U.S. Women with Invasive Cervical Cancer: Characteristics and Potential Barriers to Prevention.

Objectives: Although invasive cervical cancer (ICC) rates have declined since the advent of screening, the annual age-adjusted ICC rate in the United States remains 7.5 per 100,000 women. Failure of recommended screening and management often precedes ICC diagnoses. The study aimed to evaluate characteristics of women with incident ICC, including potential barriers to accessing preventive care. Materials and Methods: We abstracted medical records for patients with ICC identified during 2008-2020 in five U.S. population-based surveillance sites covering 1.5 million women. We identified evidence of adverse social and medical conditions, including uninsured/underinsured, language barrier, substance use disorder, incarceration, serious mental illness, severe obesity, or pregnancy at diagnosis. We calculated descriptive frequencies and compared potential barriers by race/ethnicity, and among women with and without symptoms at diagnosis using chi-square tests. Results: Among 1,606 women with ICC (median age: 49 years; non-White: 47.4%; stage I: 54.7%), the majority (68.8%) presented with symptoms. Forty-six percent of women had at least one identified potential barrier; 15% had multiple barriers. The most common potential barriers among all women were being underinsured/uninsured (17.3%), and language (17.1%). Presence of any potential barrier was more frequent among non-White women and women with than without symptoms (p < 0.05). Conclusions: In this population-based descriptive study of women with ICC, we identified adverse circumstances that might have prevented women from seeking screening and treatment to prevent cancer. Interventions to increase appropriate cervical cancer screening and management are critical for reducing cervical cancer rates.

Human Papillomavirus Vaccination Status and Correlates Among Mid-Adult Women: Connecticut, USA, 2016-2019.

Background: In 2019, the CDC expanded their recommendations for human papillomavirus (HPV) vaccination beyond age 26 years to include shared clinical decision-making (SCDM) among adults aged 27-45 years ("mid-adults"). The purpose of this study was to describe HPV vaccination status among mid-adult women before the implementation of SCDM for HPV vaccination. Methods: A cross-sectional survey was conducted during 2016-2019 in Connecticut, United States, and enrolled women born in 1981 or later (birth cohorts eligible for HPV vaccination). This analysis was restricted to participants aged 27 years and older at the time of the survey. Correlates of vaccination status, sources of vaccine information, and reasons for not receiving the vaccine were examined. Results: Among 298 participants, 64.4% had not received HPV vaccine. Other than age (younger age was associated with being vaccinated), no other demographic or behavioral correlates were associated with vaccination. Compared with unvaccinated women, vaccinated women were more likely to have heard about the HPV vaccine from a doctor (odds ratio [OR] = 3.45, 95% confidence interval [CI]: 2.00-5.88) and less likely to have heard about it from television (OR = 0.23, 95% CI: 0.13-0.41). The main reasons for not being vaccinated were "vaccine not offered" (48%) and "too old" (40%). Conclusions: A majority of mid-adult women in this study were not previously vaccinated against HPV, signaling the large opportunity for SCDM with this population. This may be facilitated by ensuring health care providers and mid-adult women know about the availability and potential benefits of HPV vaccination to inform decision making.

Human papillomavirus vaccine effectiveness by age at vaccination: A systematic review.

Human papillomavirus (HPV) vaccines work by preventing infections prior to natural exposure. Thus, it is likely more effective at younger ages, and it is important to understand how effectiveness might be diminished when administered at older ages. We conducted a systematic review of HPV vaccine effectiveness studies published between 2007 and 2022 that included an analysis of effectiveness against vaccine-type HPV infections, anogenital warts, cervical abnormalities and cervical cancer by age at vaccine initiation or completion. Searching multiple databases, 21 studies were included and results were summarized descriptively. Seventeen studies found the highest vaccine effectiveness in the youngest age group. Vaccine effectiveness estimates for younger adolescents ages 9-14 years ranged from approximately 74% to 93% and from 12% to 90% for adolescents ages 15-18 years. These results demonstrate that the HPV vaccine is most effective against HPV-related disease outcomes when given at younger ages, emphasizing the importance of on-time vaccination.

Acceptability of 4-poster deer treatment devices for community-wide tick control among residents of high Lyme disease incidence counties in Connecticut and New York, USA.

The 4-Poster Tick Control Deer Feeder (4-poster) device applies acaricide to white-tailed deer (Odocoileus virginianus) and can reduce populations of the blacklegged tick (Ixodes scapularis), which transmits the agents of Lyme disease, anaplasmosis, babesiosis, and Powassan virus disease in the Northeastern United States. While 4-poster devices have the potential to provide community-wide management of blacklegged ticks in Lyme disease endemic areas, no recent study has assessed their acceptability among residents. We conducted a survey of residents from 16 counties with high annual average Lyme disease incidence (≥ 10 cases per 100,000 persons between 2013 and 2017) in Connecticut and New York to understand perceptions and experiences related to tickborne diseases, support or concerns for placement of 4-poster devices in their community, and opinions on which entities should be responsible for tick control on private properties. Overall, 37% of 1652 respondents (5.5% response rate) would support placement of a 4-poster device on their own property, 71% would support placement on other private land in their community, and 90% would support placement on public land. Respondents who were male, rented their property, resided on larger properties, or were very or extremely concerned about encountering ticks on their property were each more likely to support placement of 4-poster devices on their own property. The primary reason for not supporting placement of a 4-poster device on one's own property was the need for weekly service visits from pest control professionals, whereas the top reason for not supporting placement on other land (private or public) was safety concerns. Most respondents (61%) felt property owners should be responsible for tick control on private properties. Communities considering 4-poster devices as part of a tick management strategy should consider targeting owners of larger properties and placing devices on public lands.

Failure to Complete Multidose Vaccine Series in Early Childhood.

BACKGROUND: Most early childhood immunizations require 3 to 4 doses to achieve optimal protection. Our objective was to identify factors associated with starting but not completing multidose vaccine series. METHODS: Using 2019 National Immunization Survey-Child data, US children ages 19 to 35 months were classified in 1 of 3 vaccination patterns: (1) completed the combined 7-vaccine series, (2) did not initiate ≥1 of the 7 vaccine series, or (3) initiated all series, but did not complete ≥1 multidose series. Associations between sociodemographic factors and vaccination pattern were evaluated using multivariable log-linked binomial regression. Analyses accounted for the survey's stratified design and complex weighting. RESULTS: Among 16 365 children, 72.9% completed the combined 7-vaccine series, 9.9% did not initiate ≥1 series, and 17.2% initiated, but did not complete ≥1 multidose series. Approximately 8.4% of children needed only 1 additional vaccine dose from 1 of the 5 multidose series to complete the combined 7-vaccine series. The strongest associations with starting but not completing multidose vaccine series were moving across state lines (adjusted prevalence ratio [aPR] = 1.45, 95% confidence interval [CI]: 1.18-1.79), number of children in the household (2 to 3: aPR = 1.29, 95% CI: 1.05-1.58; 4 or more: aPR = 1.68, 95% CI: 1.30-2.18), and lack of insurance coverage (aPR = 2.03, 95% CI: 1.42-2.91). CONCLUSIONS: More than 1 in 6 US children initiated but did not complete all doses in multidose vaccine series, suggesting children experienced structural barriers to vaccination. Increased focus on strategies to encourage multidose series completion is needed to optimize protection from preventable diseases and achieve vaccination coverage goals.

Estimated Effectiveness of JYNNEOS Vaccine in Preventing Mpox: A Multijurisdictional Case-Control Study - United States, August 19, 2022-March 31, 2023.

As of March 31, 2023, more than 30,000 monkeypox (mpox) cases had been reported in the United States in an outbreak that has disproportionately affected gay, bisexual, and other men who have sex with men (MSM) and transgender persons (1). JYNNEOS vaccine (Modified Vaccinia Ankara vaccine, Bavarian Nordic) was approved by the Food and Drug Administration (FDA) in 2019 for the prevention of smallpox and mpox via subcutaneous injection as a 2-dose series (0.5 mL per dose, administered 4 weeks apart) (2). To expand vaccine access, an Emergency Use Authorization was issued by FDA on August 9, 2022, for dose-sparing intradermal injection of JYNNEOS as a 2-dose series (0.1 mL per dose, administered 4 weeks apart) (3). Vaccination was available to persons with known or presumed exposure to a person with mpox (postexposure prophylaxis [PEP]), as well as persons at increased risk for mpox or who might benefit from vaccination (preexposure mpox prophylaxis [PrEP]) (4). Because information on JYNNEOS vaccine effectiveness (VE) is limited, a matched case-control study was conducted in 12 U.S. jurisdictions,† including nine Emerging Infections Program sites and three Epidemiology and Laboratory Capacity sites,§ to evaluate VE against mpox among MSM and transgender adults aged 18-49 years. During August 19, 2022-March 31, 2023, a total of 309 case-patients were matched to 608 control patients. Adjusted VE was 75.2% (95% CI = 61.2% to 84.2%) for partial vaccination (1 dose) and 85.9% (95% CI = 73.8% to 92.4%) for full vaccination (2 doses). Adjusted VE for full vaccination by subcutaneous, intradermal, and heterologous routes of administration was 88.9% (95% CI = 56.0% to 97.2%), 80.3% (95% CI = 22.9% to 95.0%), and 86.9% (95% CI = 69.1% to 94.5%), respectively. Adjusted VE for full vaccination among immunocompromised participants was 70.2% (95% CI = -37.9% to 93.6%) and among immunocompetent participants was 87.8% (95% CI = 57.5% to 96.5%). JYNNEOS is effective at reducing the risk for mpox. Because duration of protection of 1 versus 2 doses remains unknown, persons at increased risk for mpox exposure should receive the 2-dose series as recommended by the Advisory Committee on Immunization Practices (ACIP),¶ regardless of administration route or immunocompromise status.

Trends in and Risk Factors for Recurrent Clostridioides difficile Infection, New Haven County, Connecticut, USA, 2015-2020.

Recurrent Clostridioides difficile infection (RCDI) causes an increased burden on the healthcare system. We calculated RCDI incidence and identified factors associated with RCDI cases in New Haven County, Connecticut, USA, during 2015-2020 by using data from population-based laboratory surveillance. A subset of C. difficile cases had complete chart reviews conducted for RCDI and potentially associated variables. RCDI was defined as a positive C. difficile specimen occurring 2-8 weeks after incident C. difficile infection. We compared cases with and without RCDI by using multiple regression. RCDI occurred in 12.0% of 4,301 chart-reviewed C. difficile cases, showing a U-shaped time trend with a sharp increase in 2020, mostly because of an increase in hospital-onset cases. Malignancy (odds ratio 1.51 [95% CI 1.11-2.07]) and antecedent nitrofurantoin use (odds ratio 2.37 [95% CI 1.23-4.58]) were medical risk factors for RCDI. The 2020 increase may reflect the impact of the COVID-19 pandemic.

"The Squeaky Wheel Gets the Grease": Rental Assistance Applicants' Quests for a Rationed and Scarce Resource.

In 2016, only one in five eligible U.S. households received rental assistance and waiting lists averaged two years nationally. The gap between available rental assistance and need requires systems to allocate this scarce resource. The way potential rental assistance recipients experience and navigate these systems is likely to shape who ultimately receives assistance. We draw on repeated qualitative interviews (N=238) with low-income New Haven residents (N=54) to examine how participants understand and navigate rental assistance applications and waiting lists. Participants encountered multiple challenges in their search for rental assistance. They described an opaque and complex application and waiting process requiring significant knowledge to navigate. They also described considerable labor associated with monitoring waiting lists, a challenge made more difficult for some by their lack of a stable address. Additionally, participants described significant labor and knowledge required to strategically navigate prioritization systems that often required them to advocate for their deservingness of scarce housing resources. Our findings suggest that the allocation of rental assistance through complex processes that depend on applicant knowledge, labor, and advocacy may create barriers to housing, particularly for more vulnerable and marginalized housing seekers.

Clinical and Public Health Considerations for HPV Vaccination in Midadulthood: A Narrative Review.

Human papillomavirus (HPV) is an important cause of anogenital and oropharyngeal cancers, anogenital warts, and recurrent respiratory papillomatosis. Beginning in 2019, US guidelines recommended shared clinical decision-making (SCDM) for HPV vaccination among midadults (27-45 years). We conducted a narrative review of existing literature on HPV vaccination in midadults. The available evidence demonstrates that HPV vaccination in midadults is safe, efficacious, and likely to benefit both HPV-naïve midadults and those with previous infections. However, gaps in knowledge related to HPV vaccination have been identified among clinicians and midadult patients. Universal midadult HPV vaccination in the United States could avert 20 934-37 856 cancer cases over 100 years, costing $141 000-$1 471 000 per quality-adjusted life-year gained. Wide variation in these estimates reflects uncertainties in sexual behavior, HPV natural history, and naturally acquired immunity. Greater awareness among clinicians and midadult patients and broad implementation of SCDM may accelerate progress toward eliminating HPV-associated cancers and other diseases.

Messaging of Different Disease Outcomes for Human Papillomavirus Vaccination: A Systematic Review.

PURPOSE: The purpose of this systematic review was to assess how messaging for human papillomavirus (HPV) vaccination to prevent different health outcomes (sexually transmitted infection, anogenital warts ([AGW], and/or cancer) influences intentions or initiation for the vaccine series. METHODS: We searched PubMed, MEDLINE, and Embase databases for all previously published articles with an evaluation, discussion, or comparison of messages containing content about HPV infections, AGW, precancers, or cancer through June 3, 2021. Results about messages were summarized by study population and design. RESULTS: We identified 25 studies evaluating or comparing messages containing content about HPV-associated outcomes. Study designs included randomized trials (n = 12), cross-sectional surveys (n = 8), and qualitative approaches (n = 5). Few studies directly compared different messages using randomized designs or included vaccination uptake as the outcome. While many studies found support for cancer prevention messages, some studies also found equal or greater support for messages focusing on prevention of sexually transmitted infection/AGW. Variability was observed within and between studied populations (parents/adults, adolescents, young adults, healthcare providers, and adult males) and gender (male and female adolescents). DISCUSSION: A greater understanding and deeper attention to myriad health outcomes of HPV infections could increase vaccination uptake in a variety of populations for health promotion across the lifespan.

HPV type-specific trends in cervical precancers in the United States, 2008 to 2016.

Declines in cervical intraepithelial neoplasia grades 2 to 3 and adenocarcinoma in situ (CIN2+) observed among young women suggest impact from human papillomavirus (HPV) vaccination. To further evaluate vaccine impact including cross-protection and type replacement, we described high-risk (HR)-HPV type-specific cervical precancer incidence rates among women aged 20 to 39 years, 2008 to 2016. We analyzed cross-sectional population-based data on 18 344 cases of CIN2+ from a 5-site surveillance system. Diagnostic specimens were tested for individual HPV types, including 14 HR-HPV types (HPV16/18/31/33/35/39/45/51/52/56/58/59/66/68). We estimated age-specific annual HR-HPV type-specific CIN2+ incidence per 100 000 screened women for individual types, vaccine HR-HPV types (HPV16/18) and nonvaccine HR-HPV types (non-HPV16/18). We evaluated trends using average annual percent changes (AAPC) and 95% confidence intervals (CI), and estimated total declines by comparing 2015-2016 to 2008-2009 using incidence rate ratios. Among 20-24-year-olds, HPV16/18-CIN2+ declined from 2008 through 2016 (AAPC: -21.3%, 95% CI: -28.1%, -13.8%), whereas no trend was observed for non-HPV16/18-CIN2+ (AAPC: -1.8%, 95% CI: -8.1%, 4.9%). After 2010, CIN2+ among 20-24-year-olds was more often caused by nonvaccine vs vaccine HR-HPV types. No significant declining trends were observed in older age groups. In 2015-2016 compared with 2008-2009, HPV16-CIN2+ declined 78%, HPV18-CIN2+ 72% and HPV31-CIN2+ 51% among 20-24-year-olds; no increases were observed in type-specific CIN2+ incidence. Among 25-29-year-olds, HPV16-CIN2+ declined 18%; CIN2+ attributed to seven nonvaccine types increased significantly. No significant declines were observed in older groups. Significant declines in HPV16/18-CIN2+ in 20-24-year-olds and HPV16-CIN2+ in 25-29-year-olds corroborate impact of HPV vaccination. A declining trend in HPV31-CIN2+ is consistent with cross-protection from vaccination.

A review of data systems for assessing the impact of HPV vaccination in selected high-income countries.

INTRODUCTION: The introduction of effective human papillomavirus (HPV) vaccination, screening, and treatment programs has led the World Health Organization to call for the global elimination of cervical cancer. Assessing progress toward this goal is supported through monitoring vaccination coverage and its impact. AREAS COVERED: We performed a targeted review to assess the characteristics of HPV-related data systems from seven high-income countries (HICs) that represented varied approaches, including Australia, Canada, France, Italy, Scotland, Sweden, and the United States (US). Included data systems focused on preventive and early detection measures: HPV vaccination and cervical screening programs, as well as HPV-related disease outcomes. Differences were observed in approach to development of data systems, along with variation in geographical scope and methods of data collection. EXPERT OPINION: A challenge exists in how to best follow-up the ongoing global-scale elimination efforts in a comprehensive manner. These sources provide a wealth of information regarding the strengths and limitations of, and notable variation among, current data systems used in HICs. This review can inform improvements to existing prevention programs and the implementation of new programs in other countries, and thus support optimization of cervical cancer prevention policy.

Understanding the Factors Influencing Health Care Provider Recommendations about Adolescent Vaccines: A Proposed Framework.

Health care provider recommendations are among the most important factors influencing parents' decisions to vaccinate their adolescents. However, delivery of high-quality health care provider recommendations for vaccination is not universal. There is wide variation in the strength, timeliness and consistency of the delivery of recommendations for all adolescent vaccines. The factors that influence health care providers' recommendations are multi-level and can be conceptualized in much the same way as vaccine acceptance among parents. Health care providers are influenced by their own attitudes and beliefs about a vaccine and also by the patient they are treating and by the community in which they practice as well as state and national level vaccine policy. We propose a multi-level framework for understanding the factors that influence health care providers' recommendations at the individual, interpersonal and community level to both develop and adapt interventions to improve providers' recommendations.

Parents' Acceptance of COVID-19 Compared to Human Papillomavirus Vaccines.

PURPOSE: The first vaccine against SARS-CoV-2 (COVID-19) for adolescents 16 years and older in the United States received Emergency Use Authorization in December 2020. Soon after its approval, parents expressed concerns about vaccine safety for adolescents. Similar concerns about vaccine safety partially explain suboptimal human papillomavirus (HPV) vaccine uptake. This qualitative study explores similarities and differences in parents' attitudes about these two vaccines. METHODS: Parents were recruited through social media and at health centers in Alabama. Semi-structured interviews with parents of adolescents aged 9-17 years were conducted before and after Alabama expanded age eligibility to those 16 and older. Topics included knowledge about HPV and COVID-19 vaccines, and parents' intentions to have children vaccinated. Interviews were analyzed using thematic analysis. RESULTS: From March 11, 2021 to April 24, 2021, 21 in-depth interviews were conducted. Parents discussed the importance of HPV and COVID-19 vaccines for protecting their children's health but differences between the two related to community protection. Parents were concerned about vaccine safety but media coverage about the COVID-19 vaccine led to more favorable attitudes about the benefits of vaccination, which was not observed for HPV vaccines. Instead for HPV vaccination, parents wanted their healthcare providers' opinions about the vaccine before making a vaccination decision. DISCUSSION: Parents had similar concerns about HPV and COVID-19 vaccines. Although provider recommendations can improve vaccine uptake, local news reports were seen to have a positive impact on COVID-19 vaccine acceptance in lieu of provider recommendation. Disseminating information online could be beneficial to promote HPV and COVID-19 vaccines.

"I can't do it": A qualitative study exploring case and contact experiences with COVID-19 contact tracing.

BACKGROUND: Low engagement in contact tracing for COVID-19 dramatically reduces its impact, but little is known about how experiences, environments and characteristics of cases and contacts influence engagement. METHODS: We recruited a convenience sample of COVID-19 cases and contacts from the New Haven Health Department's contact tracing program for interviews about their contact tracing experiences. We analyzed transcripts thematically, organized themes using the Capability, Opportunity, Motivation, Behavior (COM-B) model, and identified candidate interventions using the linked Behavior Change Wheel Framework. RESULTS: We interviewed 21 cases and 12 contacts. Many felt physically or psychologically incapable of contact tracing participation due to symptoms or uncertainty about protocols. Environmental factors and social contacts also influenced engagement. Finally, physical symptoms, emotions and low trust in and expectations of public health authorities influenced motivation to participate. CONCLUSION: To improve contact tracing uptake, programs should respond to clients' physical and emotional needs; increase clarity of public communications; address structural and social factors that shape behaviors and opportunities; and establish and maintain trust. We identify multiple potential interventions that may help achieve these goals.

Chlamydia Vaccination: Parent Opinions and Implications for Future Promotion Programs.

BACKGROUND: Chlamydia vaccines are currently under development and have the potential to lower the incidence of infection and disease, which are highest among adolescents and young adults. Ideally, a chlamydia vaccine would be administered to adolescents before sexual debut, a time when parents are the primary vaccine decision makers. This study explores parent opinions about an adolescent chlamydia vaccine to understand barriers and facilitators to uptake. METHODS: Semistructured interviews were conducted with parents of adolescents. Topics included conversations parents have with their children about chlamydia, opinions on chlamydia vaccine development, and vaccine characteristics, such as efficacy and cost. Interviews were analyzed using a thematic analysis approach. RESULTS: From March to April 2021, 21 interviews were completed. Few parents discuss chlamydia with their children and sex education was seen as limited. Overall, 16 parents indicated that a chlamydia vaccine is needed. However, there were mixed opinions about vaccinating their own children, related to the need to vaccinate at a young age, vaccine efficacy, and confusion about benefits of vaccination. Finally, healthcare provider recommendations were seen as important before deciding to vaccinate a child. CONCLUSIONS: Although parents think that chlamydia vaccines are needed, lack of awareness about infections and potential benefits of vaccination could serve as barriers to uptake. Healthcare provider recommendations can help to improve knowledge and vaccine uptake. However, there is a need for multilevel approaches to improve chlamydia awareness and ensure that vaccination initiation and completion rates remain high.

Perceived Need and Acceptance of a Future Chlamydia Vaccine Among Health Care Providers.

BACKGROUND: Chlamydia vaccination is a potentially important strategy to prevent infections and reduce the global burden of disease. Ideally, chlamydia immunization programs would require vaccinating adolescents before they engage in sexual activity. Communication by health care providers (HCPs) has been shown to have an impact on vaccine acceptance. Therefore, it is imperative to understand their opinions on chlamydia vaccines and factors that would promote strong vaccine recommendations to patients to promote uptake. METHODS: Semi-structured interviews with adolescent HCPs were conducted and focused on perceived need for chlamydia vaccine. Additional topics included vaccine characteristics, such as efficacy, cost, and booster vaccines, and potential vaccine recommendation strategies. RESULTS: From January to July 2021, 22 interviews were completed. Health care providers discussed how chlamydia vaccines are needed, especially in settings with high prevalence rates. Health care providers thought a chlamydia vaccine would need to be very efficacious in preventing infections and related sequalae and cost-effective. However, there were concerns about low completion rates if this vaccine required multiple doses or boosters. In addition, vaccine misinformation was prevalent among HCPs regarding potential benefits of vaccination. CONCLUSIONS: Health care providers' perceptions that an adolescent chlamydia vaccine would be beneficial offers great promise for future promotion. However, there is need for targeted education programs about chlamydia and the benefits of vaccination for HCPs. These programs will be especially important in order for HCPs to effectively communicate about the benefits of vaccination to parents and adolescents provide strong vaccine recommendations.

Combining genomic and epidemiological data to compare the transmissibility of SARS-CoV-2 variants Alpha and Iota.

SARS-CoV-2 variants shaped the second year of the COVID-19 pandemic and the discourse around effective control measures. Evaluating the threat posed by a new variant is essential for adapting response efforts when community transmission is detected. In this study, we compare the dynamics of two variants, Alpha and Iota, by integrating genomic surveillance data to estimate the effective reproduction number (Rt) of the variants. We use Connecticut, United States, in which Alpha and Iota co-circulated in 2021. We find that the Rt of these variants were up to 50% larger than that of other variants. We then use phylogeography to show that while both variants were introduced into Connecticut at comparable frequencies, clades that resulted from introductions of Alpha were larger than those resulting from Iota introductions. By monitoring the dynamics of individual variants throughout our study period, we demonstrate the importance of routine surveillance in the response to COVID-19.

Assessment of Clinical Effectiveness of BNT162b2 COVID-19 Vaccine in US Adolescents.

Importance: The emergence of the B.1.617.2 (Delta) variant of SARS-CoV-2 has led to increases in both infections and hospitalizations among adolescents. Little is known about the effectiveness of the BNT162b2 vaccine in adolescents in the general population, as opposed to a clinical trial population. Objective: To estimate the effectiveness of the BNT162b2 vaccine in adolescents aged 12 to 18 years. Design, Setting, and Participants: This was a matched case-control study among adolescents (aged 12-18 years) who had results from a SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR) test. Immunization histories, relevant clinical data, and RT-PCR test results were obtained from the Yale New Haven Health System's medical records between June 1, 2021, and August 15, 2021, when the Delta variant caused 92% of infections in Connecticut. Case participants were defined as adolescents who had a positive test result and an associated medical encounter. Control participants were defined as those who had a negative test result and were matched to a case participant by age, county of residence, and date of testing. Exposures: Adolescents were defined as fully immunized if they had received 2 doses of vaccine at least 14 days before focal time. Main Outcomes and Measures: The primary outcome measured was SARS-CoV-2 infection confirmed by RT-PCR. The vaccine's effectiveness (VE) was estimated using matched odds ratios from conditional logistic regression models. Secondary measures included estimated VE by clinical symptoms, number of vaccine doses received, and elapsed time from immunization. Results: A total of 6901 adolescents were tested for SARS-CoV-2. The final sample comprised 186 case participants and 356 matched control participants. The median age was 14 (IQR, 13-16) years, 262 (48%) identified as female, 81 (15%) as Black, 82 (15%) as Hispanic, and 297 (55%) as White. Overall, 134 (25%) were fully immunized (case participants, 10 [5%]; control participants, 124 [35%]). The median time between immunization and the SARS-CoV-2 test was 62 days (range, 17-129 days). Within 4 months of receiving 2 doses, VE against any infection was estimated to be 91% (95% CI, 80%-96%); against asymptomatic infection, 85% (95% CI, 57%-95%). Effectiveness after a single dose was estimated to be 74% (95% CI, 18%-92%). Conclusions and Relevance: In this retrospective case-control study of US adolescents, 2 doses of BNT162b2 vaccine appeared to provide excellent protection for at least 4 months after immunization against both symptomatic and asymptomatic SARS-CoV-2 infections.