A qualitative exploration of the impacts of COVID-19 in two rural Southwestern Alaska communities.

This manuscript presents a qualitative exploration of the experiences of people in two Southwestern Alaska communities during the emergence of COVID-19 and subsequent pandemic response. The project used principles of community based participatory research and honoured Indigenous ways of knowing throughout the study design, data collection, analysis, and dissemination. Data was collected in 2022 through group and individual conversations with community members, exploring impacts of the COVID-19 pandemic. Participants included Elders, community health workers, Tribal council members, government employees, school personnel, and emergency response personnel. Notes and written responses were coded using thematic qualitative analysis. The most frequently identified themes were 1) feeling disconnected from family, friends, and other relationships, 2) death, 3) the Tribal councils did a good job, and 4) loss of celebrations and ceremonies. While the findings highlighted grief and a loss of social cohesion due to the pandemic, they also included indicators of resilience and thriving, such as appropriate and responsive local governance, revitalisation of traditional medicines, and coming together as a community to survive. This case study was conducted as part of an international collaboration to identify community-driven, evidence-based recommendations to inform pan-Arctic collaboration and decision making in public health during global emergencies.

Diverse methodological approaches to a Circumpolar multi-site case study which upholds and responds to local and Indigenous community research processes in the Arctic.

This paper outlines the methodological approaches to a multi-site Circumpolar case study exploring the impacts of COVID-19 on Indigenous and remote communities in 7 of 8 Arctic countries. Researchers involved with the project implemented a three-phase multi-site case study to assess the positive and negative societal outcomes associated with the COVID-19 pandemic in Arctic communities from 2020 to 2023. The goal of the multi-site case study was to identify community-driven models and evidence-based promising practices and recommendations that can help inform cohesive and coordinated public health responses and protocols related to future public health emergencies in the Arctic. Research sites included a minimum of 1 one community each from Canada (Nunavut,) United States of America (Alaska), Greenland, Iceland, Norway, Sweden, Finland. The approaches used for our multi-site case study provide a comprehensive, evidence-based account of the complex health challenges facing Arctic communities, offering insights into the effectiveness of interventions, while also privileging Indigenous local knowledge and voices. The mixed method multi-site case study approach enriched the understanding of unique regional health disparities and strengths during the pandemic. These methodological approaches serve as a valuable resource for policymakers, researchers, and healthcare professionals, informing future strategies and interventions.

Novel lambdapapillomavirus in northern sea otters Enhydra lutris kenyoni, associated with oral hyperplastic nodules.

A novel papillomavirus (PV) associated with hyperplastic nodules scattered over the muco-cutaneous border of the oral cavity of a dead, wild, subadult northern sea otter Enhydra lutris kenyoni (NSO) in 2004 in Homer, Alaska, USA, was genetically characterized. Primers for the amplification of 2 large overlapping DNA fragments that contained the complete genome of the NSO PV were designed. Sanger methodology generated sequences from which new specific primers were designed for the primer-walking approach. The NSO PV genome consists of 8085 nucleotides and contains an early region composed of E6, E7, E1, and E2 open reading frames (ORFs), an E4 ORF (contained within E2) lacking an in-frame proximal ATG start codon, an unusually long (907 nucleotide) stretch lacking any ORFs, a late region that contains the capsid genes L2 and L1, and a non-coding regulatory region (ncRR). This NSO PV has been tentatively named Enhydra lutris kenyoni PV2 (ElkPV2). Pairwise and multiple sequence alignments of the complete L1 ORF nucleotides and concatenated E1-E2-L1 amino acid sequences showed that the NSO PV is a novel PV, phylogenetically most closely related to southern sea otter PV1. The carboxy end of the E6 oncoprotein does not contain the PDZ-binding motif with a strong correlation with oncogenicity, suggesting a low-risk PV, which is in agreement with histopathological findings. However, the ElkPV2 E7 oncoprotein does contain the retinoblastoma (pRb) binding domain LXCXE (LQCYE in ElkPV2), associated with oncogenicity in some high-risk PVs. Further studies on the prevalence and clinical significance of ElkPV2 infections in NSO are needed.

Suspected True Hermaphroditism in a Free-ranging Gray Wolf (Canis lupus) in Interior Alaska, USA.

Hermaphroditism or intersexuality occurs endogenously in most mammal species. We document the behavior and physical and anatomic appearance of a suspected true hermaphroditic free-ranging wild gray wolf (Canis lupus) in Denali National Park and Preserve, Alaska, USA.

Cyclical Migration in Alaska Native Elders and Its Impact on Elders' Identity and Later Life Well-Being.

OBJECTIVES: This paper outlines the unique culturally driven cyclical migration of Alaska Native (AN) Elders, distinct from previously described migration patterns in that Elders spend extended time in more than one community. We describe this Indigenous cyclical migration of AN Elders and its influence on their identity and later life health and well-being. METHODS: Interviews with 124 AN Elders were conducted across 5 regions of Alaska: Bristol Bay, Interior, Norton Sound, Aleutian Pribilof Islands, and Southcentral. Within this sample, 87 participants engaged in cyclical migration. Thematic analysis was employed to identify themes related to Elders' cyclical migration between rural and urban communities and the impact on their identity and later life health and well-being. RESULTS: We identified 2 distinct patterns of Indigenous cyclical migration-Elders living primarily in rural communities migrating to urban communities and Elders living primarily in urban communities migrating to rural communities. Elders engaged in these 2 patterns of cyclical migration to maintain cultural practices, access social, and health care services to maintain their physical health and well-being, and continue their community roles contributing to their AN Elder identity. DISCUSSION: This study builds upon existing migration theories by introducing a cyclical pattern uniquely driven by AN identity, culture, and traditional practices. Findings illustrate how AN communities can support Elders who experience cyclical migration patterns to ensure they age successfully in both locations. Future research should explore cyclical migration patterns among other Indigenous populations with migration histories.

Application of COVIDTracer to Inform Public Health Workforce Planning in Alaska During the COVID-19 Pandemic.

The COVID-19 pandemic has caused social and economic disruption worldwide and spurred numerous mitigation strategies, including state investments in training a large contact tracing and case investigation workforce. A team at the University of Alaska Anchorage evaluated implementation of the COVID-19 contact tracing and case investigation program of the State of Alaska Department of Health and Social Services, Division of Public Health, Section of Public Health Nursing. As part of that evaluation, the team used COVIDTracer, a spreadsheet modeling tool. COVIDTracer generated projections of COVID-19 case counts that informed estimates of workforce needs and case prioritization strategies. Case count projections approximated the reported epidemiologic curve with a median 7% difference in the first month. The accuracy of case count predictions declined after 1 month with a median difference of 80% in the second month. COVIDTracer inputs included previous case counts, the average length of time for telephone calls to cases and outreach to identified contacts, and the average number of contacts per case. As each variable increased, so too did estimated workforce needs. Decreasing the average time from exposure to outreach from 10 to 5 days reduced case counts estimated by COVIDTracer by approximately 93% during a 5-month period. COVIDTracer estimates informed Alaska's workforce planning and decisions about prioritizing case investigation during the pandemic. Lessons learned included the importance of being able to rapidly scale up and scale down workforce to adjust to a dynamic crisis and the limitations of prediction modeling (eg, that COVIDTracer was accurate for only about 1 month into the future). These findings may be useful for future pandemic preparedness planning and other public health emergency response activities.

Economic incentives surrounding fertility: Evidence from Alaska's permanent fund dividend.

The Alaska Permanent Fund Dividend provided an incentive that increased fertility. This paper estimates the impact of the dividend transfer on fertility rates in Alaska compared to other states using the synthetic control methodology. For the period from 1982 to 1988, fertility on average increased annually in Alaska by 11.3 births per 1000 women aged 15-44-a 13.1 percent increase over the counterfactual. This was driven by women over 20. Fertility increased for women aged 20-24 by 12.4 percent, those aged 25-34 by 14.3 percent, and those aged 35-44 by 16.9 percent. The paper also finds support that narrowing the gap between births, increase in total fertility rate, and no change in abortion are potential channels for the observed increase in fertility. No change in the fertility for the adolescents combined with no change in abortion suggests that the increase in fertility in Alaska was planned.

Invasive Pneumococcal Disease and Potential Impact of Pneumococcal Conjugate Vaccines Among Adults, Including Persons Experiencing Homelessness-Alaska, 2011-2020.

BACKGROUND: Adults aged ≥65 years, adults with certain underlying medical conditions, and persons experiencing homelessness are at increased risk for invasive pneumococcal disease (IPD). Two new pneumococcal conjugate vaccines, 15-valent pneumococcal conjugate vaccine (PCV15) and 20-valent pneumococcal conjugate vaccine (PCV20), were recently approved for use in US adults. We describe the epidemiology of IPD among Alaska adults and estimate the proportion of IPD cases potentially preventable by new vaccines. METHODS: We used statewide, laboratory-based surveillance data to calculate and compare IPD incidence rates and 95% confidence intervals (CIs) among Alaska adults aged ≥18 years during 2011-2020 and estimate the proportion of IPD cases that were caused by serotypes in PCV15 and PCV20. RESULTS: During 2011-2020, 1164 IPD cases were reported among Alaska adults for an average annual incidence of 21.3 cases per 100 000 adults per year (95% CI, 20.1-22.5). Incidence increased significantly during the study period (P < .01). IPD incidence among Alaska Native adults was 4.7 times higher than among non-Alaska Native adults (95% CI, 4.2-5.2). Among adults experiencing homelessness in Anchorage, IPD incidence was 72 times higher than in the general adult population (95% CI, 59-89). Overall, 1032 (89%) Alaska adults with IPD had an indication for pneumococcal vaccine according to updated vaccination guidelines; 456 (39%) and 700 (60%) cases were caused by serotypes in PCV15 and PCV20, respectively. CONCLUSIONS: Use of PCV15 and PCV20 could substantially reduce IPD among adults in Alaska, including Alaska Native adults and adults experiencing homelessness.

Molecular detection and characterization of highly pathogenic H5N1 clade 2.3.4.4b avian influenza viruses among hunter-harvested wild birds provides evidence for three independent introductions into Alaska.

We detected and characterized highly pathogenic avian influenza viruses among hunter-harvested wild waterfowl inhabiting western Alaska during September-October 2022 using a molecular sequencing pipeline applied to RNA extracts derived directly from original swab samples. Genomic characterization of 10 H5 clade 2.3.4.4b avian influenza viruses detected with high confidence provided evidence for three independent viral introductions into Alaska. Our results highlight the utility and some potential limits of applying molecular processing approaches directly to RNA extracts from original swab samples for viral research and monitoring.

Association between gene methylation and experiences of historical trauma in Alaska Native peoples.

BACKGROUND: Historical trauma experienced by Indigenous peoples of North America is correlated with health disparities and is hypothesized to be associated with DNA methylation. Massive group traumas such as genocide, loss of land and foodways, and forced conversion to Western lifeways may be embodied and affect individuals, families, communities, cultures, and health. This study approaches research with Alaska Native people using a community-engaged approach designed to create mutually-beneficial partnerships, including intentional relationship development, capacity building, and sample and data care. METHODS: A total of 117 Alaska Native individuals from two regions of Alaska joined the research study. Participants completed surveys on cultural identification, historical trauma (historical loss scale and historical loss associated symptoms scale), and general wellbeing. Participants provided a blood sample which was used to assess DNA methylation with the Illumina Infinium MethylationEPIC array. RESULTS: We report an association between historical loss associated symptoms and DNA methylation at five CpG sites, evidencing the embodiment of historical trauma. We further report an association between cultural identification and general wellbeing, complementing evidence from oral narratives and additional studies that multiple aspects of cultural connection may buffer the effects of and/or aid in the healing process from historical trauma. CONCLUSION: A community-engaged approach emphasizes balanced partnerships between communities and researchers. Here, this approach helps better understand embodiment of historical trauma in Alaska Native peoples. This analysis reveals links between the historical trauma response and DNA methylation. Indigenous communities have been stigmatized for public health issues instead caused by systemic inequalities, social disparities, and discrimination, and we argue that the social determinants of health model in Alaska Native peoples must include the vast impact of historical trauma and ongoing colonial violence.

Cancer Screening Prevalence among Participants in the Southcentral Alaska Education and Research towards Health (EARTH) Study at Baseline and Follow-Up.

Alaska Native communities are working to prevent cancer through increased cancer screening and early detection. We examined the prevalence of self-reported colorectal (CRC), cervical, and breast cancer screening among Alaska Native participants in the southcentral Alaska Education and Research toward Health (EARTH) study at baseline (2004-2006) and ten-year follow-up (2015-2017); participant characteristics associated with screening; and changes in screening prevalence over time. A total of 385 participants completed questionnaires at follow-up; 72% were women. Of those eligible for CRC screening, 53% of follow-up participants reported a CRC screening test within the past 5 years, significantly less than at baseline (70%) (p = 0.02). There was also a significant decline in cervical cancer screening between baseline and follow-up: 73% of women at follow-up vs. 90% at baseline reported screening within the past three years (p < 0.01). There was no significant difference in reported breast cancer screening between baseline (78%) and follow-up (77%). Colorectal and cervical cancer screening prevalence in an urban, southcentral Alaska Native cohort declined over 10 years of follow-up. Increased cancer screening and prevention are needed to decrease Alaska Native cancer-related morbidity and mortality.

Temporally Associated Invasive Pneumococcal Disease and SARS-CoV-2 Infection, Alaska, USA, 2020-2021.

Streptococcus pneumoniae can co-infect persons who have viral respiratory tract infections. However, research on S. pneumoniae infections that are temporally associated with SARS-CoV-2 infections is limited. We described the epidemiology and clinical course of patients who had invasive pneumococcal disease (IPD) and temporally associated SARS-CoV-2 infections in Alaska, USA, during January 1, 2020-December 23, 2021. Of 271 patients who had laboratory-confirmed IPD, 55 (20%) had a positive SARS-CoV-2 test result. We observed no major differences in age, race, sex, or underlying medical conditions among IPD patients with and without SARS-CoV-2. However, a larger proportion of IPD patients with SARS-CoV-2 died (16%, n = 9) than for those with IPD alone (4%, n = 9) (p<0.01). IPD patients with SARS-CoV-2 were also more likely to be experiencing homelessness (adjusted OR 3.5; 95% CI 1.7-7.5). Our study highlights the risk for dual infection and ongoing benefits of pneumococcal and COVID-19 vaccination, especially among vulnerable populations.

Prevalence of Childhood Hearing Loss in Rural Alaska.

OBJECTIVES: Childhood hearing loss has well-known lifelong consequences. Certain rural populations are at higher risk for infection-related hearing loss. For Alaska Native children, historical data on hearing loss prevalence suggest a higher burden of infection-related hearing loss, but updated prevalence data are urgently needed in this high-risk population. DESIGN: Hearing data were collected as part of two school-based cluster-randomized trials in 15 communities in rural northwest Alaska over two academic years (2017-2019). All enrolled children from preschool to 12th grade were eligible. Pure-tone thresholds were obtained using standard audiometry and conditioned play when indicated. The analysis included the first available audiometric assessment for each child (n = 1634 participants, 3 to 21 years), except for the high-frequency analysis, which was limited to year 2 when higher frequencies were collected. Multiple imputation was used to quantify the prevalence of hearing loss in younger children, where missing data were more frequent due to the need for behavioral responses. Hearing loss in either ear was evaluated using both the former World Health Organization (WHO) definition (pure-tone average [PTA] > 25 dB) and the new WHO definition (PTA ≥ 20 dB), which was published after the study. Analyses with the new definition were limited to children 7 years and older due to incomplete data obtained on younger children at lower thresholds. RESULTS: The overall prevalence of hearing loss (PTA > 25 dB; 0.5, 1, 2, 4 kHz) was 10.5% (95% confidence interval [CI], 8.9 to 12.1). Hearing loss was predominately mild (PTA >25 to 40 dB; 8.9%, 95% CI, 7.4 to 10.5). The prevalence of unilateral hearing loss was 7.7% (95% CI, 6.3 to 9.0). Conductive hearing loss (air-bone gap of ≥ 10 dB) was the most common hearing loss type (9.1%, 95% CI, 7.6 to 10.7). Stratified by age, hearing loss (PTA >25 dB) was more common in children 3 to 6 years (14.9%, 95% CI, 11.4 to 18.5) compared to children 7 years and older (8.7%, 95% CI, 7.1 to 10.4). In children 7 years and older, the new WHO definition increased the prevalence of hearing loss to 23.4% (95% CI, 21.0 to 25.8) compared to the former definition (8.7%, 95% CI, 7.1 to 10.4). Middle ear disease prevalence was 17.6% (95% CI, 15.7 to 19.4) and was higher in younger children (23.6%, 95% CI, 19.7 to 27.6) compared to older children (15.2%, 95% CI, 13.2 to 17.3). High-frequency hearing loss (4, 6, 8kHz) was present in 20.5% (95% CI, 18.4 to 22.7 [PTA >25 dB]) of all children and 22.8% (95% CI, 20.3 to 25.3 [PTA >25 dB]) and 29.7% (95% CI, 27.0 to 32.4 [PTA ≥ 20 dB]) of children 7 years and older (limited to year 2). CONCLUSIONS: This analysis represents the first prevalence study on childhood hearing loss in Alaska in over 60 years and is the largest cohort with hearing data ever collected in rural Alaska. Our results highlight that hearing loss continues to be common in rural Alaska Native children, with middle ear disease more prevalent in younger children and high-frequency hearing loss more prevalent with increasing age. Prevention efforts may benefit from managing hearing loss type by age. Lastly, continued research is needed on the impact of the new WHO definition of hearing loss on field studies.

Incorporating resilience when assessing pandemic risk in the Arctic: a case study of Alaska.

The discourse on vulnerability to COVID-19 or any other pandemic is about the susceptibility to the effects of disease outbreaks. Over time, vulnerability has been assessed through various indices calculated using a confluence of societal factors. However, categorising Arctic communities, without considering their socioeconomic, cultural and demographic uniqueness, into the high and low continuum of vulnerability using universal indicators will undoubtedly result in the underestimation of the communities' capacity to withstand and recover from pandemic exposure. By recognising vulnerability and resilience as two separate but interrelated dimensions, this study reviews the Arctic communities' ability to cope with pandemic risks. In particular, we have developed a pandemic vulnerability-resilience framework for Alaska to examine the potential community-level risks of COVID-19 or future pandemics. Based on the combined assessment of the vulnerability and resilience indices, we found that not all highly vulnerable census areas and boroughs had experienced COVID-19 epidemiological outcomes with similar severity. The more resilient a census area or borough is, the lower the cumulative death per 100 000 and case fatality ratio in that area. The insight that pandemic risks are the result of the interaction between vulnerability and resilience could help public officials and concerned parties to accurately identify the populations and communities at most risk or with the greatest need, which, in turn, helps in the efficient allocation of resources and services before, during and after a pandemic. A resilience-vulnerability-focused approach described in this paper can be applied to assess the potential effect of COVID-19 and similar future health crises in remote regions or regions with large Indigenous populations in other parts of the world.

Exploring factors associated with parent-reported early childhood caries with Alaska's childhood understanding behaviors survey data.

OBJECTIVES: Early Childhood Caries (ECC) can negatively impact the lives of young children, despite being preventable. The purpose of this study was to utilize available data in Alaska to describe changes in parent reports of ECC, and identify factors related to ECC. METHODS: The Childhood Understanding Behaviors Survey (CUBS) is a population-based survey of parents of 3-year-old children and was utilized to describe changes in: parent-reported ECC among children with a dental visit, access to and or utilization of dental care, and consumption of three or more cups of sweetened beverages between 2009-2011 and 2016-2019. Logistic regression modeling was used to explore factors associated with parent-reported ECC among children with a dental visit. RESULTS: Over time, a significantly smaller proportions of parents whose 3-year-old child had seen a dental professional reported ECC. Additionally, a smaller proportion of parents reported three or more cups of sweetened beverage consumption by their child, while larger proportions had seen a dental professional by age 3. Factors associated with parent-reported ECC included consumption of three or more cups of sweetened beverages, and enrollment in Medicaid or Tribal health care insurance, while protective factors included a parent earning a college degree, and military insurance. CONCLUSIONS: Although at the statewide level, improvements were observed in parent-reported measures over time, regional disparities were apparent. Social and economic factors as well as excessive consumption of sweetened beverages appear to play important roles in ECC. CUBS data can help identify trends in ECC within Alaska.

Effectiveness of the COVID-19 vaccines on preventing symptomatic SARS-CoV-2 infections and hospitalizations in Southwestern Alaska, January-December 2021.

The population in rural southwest Alaska has been disproportionately affected by COVID-19. To assess the benefit of COVID-19 vaccines, we analyzed data from the regional health system. We estimated vaccine effectiveness (VE) during January 16-December 3, 2021, against symptomatic SARS-CoV-2 infection after a primary series or booster dose, and overall VE against hospitalization. VE of a primary series against symptomatic infection among adult residents was 91.3% (95% CI: 85.7, 95.2) during January 16-May 7, 2021, 50.3% (95% CI, 41.1%-58.8%) during July 17-September 24, and 37.0% (95% CI, 27.8-45.0) during September 25-December 3, 2021; VE of a booster dose during September 25-December 3, 2021, was 92.1% (95% CI: 87.2-95.2). During the overall study period, VE against hospitalization was 91.9% (95% CI: 85.4-95.5). COVID-19 vaccination offered strong protection against hospitalization and a booster dose restored protection against symptomatic infection.

Replication and validation of a statewide linkage method to estimate incidence proportion of child maltreatment.

PURPOSE: To study familial factors associated with child maltreatment in a birth population, Alaska piloted a mixed-design method that linked child welfare data with the Pregnancy Risk Assessment Monitoring System (PRAMS). We replicated this approach in Oregon and validated it in both states. METHODS: We linked vital records, child welfare, and PRAMS data to create two 2009 birth cohorts for each state: one based on vital records (full birth cohort) and one on PRAMS (stratified random sample). For each cohort, we estimated the incidence proportions (IP) of child maltreatment before age 9 years and compared those estimated using PRAMS with those observed using the full birth cohort. RESULTS: The Oregon PRAMS cohort estimated that 28.7% (95% CI: 24.0, 33.4), 20.9% (17.1, 24.7), and 8.3% (6.0, 10.5) of children experienced an alleged, investigated, and substantiated maltreatment, respectively, versus 32.0%, 25.0%, and 9.9% from the birth cohort. The corresponding Alaska estimates were 29.1% (26.1, 32.0), 22.6% (19.9, 25.2), and 8.3% (6.7, 9.9) of children from the PRAMS cohort versus 29.1%, 23.5%, and 9.1% in the birth cohort. CONCLUSIONS: The IP of child maltreatment in two states was accurately estimated with PRAMS cohorts. Researchers can study a comprehensive set of factors that may influence child maltreatment by incorporating PRAMS into birth cohort linkages.

Did text-based news-media coverage about the COVID-19 pandemic increase vaccine uptake? A population-based study in Alaska.

COVID-19 vaccinations protect against severe infection, hospitalisation, and death. News media can be an important source of information for the public during a health crisis. This study explores the extent to which local or statewide text-based news coverage of the pandemic was related to the uptake of initial doses of COVID-19 vaccines among adults in Alaska. Multilevel modelling was employed to explore the association between news media intensity and vaccine uptake rates across boroughs and census areas, while controlling for relevant covariates. Results suggest that the intensity of news media did not significantly influence vaccine uptake during the majority of this time period and had a negative affect during the Delta-surge in the fall of 2021. However, the political lean and median age of boroughs or census areas were significantly associated with vaccine uptake. Race, poverty, or education were not significant determinants of vaccine uptake suggesting there are unique differences in Alaska compared to the U.S., particularly amongst Alaska Native people. The political environment in Alaska surrounding the pandemic was polarized. Future research in communications and channels that can cut through this polarized and politicized environment, and reach younger adults is needed.

Association of Temperature Thresholds with Heat Illness- and Cardiorespiratory-Related Emergency Visits during Summer Months in Alaska.

BACKGROUND: Recent record-breaking hot temperatures in Alaska have raised concerns about the potential human health implications of heat exposure among this unacclimated population. OBJECTIVES: We estimated cardiorespiratory morbidity associated with days above summer (June-August) heat index (HI, apparent temperature) thresholds in three major population centers (Anchorage, Fairbanks, and the Matanuska-Susitna Valley) for the years 2015-2019. METHODS: We implemented time-stratified case-crossover analyses of emergency department (ED) visits for International Classification of Diseases, 10th Revision codes indicative of heat illness and major cardiorespiratory diagnostic codes using data from the Alaska Health Facilities Data Reporting Program. Using conditional logistic regression models, we tested maximum hourly HI temperature thresholds between 21.1°C (70°F) and 30°C (86°F) for a single day, 2 consecutive days, and the absolute number of previous consecutive days above the threshold, adjusting for the daily average concentration of particulate matter ≤2.5µg. RESULTS: There were increased odds of ED visits for heat illness above a HI threshold as low as 21.1°C (70°F) [odds ratio (OR)=13.84; 95% confidence interval (CI): 4.05, 47.29], and this increased risk continued for up to 4 d (OR=2.43; 95% CI: 1.15, 5.10). Asthma and pneumonia were the only respiratory outcomes positively associated with the HI: ED visits for both were highest the day after a heat event (Asthma: HI>27°C(80°F) OR=1.18; 95% CI: 1.00, 1.39; Pneumonia: HI>28°C(82°F) OR=1.40; 95% CI: 1.06, 1.84). There was a decreased odds of bronchitis-related ED visits when the HI was above thresholds of 21.1-28°C (70-82°F) across all lag days. We found stronger effects for ischemia and myocardial infarction (MI) than for respiratory outcomes. Multiple days of warm weather were associated with an increased risk of health impacts. For each additional preceding day above a HI of 22°C (72°F), the odds of ED visits related to ischemia increased 6% (95% CI: 1%, 12%); for each additional preceding day above a HI of 21.1°C (70°F), the odds of ED visits related to MI increased 7% (95% CI: 1%, 14%). DISCUSSION: This study demonstrates the importance of planning for extreme heat events and developing local guidance for heat warnings, even in areas with historically mild summertime climates. https://doi.org/10.1289/EHP11363.