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.     

Update: influenza activity--United States, 2003-04 season

Influenza began circulating in the United States unusually early this season, and influenza activity nationwide is expected to increase. Cases of severe disease, including deaths, have been reported in children. This report summarizes influenza activity in the United States during the weeks ending October 4-December 6, 2003. During the week ending December 6, influenza activity was reported to CDC as widespread in 24 states. The early season and the unusually high and persistent demand for vaccine have resulted in a decreasing supply of trivalent inactivated vaccine. Emphasis should be placed on vaccinating persons at high risk for complications from influenza, including healthy children aged 6-23 months. Healthy persons aged 5-49 years who wish to receive vaccine should consider being vaccinated with the intranasally administered live, attenuated influenza vaccine (LAIV), a substantial supply of which remains available.     

Update: influenza activity--United States, 2003-04 season

This report summarizes influenza activity in the United States during September 29, 2003-March 27, 2004, and updates the previous summary. This report also summarizes human infections with avian influenza viruses related to poultry outbreaks in North America. Preliminary data collected through CDC influenza surveillance indicate that national influenza activity peaked during late November-December. The most frequently isolated viruses were influenza A (H3N2), and approximately 87% of these were similar to the drift variant A/Fujian/411/2002.     

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.     

Influenza vaccination coverage among pregnant women --- United States, 2010-11 influenza season

Women are at increased risk for morbidity and mortality from influenza during pregnancy. Vaccinating pregnant women for influenza can protect both the women and their infants, especially infants aged <6 months who are not old enough to receive influenza vaccination. Since 2004, the Advisory Committee on Immunization Practices and the American College of Obstetricians and Gynecologists have recommended inactivated influenza vaccine for all women who are pregnant during influenza season, regardless of trimester. Before 2009, estimated influenza vaccination coverage among pregnant women had been consistently low (approximately 15%). However, vaccination levels increased substantially in response to the 2009 influenza A (H1N1) pandemic to nearly 50%. To estimate influenza vaccination coverage among pregnant women for the 2010-11 season, CDC analyzed data from an Internet panel survey conducted in April 2011 among women who were pregnant any time during October 2010-January 2011. Among 1,457 survey respondents, 49% reported that they had received influenza vaccination: 12% were vaccinated before pregnancy, 32% during pregnancy, and 5% after pregnancy. Women offered influenza vaccination by a health-care provider (62%) were more likely to be vaccinated (71%) than other women (14%) and were more likely to have positive attitudes about vaccine effectiveness and safety. These results indicate that the higher vaccination level achieved the previous season (2009-10) was sustained and emphasize the critical role of health-care providers in promoting influenza vaccination. Continued efforts are needed to encourage health-care providers to strongly recommend and offer influenza vaccination to pregnant patients to protect both the mothers and their infants.     

Influenza vaccination coverage among health-care personnel --- United States, 2010-11 influenza season

The Advisory Committee on Immunization Practices (ACIP) and the Healthcare Infection Control Practices Advisory Committee recommend that all U.S. health-care personnel (HCP) be vaccinated annually against influenza. Nonetheless, influenza vaccination coverage among HCP in the United States has increased slowly over the past decade; during the 2009-10 influenza season, 61.9% of HCP received seasonal influenza vaccination. To update data with estimates from the 2010-11 influenza season, CDC conducted an Internet-based survey of 1,931 HCP who participated in three online survey panels. This report summarizes the results of that survey, which indicated that overall influenza vaccination coverage among HCP was 63.5% during the 2010--11 influenza season, similar to coverage for the 2009-10 season. Among HCP who reported working at a facility where vaccination was required by their employer, 98.1% were vaccinated. Among HCP without such an employer requirement but who were offered vaccination onsite, greater coverage was associated with a personal reminder from the employer to get vaccinated (69.9%), vaccination availability at no cost (67.9%), and vaccination availability for >1 day (68.8%). Influenza vaccination of HCP is needed to protect patients from HCP-transmitted disease. Maximizing influenza vaccination for all HCP is an important part of any comprehensive infection-control program.     

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.     

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.     

Update: influenza-associated deaths reported among children aged <18 years--United States, 2003-04 influenza season

During the 2003-04 influenza season, CDC has received reports from state health departments regarding deaths among children with evidence of influenza virus infection. To help investigate these deaths, CDC has requested that all influenza-associated deaths among children aged <18 years be reported to CDC through state and local health departments during the 2003-04 season. This summary is based on preliminary data reported from 31 states as of January 6, 2004, and updates a previous report published in MMWR.     

Experiences with influenza-like illness and attitudes regarding influenza prevention--United States, 2003-04 influenza season

Despite advances in medical treatment, influenza results in approximately 36,000 deaths each year in the United States. Vaccination has been a mainstay of influenza prevention, with annual vaccination recommended for adults and children at high risk; efforts to interrupt person-to-person transmission are also important. In October 2003, CDC recommended that health-care facilities implement a Universal Respiratory Hygiene Strategy, including providing masks or facial tissues in waiting rooms to persons with respiratory symptoms. To gather information on influenza-like illness (ILI) and attitudes regarding prevention of ILI (including use of vaccine and respiratory hygiene), CDC and 11 Emerging Infections Programs (EIPs) conducted a random-digit-dialed telephone survey of noninstitutionalized U.S. civilian adults in February 2004. This report summarizes the results of that survey, which determined that 43% of adults and 69% of children aged 6 months-17 years with ILI visited a health-care provider for the illness. Eight percent of adults with ILI reported having been asked by a health-care provider to wear a mask; 82% said they would wear a mask if requested. With the limited availability of influenza vaccine this season, the use of masks by persons with cough illnesses in health-care settings, a component of the Universal Respiratory Hygiene Strategy, might be a helpful and acceptable method for decreasing influenza transmission.     

Update: influenza-associated deaths reported among children aged <18 years--United States, 2003-04 influenza season

Since October, 42 influenza-associated deaths among children aged <18 years have been reported to CDC. All patients had influenza virus infection detected by rapid antigen testing or other laboratory testing methods. This report describes preliminary findings based on data provided from multiple states, as of December 17, 2003. To improve surveillance, CDC has requested that all influenza-associated deaths of children aged <18 years be reported to CDC through state health departments.     

Influenza vaccination coverage among persons aged 50-64 years enrolled in commercial managed health-care plans--United States, 2003-04 and 2004-05 influenza seasons

To combat an unexpected shortage of influenza vaccine in the fall of 2004, CDC issued guidance to direct available vaccine supplies to persons in designated priority groups (e.g., persons aged >/=65 years, persons with certain health conditions, health-care workers, and close contacts of persons at high risk for complications from influenza). Analyses of influenza vaccination coverage for the 2004-05 influenza season indicated that coverage levels for adults in priority groups nearly reached the levels of previous years, whereas coverage levels among adults not in priority groups were approximately half the levels of the 2003-04 season. These findings suggested that national public health actions to direct available vaccine supply to persons at high risk for complications from influenza during the supply disruption were successful. To assess influenza vaccination coverage among persons aged 50-64 years for the 2004-05 influenza season relative to the 2003-04 season and to estimate the effect of shortages on selected subgroups, the National Committee for Quality Assurance (NCQA) analyzed data from a survey of persons enrolled in commercial managed care health plans. This report summarizes the findings of that analysis, which indicated that, although vaccination coverage declined substantially from 2003-04 to 2004-05 among all subgroups in this age range, respondents who were older or who reported poorer health status exhibited smaller relative declines in vaccination coverage between the two seasons.     

Update: influenza activity--United States and worldwide, 2003-04 season, and composition of the 2004-05 influenza vaccine

During the 2003-04 influenza season, influenza A (H1), A (H3N2), and B viruses co-circulated worldwide, and influenza A (H3N2) viruses predominated. Several Asian countries reported widespread outbreaks of avian influenza A (H5N1) among poultry. In Vietnam and Thailand, these outbreaks were associated with severe illnesses and deaths among humans. In the United States, the 2003-04 influenza season began earlier than most seasons, peaked in December, was moderately severe in terms of its impact on mortality, and was associated predominantly with influenza A (H3N2) viruses. This report 1) summarizes information collected by World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories, state and local health departments, health-care providers, vital statistics registries, and CDC and 2) describes influenza activity in the United States and worldwide during the 2003-04 influenza season and the composition of the 2004-05 influenza vaccine.     

Place of influenza vaccination among adults --- United States, 2010-11 influenza season

The 2010-11 influenza season was the first season after the 2009 influenza A (H1N1) pandemic and the first season that the Advisory Committee on Immunization Practices (ACIP) recommended influenza vaccination for all persons aged ≥6 months (1). During the pandemic, many new partnerships between public health agencies and medical and nonmedical vaccination providers were formed, increasing the number of vaccination providers (2). To provide a baseline for places where adults received influenza vaccination since the new ACIP recommendation and to help vaccination providers plan for the 2011-12 influenza season, CDC analyzed information from 46 states and the District of Columbia (DC) on influenza vaccination of adults aged ≥18 years for the 2010-11 season, collected during January-March 2011 by the Behavioral Risk Factor Surveillance System (BRFSS). This report summarizes the results of that analysis, which found that, for adults overall, a doctor's office was the most common place (39.8%) for receipt of the 2010-11 influenza vaccine, with stores (e.g., supermarkets or drug stores) (18.4%) and workplaces (17.4%) the next most common. For those aged 18-49 years and 50-64 years, a workplace was the second most common place of vaccination (25.7% and 21.1%, respectively). Persons aged ≥65 years who were not vaccinated at a doctor's office were most likely (24.3%) to have been vaccinated at a store. The results indicate that both medical and nonmedical settings are common places for adults to receive influenza vaccinations, that a doctor's office is the most important medical setting, and that workplaces and stores are important nonmedical settings.     

Update: influenza activity--United States and worldwide, 2002-03 season,and composition of the 2003-04 influenza vaccine

In collaboration with the World Health Organization (WHO), its collaborating laboratories, state and local health departments, health-care providers, and vital statistic registries, CDC conducts surveillance to monitor influenza activity and to detect antigenic changes in the circulating strains of influenza viruses. During the 2002-03 influenza season, influenza A (H1), A (H3N2), and B viruses co-circulated in the Northern Hemisphere. Human infections with avian influenza A (H5N1) and A (H7N7) viruses were reported in Hong Kong and the Netherlands, respectively. In the United States, the 2002-03 influenza season was mild; influenza A (H1) and B viruses circulated widely, and the predominant virus varied by region and time of season. This report summarizes influenza activity in the United States and worldwide during the 2002-03 influenza season and describes the composition of the 2003-04 influenza vaccine.     

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.     

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.     

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.