent state-specific progress toward the HP2010 objectives, CDC compared data from the 2004 and 2006 BRFSS surveys, which reflected vaccinations received during the 2003-04 and 2005-06 influenza seasons; data from the 2004-05 influenza season, which have been published previously, were not included in this comparison because that season was marked by a substantial shortage of influenza vaccine. This report describes the results of the analysis, which indicated that influenza vaccination coverage for the 2005-06 season did not return to levels observed before the vaccine shortage of 2004-05 and remained substantially below HP2010 targets. Comprehensive measures are needed to improve influenza vaccination coverage among adult populations in the United States, including increasing adoption of recommended adult immunization practices by health-care providers, raising public awareness about influenza vaccination, vaccinating throughout the influenza season, and ensuring stable supplies of readily available vaccine.     

Interim results: state-specific influenza vaccination coverage--United States, August 2010-February 2011

The 2010--11 influenza season was unusual because it followed the 2009 influenza A pandemic (H1N1) season and it was the first season the Advisory Committee on Immunization Practices (ACIP) recommended influenza vaccination of all persons aged ≥6 months. The season also was notable because a record number of seasonal influenza vaccine doses (approximately 163 million) were distributed in the United States. To provide preliminary state-specific influenza vaccination coverage estimates, CDC analyzed Behavioral Risk Factor Surveillance System (BRFSS) data for adults aged ≥18 years and National Immunization Survey (NIS) data for children aged 6 months-17 years collected September 2010 through March 2011. By February 28, the preliminary national vaccination coverage estimate was 49.0% for children aged 6 months-17 years; among 43 states and the District of Columbia (DC), coverage ranged from 30.2% for adults aged 18-49 years to 68.6% for adults aged ≥65 years. The record high seasonal vaccination coverage achieved during 2009-10 (41.3%) among persons aged ≥6 months in 43 states and DC was sustained during the 2010--11 season (42.8%). Coverage for Hispanic and non-Hispanic black children increased by 11-12 percentage points from 2009-10 levels. Opportunity exists to improve coverage in all age groups, particularly among adults. To accomplish that, health departments and other nonoffice-based vaccination providers can increase access to vaccination at work and school locations, pharmacies and stores, and other nonmedical sites. In addition, physicians and clinics should implement proven strategies for improving vaccination coverage (e.g., office-based protocols, including reminder/recall notification and standing orders).     

Influenza vaccination coverage among children with asthma--United States, 2004-05 influenza season

In 2005, approximately 8.9% (6.5 million) of U.S. children aged <18 years were reported to have current asthma. Children with asthma are at high risk for complications from influenza, and influenza vaccination has been determined to safely and effectively reduce rates of influenza in these children. Since its establishment in 1964, the Advisory Committee on Immunization Practices (ACIP) has recommended that all children with asthma aged > or =6 months receive vaccination with inactivated influenza vaccine during each influenza season; however, national influenza vaccination coverage rates specifically for children with asthma have not been determined. Previous studies have assessed influenza vaccination rates in children with asthma at the local level using health maintenance organization and clinician group-practice information, with estimates ranging from 10% to 43% for various influenza seasons. Another study used Behavioral Risk Factor Surveillance System (BRFSS) data to estimate influenza vaccination coverage in children aged 2-17 years with one or more conditions putting them at high risk for complications from influenza (including asthma, although asthma was not assessed separately); in that study, the national rate was estimated at 34.8% for the 2004-05 influenza season (based on a sample size of 685, which included all states and the District of Columbia [DC]). To estimate national influenza vaccination coverage rates among children aged 2-17 years with current asthma, CDC analyzed data from the 2005 National Health Interview Survey (NHIS). This report describes the results of that analysis and provides the first national estimates of influenza vaccination coverage among children with asthma. The findings indicated that although children with current asthma were more likely to receive influenza vaccination than children without current asthma, the vaccination coverage rate among children with asthma was low, at 29.0% (95% confidence interval [CI] = 24.5-33.9). These findings underscore the need to increase influenza vaccination coverage in children with asthma aged 2-17 years by identifying and overcoming barriers to vaccination.     

Influenza vaccination coverage among persons with asthma--United States, 2005-06 influenza season

During 2006, approximately 6.8 million (9.3%) U.S. children and 16.1 million (7.3%) U.S. adults were reported to have asthma. Since 1964, the Advisory Committee on Immunization Practices (ACIP) has recommended influenza vaccination of all persons with asthma because of the higher risk for medical complications from influenza for those persons. Influenza vaccination coverage of persons with asthma varies by age group and remains below Healthy People 2010 targets of 60% coverage of persons aged 18--64 years with high-risk conditions (14-29 c) and 90% of all persons aged > or =65 years (14-29 a). Influenza vaccination rates of children and older adults with asthma have not been well studied. Using 2006 National Health Interview Survey (NHIS) data, this report provides the first examination of influenza vaccination rates and related factors across a national sample of persons with asthma aged > or =2 years. The results indicated that 36.2% received influenza vaccination during the 2005--06 influenza season. Vaccination rates remained below target levels among all subgroups examined, including those reporting the greatest number of health-care visits in the past 12 months. The results of this study indicate that influenza vaccination coverage of all persons with asthma can be improved by increasing access to health care and using opportunities for vaccination during health-care visits.     

State-specific influenza vaccination coverage among adults--United States, 2006-07 influenza season

Adult groups included in the 2008 Advisory Committee on Immunization Practices (ACIP) recommendation for annual influenza vaccination include all persons aged >/=50 years, women who will be pregnant during the influenza season, persons aged 18-49 years with high-risk conditions, and other persons at increased risk for complications from influenza. Health-care personnel and household contacts and caregivers of persons at high risk also should receive annual influenza vaccination, as should adults who want to reduce their risk for becoming ill with influenza or for transmitting it to others. Healthy People 2010 influenza vaccination coverage targets are 90% among all persons aged >/=65 years and 60% among persons aged 18-64 years who have one or more high-risk conditions. Data from the 2006 and 2007 Behavioral Risk Factor Surveillance System (BRFSS) surveys indicate that influenza vaccination coverage among adults for the 2006-07 season increased significantly compared with the 2005-06 season, reaching 35.1% among persons aged 18-49 years with high-risk conditions, 42.0% among all persons aged 50-64 years, and 72.1% among all persons aged >/=65 years. However, vaccination coverage remained well below Healthy People 2010 targets. Increasing influenza vaccination coverage among adults in the United States will require more cooperation among health-care providers, professional organizations, vaccine manufacturers, and public health departments to raise public awareness about influenza vaccination and to ensure continued distribution and administration of available vaccine throughout the vaccination season.     

2013-2014年度季节性流行性感冒疫苗对儿童保护效果的病例对照研究

目的 评价2013-2014年度季节性流行性感冒疫苗（流感疫苗）对6~59月龄儿童的保护效果。方法 选择2013-2014年度6~59月龄的实验室诊断流感病例为病例组,在广州市免疫规划系统中随机选择健康儿童为对照组,进行成组病例对照研究,采用非条件Logistic回归计算保护效果。结果 本研究共纳入2 690名研究对象。2013-2014年度,流感疫苗对6~59月龄儿童的保护效果为42.3%（95% CI:27.8%~53.8%）,对36~59月龄儿童的保护效果高于6~35月龄儿童,完全免疫的保护效果高于部分免疫,性别间保护效果无统计学差异。结论 流感疫苗对6~59月龄儿童具有中等保护效果,建议6~59月龄儿童每年接种流感疫苗。