Psychosocial correlates of parents' willingness to vaccinate their children against COVID-19.

BACKGROUND: Public health guidance recommended that children who are 6 months or older be vaccinated against COVID-19 in June of 2022. In the U.S., 56% of children under 17 had not received the COVID-19 vaccination in 2023. We examine parents' willingness to vaccinate their children against COVID-19 using the theory of planned behavior in order to design effective strategies to promote vaccine uptake. METHODS: The Philadelphia Community Engagement Alliance is part of an NIH community-engaged consortium focused on addressing COVID-19 disparities across the U.S. We surveyed 1,008 Philadelphia parents (mean age 36.86, SD 6.55; 42.3% racial/ethnic minorities) between September 2021 and February 2022, a period when guidance for child vaccination was anticipated. Structural Equation Modeling analysis examined associations between parental willingness and vaccine-related attitudes, norms, and perceived control. Covariates included parents' COVID-19 vaccination status, race/ethnicity, gender, and survey completion post-CDC pediatric COVID-19 vaccination guidelines. Subgroup analyses by race/ethnicity and gender were conducted. RESULTS: Our model demonstrated good fit (χ2 = 907.37, df = 419, p<0.001; comparative fit index [CFI] = 0.951; non-normed fit index [NNFI] = 0.946; root mean square error of approximation [RMSEA] = 0.034 with 95% CI = 0.030-0.038). Attitudes ([Formula: see text] = 0.447, p<0.001) and subjective norms ([Formula: see text] = 0.309, p = 0.002) were predictors of intention. Racial/ethnic minority parents exhibited weaker vaccination intentions ([Formula: see text] = -0.053, p = 0.028) than non-Hispanic White parents. CONCLUSIONS: Parents' attitudes and norms influence their vaccination intentions. Despite the survey predating widespread child vaccine availability, findings are pertinent given the need to increase and sustain pediatric vaccinations against COVID-19. Interventions promoting positive vaccine attitudes and prosocial norms are warranted. Tailored interventions and diverse communication strategies for parental subgroups may be useful to ensure comprehensive and effective vaccination initiatives.

Social Distancing in the COVID-19 Pandemic: Associated Factors, Health Outcomes, and Implications.

Social distancing has reemerged as a public health measure for containing the spread of COVID-19. This integrative review aims to analyze the historical use of social distancing, the current application during COVID-19, individual factors that affect social distancing practices, and consequential health outcomes. We analyzed relevant literature from searches conducted on Scopus, PubMed, and PsycINFO. We found that resources, culture, age, gender, and personality are associated with the degree to which people practice social distancing. Furthermore, social distancing changes our lifestyles and behavior and results in multifaceted health outcomes, including decreased physical activity and sunlight exposure, increased weight gain, and impaired sleep quality. On the positive side, social distancing has been linked to reduced crime rates and environmental damage, as well as better social and family ties. Future interventions may be utilized to increase adherence to social distancing practices and to mitigate the negative health effects of social distancing.

Characterizing U.S. mothers with high human papillomavirus vaccine intent yet unvaccinated adolescents.

HPV vaccination rates remain suboptimal in the United States. While the current literature focuses on expressly hesitant parents, few studies have examined parents with "high intent", or those indicating they definitely will vaccinate and have had the opportunity but not yet vaccinated their adolescents. Our objective was to differentiate characteristics of mothers with high intent from those who already vaccinated their adolescents using various socioeconomic, previous vaccine decision-making, and healthcare provider relationship-related variables. English-speaking mothers or female guardians of adolescents ages 11-14 years living in low HPV vaccine uptake states within the U.S. in September 2018 were recruited from a national survey panel as part of a larger study. We assessed HPV vaccine status of their adolescents and categorized respondents into two categories: Already Vaccinated and High Intent. We assessed differences using a multivariable logistic regression model. Among 2406 mothers, 18% reported high intent vs. 82% already having vaccinated. Mothers with high intent were more likely to identify as non-Hispanic White (p = 0.01), to have a younger adolescent (p < 0.001), and to report not receiving a provider HPV vaccination recommendation (p < 0.001). Mothers who estimated that half/more (vs. less) of their child's friends have received/will receive the vaccine had higher odds of already vaccinating (p < 0.001). Our findings suggest that clinicians may be able to improve HPV vaccination uptake within their practices by giving repeated, high-quality recommendations to parents of children who are not yet vaccinated. Additionally, these findings indicate perceived social norms may play a large role in on-time vaccine uptake. Reassuring hesitant parents that most parents accept the vaccine may also improve uptake in clinical practice.

Trusted messengers and trusted messages: The role for community-based organizations in promoting COVID-19 and routine immunizations.

We sought to explore the trust and influence community-based organizations have within the communities they serve to inform public health strategies in tailoring vaccine and other health messages. A qualitative study was conducted between March 15 - April 12, 2021 of key informants in community-based organizations serving communities in and around Philadelphia, Pennsylvania. These organizations serve communities with high Social Vulnerability Index scores. We explored four key questions including: (1) What was and continues to be the impact of COVID-19 on communities; (2) How have trust and influence been cultivated in the community; (3) Who are trusted sources of information and health messengers; and (4) What are the community's perceptions about vaccines, vaccinations, and intent to vaccinate in the context of the COVID-19 pandemic. Fifteen key informants from nine community-based organizations who serve vulnerable populations (e.g., mental health, homeless, substance use, medically complex, food insecurity) were interviewed. Five key findings include: (1) The pandemic has exacerbated disparities in existing social determinants of health for individuals and families and have created new concerns for these communities; (2) components of how to build the trust and influence (e.g., demonstrate empathy, create a safe space, deliver on results)resonated with key informants; (3) regardless of the source, presenting health information in a respectful and understandable manner is key to effective delivery; (4) trust and influence can be transferred by association to a secondary messenger connected to or introduced by the primary trusted source; and (5) increased awareness about vaccines and vaccinations offers opportunities to think differently, changing previously held beliefs or attitudes, as many individuals are now more cognizant of risks associated with vaccine-preventable diseases and the importance of vaccines. Community-based organizations offer unique opportunities to address population-level health disparities as trusted vaccine messengers to deliver public health messages.

Persuading the "Movable Middle": Characteristics of effective messages to promote routine and COVID-19 vaccinations for adults and children - The impact of COVID-19 on beliefs and attitudes.

PURPOSE: We sought to 1) explore trusted sources for vaccine information, 2) describe persuasive characteristics of trusted messages promoting routine and COVID-19 vaccines for children and adults and 3) explore how the pandemic has impacted attitudes and beliefs about routine vaccinations. We conducted a mixed method cross-sectional study between May 3-June 14, 2021 including a survey and six focus groups among a sub-set of survey respondents. A total of 1,553 survey respondents (from which n = 33 participated in the focus groups) including adults without children under age nineteen years (n = 582) and parents with children under age nineteen years (n = 971). RESULTS: Primary care providers, family, and credible sources, characterized as known and well-established entities, were top sources of vaccine information. Neutrality, honesty, and having a trusted source to rely on in sorting through volumes of sometimes conflicting information were highly valued. Trustworthy qualities about sources included: 1) expertise, 2) fact-based, 3) unbiased, and 4) having an established process for sharing information. Because of the evolving nature of the pandemic, attitudes and beliefs about COVID-19 vaccine and sources of COVID-19 information differed from typical views about routine vaccines. Of 1,327 (85.4 %) survey respondents, 12.7 % and 9.4 % of adults and parents cited that the pandemic impacted their attitudes and beliefs. Among these respondents, 8 % of adults and 3 % of parents cited more favorable attitudes and beliefs about getting vaccinated with routine vaccines because of the pandemic. CONCLUSION: Vaccine attitudes and beliefs which inform intent to vaccinate can change and differ among different vaccines. Messaging should be tailored to resonate with parents and adults to improve vaccine uptake.

Exploring content of misinformation about HPV vaccine on twitter.

Although social media can be a source of guidance about HPV vaccination for parents, the information may not always be complete or accurate. We conducted a retrospective content analysis to identify content and frequencies of occurrence of disinformation and misinformation about HPV vaccine posted on Twitter between December 15, 2019, through March 31, 2020, among 3876 unique, English language #HPV Tweets, excluding retweets. We found that 24% of Tweets contained disinformation or misinformation, and the remaining 76% contained support/education. The most prevalent categories of disinformation/misinformation were (1) adverse health effects (59%), (2) mandatory vaccination (19%), and (3) inefficacy of the vaccine (14%). Among the adverse health effects Tweets, non-specific harm/injury (51%) and death (23%) were most frequent. Disinformation/misinformation Tweets vs. supportive Tweets had 5.44 (95% CI 5.33-5.56) times the incidence rate of retweet. In conclusion, almost one-quarter of #HPV Tweets contained disinformation or misinformation about the HPV vaccine and these tweets received higher audience engagement including likes and retweets. Implications for vaccine hesitancy are discussed.

Comparing COVID-19 Vaccination Outcomes with Parental Values, Beliefs, Attitudes, and Hesitancy Status, 2021-2022.

Despite the availability of safe and effective COVID-19 vaccines, vaccine acceptance has been low, particularly among parents. More information is needed on parental decision-making. We conducted a prospective cohort study from October 2021 to March 2022 among 334 parents in a large urban/suburban pediatric primary care network and linked longitudinal survey responses about attitudes and beliefs on vaccination, social norms, and access to vaccination services for COVID-19 to electronic health-record-derived vaccination outcomes for their eldest age-eligible children in June 2022. The odds of accepting two doses of COVID-19 vaccine for their child was higher in respondents who indicated the COVID-19 vaccine would be very safe (aOR [CI]: 2.69 [1.47−4.99], p = 0.001), as well as those who previously vaccinated their child against influenza (aOR [CI]: 4.07 [2.08−8.12], p < 0.001). The odds of vaccinating their child were lower for respondents who attended suburban vs. urban practices (aOR [CI]: 0.38 [0.21−0.67], p = 0.001). Parents in the cohort were active users of social media; the majority (78%) used their phone to check social media platforms at least once per day. Our findings suggest that healthcare providers and policymakers can focus on improving vaccination coverage among children living in suburban neighborhoods through targeted mobile-based messaging emphasizing safety to their parents.

Disadvantage Indices Deployed to Promote Equitable Allocation of COVID-19 Vaccines in the US: A Scoping Review of Differences and Similarities in Design.

This scoping review identifies the construction and defined purpose of disadvantage indices deployed during the initial COVID-19 vaccine rollout.

Factors Influencing Parental and Individual COVID-19 Vaccine Decision Making in a Pediatric Network.

Aspects of the COVID-19 vaccination campaign differed from routine vaccines, including emergency use authorizations, the prioritization of access, and the politicization of messaging. Subsequently, many parents reported lower vaccine confidence relative to routine vaccines, and vaccination coverage stalled below targets. This study aimed to understand parental vaccine decision making and compare COVID-19 versus routine vaccine decision making. We conducted nine virtual focus groups between 25 February 2022-11 March 2022 with parents (n = 41) of the Children's Hospital of Philadelphia's patients, recruited via email and stratified by vaccine hesitancy status (non-hesitant vs. hesitant). Transcripts were analyzed using the vaccine hesitancy matrix domains. Of 41 total participants, 25 (61.0%) were non-hesitant, 16 (39.0%) were hesitant or their children were not up-to-date on adolescent vaccines, and most self-identified as female (95.1%) and White/Caucasian (61.0%). Most participants (87.5%) were fully vaccinated against COVID-19 and many of their first children (n = 26, 63.4%) were vaccinated against influenza. Several themes emerged regarding decision making: individual influences, group influences, vaccine and vaccine program influences, and contextual influences. While some influences were similar for routine and COVID-19 vaccine decision making (e.g., needing evidence-based information), other factors were vaccine- or situation-specific. Building trust requires a multi-faceted concerted effort that involves addressing the complex vaccine decision-making process.

Marijuana Use Among Women of Reproductive Age With Disabilities.

INTRODUCTION: Despite the increasing prevalence and potential adverse health outcomes associated with marijuana use, limited research exists related to its use in women of reproductive age with disabilities. The purpose of this study is to examine the past-month marijuana use in women of reproductive age with disabilities. METHODS: Data from the 2015-2019 National Survey on Drug Use and Health included 76,765 women of reproductive age (18-44 years). Descriptive statistics and adjusted logistic regression analyses were conducted to assess the associations between past-month marijuana use and overall disability, including the type of disability. RESULTS: In this sample, 12.6% of women reported past-month marijuana use. Approximately, 21% of women with disabilities reported past-month marijuana use, compared with only 11.1% of women without a disability. Marijuana use was more prevalent in women with disabilities who were younger (aged ≤25 years), who were non-Hispanic White, who were nonmarried, who had at least some college education, and who used alcohol or tobacco. Women with disabilities had 1.68 (95% CI=1.57, 1.80) higher odds of reporting past-month marijuana use than those with no disabilities. The odds of past-month marijuana use were higher among those with cognitive (AOR=1.78, 95% CI=1.64, 1.94), sensory (AOR=1.30, 95% CI=1.12, 1.51), and daily activities-related (AOR=1.64, 95% CI=1.49, 1.80) disabilities than among their counterparts without disabilities. CONCLUSIONS: This study found an increased prevalence of past-month marijuana use among women of reproductive age with disabilities. Enhanced screening and counseling using evidence-based practices during routine care for women with disabilities may be necessary to mitigate marijuana use.

Efficacy of tailored messages to improve behavioral intent to accept HPV vaccination among mothers may be moderated by sociodemographics.

We assessed differences in response to a tailored recommendation intervention for HPV vaccine by participants' sociodemographic characteristics in this exploratory sub-analysis of a larger web-based, randomized-controlled trial on tailored messaging among mothers with low intent to vaccinate their 11-14-year-old child against HPV. The intervention consisted of pre-recorded video messages tailored to 1-5 common concerns about HPV vaccine. In these exploratory analyses, we used generalized linear models to assess differences in post-intervention intent across intervention arms, stratified by sociodemographic characteristics among 496 trial participants. We found significantly higher post-intervention intent in the intervention participants versus the control group among mothers: 1) with younger children; 2) with white vs. black children; 3) with Non-Hispanic children; 4) who were younger; 5) with some college or vocational training; with household incomes of ≥$100,000; and 7) with 1-2 children. Our findings of effect modification by certain sociodemographic factors such as age, race/ethnicity, and household income should be considered when designing similar tailored messaging interventions.

Opioid use in pregnant women with mental health-related disabilities.

PURPOSE: The purpose of this study was to examine associations between opioid use and the degree of mental health-related disability due to emotional/behavioral problems as measured by the World Health Organization Disability Assessment Schedule (WHODAS) instrument in a national sample of pregnant women. METHODS: We used data from the National Survey on Drug Use and Health 2014-2017 which included 2,888 pregnant women 18 years or older. The WHODAS instrument was utilized to measure disability as the degree of functional impairment due to emotional/behavioral problems experienced by the respondent. Multinomial logistic regression models were built to assess the magnitude and direction of the association between severity of mental health-related disability with opioid use and abuse/dependency in the past year. RESULTS: Approximately 30% of pregnant women suffered from moderate/severe mental health-related disability, and 2% reported opioid abuse/dependency. Compared to those with no opioid use, the odds of opioid use in the past year for individuals with moderate/severe mental health-related disability were 1.73 (95% CI 1.36, 2.21) times higher than those with no/mild disability. Similarly, the odds of opioid abuse/dependency were at least three times higher (OR 3.51; 95% CI 1.80, 6.84) among those with moderate/severe mental health-related disability relative to pregnant women with no/mild disability. CONCLUSIONS: Clinicians should consider screening for both opioid use and mental health conditions and related disabilities using screening tools such as the WHODAS during the initial prenatal visits.

Tailored Messages Addressing Human Papillomavirus Vaccination Concerns Improves Behavioral Intent Among Mothers: A Randomized Controlled Trial.

PURPOSE: The aim of the study was to determine whether supplementing a bundled recommendation (recommendation for all 11- to 12-year-old platform vaccines) with tailored messaging that addressed one versus all parental concerns improved human papillomavirus (HPV) vaccination intent among mothers. METHODS: We conducted a Web-based randomized controlled trial, randomizing mothers who did not intend to vaccinate their 11- to 14-year-old child against HPV to (1) bundled recommendation video ("control"); (2) control + video addressing the top HPV vaccine concern; or (3) control + ≥1 videos addressing all concerns. Outcomes were HPV vaccination intent (1 = extremely unlikely and 10 = extremely likely) and strength of main concern (1 = a little concerned and 10 = very concerned). We assessed differences in intervention effects using generalized linear models for vaccine intent and mixed models for the strength of main concern. RESULTS: Of the 762 mothers, 51% had a female child, 82% of children were white, and 90% were non-Hispanic. The mean intent to vaccinate postintervention ranged from 3.5 (95% confidence interval [CI] = 3.1-3.8) in the control group to 4.2 (95% CI = 3.9-4.6) in the all-concerns group (p = .01). The mean strength of the concerns declined pre- to postintervention by .1 (95% CI = -.1 to .3) in the control group (p = .42), .6 (95% CI = .4-.9) in the top concern group (p < .001), and .7 (95% CI = .5-1.0) in the all-concerns group (p < .001). However, the mean strength of the main concerns postintervention remained high (≥7.0 for each group). CONCLUSIONS: Tailored messages addressing all concerns improved HPV vaccination intent and reduced the strength of the main concern more than bundled messages alone, but intent remained low and strength of the main concerns remained high in this vaccine-hesitant population.

Exploring variation in parental worries about HPV vaccination: a latent-class analysis.

Background. Prior research has identified diverse worries that parents have about HPV vaccination. We sought to understand how parents prioritize worries and to identify subgroups of parents according to shared patterns of worry. Methods. We surveyed a national sample of 431 U.S. parents of adolescents who reported never having talked to their child's healthcare provider about HPV vaccination. Parents completed a best-worst scaling experiment designed to prioritize 11 common worries about HPV vaccination. The experiment used a balanced incomplete block design to present 11 choice tasks consisting of repeated subsets of worries. We used conditional logistic regression to prioritize worries and latent class models with 1-10 classes to identify subgroups of parents with shared worries. Results. Parents most often worried about long-term side effects of HPV vaccination, which about one-third (36%) ranked as their top worry. Other common top-ranked worries were how new the vaccine is (12%), motives of drug companies (12%), short-term side effects (10%), and that it may be unnecessary (10%). Latent class analyses suggested a relatively large number of distinct worry profiles, with most classes characterized by a worry about long-term side effects in combination with one other worry. Discussion. Our findings suggest that providers should be prepared to address concerns about long-term side effects, as this worry was prioritized across many subgroups of parents. However, to best address worry, a tailored, rather than targeted, communication approach may be needed.

Provider-level rates of HEDIS-consistent HPV vaccination in a regional health plan.

Background. Health insurers are well-positioned to address low HPV vaccination coverage in the US through initiatives such as provider assessment and feedback. However, little is known about the feasibility of using administrative claims data to assess provider performance on vaccine delivery. Methods. We used administrative claims data from a regional health plan to estimate provider performance on the 2013-2015 Healthcare Effectiveness Data and Information Set (HEDIS) measure for HPV vaccine. This measure required that a girl receive three doses of HPV vaccine by age 13. Providers who administered ≥1 dose in a HEDIS-consistent series received credit for meeting the goal. Results. From January 2008-April 2015, 1,975 (8.5%) of 11-12 year-old girls in our sample received a HEDIS-consistent HPV vaccine series. Our sample of providers consisted of 1,236 who had ≥10 well-visits with different female patients, and 94% of these were pediatricians. A substantial minority of providers (39.4%) did not administer any HEDIS-consistent HPV vaccine doses. Only 5.5% of providers administered HPV vaccine doses that were part of a HEDIS-consistent series to at least one-quarter of their patients. These estimates did not vary by provider sex or age. Doses in a HEDIS-consistent vaccine series were often attributed to multiple providers. Conclusions. In a regional health plan, only 5.5% of providers in our sample administered doses that were part of a complete, three-dose HPV vaccine series to at least one-quarter of their 11-12 year-old female patients.

Coaching primary care clinics for HPV vaccination quality improvement: Comparing in-person and webinar implementation.

State health departments commonly use quality improvement coaching as an implementation strategy for improving low human papillomavirus (HPV) vaccination coverage, but such coaching can be resource intensive. To explore opportunities for improving efficiency, we compared in-person and webinar delivery of coaching sessions on implementation outcomes, including reach, acceptability, and delivery cost. In 2015, we randomly assigned 148 high-volume primary care clinics in Illinois, Michigan, and Washington State to receive either in-person or webinar coaching. Coaching sessions lasted about 1 hr and used our Immunization Report Card to facilitate assessment and feedback. Clinics served over 213,000 patients ages 11-17. We used provider surveys and delivery cost assessment to collect implementation data. This report is focused exclusively on the implementation aspects of the intervention. More providers attended in-person than webinar coaching sessions (mean 9 vs. 5 providers per clinic, respectively, p = .004). More providers shared the Immunization Report Card at clinic staff meetings in the in-person than webinar arm (49% vs. 20%; p = .029). In both arms, providers' belief that their clinics' HPV vaccination coverage was too low increased, as did their self-efficacy to help their clinics improve (p < .05). Providers rated coaching sessions in the two arms equally highly on acceptability. Delivery cost per clinic was $733 for in-person coaching versus $461 for webinar coaching. In-person and webinar coaching were well received and yielded improvements in provider beliefs and self-efficacy regarding HPV vaccine quality improvement. In summary, in-person coaching cost more than webinar coaching per clinic reached, but reached more providers. Further implementation research is needed to understand how and for whom webinar coaching may be appropriate.

Importance of a team approach to recommending the human papillomavirus vaccination.

BACKGROUND AND PURPOSE: Few studies have examined human papillomavirus (HPV) vaccine communication in the context of the health care team. METHODS: In 2016, the investigators conducted a national, online survey of U.S. parents who reported having discussed HPV vaccination with their adolescent's health care team. Multivariable logistic regression assessed associations between HPV vaccine initiation (≥1 dose) and having: 1) discussed HPV vaccination with multiple team members and 2) received congruent recommendations about HPV vaccination. CONCLUSIONS: Of the 795 parents in the sample, about half (52%) reported discussing HPV vaccination with multiple team members, including nurse practitioners, nurses, and physicians. Most reported receiving congruent recommendations for (76%) or against (12%) HPV vaccination; few (12%) received mixed recommendations. Parents who discussed HPV vaccination with multiple team members had greater odds of series initiation (odds ratio [OR] = 2.34, 95% CI: 1.61-3.40), whereas those who received mixed versus congruent recommendations for HPV vaccination had lower odds of vaccination (OR = 0.56, 95% CI: 0.33-0.95). IMPLICATIONS FOR PRACTICE: Findings suggest that a coordinated team approach to recommendations may encourage HPV vaccination. Nurse practitioners are well positioned to facilitate coordination efforts within their clinical practices.

Parents' Views on the Best and Worst Reasons for Guideline-Consistent HPV Vaccination.

Background: Human papillomavirus (HPV) vaccination could prevent most HPV-associated cancers, but few U.S. adolescents are vaccinated according to guidelines. To inform efforts to counsel parents more effectively, we sought to quantify their views on the best and worst reasons for guideline-consistent HPV vaccination. We hypothesized that parents' views would differ according to their vaccination confidence.Methods: We developed a best-worst scaling experiment to evaluate 11 reasons healthcare providers commonly give for HPV vaccination. The instrument was administered in 2016 via a national online survey to 1,177 parents of adolescents. Parents completed 11 choice tasks of 5 reasons each, indicating the best and worst reason in each task. We used conditional logistic regression to rank reasons for the sample overall and by vaccination confidence (low/high).Results: Parents viewed cancer prevention as the best reason for HPV vaccination (P < 0.001). Other commonly endorsed reasons were preventing a common infection, having lasting benefits, or being a safe vaccine (all P < 0.001). Reasons viewed as worst were: It is a scientific breakthrough; I got it for my own child; and your child is due (all P < 0.001). Stratified analyses indicated small differences in how often parents with low versus high vaccination confidence endorsed messages (P < 0.001), but the two groups ranked reasons similarly overall.Conclusions: Parents prioritized cancer prevention as the best reason for guideline-consistent HPV vaccination. Several other common reasons, including having vaccinated one's own child, may warrant additional testing.Impact: Providers should emphasize cancer prevention when discussing HPV vaccination, as recommended by the Centers for Disease Control and Prevention, the President's Cancer Panel, and others. Cancer Epidemiol Biomarkers Prev; 27(7); 762-7. ©2018 AACR.

US adolescents at risk for not meeting physical activity recommendations by season.

BACKGROUND: We sought to identify regional and seasonal variation in not meeting physical activity (PA) recommendations of ≥60 min a day of moderate-to-vigorous PA (MVPA) and 3 h of vigorous PA per week (VPA) in a longitudinal cohort of United States (US) adolescents. METHODS: Participants in the Growing Up Today Study 2, a prospective study of 10,918 adolescents, self-reported season-specific weekly hours of MVPA and VPA from 2004 through 2011. To assess variation in PA by climate, we grouped the contiguous US into nine climatically consistent geographic regions. We also examined MVPA and VPA by season, sex, ethnicity, weight status, and age group. RESULTS: The majority (85%) of adolescents did not meet the MVPA recommendation, and 91% did not meet the VPA recommendation, for one or more seasons over the four study years. Across all climate regions, adolescents were two times more likely to not meet the MVPA recommendation during the winter compared to summer (odds ratio 2.02, 95% confidence interval: 1.96-2.08). CONCLUSION: Regardless of climate region, gender, ethnicity, or age group, adolescents were more likely not to meet MVPA or VPA recommendations in the winter than the summer. Adolescents may benefit from interventions aimed at increasing PA in the winter.