U.S. COVID-19 vaccine distribution strategies, systems, performance, and lessons learned, December 2020 - May 2023.

During December 2020 through May 2023, the Centers for Disease Control and Prevention's (CDC) Immunization Services Division supported and executed the largest vaccine distribution effort in U.S. history, delivering nearly one billion doses of COVID-19 vaccine to vaccine providers in all 50 states, District of Columbia, Puerto Rico, Virgin Islands, Guam, Federated States of Micronesia, American Samoa, Marshall Islands, Northern Mariana Islands, and Palau. While existing infrastructure, ordering, and distribution mechanisms were in place from the Vaccines for Children Program (VFC) and experience had been gained during the 2009 H1N1 pandemic and incorporated into influenza vaccination pandemic planning, the scale and complexity of the national mobilization against a novel coronavirus resulted in many previously unforeseen challenges, particularly related to transporting and storing the majority of the U.S. COVID-19 vaccine at frozen and ultra-cold temperatures. This article describes the infrastructure supporting the distribution of U.S. government-purchased COVID-19 vaccines that was in place pre-pandemic, and the infrastructure, processes, and communications efforts developed to support the heightened demands of the COVID-19 vaccination program, and describes lessons learned.

Effects of the COVID-19 Pandemic on Routine Pediatric Vaccine Ordering and Administration - United States, 2020.

On March 13, 2020, the president of the United States declared a national emergency in response to the coronavirus disease 2019 (COVID-19) pandemic (1). With reports of laboratory-confirmed cases in all 50 states by that time (2), disruptions were anticipated in the U.S. health care system's ability to continue providing routine preventive and other nonemergency care. In addition, many states and localities issued shelter-in-place or stay-at-home orders to reduce the spread of COVID-19, limiting movement outside the home to essential activities (3). On March 24, CDC posted guidance emphasizing the importance of routine well child care and immunization, particularly for children aged ≤24 months, when many childhood vaccines are recommended.

Temporary vaccine recommendations and provider compliance: a survey of pediatric practices during the 2003-2004 pneumococcal conjugate vaccine shortage.

OBJECTIVE: Heptavalent pneumococcal conjugate vaccine was in short supply from December 2003 to August 2004. The Centers for Disease Control and Prevention with the American Academy of Pediatrics and the American Academy of Family Physicians made recommendations to providers to withhold third and fourth doses of heptavalent pneumococcal conjugate vaccine to ensure availability for those at highest risk. Previous studies of vaccine shortages have demonstrated that provider compliance with temporary recommendations is low. The objective of this study was to collect timely data about awareness and adherence to temporary recommendations and current supply status of heptavalent pneumococcal conjugate vaccine in pediatric practices. METHODS: A 2-phase telephone survey of pediatric practices was conducted during a 10-week period during the 2003-2004 heptavalent pneumococcal conjugate vaccine shortage. Immunization nurses at randomly selected sites with physician-members of the American Academy of Pediatrics were asked a series of questions. RESULTS: In both study phases, >90% of participating practices were aware of the recommendations and reported adhering to the recommendations. In phase 1, practices with insufficient supply were more likely to implement recommendations than practices with sufficient supply. Participants identified health departments and Wyeth Vaccines as the most common sources of information. At least 65% of the practices in each phase reported use of tracking systems for children who missed doses. CONCLUSIONS: Most pediatric practices surveyed were aware of the shortage and were implementing the heptavalent pneumococcal conjugate vaccine recommendations. Simplified recommendations and collaborative efforts to develop and widely disseminate interim recommendations may result in increased compliance by providers.

Gaps in vaccine financing for underinsured children in the United States.

CONTEXT: The number of new vaccines recommended for children and adolescents has nearly doubled during the past 5 years, and the cost of fully vaccinating a child has increased dramatically in the past decade. Anecdotal reports from state policy makers and clinicians suggest that new gaps have arisen in financial coverage of vaccines for children who are underinsured (ie, have private insurance that does not cover all recommended vaccines). In 2000, approximately 14% of children were underinsured for vaccines in the United States. OBJECTIVES: To describe variation among states in the provision of new vaccines to underinsured children and to identify barriers to state purchase and distribution of new vaccines. DESIGN, SETTING, AND PARTICIPANTS: A 2-phase mixed-methods study of state immunization program managers in the United States. The first phase included 1-hour qualitative telephone interviews conducted from November to December 2005 with 9 program managers chosen to represent different state vaccine financing policies. The second phase incorporated findings from phase 1 to develop a national telephone and paper-based survey of state immunization program managers that was conducted from January to June 2006. MAIN OUTCOME MEASURES: Percentage of states in which underinsured children are unable to receive publicly purchased vaccines in the private or public sectors. RESULTS: Immunization program managers from 48 states (96%) participated in the study. Underinsured children were not eligible to receive publicly purchased meningococcal conjugate or pneumococcal conjugate vaccines in the private sector in 70% and 50% of states, respectively, or in the public sector in 40% and 17% of states, respectively. Due to limited financing for new vaccines, 10 states changed their policies for provision of publicly purchased vaccines between 2004 and early 2006 to restrict access to selected new vaccines for underinsured children. The most commonly cited barriers to implementation in underinsured children were lack of sufficient federal and state funding to purchase vaccines. CONCLUSIONS: The current vaccine financing system has resulted in gaps for underinsured children in the United States, many of whom are now unable to receive publicly purchased vaccines in either the private or public sectors. Additional strategies are needed to ensure financial coverage for all vaccines, particularly new vaccines, among this vulnerable population.

Influenza vaccination coverage of children aged 6 to 23 months: the 2002-2003 and 2003-2004 influenza seasons.

BACKGROUND: Beginning in 2002 the Advisory Committee on Immunization Practices encouraged, when feasible, annual influenza vaccination of all children aged 6 to 23 months and household contacts and out-of-home caregivers of children < 2 years of age. OBJECTIVE: We sought to report influenza vaccination coverage for the 2002-2003 and 2003-2004 influenza seasons among children aged 6 to 23 months according to demographic and immunization-provider characteristics. METHODS: Data from the 2003 and 2004 National Immunization Survey were analyzed. Two measures of childhood influenza vaccination are reported: receipt of > or = 1 influenza vaccination and full vaccination (ie, receipt of the appropriate number of doses on the basis of previous vaccination history). chi2 tests and logistic-regression analyses to test for associations between influenza vaccination status and demographic characteristics were performed. RESULTS: In the 2002-2003 and 2003-2004 influenza seasons only 7.4% and 17.5%, respectively, of children aged 6 to 23 months received > or = 1 influenza vaccination, whereas only 4.4% and 8.4%, respectively, were fully vaccinated. In both seasons, adjusted influenza vaccination coverage was significantly lower among children living below the poverty level; non-Hispanic black children; older children; children with less-educated mothers; children vaccinated only at public clinics; and children not residing in a metropolitan statistical area. CONCLUSION: During the first 2 years of the Advisory Committee on Immunization Practices' encouragement for children aged 6 to 23 months to receive influenza vaccination, coverage was low, with significant demographic differences in receipt of vaccination. Beginning with the 2004-2005 influenza season, they replaced the encouragement with a recommendation that children aged 6 to 23 months receive annual influenza vaccination. Substantial work remains to fully and equitably implement this new recommendation and ensure vaccination with 2 doses for previously unvaccinated children.

Use of a new combined vaccine in pediatric practices.

OBJECTIVE: On December 13, 2002, Pediarix, a combination vaccine that contains diphtheria, tetanus, acellular pertussis; hepatitis B; and inactivated polio vaccines, was licensed by the Food and Drug Administration for use in the primary immunization series. Use of this vaccine decreases the number of injections that children receive when completing their primary immunization series at the 2-, 4-, and 6-month well-child visits. The objective of this study was to determine the factors that influence the use of this combined vaccine in private pediatric practices, with particular attention to the perceived economic impact of Pediarix and actions taken to address this impact within the private pediatric setting. METHODS: A mail survey study was conducted of a random sample of 565 practicing pediatricians that was obtained from the American Medical Association Masterfile. Frequency distributions were developed for all responses, and the vaccine financing policies of the state of practice for each respondent were determined. Chi2 analysis was performed to assess any associations of the predictor variables with the outcome variables of interest, use or consideration of use of the Pediarix vaccine. Logistic regression was used to determine the independent association of the predictor variables with use or consideration of use of Pediarix. Regression models that did and did not include practice ownership as a predictor variable were developed. RESULTS: Response rate was 63% (N = 355). A total of 39% (n = 123) of the respondents' practices were purchasing Pediarix for use with their private patients. An additional 18% (n = 55) were considering purchasing the vaccine. Those who were in practices that were owned by hospitals or health systems were more likely than those who were in solo or group practices to purchase Pediarix for their private patients. Approximately half of the remaining respondents order Pediarix through their state immunization program. Among the 52% of respondents who did not, 23% reported that the vaccine was not yet available through their state program, and 47% stated that they did not want to use different vaccines for their public and private patients. Only 11% believed that Pediarix was not compatible with their other vaccine products. Physicians that currently were purchasing or considering purchasing Pediarix were more likely to be influenced by both parental and provider desire to decrease the number of injections at a single visit and the reduced time for immunization delivery. Fewer than 1% of respondents reported either having experienced or expecting to experience a significant decrease in practice revenue as a result of the use of Pediarix. CONCLUSIONS: Although use of the vaccine results in fewer administration fees for most physicians, the magnitude of the change seemed not to be significant for the majority of respondents or was outweighed by other factors. It also is possible that larger practices or buying cooperatives were able to negotiate discounted rates for Pediarix relative to the constituent products. This may have been a strategy of manufacturers and/or distributors to provide incentive for practices to switch to the combination product. Of note was the appreciation of respondents for the preferences of patients for fewer vaccines and, to a lesser degree, for the decrease in office staff time required to provide vaccination with multiple antigens when using Pediarix. Also, the role of the availability of a given vaccine through the Vaccines for Children program is important in its adoption into practice.

Impact of state vaccine financing policy on uptake of heptavalent pneumococcal conjugate vaccine.

OBJECTIVE: We examined heptavalent pneumococcal conjugate vaccine (PCV7) uptake among children aged 19 to 35 months in the United States and determined how uptake rates differed by state vaccine financing policy. METHODS: We analyzed data from the 2001-2003 National Immunization Survey. States that changed their vaccine financing policy between 2001 and 2003 (n=17) were excluded from analysis. Logistic regression was performed to identify the association between state vaccine financing policy and receipt of 3 or more doses of PCV7 after control for demographic characteristics. RESULTS: The proportion of children receiving 3 or more doses increased from 6.7% in 2001 to 69.0% in 2003. After controlling for demographic characteristics, children residing in states that provided all vaccines except PCV7 to all children had lower odds of receiving 3 or more doses compared to children residing in states that provided PCV7 only to children eligible for the Vaccines for Children program (odds ratio=0.58; 95% confidence interval=0.51, 0.66). CONCLUSION: It is essential that we continue to monitor the effect that state vaccine financing policy has on the delivery of PCV7 and future vaccines, which are likely to be increasingly expensive.

Disparities between white and African-American children in immunization coverage.

INTRODUCTION: A recent study has shown that the national-scale difference in immunization coverage between non-Hispanic white (abbreviated "white") and non-Hispanic African-American (abbreviated "African-American") children aged 19-35 months in the United States has increased by about 1 percentage point annually. We examined how this widening gap differs with geography and income. METHODS: We used data from the National Immunization Survey, 1998-2003, a national telephone survey. We examined differences between white and African-American children in immunization coverage within income groups (at or above versus below the federal poverty level) for each census region (northeast, south, midwest and west). We tested the hypothesis of constant disparity over time. RESULTS: Among households at or above the federal poverty level in the northeast census region, disparity is widening (white coverage minus African-American coverage was -0.5 in 1998 but 15.5 in 2003). Among household at or above the federal poverty level in the midwest census region, disparity is narrowing (white coverage minus African-American coverage was 13.9 in 1998 but 2.5 in 2003). We found no significant evidence of a trend in other groups. CONCLUSIONS: Widening national-level disparity in immunization coverage is primarily attributable to trends in the northeast census region. Addressing the widening disparity in coverage requires new strategies that consider current social and economic contexts.

Vaccine shortages: history, impact, and prospects for the future.

Vaccine shortages can result from higher-than-expected demand, interruptions in production/supply, or a lack of resources to purchase vaccines. Each of these factors has played a role in vaccine shortages in the United States during the past 20 years. Since 2000, the United States has experienced an unprecedented series of shortages of vaccines recommended for widespread use against 9 diseases, after more than 15 years without vaccine supply problems. In developing countries, the major cause of vaccine shortages is lack of resources to purchase them. Although there are several steps that could reduce the likelihood of future vaccine shortages, many would take several years to implement. Consequently, we will probably continue to see occasional shortages of vaccines in the United States in the next few years.

Differential effects of the DTaP and MMR vaccine shortages on timeliness of childhood vaccination coverage.

OBJECTIVES: We determined the effect of diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP) and measles, mumps, rubella (MMR) vaccine shortages on timeliness of the third dose of DTaP (DTaP3), the fourth dose of DTaP (DTaP4), and the first dose of MMR (MMR1) among subgroups of preschool children. METHODS: Data from the 2001 and 2002 National Immunization Surveys were analyzed. Children age-eligible to receive DTaP3, DTaP4, or MMR1 during the shortages were considered subject to the shortage, and those not age-eligible were not subject to the shortage; timeliness of vaccinations was compared. RESULTS: Among children vaccinated only at public clinics, children residing outside metropolitan statistical areas, and children in the Southern Census Region, those age-eligible to receive DTaP4 during the shortage were less likely to be vaccinated by 19 months of age than children not subject to the shortage. CONCLUSIONS: There was notable disparity in the effects of the recent vaccine shortages; children vaccinated only in public clinics, in rural areas, or in the Southern United States were differentially affected by the shortages.

The United States pediatric vaccine stockpile program.

The initial goal of the national vaccine stockpile program was to establish a 6-month supply of all recommended childhood vaccines, to meet national demands if a manufacturing process was interrupted. When the first vaccine stockpiles were created in 1983, the childhood immunization schedule was much less complicated than it is today, and the first stockpiles included only measles-mumps-rubella, poliovirus, and pertussis vaccines, as well as diphtheria and tetanus toxoids. However, today's vaccine needs are much greater, and current stockpiles do not include all recommended childhood vaccines, partially because inclusion of vaccines that are universally recommended, fully implemented, and produced by a single manufacturer has been made a priority. Future planning must also consider substantially higher vaccine costs, the development of new combination vaccines, a wide range of production times, and changes in immunization recommendations. Expansion and strengthening of the national vaccine stockpile program are critical to protect against future disruptions in vaccine supply.

Influenza vaccination of high-risk children: what the providers say.

BACKGROUND: Despite a longstanding national recommendation to administer influenza vaccine to children at high risk for disease complications, physicians' adherence remains low. This study evaluated physicians' perspectives on previously documented and persistent under-utilization of influenza vaccine for high-risk children. METHODS: A cross-sectional survey mailed in 2001-2002 to a nationally representative sample of 1460 U.S. physicians in four key medical specialties. The primary outcome was whether the physician provided annual influenza vaccine to children with asthma or other cardiopulmonary diseases. The hypothesis was that factors predicting reported use would fall into four categories: (1) physician knowledge, (2) physician endorsement of recommendation, (3) perceived barriers, and (4) practice patterns. RESULTS: The overall response rate was 55% (n=600), but differed by specialty. Most physicians were knowledgeable about the recommendation, but collectively tended to overestimate their own achievements in immunizing high-risk children. Adherence varied by physician specialty, endorsement of recommendation, perceived barriers (including difficulty identifying subpopulations of high-risk children and confusion about who should vaccinate those receiving care from multiple providers), and under-utilization of strategies known to improve vaccination rates. CONCLUSIONS: Better communication strategies are needed to resolve confusion about providing influenza vaccine to high-risk children in subspecialty settings. Because of the difficulties in selectively identifying high-risk patient subgroups, research is needed to assist in putting support strategies into practice. Findings from research in promising areas of practice-based quality improvement may be particularly applicable.

Status of quality improvement activities to improve immunization practices and delivery: findings from the immunization quality improvement symposium, October 2003.

The Centers for Disease Control and Prevention convened a symposium on 22-23 October 2003 to bring together investigators and stakeholders working to apply the quality improvement (QI) approaches to immunization delivery in individual medical practices. The goal was to identify effective program components and further development of model programs. A call for projects was widely disseminated; of 61 submissions received, eight projects were selected. Three of the eight programs used the "train the trainer" approach, three used site-specific training, one used a "practice collaborative" approach, and one employed the use of tracking and outreach workers to effect change. At the symposium, invited experts reviewed each program. Common program features that appeared effective included involvement of a variety of staff within the office environment, collection and review of site-specific performance measurements to identify gaps in delivery, periodic monitoring of performance measurement to revise interventions and maintain the improvements, and provision of formal continuing education credits. While research is needed on ways to promote and integrate QI into practices, it is likely that a variety of QI strategies will be shown to be effective, depending on the clinical settings. The field will benefit from standardized outcome measures, cost analysis, and evaluation, so comparisons can be made among different programs.

Economic evaluation of the 7-vaccine routine childhood immunization schedule in the United States, 2001.

OBJECTIVE: To evaluate the economic impact of the routine US childhood immunization schedule: diphtheria and tetanus toxoids and acellular pertussis; tetanus and diphtheria toxoids; Haemophilus influenzae type b conjugate; inactivated poliovirus; measles, mumps, and rubella; hepatitis B; and varicella vaccines. DESIGN: Decision tree-based analysis was conducted using population-based vaccination coverage, published vaccine efficacies, historical data on disease incidence before vaccination, and disease incidence reported for 1995-2001. Costs were estimated using the direct cost and societal (direct and indirect costs) perspectives. Program costs included vaccine, administration, vaccine-associated adverse events, and parent travel and time lost. All costs were inflated to 2001 US dollars, and all costs and benefits in the future were discounted at a 3% annual rate. PARTICIPANTS: A hypothetical 2001 US birth cohort of 3,803,295 infants was followed up from birth through death. MAIN OUTCOME MEASURES: Net present value (net savings) and benefit-cost ratios of routine immunization. RESULTS: Routine childhood immunization with the 7 vaccines was cost saving from the direct cost and societal perspectives, with net savings of 9.9 billion dollars and 43.3 billion dollars, respectively. Without routine vaccination, direct and societal costs of diphtheria, tetanus, pertussis, H influenzae type b, poliomyelitis, measles, mumps, rubella, congenital rubella syndrome, hepatitis B, and varicella would be 12.3 billion dollars and 46.6 billion dollars, respectively. Direct and societal costs for the vaccination program were an estimated 2.3 billion dollars and 2.8 billion dollars, respectively. Direct and societal benefit-cost ratios for routine childhood vaccination were 5.3 and 16.5, respectively. CONCLUSION: Regardless of the perspective, the current routine childhood immunization schedule results in substantial cost savings.

Impact of the introduction of pneumococcal conjugate vaccine on immunization coverage among infants.

BACKGROUND: The introduction of pneumococcal conjugate vaccine (PCV) to the U.S. recommended childhood immunization schedule in the year 2000 added three injections to the number of vaccinations a child is expected to receive during the first year of life. Surveys have suggested that the addition of PCV has led some immunization providers to move other routine childhood vaccinations to later ages, which could increase the possibility of missing these vaccines. The purpose of this study was to evaluate whether introduction of PCV affected immunization coverage for recommended childhood vaccinations among 13-month olds in four large provider groups. METHODS: In this retrospective cohort study, we analyzed computerized data on vaccinations for 33,319 children in four large provider groups before and after the introduction of PCV. The primary outcome was whether the child was up to date for all non-PCV recommended vaccinations at 13 months of age. Logistic regression was used to evaluate the association between PCV introduction and the primary outcome. The secondary outcome was the number of days spent underimmunized by 13 months. The association between PCV introduction and the secondary outcome was evaluated using a two-part modelling approach using logistic and negative binomial regression. RESULTS: Overall, 93% of children were up-to-date at 13 months, and 70% received all non-PCV vaccinations without any delay. Among the entire study population, immunization coverage was maintained or slightly increased from the pre-PCV to post-PCV periods. After multivariate adjustment, children born after PCV entered routine use were less likely to be up-to-date at 13 months in one provider group (Group C: OR = 0.5; 95% CI: 0.3-0.8) and were less likely to have received all vaccine doses without any delay in two Groups (Group B: OR = 0.4, 95% CI: 0.3 - 0.6; Group C: OR = 0.5, 95% CI: 0.4-0.7). This represented 3% fewer children in Group C who were up-to-date and 14% (Group C) to 16% (Group B) fewer children who spent no time underimmunized at 13 months after PCV entered routine use compared to the pre-PCV baseline. Some disruptions in immunization delivery were also observed concurrent with temporary recommendations to suspend the birth dose of hepatitis B vaccine, preceding the introduction of PCV. CONCLUSION: These findings suggest that the introduction of PCV did not harm overall immunization coverage rates in populations with good access to primary care. However, we did observe some disruptions in the timely delivery of other vaccines coincident with the introduction of PCV and the suspension of the birth dose of hepatitis B vaccine. This study highlights the need for continued vigilance in coming years as the U.S. introduces new childhood vaccines and policies that may change the timing of existing vaccines.

The association between having a medical home and vaccination coverage among children eligible for the vaccines for children program.

BACKGROUND: The Vaccines for Children (VFC) program is designed to reduce the cost of vaccines for vulnerable children, including Medicaid-eligible children, American Indian/Alaska Native children, uninsured children, and underinsured children whose health insurance does not cover the cost of vaccinations. A desired consequence of the program is to promote comprehensive continuous medical care within a medical home for these children. OBJECTIVES: To explore how having a medical home is associated with vaccination coverage among children eligible for the program. PARTICIPANTS: A total of 24514 children 19 to 35 months of age sampled by the National Immunization Survey. DESIGN: VFC eligibility was evaluated for 24514 children 19 to 35 months of age who were sampled by the National Immunization Survey. Children were considered to have a medical home if they had a doctor, nurse, or physician's assistant who provided them with ongoing routine care, including well-child care, preventive care, and sick care, according to their parents. Sampled children were determined to be 4:3:1:3:3 up-to-date (UTD) if their vaccination providers reported administering >or=4 doses of diphtheria-tetanus toxoids-acellular pertussis vaccine, >or=3 doses of polio vaccine, >or=1 dose of measles-mumps-rubella vaccine, >or=3 doses of Haemophilus influenzae type b vaccine, and >or=3 doses of hepatitis B vaccine. RESULTS: Nationally, 44.9% of all children were VFC eligible and 93.0% of the VFC-eligible children received all vaccine doses at a provider enrolled in the VFC program. Compared with children who were not VFC eligible, VFC-eligible children were less likely to be UTD (70.8% vs 77.7%) and less likely to have a medical home (82.1% vs 95.0%). However, among VFC-eligible children, children who had a medical home were significantly more likely to be UTD, compared with children who did not have a medical home (72.3% vs 63.5%). Also, among VFC-eligible children who had a medical home, children who used their medical home consistently to receive all of their vaccination doses were significantly more likely to be UTD, compared with children who did not receive all of their doses from their medical home (75.3% vs 65.7%). Finally, the 4:3:1:3:3 vaccination coverage rate among VFC-eligible children who received all of their vaccination doses from their medical home was not significantly different from that among non-VFC-eligible children, after controlling for significant differences in sociodemographic factors between these groups (adjusted difference: 2.8%; 95% confidence interval: -0.1% to 5.7%). CONCLUSIONS: Although the vaccination coverage rate among VFC-eligible children who had a medical home and received all vaccine doses from their medical home was essentially equivalent to that of non-VFC-eligible children, substantial percentages of VFC-eligible children either did not have a medical home or did not use their medical home to receive all of their recommended vaccinations. The vaccination coverage rate among these children was significantly lower. This suggests that there may be opportunities to increase vaccination coverage by removing barriers that prevent the adoption and consistent use of a medical home among these children.