Poxvirus Vaccines: Past, Present, and Future.

Smallpox was a significant cause of mortality for over three thousand years, amounting to 10% of deaths yearly. Edward Jenner discovered smallpox vaccination in 1796, which rapidly became a smallpox infection preventive practice throughout the world and eradicated smallpox infection by 1980. After smallpox eradication, monkeypox vaccines have been used primarily in research and in outbreaks in Africa, where the disease is endemic. In the present, the vaccines are being used for people who work with animals or in high-risk areas, as well as for healthcare workers treating patients with monkeypox. Among all orthopoxviruses (OPXV), monkeypox viral (MPXV) infection occurs mainly in cynomolgus monkeys, natural reservoirs, and occasionally causes severe multi-organ infection in humans, who were the incidental hosts. The first case of the present epidemic of MXPV was identified on May 7, 2022, and rapidly increased the number of cases. In this regard, the WHO declared the outbreak, an international public health emergency on July 23, 2022. The first monkeypox vaccine was developed in the 1960s by the US Army and was based on the vaccinia virus, which is also used in smallpox vaccines. In recent years, newer monkeypox vaccines have been developed based on other viruses such as Modified Vaccinia Ankara (MVA). These newer vaccines are safer and can provide longer-lasting immunity with fewer side effects. For the future, there is ongoing research to improve the current vaccines and to develop new ones. One notable advance has been the development of a recombinant vaccine that uses a genetically modified vaccinia virus to express monkeypox antigens. This vaccine has shown promising results in pre-clinical trials and is currently undergoing further testing in clinical trials. Another recent development has been the use of a DNA vaccine, which delivers genetic material encoding monkeypox antigens directly into cells. This type of vaccine has shown effectiveness in animal studies and is also undergoing clinical testing in humans. Overall, these recent advances in monkeypox vaccine development hold promise for protecting individuals against this potentially serious disease.

Shared Clinical Decision-Making Recommendations for Adult Immunization: What Do Physicians Think?

BACKGROUND: In 2019, the Advisory Committee on Immunization Practices (ACIP) incorporated the terminology "shared clinical decision-making" (SDM) into recommendations for two adult vaccines. OBJECTIVE: To assess among general internal medicine physicians (GIMs) and family physicians (FPs) nationally (1) attitudes about and experience with ACIP SDM recommendations, (2) knowledge of insurance reimbursement for vaccines with SDM recommendations, (3) how SDM recommendations are incorporated into vaccine forecasting software, and (4) physician and practice characteristics associated with not knowing how to implement SDM. DESIGN: Survey conducted in October 2019-January 2020 by mail or internet based on preference. PARTICIPANTS: Networks of GIMs and FPs recruited from American College of Physicians (ACP) and American Academy of Family Physicians (AAFP) who practice ≥ 50% in primary care. Post-stratification quota sampling performed to ensure networks similar to ACP and AAFP memberships. MAIN MEASURES: Responses on 4-point Likert scales (attitudes/experiences), true/false options (knowledge), and categorical response options (forecasting). Multivariable modeling with outcome of "not knowing how to implement SDM" conducted. KEY RESULTS: Response rate was 64% (617/968). Most physicians strongly/somewhat agreed SDM requires more time than routine recommendations (90%FP; 95%GIM, p = 0.02) and that they need specific talking points to guide SDM discussions (79%FP; 84%GIM, p = NS). There was both support for SDM recommendations for certain vaccines (81%FP; 75%GIM, p = 0.06) and agreement that SDM creates confusion (64%FP; 76%GIM, p = 0.001). Only 41%FP and 43%GIM knew vaccines recommended for SDM would be covered by most health insurance. Overall, 38% reported SDM recommendations are displayed as "recommended" and 23% that they did not result in any recommendation in forecasting software. In adjusted multivariable models, GIMs [risk ratio 1.44 (1.15-1.81)] and females [1.28 (1.02-1.60)] were significantly associated with not knowing how to implement SDM recommendations CONCLUSIONS: To be successful in a primary care setting, SDM for adult vaccination will require thoughtful implementation with decision-making support for patients and physicians.

Safety of zoster vaccine in elderly adults following documented herpes zoster.

BACKGROUND: After completion of the Shingles Prevention Study (SPS; Department of Veterans Affairs Cooperative Studies Program Number 403), SPS participants who had initially received placebo were offered investigational zoster vaccine without charge. This provided an opportunity to determine the relative safety of zoster vaccine in older adults following documented herpes zoster (HZ). METHODS: A total of 13 681 SPS placebo recipients who elected to receive zoster vaccine were followed for serious adverse events (SAE) for 28 days after vaccination. In contrast to the SPS, a prior episode of HZ was not a contraindication to receiving zoster vaccine. The SPS placebo recipients who received zoster vaccine included 420 who had developed documented HZ during the SPS. RESULTS: The mean interval between the onset of HZ and the receipt of zoster vaccine in the 420 recipients with prior HZ was 3.61 years (median interval, 3.77 years [range, 3-85 months]); the interval was <5 years for approximately 80% of recipients. The proportion of vaccinated SPS placebo recipients with prior HZ who developed ≥ 1 SAE (0.95%) was not significantly different from that of vaccinated SPS placebo recipients with no prior history of HZ (0.66%), and the distribution of SAEs in the 2 groups was comparable. CONCLUSIONS: These results demonstrate that the general safety of zoster vaccine in older persons is not altered by a recent history of documented HZ, supporting the safety aspect of the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices recommendation to administer zoster vaccine to all persons ≥ 60 years of age with no contraindications, regardless of a prior history of HZ.

Exploring meningococcal serogroup B vaccination conversations under shared clinical decision-making in the US.

OBJECTIVE: In 2019, the United States Advisory Committee on Immunization Practices (ACIP) updated their meningococcal serogroup B (MenB) vaccination recommendation for 16-|23-year-olds from individual to shared clinical decision-making (SCDM). SCDM recommendations are individually based and informed by a decision process between patients and healthcare providers (HCPs). MenB vaccination among 16-23-year-olds remains low. We examined recorded conversations in which MenB vaccine-related discussions between HCPs and patients/caregivers took place, and how these interactions changed following the updated SCDM recommendation. METHODS: An analysis of recordings where MenB vaccination was discussed between HCPs and patients (16-|23 years old)/caregivers was conducted using retrospective anonymized dialogue data (January 2015-October 2022). Shared decision-making strength was measured using a modified OPTION5 framework. RESULTS: Of 97 included recorded conversations, the average duration was 11.3 min. Within these conversations, MenB disease was discussed for 0.25 min (38.9% of words in total vaccine-preventable diseases discussion) and MenB vaccination was discussed for 1.36 min (60.9% of words in total vaccine discussion), on average. HCPs spoke 78.8% of MenB vaccine-related words and most (99.0%) initiated the MenB vaccination discussion. In 40.2% of recordings, HCPs acknowledged the MenB vaccine without providing a clear recommendation. HCP recommendations often favored MenB vaccination (87.0%) and recommendations were 21.4% stronger post-recommendation change to SCDM. As measured by the modified OPTION5 framework, most recordings did not reflect a high degree of shared decision-making between HCPs and patients/caregivers. CONCLUSIONS: MenB vaccination discussions were brief, and the degree of shared decision-making was low. Targeted education of HCPs and patients/caregivers may improve MenB vaccination awareness, SCDM implementation, and vaccine uptake.

Meningitis is a serious and sometimes deadly disease. In the United States (US), the Centers for Disease Control and Prevention (CDC) recommends that 16­23-year-olds get vaccinated against meningococcal serogroup B (MenB), which causes a specific type of meningitis called invasive meningococcal disease. As of 2019, the CDC recommends that healthcare providers and patients or their caregivers have a shared decision-making discussion about deciding to get vaccinated against MenB. Despite these recommendations, vaccination against MenB among 16­23-year-olds is very low. Only about 3 in 10 17-year-olds had received the MenB vaccine in 2022. We studied conversations between healthcare providers and patients or their caregivers that included discussions of MenB vaccination. These discussions were largely brief and led by the healthcare providers. We found that healthcare providers most often made recommendations that were in favor of their patients getting vaccinated against MenB. However, we also found that healthcare providers missed many opportunities to have these shared decision-making discussions about MenB vaccination with patients or their caregivers. Providing education and resources for patients, caregivers, and healthcare providers focused on increasing awareness about MenB vaccination and the role they can play in having shared decision-making discussions may lead to more adolescents and young adults getting vaccinated against MenB. More research is needed to find out how we can improve MenB vaccination coverage in the US.

Past, present, and future policy considerations regarding meningococcal vaccination in the United States.

INTRODUCTION: In 2005, the United States Advisory Committee on Immunization Practices (ACIP) recommended routine vaccination against invasive meningococcal disease (IMD) caused by serogroups A, C, W, and Y (MenACWY) for all 11-12-year-olds, as well as 2-10-year-olds at high risk. In 2010, a booster dose was recommended for all 16-year-olds, as well as for high-risk patients every 3-5 years. In 2015, optional (as opposed to routine) vaccination against meningococcal serogroup B (MenB) at the preferred age of 16-18 years was recommended (Category B, later changed to shared clinical decision-making). In 2023, a vaccine (MenABCWY) against the five serogroups primarily responsible for IMD in the U.S. became available. AREAS COVERED: This review summarizes the evolution of public policy that led to each milestone vaccine recommendation, reviews epidemiologic data published following the recommendations, and discusses the current state of meningococcal immunization policy. EXPERT OPINION: The use of MenABCWY has the potential to consolidate policy, improve coverage rates for the five serogroups, address disparities in vaccination coverage, and simplify vaccine delivery.

Tetanus, diphtheria, acellular pertussis vaccine during pregnancy: pregnancy and infant health outcomes.

OBJECTIVE: To assess pregnancy and birth outcomes in infants born to women who did or did not receive tetanus, diphtheria, acellular pertussis (Tdap) vaccine during pregnancy. STUDY DESIGN: Retrospective cohort. Pregnant women 12-45 years of age who received Tdap at Intermountain Healthcare facilities and their infants were identified and compared with mother-infant pairs without documented Tdap from May 2005 through August 2009. Primary measures included pregnancy outcomes and infant health outcomes at birth through 12 months. RESULTS: From 162,448 pregnancies we identified 138 women (0.08%) with documented Tdap administration during pregnancy (cases); 552 pregnant women without documented Tdap were randomly selected as controls. Of 138 immunized women, 63% received Tdap in the first trimester and 37% after. Tdap was given most commonly as wound prophylaxis. The incidence of spontaneous or elective abortion was no greater in Tdap cases than in controls. There were no significant differences in preterm delivery, gestational age, or birth weight between groups. One or more congenital anomaly was identified in 3.7% (95% CI 1.2%-8.5%) of case infants and 4.4% (95% CI 2.7%-6.5%) of control infants (P = .749). In infants born to women receiving Tdap during pregnancy, 3.6% (0.8%-10.2%) had International Classification of Diseases, Ninth Revision, Clinical Modification diagnoses consistent with complex chronic conditions within 12 months compared with 10.4% (95% CI 7.2%-14.4%) of infants of controls (P = .054). CONCLUSIONS: Documented Tdap administration during pregnancy was uncommon and occurred most often in the first trimester as prophylaxis following trauma. No increase in adverse outcomes was identified in infants born to women receiving Tdap compared with infants of controls.

Which newborns missed the hepatitis B birth dose vaccination among U.S. children?

OBJECTIVES: Hepatitis B birth dose vaccination is a critical step in preventing perinatal hepatitis B virus infection. This study assesses the prevalence of children who missed the birth dose of hepatitis B vaccination and identifies socio-demographic factors associated with non-receipt of the birth dose among children in the United States. METHODS: A survey observation study was conducted with the national representative sample of 17,053 U.S. children aged 19-35 months obtained from the 2009 National Immunization Survey. Categorical data analysis and multivariable logistic regression in the context of complex sample survey were applied to evaluate the prevalence and determine the independent risk factors. RESULTS: 39.2% of children missed the birth dose of hepatitis B vaccination. Children who reside in states without a universal hepatitis B vaccine supply policy, are not covered by health insurance, and have only 1 vaccination provider are significantly associated with non-receipt of the birth dose hepatitis B vaccination. CONCLUSIONS: Children who reside in states without a universal hepatitis B vaccine supply policy, and who are not covered by health insurance are two important modifiable risk factors for not receiving the birth dose hepatitis B vaccination. Future intervention studies could be needed to help control those modifiable risk factors.

A summary of the Advisory Committee for Immunization Practices (ACIP) use of a benefit-risk assessment framework during the first year of COVID-19 vaccine administration in the United States.

To inform Advisory Committee for Immunization Practices (ACIP) COVID-19 vaccine policy decisions, we developed a benefit-risk assessment framework that directly compared the estimated benefits of COVID-19 vaccination to individuals (e.g., prevention of COVID-19-associated hospitalization) with risks associated with COVID-19 vaccines. This assessment framework originated following the identification of thrombosis with thrombocytopenia syndrome (TTS) after Janssen COVID-19 vaccination in April 2021. We adapted the benefit-risk assessment framework for use in subsequent policy decisions, including the adverse events of myocarditis and Guillain-Barre syndrome (GBS) following mRNA and Janssen COVID-19 vaccination respectively, expansion of COVID-19 vaccine approvals or authorizations to new age groups, and use of booster doses. Over the first year of COVID-19 vaccine administration in the United States (December 2020-December 2021), we used the benefit-risk assessment framework to inform seven different ACIP policy decisions. This framework allowed for rapid and direct comparison of the benefits and potential harms of vaccination, which may be helpful in informing other vaccine policy decisions. The assessments were a useful tool for decision-making but required reliable and granular data to stratify analyses and appropriately focus on populations most at risk for a specific adverse event. Additionally, careful decision-making was needed on parameters for data inputs. Sensitivity analyses were used where data were limited or uncertain; adjustments in the methodology were made over time to ensure the assessments remained relevant and applicable to the policy questions under consideration.

Vaccine patterns among patients diagnosed with Guillain-Barré Syndrome and matched counterparts in a Medicare supplemental population, 2000-2020.

Some vaccines have a small risk of Guillain-Barré Syndrome (GBS), a rare autoimmune disorder characterized by paralysis if untreated. The CDC's Advisory Committee on Immunization Practices (ACIP) guidelines do not consider GBS a precaution for future vaccines unless GBS developed within six weeks after a tetanus-toxoid-containing vaccine or influenza vaccine. Our goal was to describe vaccine patterns before and after GBS diagnosis. We matched each of 709 patients diagnosed with GBS from 2002 to 2020 with Medicare supplemental insurance to 10 counterparts without GBS (1:10) on age and sex. Propensity score-based weighting balanced covariates between groups, and we estimated weighted mean cumulative counts (wMCC) of vaccines/person before and after GBS diagnosis. Among patients with GBS, 7% were diagnosed within 42 days after a vaccine. Prior to GBS diagnosis, the wMCC of vaccines per person was similar between GBS cases and matched counterparts, but after two years of follow-up, GBS patients received 21 fewer vaccines/100 people than counterparts (wMCC difference -0.21 vaccines/person, 95% CI -0.24 to -0.18); GBS patients received 16 vaccines/100 people while matched counterparts received 36/100. Vaccine use was reduced following GBS diagnosis despite no ACIP precaution for most (93%) patients in this study. The observed drop in vaccines after GBS diagnosis indicates a disconnect between clinical practice and current recommendations.

Immunization, not vaccination: monoclonal antibodies for infant RSV prevention and the US vaccines for children program.

In the US, RSV imposes significant burdens on infants, households, and the health system. Yet the only licensed immunization is accessible to only certain risk groups comprising 2% of the infant population, leaving the remaining 98% unprotected. An effective immunization for all infants is a significant public health priority. One possible solution is the FDA-approved monoclonal antibody nirsevimab, which recent evidence suggests is safe and effective in preventing RSV in all infants, and which is currently being considered for inclusion in the pediatric immunization schedule and the federal Vaccines for Children (VFC) program. But the question arises whether passive immunization products like nirsevimab ought to be eligible for the VFC, which nominally and traditionally centers on vaccines providing active immunity. Addressing this is urgent because VFC inclusion will be decided on imminently. I argue there are strong policy grounds, i.e., reasons grounded in the ultimate health system goals of maximizing population health or social welfare subject to resource constraints, not to exclude passive immunization from VFC eligibility. Active and passive immunizations both provide adaptive immunity and can therefore produce qualitatively similar effects on risks of infection, disease, and transmission; on disease severity and duration; and on health, welfare, and health resource use. The distinction between active and passive immunization does not intrinsically matter since what matters for the attainment of health system goals is the extent of immunity conferred, not whether immunity is active or passive. Nor can passivity be considered a useful proxy for conferring a lesser extent of immunity, since no such proxy is needed (existing valuation methods can cope with variations in product attributes), and it is a poor proxy (passive immunizations can be better for individuals with impaired immune systems and can have comparable effectiveness durations and economic value as vaccines).

Safety of measles, mumps, and rubella vaccine in adolescents and adults in the vaccine safety Datalink.

Background: Measles, mumps, and rubella vaccine (MMR) is routinely administered to children; however, adolescents and adults may receive MMR for various reasons. Safety studies in adolescents and adults are limited. We report on safety of MMR in this age group in the Vaccine Safety Datalink. Methods: We included adolescents (aged 9-17 years) and adults (aged ≥ 18 years) who received ≥ 1 dose of MMR from January 1, 2010-December 31, 2018. Pre-specified outcomes were identified by diagnosis codes. Clinically serious outcomes included anaphylaxis, encephalitis/myelitis, Guillain-Barré syndrome, immune thrombocytopenia, meningitis, and seizure. Non-serious outcomes were allergic reaction, arthropathy, fever, injection site reaction, lymphadenopathy, non-specific reaction, parotitis, rash, and syncope. All serious outcomes underwent medical record review. Outcome-specific incidence was calculated in pre-defined post-vaccination windows. A self-controlled risk interval design was used to determine the relative risk of each outcome in a risk window after vaccination compared to a more distal control window. Results: During the study period, 276,327 MMR doses were administered to adolescents and adults. Mean age of vaccinees was 34.8 years; 65.8 % were female; 53.2 % of doses were administered simultaneously with ≥ 1 other vaccine. Serious outcomes were rare, with incidence ≤ 6 per 100,000 doses for each outcome assessed, and none had a significant elevation in incidence during the risk window compared to the control window. Incidence of non-serious outcomes per 100,000 doses ranged from 3.4 for parotitis to 263.0 for arthropathy. Other common outcomes included injection site reaction and rash (157.0 and 112.9 per 100,000 doses, respectively). Significantly more outcomes were observed during the risk window compared to the control window for all non-serious outcomes except parotitis. Some variability was observed by sex and age group. Conclusion: Serious outcomes after MMR are rare in adolescents and adults, but vaccinees should be counseled regarding anticipated local and systemic non-serious adverse events.

Why the American Academy of Pediatrics recommends initiating HPV vaccine at age 9.

The American Academy of Pediatrics (AAP) recommends starting the human papillomavirus (HPV) vaccine series between 9 and 12 years, at an age that the provider deems optimal for acceptance and completion of the vaccination series. This recommendation differs from the Advisory Committee on Immunization Practices (ACIP), which recommends HPV vaccination be initiated at age 11 or 12 years, stating the series can be started at age 9 years. This commentary discusses the reasoning behind AAP's decision to differ from ACIP, as the AAP and ACIP schedules are essentially harmonized for all other vaccines. Reasons include recognition that (1) vaccination uptake is suboptimal; (2) offering vaccination earlier offers provider's flexibility in introducing the vaccine; (3) initiating the vaccine at age 9 or 10 may be preferable for parents or adolescents who do not want to receive ≥3 concomitant vaccines at age 11 or 12; (4) earlier initiation may disentangle HPV recommendations from discussions of sexuality; (5) earlier recommendation might alleviate HPV vaccine hesitancy "fatigue;" (6) the immune response is robust at younger ages with no evidence of waning protection; and (7) there is a dearth of evidence supporting starting the recommendation at age 11 or 12 within the "adolescent immunization platform."

Factors contributing to missed opportunities for human papillomavirus vaccination among adolescents, ages 11 to 13, in Iowa.

Introduction: Rates of human papillomavirus (HPV) vaccination remain low and missed opportunities for HPV vaccination are widespread. Researchers have identified factors related to HPV vaccination, but less is known about missed opportunities. Methods: We used medical claims data from a large Midwestern insurance provider to explore relationships between adolescent and provider characteristics and missed opportunities for HPV vaccination. We stratified models by initiation status with adolescents who had received one or more HPV vaccinations in one group (n = 6,123) and adolescents with no record of an HPV vaccination in the other (n = 8,107). Results: There were significant differences in comparisons of all variables between initiators and non-initiators. Notably, non-initiators had lower rates of vaccination for HPV and other adolescent vaccinations, and fewer well-child visits. For all adolescents, birth year, having other recommended vaccines, and number of well-child visits were significantly associated with missed opportunities. Additionally, among initiators, pediatrician as a primary care provider and being in a rural area were significantly associated. Discussion: Overall, adolescents with greater healthcare utilization had more missed opportunities, indicating that, despite increased numbers of visits, providers are not taking advantage of these opportunities to vaccinate. Future research should prioritize developing a deeper understanding of why these missed opportunities are occurring and implementing new and existing strategies to prevent them. Reducing missed opportunities will help to prevent future HPV-related cancers and the significant morbidity and mortality that they can cause.

HPV vaccination initiation among white, black and Middle East North African (MENA) males.

Objectives: US males initiate HPV vaccination at older ages than females and currently have low population coverage. We aim to describe the prevalence and predictors of HPV vaccination initiation among males of White, Black, and Middle-Eastern/North-African (MENA) descent in southeast Michigan. Methods: We conducted three community-based surveys in 2019 that provided primary data via self report. Using population weights and multivariate modeling, we measured the prevalence and predictors of HPV vaccine initiation in each race/ethnicity of men (age 18-34 years) analyzed. Results: The vaccine initiation rates were 44.5 % (95 % CI: 44.4, 44.6) for White men, 46.2 % (46.0, 46.4) for Black men, and 23.2 % (22.8, 23.6) for MENA men, (p < 0.001). Being a student, compared to unemployed or disabled, was significantly associated with HPV vaccine initiation across all three races/ethnicities. Married men of any race/ethnicity were unlikely to be vaccinated. MENA men born in the US and having some college education were also more likely to initiate HPV vaccination. Conclusions: White, Black, and MENA men are not vaccinated in accord with Healthy (Healthy People 2030, 2022) goals. Each race/ethnicity has different predictors of vaccination.

Vaccination in Chronic Liver Disease: An Update.

Patients with chronic liver disease (CLD) with or without cirrhosis remain at risk of developing hepatic decompensation when infected with viral or bacterial pathogens. The Advisory Committee on Immunization Practices (ACIP) currently recommends vaccination in CLD against hepatitis A virus (HAV), hepatitis B virus (HBV), influenza, pneumococcus, herpes zoster, tetanus, diphtheria, pertussis, and SARS-CoV-2. Inactivated vaccines are preferred over live attenuated ones, especially in transplant recipients where live vaccines are contraindicated. As the severity of the liver disease progresses, vaccine efficacy declines, and therefore, vaccines should be ideally administered early in the disease course for optimal immune response. Despite the strong recommendations, overall vaccination coverage in CLD remains poor; however, it is encouraging to note that in recent years coverage against influenza and pneumococcus has shown some improvement. Inadequate access to healthcare, lack of information on vaccine safety, poor financial reimbursement for healthcare providers, and vaccine misinformation are often responsible for low immunization rates. This review summarizes the impact of vaccine-preventable illness in those with CLD, updated vaccine guidelines, seroconversion rates in the vaccinated, and barriers faced by healthcare professionals in immunizing those with liver disease.

Evaluating vaccination coverage and timeliness in American Indian/Alaska Native and non-Hispanic White children using state immunization information system data, 2015-2017.

Comprehensive estimates of vaccination coverage and timeliness of vaccine receipt among American Indian/Alaska Native (AI/AN) children in the United States are lacking. This study's objectives were to quantify vaccination coverage and timeliness, as well as the proportion of children with specific undervaccination patterns, among AI/AN and non-Hispanic White (NHW) children ages 0-24 months in Montana, a large and primarily rural U.S. state. Data from Montana's immunization information system (IIS) for children born 2015-2017 were used to calculate days undervaccinated for all doses of seven recommended vaccine series. After stratifying by race/ethnicity, up-to-date coverage at key milestone ages and the proportion of children demonstrating specific patterns of undervaccination were reported. Among n = 3,630 AI/AN children, only 23.1% received all recommended vaccine doses on-time (i.e., zero days undervaccinated), compared to 40.4% of n = 18,022 NHW children (chi-square p < 0.001). A greater proportion of AI/AN children were delayed at each milestone age, resulting in lower overall combined 7-vaccine series completion, by age 24 months (AI/AN: 56.6%, NHW: 64.3%, chi-square p < 0.001). As compared with NHW children, a higher proportion of AI/AN children had undervaccination patterns suggestive of structural barriers to accessing immunization services and delayed starts to vaccination. More than three out of four AI/AN children experienced delays in vaccination or were missing doses needed to complete recommended vaccine series. Interventions to ensure on-time initiation of vaccine series at age 2 months, as well initiatives to encourage completion of multi-dose vaccine series, are needed to reduce immunization disparities and increase vaccination coverage among AI/AN children in Montana.

Update from the Advisory Committee on Immunization Practices.

The Advisory Committee on Immunization Practices (ACIP), a group of medical and public health experts, meets 3 times per year to develop recommendations for vaccine use in the United States. There are usually 15 voting members; members' terms are for 4 years. ACIP members and Centers for Disease Control and Prevention staff discuss the epidemiology of vaccine-preventable diseases and vaccine research, effectiveness, safety data, and results from clinical trials. Representatives from the American Academy of Pediatrics (Y. A. M., D. W. K.) and the Pediatric Infectious Diseases Society (S. T. O.) are present as liaisons to the ACIP. The ACIP met on 23-24 October 2019 to discuss pertussis vaccines, the child/adolescent and adult immunization schedule, influenza vaccine effectiveness and safety, Ebola vaccine, orthopoxvirus vaccines, Dengue vaccine, rabies vaccine, measles, and vaccine safety update.

Update From the Advisory Committee on Immunization Practices.

The Advisory Committee on Immunization Practices (ACIP), a group of medical and public health experts, normally meets 3 times per year to develop recommendations for vaccine use in the United States. Because of the severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) pandemic, there are several SARS-CoV-2 vaccines currently in late-stage clinical trials, so the ACIP is now meeting monthly for single day meetings, with plans to continue standard 2- to 3-day meetings as per usual (February, June, and October). Emergency meetings of ACIP may occur if a vaccine candidate receives an Emergency Use Authorization from the food and drug administration (FDA). This Update provides a combined summary of the August 26 and September 22, 2020, meetings, both of which focused completely on Coronavirus disease 2019 (COVID-19) vaccines. The representatives from the American Academy of Pediatrics (Y. A. M. and D. W. K.) and the Pediatric Infectious Diseases Society (S. T. O.) are present as liaisons to the ACIP.

Characteristics of vaccinating providers reported through Medicare claims in office-based settings: Volume of influenza and pneumococcal vaccinations.

Vaccination coverage among older adults is low in the United States. A recommendation from a provider is a strong predictor of vaccine receipt. Using Medicare Fee-For-Service data (2015-2017) this study characterized providers by the number of influenza and pneumococcal vaccines administered in physician offices, age, gender, and professional specialty to determine the volume of vaccines provided by individual providers and characteristics of these providers. Half of all vaccinations were provided by 10% of providers. The mean age of 224,483 and 165,710 unique influenza and pneumococcal providers respectively was 49 years (SD: 12 years) with males and females equally distributed. The highest vaccinating quartile of providers tended to be older, more likely male and more likely general physicians. Those who administered a high volume of one vaccine were likely to administer a high volume of the other. Providers administering vaccines in office-based settings can do more to increase vaccination coverage rates.

Determinants of Meningococcal ACWY vaccination in adolescents in the US: completion and compliance with the CDC recommendations.

Since 2011, the Advisory Committee on Immunization Practices (ACIP) guidelines for routine MenACWY vaccination in the US include a primary dose before age 16 y, preferably at ages 11-12 y, with a booster dose at age 16 y. Data on rates and drivers of meningococcal vaccination completion (receipt of both doses) and compliance with recommendations (receipt of primary dose at ages 11-12 y followed by booster at 16 y) down to state-level are limited.This study evaluated rates and determinants of MenACWY vaccination completion and compliance in adolescents aged 17 y based on data from the annual National Immunization Survey-Teen between 2011 and 2016. Individual- and state-level determinants of completion and compliance were assessed using uni-level and multi-level multivariable regression models. Average national rates were 23.2% and 12.1% for completion and compliance, respectively, with large inter-state variation observed (completion: 8.7-39.7%; compliance: 3.1-26.2%). Beyond the state of residence, factors significantly associated with a higher likelihood of both completion and compliance included being male, up-to-date on other routine vaccines, having private or hospital-based vaccine providers (vs. public) and having >1 child in the household. Factors specifically associated with completion included having >1 annual health-care visit and presence of a booster-dose vaccine mandate, while a history of asthma and high-risk health conditions had a positive association with compliance. State-level determinants of completion and compliance included pediatricians-to-children ratio and the proportion of Immunization Information System use among adolescents, respectively. Outcomes of this study may help guide clinical, policy and educational interventions to further increase MenACWY completion rates and reduce disparities in vaccination.