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In October 2021, Emergency Use Authorization of Coronavirus Disease 2019 (COVID-19) vaccines was granted for children aged 5-11. To ensure vaccine uptake in children upon approval, California will implement a state-wide executive order mandating COVID-19 vaccination for school children following full US FDA approval. This study uses survey data collected between November 6th, 2020 and December 14th, 2020 (n = 2091) to identify how sociodemographic characteristics and attitudes towards childhood vaccines among California parents were associated with their intentions to vaccinate their child against COVID-19. About one quarter (26 %) of surveyed California parents did not intend to vaccinate their child, suggesting skepticism towards the COVID-19 vaccine for children and the potential for pushback to a COVID-19 vaccine school-entry mandate. However, 17 % were unsure of their decision, suggesting the potential for public health messaging to make a positive impact on COVID-19 vaccine confidence and uptake. This study identifies characteristics of hesitant parents in California to prioritize for research and outreach. These data also provide a baseline for parental attitudes towards vaccinating children against COVID-19 in California, which will be useful for characterizing changes in attitudes towards childhood COVID-19 vaccination over time.

Vaccine confidence and coverage decreased following a death temporally but not causally related to measles vaccination in Ukraine in 2008. Large measles outbreaks including international exportations followed. Herein we characterize this experience including associated costs.Mixed-methods were used to characterize this vaccine safety incident and quantify health and economic costs. Qualitative interviews illuminate the incident, social climate, and corruption that influenced vaccine confidence in Ukraine. A literature review explored attitudes toward vaccines in the USSR and post-independence Ukraine. Infectious disease incidence was examined before and after the vaccine safety incident. An economic analysis estimated associated healthcare costs, including prevention and outbreak control measures, additional vaccination activities due to failure of the 2008 campaign, treatment costs for new cases domestically and foreign exportation, and productivity loss from treatment time and mortality for new cases.Vaccine hesitancy and distrust in government and public health programs due to corruption existed in Ukraine before the vaccine safety incident. The mishandling of the 2008 incident catalyzed the decline of vaccine confidence and prompted poor procurement decisions, leading to a drop in infant vaccination coverage, increased domestic measles cases, and exportation of measles. The estimated cost of this incident was approximately $140 million from 2008 to 2018.Absent a rapid and credible vaccine safety response, a coincidental death following immunization resulted in major outbreaks of measles with substantial economic costs. Adequate investments in a post-licensure safety system may help avoid similar future incidents.

To evaluate the impact of a multi-component intervention package of maternal immunization uptake in obstetric care clinics.In a multi-level, cluster- and individually-randomized controlled trial we implemented an evidence-based intervention that targeted practice-, provider- and patient-level barriers to vaccine uptake. Obstetric practices were randomized to receive the practice and provider-level interventions or continue their normal standard of care. We enrolled pregnant women at practices in Georgia and Colorado and randomized women into patient-level intervention and control groups, resulting in four study arms. The primary outcomes were receipt of the influenza and tetanus, diphtheria and acellular pertussis (Tdap) vaccines during pregnancy. A sample size of 550 women per arm (2200 total) was planned and enrolled to compare the intervention between the four study arms.Between June 2017 and July 2018, 4907 women were screened and 2200 women were randomized, 550 to each of the four study arms. We were unable to follow-up with 108 women, for a final sample size of 2092. Sample characteristics and sample size were similar among study arms. There was no significant increase in Tdap or influenza vaccine uptake overall. Among women who had no intention of or were unsure about receiving the influenza vaccine during pregnancy, those who received just the patient-level intervention were 61% more likely to receive the influenza vaccine than those in the control arm (Relative risk: 1.61; 95% Confidence Interval: 1.18-2.21). There was no significant difference in vaccine uptake for either influenza or tetanus, diphtheria and acellular pertussis between the four arms of the study.This trial highlights the need for more targeted interventions to improve vaccine uptake. Future work should focus on clinics with low baseline vaccine uptake and the patient-level intervention should be expanded and targeted towards women with low vaccine confidence.

The development of the mutant omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the coronavirus disease 2019 (COVID-19) pandemic raised the importance of reevaluating the risk and benefit of COVID-19 vaccines. With a decision tree model, we calculated the benefit-risk ratio and the benefit-risk difference of receiving monovalent messenger RNA (mRNA) COVID-19 vaccine (primary 2 doses, a third dose, and a fourth dose) in the 4–5 months after vaccination using quality-adjusted life years. The analysis was stratified by age, sex, and the presence of comorbidity. Evidence from peer-reviewed publications and gray literature was reviewed on September 16, 2022, to inform the study. Benefit-risk ratios for receipt of the BNT162b2 vaccine (Pfizer-BioNTech) ranged from 6.8 for males aged 12–17 years without comorbidity for the primary doses to 221.3 for females aged ≥65 years with comorbidity for the third dose. The benefit-risk ratios for receipt of the mRNA-1273 vaccine (Moderna) ranged from 7.2 for males aged 18–29 years without comorbidity for the primary doses to 101.4 for females aged ≥65 years with comorbidity for the third dose. In all scenarios of the one-way sensitivity analysis, the benefit-risk ratios were more than 1, irrespective of age, sex, comorbidity status, and type of vaccine, for both primary and booster doses. The benefits of mRNA COVID-19 vaccines in protecting against the omicron variant outweigh the risks, irrespective of age, sex, and comorbidity.

INTRODUCTION: Safe and effective vaccines against Coronavirus Disease 2019 (COVID-19) provide the best opportunity to control the pandemic. Having safe and efficacious vaccines available is only half the equation; people must also take them. We describe a study to identify COVID-19 vaccine attitudes, values and intentions immediately preceding authorization of COVID-19 vaccines in the US. METHODS: A national panel survey was conducted to measure intent to receive COVID-19 vaccines as well as disease and vaccine attitudes, values and trust in local, state and federal public health authorities. RESULTS: Greater than 80% of respondents reported confidence they could adhere to COVID recommendations such as mask wearing, social distancing and hand washing. The majority of respondents (70%) reported believing that current drugs were somewhat or very good at treating COVID-19 infection. Vaccine intent fell into three groups: Intenders (50%), Wait and Learn (40%), and Unlikelys (10%). Intent to get vaccinated was substantially lower among African American (32%), and higher among men (56%), those over 60 years of age (61%), those with a Bachelor's degree or higher (63%), and Democrats (63%). The Wait and Learn group, compared to the Intenders, were less likely to report being diagnosed with a high risk condition for COVID-19, receiving an influenza vaccine in the past 12 months, discussing COVID-19 vaccine with their healthcare provider, perceiving COVID-19 as severe, considering a COVID-19 vaccine important to stop the spread of infection, and wering a mask usually or almost always. CONCLUSION: Only half of US adults intend to accept COVID-19 vaccines; most others (40%) are uncertain. Levels of immunity associated with community protection will not be achieved without reaching those who are currently uncertain. Characterizing COVID-19 vaccine attitudes and intentions and ascertaining values and trust in local, state, and federal public health authorities that impact vaccine decision-making are essential.

Although vaccines are considered one of the most effective medical interventions to prevent vaccine preventable disease and associated morbidity and mortality, a number of recent outbreaks are threatening the gains made by vaccines. Vaccine hesitancy is a key driver of vaccine refusal and has been associated with vaccine preventable outbreaks. While parents seek information from many sources to inform their vaccine decision-making process, they continue to view their child's pediatric provider as a trusted source of vaccine information. The communication that occurs between a provider and parent with regards to vaccination is critical in reducing concerns and nudging parents toward vaccine acceptance. However, vaccine-hesitant parents raise issues in this encounter that many providers feel ill-equipped to answer, due to lack of training on evidence-based communication strategies. We focus on promising approaches related to patient-provider communication within the context of vaccination. We found empirical evidence that the use of a presumptive format to recommend vaccines, motivational interviewing, and tailoring information to increase message salience are approaches that can positively affect vaccine acceptance. As providers continue to serve as important influencers in the vaccine decision-making process, it is evident that there is a need to continue to identify evidence-based, and practically implementable approaches to mitigate parental vaccine hesitancy. Providers play a key role in improving coverage rates, and therefore it is paramount to seek ways to improve how providers communicate about vaccines.

Infectious disease outbreaks highlight the importance of trust in public health authorities to avoid fear and improve adherence to recommendations. There is currently no established and validated measure for trust in public health authorities. We aimed to develop and validate an instrument that measures trust in public health authorities and to assess the association between trust in public health authorities and vaccine attitudes. We developed 20 items to measure trust in public health authorities. After implementing a survey in January 2020, we investigated relationships between the items, reduced the number of items, and identified latent constructs of the scale. We assessed variability in trust and how trust was associated with vaccine attitudes, beliefs, and self-reported vaccine acceptance. The pool was reduced to a 14-item trust in public health authorities scale and we found that this trust model was strongly associated with acceptance of vaccines. Our scale can be used to examine the relationship between trust in public health authorities and adherence to public health recommendations. The measure needs to be validated in other settings to determine whether they are associated with other areas where the public question public health authority recommendations.

The US response to coronavirus disease 2019 (COVID-19) has been plagued with politics driving public health and messaging. As a result, COVID-19 vaccine rollout is occurring in an environment ill equipped to achieve broad acceptance of the vaccine. Addressing public concerns unlocks the potential for high vaccine coverage; this is best achieved when science and values, not politics, inform public health. A multifaceted and thorough engagement and communication plan that is responsive to the concerns and values of different groups must be swiftly yet carefully implemented in a coordinated manner by federal, state, and local governments. Effective communication will require rapid and rigorous science to promptly differentiate between adverse events following immunization that are causally related versus simply coincidental. Health care providers, in particular, will need support to process the otherwise potentially overwhelming amount of relevant information and effectively integrate it into discussions with their patients to support their decision making. An equitable COVID-19 immunization program could substantively reduce the disproportionate risks associated with this pandemic.

Limited studies are available on how decisions and perceptions on SARS-CoV-2 vaccination have changed since the start of vaccination availability. We performed a qualitative study to identify factors critical to SARS-CoV-2 vaccination decision making and how perspectives evolved among African American/Black, Native American, and Hispanic communities disproportionately affected by COVID-19 and social and economic disadvantage. We conducted 16 virtual meetings, with 232 participants in wave 1 meetings (December 2020) and with 206 returning participants in wave 2 meetings (January and February 2021). Wave 1 vaccine concerns in all communities included information needs, vaccine safety, and speed of vaccine development. Lack of trust in government and the pharmaceutical industry was influential, particularly among African American/Black and Native American participants. Participants showed more willingness to get vaccinated at wave 2 than at wave 1, indicating that many of their information needs had been addressed. Hesitancy remained greater among African American/Black and Native American participants than among Hispanic participants. Participants in all groups indicated that conversations tailored to their community and with those most trustworthy to them would be helpful. To overcome vaccine hesitancy, we propose a model of fully considered SARS-CoV-2 vaccine decision making, whereby public health departments supply information, align with community values and recognize lived experiences, offer support for decision making, and make vaccination easy and convenient.

Scientists are trained to be skeptical and not overstate the existing evidence. This cautiousness is a valuable asset when working in scientific research, where the goal is the pursuit of knowledge and truth. It becomes a handicap when scientists are asked to communicate to the public about pressing topics such as COVID-19 vaccines. Often in such contexts, immediate recommendations are sought, and decisions must be made even when complete evidence is lacking. For scientists to be effective public communicators, they must adjust their mindset and embrace brevity, clarity, and other principles of effective communication. Focusing messages on what is known fosters public confidence in taking needed actions, whereas focusing on what is still unknown fosters inaction and seeds doubt. The implementation of principles of effective communication does not inherently conflict with maintaining scientific accuracy and acknowledging uncertainty, but it does require additional care, effort, and training.

Objectives: We aimed to elucidate public values regarding the use of genomics to improve vaccine development and use (vaccinomics). Methods: Adults ≥18 years-old were recruited through social media and community organizations, and randomly assigned to one of four nested discussion groups in Boulder, CO and Baltimore, MD. Participants rated their confidence in vaccine safety and effectiveness prior to and after discussing vaccinomics. Before departing, they prioritized funding for vaccinomics versus federal priorities (vaccine safety and efficacy, new vaccines, and free vaccines) and chronic diseases (cancer, heart disease, and diabetes). Grounded Theory-influenced methods were used to identify themes. Results: Participants broadly supported vaccinomics. Emergent themes: concerns about reduced privacy/confidentiality, increased genetically based stigma/discrimination, and reduced agency to make vaccine-related decisions through genetically based prioritization. Participants supported vaccinomics’ potential for increased personalization. Some participants favored prioritizing others over themselves during a vaccine shortage, while others did not. Some participants worried health insurance companies would discriminate against them based on information discovered through vaccinomics. Participants feared inequitable implementation of vaccinomics would contribute to discrimination and marginalization of vulnerable populations. Discussing vaccinomics did not impact perceptions of vaccine safety and effectiveness. Federal funding for vaccinomics was broadly supported. Conclusion: Participants supported vaccinomics’ potential for increased personalization, noting policy safeguards to facilitate equitable implementation and protect privacy were needed. Despite some concerns, participants hoped vaccinomics would improve vaccine safety and effectiveness. Policies regarding vaccinomics’ implementation must address public concerns about the privacy and confidentiality of genetic information and potential inequities in access to vaccinomics’ benefits.

Background As a priority group, healthcare personnel (HCP) will be key to the success of coronavirus disease 2019 (COVID-19) vaccination programs. This study assessed HCP willingness to get vaccinated and identified specific concerns that would undermine vaccination efforts. Methods We conducted a cross-sectional survey of HCP, including clinical and nonclinical staff, researchers, and trainees, between 23 November and 5 December 2020. The survey evaluated attitudes, beliefs, and willingness to get vaccinated. Results There were 5287 respondents with a mean (SD) age of 42.5 (13.56) years; 72.8% were female (n = 3842). Overall, 57.5 % of individuals expressed intent to receive COVID-19 vaccine; 80.4% were physicians and scientists representing the largest group. 33.6% of registered nurses, 31.6% of allied health professionals, and 32% of master’s level clinicians were unsure they would take the vaccine (P Conclusions We observed that self-reported willingness to receive vaccination against COVID-19 differs by hospital roles, with physicians and research scientists showing the highest acceptance. These findings highlight important heterogeneity in personal attitudes among HCPs around COVID-19 vaccines and highlight a need for tailored communication strategies.

BACKGROUND Accurate and timely COVID-19 vaccination coverage data are vital for informing targeted, effective messaging and outreach and identifying barriers to equitable health service access. However, gathering vaccination rate data is challenging, and efforts often result in information that is either limited in scope (eg, limited to administrative data) or delayed (impeding the ability to rapidly respond). The evaluation of innovative technologies and approaches that can assist in addressing these limitations globally are needed. OBJECTIVE The objective of this survey study was to assess the validity of Random Domain Intercept Technology (RDIT; RIWI Corp) for tracking self-reported vaccination rates in real time at the US national and state levels. RDIT—a form of online intercept sampling—has the potential to address the limitations of current vaccination tracking systems by allowing for the measurement of additional data (eg, attitudinal data) and real-time, rapid data collection anywhere there is web access. METHODS We used RDIT from June 30 to July 26, 2021, to reach a broad sample of US adult (aged ≥18 years) web users and asked questions related to COVID-19 vaccination. Self-reported vaccination status was used as the focus of this validation exercise. National- and state-level RDIT-based vaccination rates were compared to Centers for Disease Control and Prevention (CDC)–reported national and state vaccination rates. Johns Hopkins University’s and Emory University’s institutional review boards designated this project as public health practice to inform message development (not human subjects research). RESULTS By using RDIT, 63,853 adult web users reported their vaccination status (6.2% of the entire 1,026,850 American web-using population that was exposed to the survey). At the national level, the RDIT-based estimate of adult COVID-19 vaccine coverage was slightly higher (44,524/63,853, 69.7%; 95% CI 69.4%-70.1%) than the CDC-reported estimate (67.9%) on July 15, 2021 (ie, midway through data collection; t63,852=10.06; Pr=0.90; P CONCLUSIONS This broad-reaching, real-time data stream may provide unique advantages for tracking the use of a range of vaccines and for the timely evaluation of vaccination interventions. Moreover, RDIT could be harnessed to rapidly assess demographic, attitudinal, and behavioral constructs that are not available in administrative data, which could allow for deeper insights into the real-time predictors of vaccine uptake–enabling targeted and timely interventions.

Background Accurate and timely COVID-19 vaccination coverage data are vital for informing targeted, effective messaging and outreach and identifying barriers to equitable health service access. However, gathering vaccination rate data is challenging, and efforts often result in information that is either limited in scope (eg, limited to administrative data) or delayed (impeding the ability to rapidly respond). The evaluation of innovative technologies and approaches that can assist in addressing these limitations globally are needed. Objective The objective of this survey study was to assess the validity of Random Domain Intercept Technology (RDIT; RIWI Corp) for tracking self-reported vaccination rates in real time at the US national and state levels. RDIT—a form of online intercept sampling—has the potential to address the limitations of current vaccination tracking systems by allowing for the measurement of additional data (eg, attitudinal data) and real-time, rapid data collection anywhere there is web access. Methods We used RDIT from June 30 to July 26, 2021, to reach a broad sample of US adult (aged ≥18 years) web users and asked questions related to COVID-19 vaccination. Self-reported vaccination status was used as the focus of this validation exercise. National- and state-level RDIT-based vaccination rates were compared to Centers for Disease Control and Prevention (CDC)–reported national and state vaccination rates. Johns Hopkins University’s and Emory University’s institutional review boards designated this project as public health practice to inform message development (not human subjects research). Results By using RDIT, 63,853 adult web users reported their vaccination status (6.2% of the entire 1,026,850 American web-using population that was exposed to the survey). At the national level, the RDIT-based estimate of adult COVID-19 vaccine coverage was slightly higher (44,524/63,853, 69.7%; 95% CI 69.4%-70.1%) than the CDC-reported estimate (67.9%) on July 15, 2021 (ie, midway through data collection; t63,852=10.06; P Conclusions This broad-reaching, real-time data stream may provide unique advantages for tracking the use of a range of vaccines and for the timely evaluation of vaccination interventions. Moreover, RDIT could be harnessed to rapidly assess demographic, attitudinal, and behavioral constructs that are not available in administrative data, which could allow for deeper insights into the real-time predictors of vaccine uptake–enabling targeted and timely interventions.

INTRODUCTION. Maternal vaccination is critical for improving maternal and child health. Quality Improvement (QI) models(), such as the Centers for Disease Control and Prevention’s (CDC) Assessment, Feedback, Incentives, eXchange (AFIX)() model, have not yet been adapted to maternal vaccinations. This study assesses the impact of AFIX-OB, an adapted version of AFIX for obstetric settings, on maternal vaccination rates. METHODS. Between December 2016 and May 2018, state health departments and obstetric practices in Colorado and Georgia implemented the adapted AFIX-OB model. The model addressed unique patterns in patient encounters, practice flow, health records systems and competing clinical priorities in the obstetric setting through a menu of clearly-defined QI strategies, bi-weekly technical assistance meetings with designated immunization champions, incentives for champions/staff, and adapted tools to aid each practice during implementation. Vaccination rates were assessed by random chart reviews pre- and post-intervention. RESULTS. The AFIX-OB model was evaluated in eleven obstetric practices in two states as part of a multi-level intervention to increase maternal vaccination. Post AFIX-OB implementation, documented influenza vaccination rates increased from 56% at baseline to 65% (p

Immunization is one of the most effective ways to prevent infectious diseases. However, vaccination rates are suboptimal in the United States. Obstetric providers are critical in influencing vaccine decision making among pregnant women, as trust between a patient and provider may facilitate willingness to accept vaccination. Little is known about how power between a patient and provider affects vaccine acceptance. This study explored pregnant women’s trust in obstetric providers within the context of vaccines. Using concepts from the relational theory of power, we conducted 40 in-depth interviews with a purposive sample of pregnant women from four Ob-Gyn practices each in Georgia and Colorado. Results suggest that to enhance trust, providers could gain distributive power by conveying empathy. Designated power through medical experience was associated with both trust and distrust, as some women trusted their providers because of their authority and medical credentials, while others viewed authority and experience as reasons to distrust their provider. To increase acceptance, providers should acknowledge the underlying power dynamics within these interpersonal relationships and strengthen rapport with patients through empathy and dialogue.

Background Infants too young to be fully vaccinated are vulnerable to potentially deadly influenza and pertussis infections. The cocooning strategy limits this risk by vaccinating those likely to interact with the infant and mother during this vulnerable time, such as close friends and family members. Distribution of accurate and accessible vaccine information through existing social networks could be an important tool in increasing vaccine confidence and coverage. Methods We surveyed 1095 pregnant women from diverse prenatal care practices in Georgia and Colorado. These women were surveyed through a mobile app to assess vaccine intentions, attitudes, beliefs, norms, and levels of trust, and then presented brief individually-tailored educational videos about maternal and infant vaccines and the cocooning strategy. They were then given the opportunity to refer up to six contacts to enroll in the app and receive similar vaccine education. Results Twenty-eight percent of these women referred at least one contact, with an average of 2.67 contacts per referring woman. Most referrals (93%) were partners, parents, siblings, relatives, or close friends. Attitudinal constructs significantly associated with increased likelihood of referring contacts included: intention to receive maternal influenza vaccine, perceived safety of maternal Tdap vaccine, perceived efficacy of maternal influenza vaccine, perceived susceptibility to and severity of influenza during pregnancy, and trust in vaccine information from the Centers for Disease Control and Prevention (CDC) and academic institutions. Uncertainty about infant vaccine intentions was associated with decreased likelihood of referring contacts. Conclusions Pregnant women who valued vaccination and trusted vaccine information from academic institutions were more likely to refer an educational app about vaccines than those who did not. Further research is needed to determine the potential impact of this strategy on vaccine coverage when implemented on a large scale. Trial registration The survey informing this article was part of a randomized controlled trial funded by the National Institutes of Health [clinicaltrials.gov registration number NCT02898688].

Adherence to public health recommendations is critical for public safety and well-being. Effective and appropriate communication plays an important role in whether populations trust government and public health authorities, and the extent to which people follow public health recommendations. Poor trust in communication from public health authorities can pose significant challenges for mitigating public health emergencies and maintaining health security. This study aimed to explore the importance of trust in and understanding of communication from public health authorities in improving adherence to public health recommendations, and how that communication can be improved to develop and maintain public trust, particularly in the context of public health emergencies. To understand which factors are important for public trust in communication from public health authorities, we conducted in-depth interviews (n = 25) with a racially and demographically diverse group of individuals living in Baltimore. We found that communication source and communication transparency, such as timeliness, completeness, and clarity of information, were critical constructs of trust in communication from public health authorities. We also found that many participants misunderstood the flow of information from public health authorities to news media, and many were unaware that public health authorities provide the most reliable source of health information and recommendations during a public health emergency. To ensure adherence to public health recommendations, the public needs to trust that public health authorities are providing accurate, practical, and prudent recommendations. Drawing on these results, we provide several recommendations for developing and optimizing communication from various public health authorities.

Vaccination is one of public health's greatest achievements, responsible for saving billions of lives. Yet, 20% of children worldwide are not fully protected, leading to 1·5 million child deaths annually from vaccine-preventable diseases. Millions more people have severe disabling illnesses, cancers, and disabilities stemming from underimmunisation. Reasons for falling vaccination rates globally include low public trust in vaccines, constraints on affordability or access, and insufficient governmental vaccine investments. Consequently, an emerging crisis in vaccine hesitancy ranges from hyperlocal to national and worldwide. Outbreaks often originate in small, insular communities with low immunisation rates. Local outbreaks can spread rapidly, however, transcending borders. Following an assessment of underlying determinants of low vaccination rates, we offer an action based on scientific evidence, ethics, and human rights that spans multiple governments, organisations, disciplines, and sectors.

In 2015, California passed Senate Bill No. 277 (SB 277) and became the first state in more than 30 years to eliminate nonmedical exemptions to mandatory childhood immunizations for school entry. One concern that emerged was that the law created an incentive for parents to remove children from brick-and-mortar schools to bypass the immunization requirements.To assess the trends in homeschooling rates after the elimination of nonmedical exemptions to the requirement of childhood immunizations for school entry.This preintervention-postintervention cross-sectional study calculated homeschooling rates as the number of students in kindergarten through grade 8 (K-8) enrolled through each of California's 3 homeschooling mechanisms (independent study program, private school affidavit, and private school satellite program) divided by all K-8 students enrolled in the same academic year. Data on homeschooling rates were obtained from the California Department of Education. Interrupted time series analyses were conducted using a linear regression model in which the outcome variable was the percentage of students enrolled in a homeschool program before and after SB 277. Data were collected and analyzed from October 3, 2012, to October 2, 2019.Passage of SB 277, which eliminated nonmedical exemptions to childhood immunizations for school entry.Homeschooling rates for K-8 students.Among the students included in the analysis, the homeschooling enrollment for K-8 students in California increased from 35 122 students (0.8%) during the 2012-2013 school year to 86 574 students (1.9%) during the 2019-2020 school year; however, the implementation of SB 277 was not associated with an increase in the percentage of students enrolled in homeschooling programs in California beyond the secular trend. The increase in homeschooling was greatest for the lower grade levels: kindergarten homeschooling enrollment increased from 2068 students (0.4%) in the 2012-2013 school year to 10 553 students (1.9%) in the 2019-2020 school year, whereas the grade 8 homeschool enrollment rate increased from 5146 students (1.0%) in the 2012-2013 school year to 10 485 students (2.0%) in the 2019-2020 school year. Independent study programs accounted for 20 149 students (45.3%) of homeschooling enrollment, private school affidavits accounted for 19 333 students (43.5%), and private school satellite programs accounted for 4935 students (11.1%) during the 2015-2016 school year.The findings of this study suggest that legislative action to limit nonmedical exemptions for compulsory vaccination for school entry is not associated with removal of students from classroom-based instruction in brick-and-mortar institutions.

BACKGROUND: In 2018, Facebook introduced Ad Archive as a platform to improve transparency in advertisements related to politics and “issues of national importance.” Vaccine-related Facebook advertising is publicly available for the first time. After measles outbreaks in the US brought renewed attention to the possible role of Facebook advertising in the spread of vaccine-related misinformation, Facebook announced steps to limit vaccine-related misinformation. This study serves as a baseline of advertising before new policies went into effect. METHODS: Using the keyword ‘vaccine’, we searched Ad Archive on December 13, 2018 and again on February 22, 2019. We exported data for 505 advertisements. A team of annotators sorted advertisements by content: pro-vaccine, anti-vaccine, not relevant. We also conducted a thematic analysis of major advertising themes. We ran Mann-Whitney U tests to compare ad performance metrics. RESULTS: 309 advertisements were included in analysis with 163 (53%) pro-vaccine advertisements and 145 (47%) anti-vaccine advertisements. Despite a similar number of advertisements, the median number of ads per buyer was significantly higher for anti-vaccine ads. First time buyers are less likely to complete disclosure information and risk ad removal. Thematically, anti-vaccine advertising messages are relatively uniform and emphasize vaccine harms (55%). In contrast, pro-vaccine advertisements come from a diverse set of buyers (83 unique) with varied goals including promoting vaccination (49%), vaccine related philanthropy (15%), and vaccine related policy (14%). CONCLUSIONS: A small set of anti-vaccine advertisement buyers have leveraged Facebook advertisements to reach targeted audiences. By deeming all vaccine-related content an issue of “national importance,” Facebook has further the politicized vaccines. The implementation of a blanket disclosure policy also limits which ads can successfully run on Facebook. Under current policies, improving transparency and limiting misinformation are not separate goals. Public health communication efforts should consider the impact on Facebook users’ vaccine attitudes and behaviors.