Pathogen genomics in public health laboratories: successes, challenges, and lessons learned from California's SARS-CoV-2 Whole-Genome Sequencing Initiative, California COVIDNet.

The capacity for pathogen genomics in public health expanded rapidly during the coronavirus disease 2019 (COVID-19) pandemic, but many public health laboratories did not have the infrastructure in place to handle the vast amount of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequence data generated. The California Department of Public Health, in partnership with Theiagen Genomics, was an early adopter of cloud-based resources for bioinformatics and genomic epidemiology, resulting in the creation of a SARS-CoV-2 genomic surveillance system that combined the efforts of more than 40 sequencing laboratories across government, academia and industry to form California COVIDNet, California's SARS-CoV-2 Whole-Genome Sequencing Initiative. Open-source bioinformatics workflows, ongoing training sessions for the public health workforce, and automated data transfer to visualization tools all contributed to the success of California COVIDNet. While challenges remain for public health genomic surveillance worldwide, California COVIDNet serves as a framework for a scaled and successful bioinformatics infrastructure that has expanded beyond SARS-CoV-2 to other pathogens of public health importance.

COVID-19 vaccination dynamics in the US: coverage velocity and carrying capacity based on socio-demographic vulnerability indices in California's pediatric population.

Introduction: COVID-19 vaccine inequities have been widespread across California, the United States, and globally. As COVID-19 vaccine inequities have not been fully understood in the youth population, it is vital to determine possible factors that drive inequities to enable actionable change that promotes vaccine equity among vulnerable minor populations. Methods: The present study used the social vulnerability index (SVI) and daily vaccination numbers within the age groups of 12-17, 5-11, and under 5 years old across all 58 California counties to model the growth velocity and the anticipated maximum proportion of population vaccinated. Results: Overall, highly vulnerable counties, when compared to low and moderately vulnerable counties, experienced a lower vaccination rate in the 12-17 and 5-11 year-old age groups. For age groups 5-11 and under 5 years old, highly vulnerable counties are expected to achieve a lower overall total proportion of residents vaccinated. In highly vulnerable counties in terms of socioeconomic status and household composition and disability, the 12-17 and 5-11 year-old age groups experienced lower vaccination rates. Additionally, in the 12-17 age group, high vulnerability counties are expected to achieve a higher proportion of residents vaccinated compared to less vulnerable counterparts. Discussion: These findings elucidate shortcomings in vaccine uptake in certain pediatric populations across California and may help guide health policies and future allocation of vaccines, with special emphasis placed on vulnerable populations, especially with respect to socioeconomic status and household composition and disability.

Overall and Telehealth Addiction Treatment Utilization by Age, Race, Ethnicity, and Socioeconomic Status in California After COVID-19 Policy Changes.

Importance: Addiction treatment rapidly transitioned to a primarily telehealth modality (telephone and video) during the COVID-19 pandemic, raising concerns about disparities in utilization. Objective: To examine whether there were differences in overall and telehealth addiction treatment utilization after telehealth policy changes during the COVID-19 pandemic by age, race, ethnicity, and socioeconomic status. Design, Setting, and Participants: This cohort study examined electronic health record and claims data from Kaiser Permanente Northern California for adults (age ≥18 years) with drug use problems before the COVID-19 pandemic (from March 1, 2019, to December 31, 2019) and during the early phase of the COVID-19 pandemic (March 1, 2020, to December 31, 2020; hereafter referred to as COVID-19 onset). Analyses were conducted between March 2021 and March 2023. Exposure: The expansion of telehealth services during COVID-19 onset. Main Outcomes and Measures: Generalized estimating equation models were fit to compare addiction treatment utilization during COVID-19 onset with that before the COVID-19 pandemic. Utilization measures included the Healthcare Effectiveness Data and Information Set of treatment initiation and engagement (including inpatient, outpatient, and telehealth encounters or receipt of medication for opioid use disorder [OUD]), 12-week retention (days in treatment), and OUD pharmacotherapy retention. Telehealth treatment initiation and engagement were also examined. Differences in changes in utilization by age group, race, ethnicity, and socioeconomic status (SES) were examined. Results: Among the 19 648 participants in the pre-COVID-19 cohort (58.5% male; mean [SD] age, 41.0 [17.5] years), 1.6% were American Indian or Alaska Native; 7.5%, Asian or Pacific Islander; 14.3%, Black; 20.8%, Latino or Hispanic; 53.4%, White; and 2.5%, unknown race. Among the 16 959 participants in the COVID-19 onset cohort (56.5% male; mean [SD] age, 38.9 [16.3] years), 1.6% were American Indian or Alaska Native; 7.4%, Asian or Pacific Islander; 14.6%, Black; 22.2%, Latino or Hispanic; 51.0%, White; and 3.2%, unknown race. Odds of overall treatment initiation increased from before the COVID-19 pandemic to COVID-19 onset for all age, race, ethnicity, and SES subgroups except for patients aged 50 years or older; patients aged 18 to 34 years had the greatest increases (adjusted odds ratio [aOR], 1.31; 95% CI, 1.22-1.40). Odds of telehealth treatment initiation increased for all patient subgroups without variation by race, ethnicity, or SES, although increases were greater for patients aged 18 to 34 years (aOR, 7.17; 95% CI, 6.24-8.24). Odds of overall treatment engagement increased (aOR, 1.13; 95% CI, 1.03-1.24) without variation by patient subgroups. Retention increased by 1.4 days (95% CI, 0.6-2.2 days), and OUD pharmacotherapy retention did not change (adjusted mean difference, -5.2 days; 95% CI, -12.7 to 2.4 days). Conclusions: In this cohort study of insured adults with drug use problems, there were increases in overall and telehealth addiction treatment utilization after telehealth policies changed during the COVID-19 pandemic. There was no evidence that disparities were exacerbated, and younger adults may have particularly benefited from the transition to telehealth.

The role of the California tier system in controlling population mobility during the COVID-19 pandemic.

BACKGROUND: Policies to restrict population mobility are a commonly used strategy to limit the transmission of contagious diseases. Among measures implemented during the COVID-19 pandemic were dynamic stay-at-home orders informed by real-time, regional-level data. California was the first state in the U.S. to implement this novel approach; however, the effectiveness of California's four-tier system on population mobility has not been quantified. METHODS: Utilizing data from mobile devices and county-level demographic data, we evaluated the impact of policy changes on population mobility and explored whether demographic characteristics explained variability in responsiveness to policy changes. For each California county, we calculated the proportion of people staying home and the average number of daily trips taken per 100 persons, across different trip distances and compared this to pre-COVID-19 levels. RESULTS: We found that overall mobility decreased when counties moved to a more restrictive tier and increased when moving to a less restrictive tier, as the policy intended. When placed in a more restrictive tier, the greatest decrease in mobility was observed for shorter and medium-range trips, while there was an unexpected increase in the longer trips. The mobility response varied by geographic region, as well as county-level median income, gross domestic product, economic, social, and educational contexts, the prevalence of farms, and recent election results. CONCLUSIONS: This analysis provides evidence of the effectiveness of the tier-based system in decreasing overall population mobility to ultimately reduce COVID-19 transmission. Results demonstrate that socio-political demographic indicators drive important variability in such patterns across counties.

Borrelia miyamotoi Infection in Immunocompromised Man, California, USA, 2021.

Infection with Borrelia miyamotoi in California, USA, has been suggested by serologic studies. We diagnosed B. miyamotoi infection in an immunocompromised man in California. Diagnosis was aided by plasma microbial cell-free DNA sequencing. We conclude that the infection was acquired in California.

Assessing the accuracy of California county level COVID-19 hospitalization forecasts to inform public policy decision making.

BACKGROUND: The COVID-19 pandemic has highlighted the role of infectious disease forecasting in informing public policy. However, significant barriers remain for effectively linking infectious disease forecasts to public health decision making, including a lack of model validation. Forecasting model performance and accuracy should be evaluated retrospectively to understand under which conditions models were reliable and could be improved in the future. METHODS: Using archived forecasts from the California Department of Public Health's California COVID Assessment Tool ( https://calcat.covid19.ca.gov/cacovidmodels/ ), we compared how well different forecasting models predicted COVID-19 hospitalization census across California counties and regions during periods of Alpha, Delta, and Omicron variant predominance. RESULTS: Based on mean absolute error estimates, forecasting models had variable performance across counties and through time. When accounting for model availability across counties and dates, some individual models performed consistently better than the ensemble model, but model rankings still differed across counties. Local transmission trends, variant prevalence, and county population size were informative predictors for determining which model performed best for a given county based on a random forest classification analysis. Overall, the ensemble model performed worse in less populous counties, in part because of fewer model contributors in these locations. CONCLUSIONS: Ensemble model predictions could be improved by incorporating geographic heterogeneity in model coverage and performance. Consistency in model reporting and improved model validation can strengthen the role of infectious disease forecasting in real-time public health decision making.

Rapid Expansion and Adaptability of California Medical Disaster Teams.

The California Medical Assistance Team (CAL-MAT) program is coordinated by the California Emergency Medical Services Authority (EMSA). The program was developed to deploy and support medical personnel for disaster medical response. During the coronavirus disease (COVID-19) pandemic, the program and missions grew rapidly in response to medical surge, programs for testing and vaccination, and other concurrent disasters. CAL-MAT enrollment increased 10-fold from approximately 200 members at the beginning of 2020, to an estimated 2200 members by June 2021. This article describes the flexible use of a state-managed disaster medical response program within California and some of the challenges associated with rapid expansion and varied demands during the COVID-19 surges of March 2020-March 2022. CAL-MAT may serve as a model for development of similar state-sponsored or other disaster medical response teams.

Lessons Learned From a COVID-19 Dog Screening Pilot in California K-12 Schools.

This diagnostic study describes a dog screening program used to identify COVID-19 infections among schoolchildren.

Pregnant in a Pandemic: Mental Wellbeing and Associated Healthy Behaviors Among Pregnant People in California During COVID-19.

INTRODUCTION: Pregnancy is a time of increased vulnerability to mental health disorders. Additionally, the COVID-19 pandemic has increased the incidence of depression and anxiety. Thus, we aimed to assess mental health and associated healthy behaviors of pregnant people in California during the pandemic in order to contextualize prenatal well-being during the first pandemic of the twenty-first century. METHODS: We conducted an online cross-sectional study of 433 pregnant people from June 6 through July 29, 2020. We explored 3 hypotheses: (1) mental health would be worse during the pandemic than in general pregnant samples to date; (2) first-time pregnant people would have worse mental health; and (3) healthy behaviors would be positively related to mental health. RESULTS: Many of our participants (22%) reported clinically significant depressive symptoms and 31% reported clinically significant anxiety symptoms. Multiparous pregnant people were more likely to express worries about their own health and wellbeing and the process of childbirth than were primiparous pregnant people. Additionally, as pregnancy advanced, sleep and nutrition worsened, while physical activity increased. Lastly, anxious-depressive symptomology was significantly predictive of participant sleep behaviors, nutrition, and physical activity during the past week. DISCUSSION: Pregnant people had worse mental health during the pandemic, and this was associated with worse health-promoting behaviors. Given that the COVID-19 pandemic and associated risks are likely to persist due to low vaccination rates and the emergence of variants with high infection rates, care that promotes mental and physical well-being for the pregnant population should be a public health priority.

Sheltering in Place and the Likelihood of Nonnatural Death.

Increasing hospitalizations for COVID-19 in the United States and elsewhere have ignited debate over whether to reinstate shelter-in-place policies adopted early in the pandemic to slow the spread of infection. The debate includes claims that sheltering in place influences deaths unrelated to infection or other natural causes. Testing this claim should improve the benefit/cost accounting that informs choice on reimposing sheltering in place. We used time-series methods to compare weekly nonnatural deaths in California with those in Florida. California was the first state to begin, and among the last to end, sheltering in place, while sheltering began later and ended earlier in Florida. During weeks when California had shelter-in-place orders in effect, but Florida did not, the odds that a nonnatural death occurred in California rather than Florida were 14.4% below expected levels. Sheltering-in-place policies likely reduce mortality from mechanisms unrelated to infection or other natural causes of death.

Monitoring SARS-CoV-2 incidence and seroconversion among university students and employees: a longitudinal cohort study in California, June-August 2020.

OBJECTIVES: To identify incident SARS-CoV-2 infections and inform effective mitigation strategies in university settings, we piloted an integrated symptom and exposure monitoring and testing system among a cohort of university students and employees. DESIGN: Prospective cohort study. SETTING: A public university in California from June to August 2020. PARTICIPANTS: 2180 university students and 738 university employees. PRIMARY OUTCOME MEASURES: At baseline and endline, we tested participants for active SARS-CoV-2 infection via quantitative PCR (qPCR) test and collected blood samples for antibody testing. Participants received notifications to complete additional qPCR tests throughout the study if they reported symptoms or exposures in daily surveys or were selected for surveillance testing. Viral whole genome sequencing was performed on positive qPCR samples, and phylogenetic trees were constructed with these genomes and external genomes. RESULTS: Over the study period, 57 students (2.6%) and 3 employees (0.4%) were diagnosed with SARS-CoV-2 infection via qPCR test. Phylogenetic analyses revealed that a super-spreader event among undergraduates in congregate housing accounted for at least 48% of cases among study participants but did not spread beyond campus. Test positivity was higher among participants who self-reported symptoms (incidence rate ratio (IRR) 12.7; 95% CI 7.4 to 21.8) or had household exposures (IRR 10.3; 95% CI 4.8 to 22.0) that triggered notifications to test. Most (91%) participants with newly identified antibodies at endline had been diagnosed with incident infection via qPCR test during the study. CONCLUSIONS: Our findings suggest that integrated monitoring systems can successfully identify and link at-risk students to SARS-CoV-2 testing. As the study took place before the evolution of highly transmissible variants and widespread availability of vaccines and rapid antigen tests, further research is necessary to adapt and evaluate similar systems in the present context.

Covid-19 shelter-in-place, modified reopening orders, and order compliance impact on adolescent alcohol use and drinking contexts in California: A longitudinal analysis.

INTRODUCTION: This study evaluated how Shelter-in-Place (SIP), modified reopening orders, and self-reported compliance with these orders have affected adolescent alcohol frequency and quantity of use across contexts during the COVID-19 pandemic. MATERIALS AND METHODS: Differences-in-differences (DID) models and multi-level modeling analyses were conducted on longitudinal data collected as part of a larger study on alcohol use among adolescents in California. 1,350 adolescents at baseline contributed 7,467 observations for a baseline and 5 six-month follow-up surveys. Analytic samples ranged from 3,577-6,245 participant observations based on models. Alcohol use outcomes included participant frequency (days) and quantity (number of whole drinks) of alcohol use in past 1-month and past 6-month periods. Context-specific alcohol use outcomes included past 6-month frequency and quantity of use at: restaurants, bars/nightclubs, outside, one's own home, another's home, and fraternities/sororities. Participant self-reported compliance with orders in essential business/retail spaces and at outdoor/social settings were also assessed. RESULTS: Our DID results indicated that being under a modified reopening order was associated with decreases in past 6-month quantity of alcohol use (IRR = 0.72, CI = 0.56-0.93, p < 0.05). Higher self-reported compliance with SIP orders related to social outdoor/social settings was associated with decreases in overall drinking frequency and quantity as well as decreases in frequency and quantity of alcohol use in all contexts in the past six months. Compliance with SIP orders impacting essential businesses and retail spaces was associated with decreased frequency and quantity of use at other's home and outdoors. CONCLUSIONS: Results suggest that SIP and modified reopening policies may not directly affect adolescent alcohol use or drinking contexts, and that individual compliance with such orders may be a protective factor for alcohol use.

Case Series: Unbiased Deep Sequencing Analysis of Acute Infectious Conjunctivitis in an Ambulatory Eye Center in Berkeley, California.

SIGNIFICANCE: Acute infectious conjunctivitis poses significant challenges to eye care providers. It can be highly transmissible, and because etiology is often presumed, correct treatment and management can be difficult. This study uses unbiased deep sequencing to identify causative pathogens of infectious conjunctivitis, potentially allowing for improved approaches to diagnosis and management. PURPOSES: This study aimed to identify associated pathogens of acute infectious conjunctivitis in a single ambulatory eye care center. CASE REPORTS: This study included patients who presented to the University of California Berkeley eye center with signs and symptoms suggestive of infectious conjunctivitis. From December 2021 to July 2021, samples were collected from seven subjects (ages ranging from 18 to 38). Deep sequencing identified associated pathogens in five of seven samples, including human adenovirus D, Haemophilus influenzae , Chlamydia trachomatis , and human coronavirus 229E. CONCLUSIONS: Unbiased deep sequencing identified some unexpected pathogens in subjects with acute infectious conjunctivitis. Human adenovirus D was recovered from only one patient in this series. Although all samples were obtained during the COVID-19 pandemic, only one case of human coronavirus 229E and no SARS-CoV-2 were identified.

Perceived COVID-19 risk and testing experiences in the San Ysidro U.S./Mexico border region.

Racial and ethnic disparities in COVID-19 incidence are pronounced in underserved U.S./Mexico border communities. Working and living environments in these communities can lead to increased risk of COVID-19 infection and transmission, and this increased risk is exacerbated by lack of access to testing. As part of designing a community and culturally tailored COVID-19 testing program, we surveyed community members in the San Ysidro border region. The purpose of our study was to characterize knowledge, attitudes, and beliefs of prenatal patients, prenatal caregivers, and pediatric caregivers at a Federally Qualified Health Center (FHQC) in the San Ysidro region regarding perceived risk of COVID-19 infection and access to testing. A cross-sectional survey was used to collect information on experiences accessing COVID-19 testing and perceived risk of COVID-19 infection within San Ysidro between December 29, 2020 and April 2, 2021. A total of 179 surveys were analyzed. Most participants identified as female (85%) and as Mexican/Mexican American (75%). Over half (56%) were between the age of 25 and 34 years old. Perceived Risk: 37% reported moderate to high risk of COVID-19 infection, whereas 50% reported their risk low to none. Testing Experience: Approximately 68% reported previously being tested for COVID-19. Among those tested, 97% reported having very easy or easy access to testing. Reasons for not testing included limited appointment availability, cost, not feeling sick, and concern about risk of infection while at a testing facility. This study is an important first step to understand the COVID-19 risk perceptions and testing access among patients and community members living near the U.S./Mexico border in San Ysidro, California.

COVID-19 testing strategies that fail to incorporate culturally competent methods to reach traditionally underserved communities can lead to persistent transmission and increased infection rates. During the early stages of the COVID-19 pandemic, we surveyed 179 people living in a community with high burden of COVID-19 infection about their perception of infection risk and their experiences accessing testing. Capturing and understanding these community perceptions on COVID-19 risk are vital when developing a testing program that is accessible and appropriate for the target population. In our study, we found half of survey respondents thought their risk of COVID-19 infection as low to none and over half of respondents stated they had already been tested for COVID-19. These findings provide insight to the beliefs of individuals who live and seek health care in communities with high rates of COVID-19 infection and will help guide the design and implementation of culturally tailored testing strategies.

Exploration of California School Nurse perspectives on the impact of COVID-19.

OBJECTIVE: To explore in a sample of school nurses (SN) in California the impact of the COVID-19 pandemic on school nurse health services, how school nurses mitigated the impact of COVID-19, and moral distress levels among school nurses. DESIGN AND METHODS: Nineteen (N = 19) school nurses who work in K-12 schools in California, USA participated in a mixed-methods approach involving qualitative descriptive design, inductive content analysis, and descriptive statistics. Interviews were conducted in August and September 2021. RESULTS: Five themes emerged: (1) role of the SN during the COVID-19 pandemic, (2) coordination with school administration, (3) COVID-19 related challenges and disruptions to care, (4) moral distress, and (5) coping during the pandemic. CONCLUSION: The pandemic had a profound impact on school nurses. This study provides school nurse perspectives of the impact of COVID-19 on services they delivered, the unique skills of school nurses essential to mitigation strategies, and moral distress school nurses encountered during the pandemic. Understanding the important role school nurses had during the pandemic is paramount to fully contextualize the contributions they made within public health nursing practice and inform preparedness for future pandemics.

"Prison life is very hard and it's made harder if you're isolated": COVID-19 risk mitigation strategies and the mental health of incarcerated women in California.

PURPOSE: This study aims to describe the COVID-19 risk mitigation strategies implemented in California prisons and the impact of these policies on the mental health of incarcerated women. DESIGN/METHODOLOGY/APPROACH: The authors conducted semi-structured qualitative interviews with ten women who were over the age of 50 and/or had a chronic illness and had been incarcerated in California prisons during the COVID-19 pandemic. The authors also interviewed ten health-care providers working in California jails or prisons during the pandemic. Interviews were analyzed using a grounded theory coding framework and triangulated with fieldnotes from ethnographic observations of medical and legal advocacy efforts during the pandemic. FINDINGS: Participants described being locked in their cells for 23 hours per day or more, often for days, weeks or even months at a time in an effort to reduce the spread of COVID-19. For many participants, these lockdowns and the resulting isolation from loved ones both inside and outside of the prison were detrimental to both their physical and mental health. Participants reported that access to mental health care for those in the general population was limited prior to the pandemic, and that COVID-19 risk mitigation strategies, including the cessation of group programs and shift to cell-front mental health services, created further barriers. ORIGINALITY/VALUE: There has been little qualitative research on the mental health effects of the COVID-19 pandemic on incarcerated populations. This paper provides insight into the mental health effects of both the COVID-19 pandemic and COVID-19 risk mitigation strategies for the structurally vulnerable older women incarcerated in California prisons.

The effect of COVID-19 on workplace violence in California's hospitals: An interrupted time series analysis.

AIM: This study used California's unique Workplace Violent Incident Reporting System (WVIRS) to describe changes in workplace violence (WV) exposure for hospital-based healthcare workers during the pandemic. DESIGN: Interrupted time series analysis. METHODS: We compared the linear trends in weekly WV incidents reported during the period before the COVID-19 pandemic (7/1/2017-3/20/2020) to the period following California's shutdown (3/21/2020-6/30/2021). We created mixed effects models for incidents reported in emergency departments (EDs) and in other hospital units. We used hospital volume data from the California Department of Health Care Access and Information. RESULTS: A total of 418 hospitals reported 37,561 incidents during the study period. For EDs, the number of reported incidents remained essentially constant, despite a 26% drop in outpatient visits between the first and second quarters of 2020. For other hospital units, weekly incidents initially dropped-parallel to a 13% decrease in inpatient days between the first and second quarters of 2020-but then continued parallel to the trend seen in the pre-COVID period. CONCLUSION: WV persists steadily in California's hospitals. Despite major reductions in patient volume due to COVID-19, weekly reported ED incidents remained essentially unchanged. IMPACT: Surveys and media reported that WV increased during the pandemic, but it has been difficult to measure these changes using a large-scale database. The absolute number of WV incidents did not increase during the pandemic; however, the trend in reported incidents remained constant in the context of dramatic decreases in patient volume. New federal WV prevention legislation is being considered in the U.S. California's experience of implementation should be considered to improve WV reporting and prevention. PUBLIC CONTRIBUTION: There was no public contribution to this study. The goal of this analysis was to summarize findings from administrative data. The findings presented can inform future discussion of public policy and action.

Receipt of COVID-19 and seasonal influenza vaccines in California (USA) during the 2021-2022 influenza season.

BACKGROUND: Despite lower circulation of influenza virus throughout 2020-2022 during the COVID-19 pandemic, seasonal influenza vaccination has remained a primary tool to reduce influenza-associated illness and death. The relationship between the decision to receive a COVID-19 vaccine and/or an influenza vaccine is not well understood. METHODS: We assessed predictors of receipt of 2021-2022 influenza vaccine in a secondary analysis of data from a case-control study enrolling individuals who received SARS-CoV-2 testing. We used mixed effects logistic regression to estimate factors associated with receipt of seasonal influenza vaccine. We also constructed multinomial adjusted marginal probability models of being vaccinated for COVID-19 only, seasonal influenza only, or both as compared with receipt of neither vaccination. RESULTS: Among 1261 eligible participants recruited between 22 October 2021-22 June 2022, 43% (545) were vaccinated with both seasonal influenza vaccine and >1 dose of a COVID-19 vaccine, 34% (426) received >1 dose of a COVID-19 vaccine only, 4% (49) received seasonal influenza vaccine only, and 19% (241) received neither vaccine. Receipt of >1 COVID-19 vaccine dose was associated with seasonal influenza vaccination (adjusted odds ratio [aOR]: 3.72; 95% confidence interval [CI]: 2.15-6.43); this association was stronger among participants receiving >1 COVID-19 booster dose (aOR = 16.50 [10.10-26.97]). Compared with participants testing negative for SARS- CoV-2 infection, participants testing positive had lower odds of receipt of 2021-2022 seasonal influenza vaccine (aOR = 0.64 [0.50-0.82]). CONCLUSIONS: Recipients of a COVID-19 vaccine were more likely to receive seasonal influenza vaccine during the 2021-2022 season. Factors associated with individuals' likelihood of receiving COVID-19 and seasonal influenza vaccines will be important to account for in future studies of vaccine effectiveness against both conditions. Participants who tested positive for SARS-CoV-2 in our sample were less likely to have received seasonal influenza vaccine, suggesting an opportunity to offer influenza vaccination before or after a COVID-19 diagnosis.

Risk factors for COVID-19 among Californians working outside the home, November 2020 - May 2021.

BACKGROUND: Higher incidences of COVID-19 mortality and outbreaks have been found in certain industries and occupations. Workplace factors, including working in close proximity to others and contact with the public can facilitate SARS-CoV-2 transmission, especially without appropriate protective measures. Limited information is available about workers at highest risk for SARS-CoV-2 infection. METHODS: A phone-based, nonprobability study was conducted between November 2020 and May 2021 among California workers who were tested for SARS-CoV-2. Participants were asked about demographics and workplace factors, including industry, occupation, and implementation of COVID-19 mitigation measures. Using the SARS-CoV-2 occupational exposure matrix, three exposure metrics and a combination index were used to categorize occupations. We assessed the association between workplace risks and SARS-CoV-2 test positivity using adjusted logistic regression. RESULTS: We enrolled 451 (13%) of 3475 potentially eligible workers in the study: 212 with positive and 239 with negative SARS-CoV-2 test results. Those working very close to others and with the highest combined exposure index had a positive association with SARS-CoV-2 positivity. Primarily indoor workers had a lower odds of test positivity compared to those with any outdoor work. There was no association between public-facing occupations and test positivity. Participants with employers who implemented mitigation measures in all three control categories-engineering, administrative, and personal protective equipment-had lower odds of test positivity than those with fewer mitigation measures. CONCLUSIONS: Worker groups with higher risk factors should be prioritized for outreach. Assessment of occupational risk factors collectively can provide insight to inform preventative actions for workers, employers, and public health entities.