SARS-CoV-2 viral variants can rapidly be identified for clinical decision making and population surveillance using a high-throughput digital droplet PCR assay.

Epidemiologic surveillance of circulating SARS-CoV-2 variants is essential to assess impact on clinical outcomes and vaccine efficacy. Whole genome sequencing (WGS), the gold-standard to identify variants, requires significant infrastructure and expertise. We developed a digital droplet polymerase chain reaction (ddPCR) assay that can rapidly identify circulating variants of concern/interest (VOC/VOI) using variant-specific mutation combinations in the Spike gene. To validate the assay, 800 saliva samples known to be SARS-CoV-2 positive by RT-PCR were used. During the study (July 2020-March 2022) the assay was easily adaptable to identify not only existing circulating VAC/VOI, but all new variants as they evolved. The assay can discriminate nine variants (Alpha, Beta, Gamma, Delta, Eta, Epsilon, Lambda, Mu, and Omicron) and sub-lineages (Delta 417N, Omicron BA.1, BA.2). Sequence analyses confirmed variant type for 124/124 samples tested. This ddPCR assay is an inexpensive, sensitive, high-throughput assay that can easily be adapted as new variants are identified.

Surveillance of Severe Acute Respiratory Syndrome Coronavirus 2 and Variants Using Digital Droplet Polymerase Chain Reaction at a Large University and Healthcare System in California.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with different infectivity, transmission potential, and morbidity change the characteristics of local epidemics and affect vaccine effectiveness. As part of the University of Southern California COVID-19 Pandemic Research Center's efforts to understand, control, and inform local community on coronavirus disease 2019 (COVID-19), we implemented a SARS-CoV-2 surveillance program among students, employees, and USC Keck Medical Center patients. We present the epidemiology and distribution of SARS-CoV-2 and its variants among the population. Methods: We used digital droplet reverse-transcriptase polymerase chain reaction (PCR) to analyze in real-time remnant SARS-CoV-2 PCR-positive saliva specimens stored at the USC Keck Medicine laboratory between September 2020 and April 2022. Samples were tested for the original strain (A20) and 9 SARS-CoV-2 variants: α(B.1.1.7, Q.1-Q.8), ß(B.1.351, B.1.351.2, B.1.351.3), γ(P.1, P.1.1, P.1.2), δ(B.1.617.2), δ+(or δ417N), ε(B.1.427 and B.1.429), η(B.1.525), λ(C.37) and ο(B.1.1.529, ΒΑ.1, BA.2). We reviewed deidentified health information from positive cases including demographics, history of COVID-19 (eg, symptoms, hospitalizations, and repeat infections), and COVID-19 vaccination status. Results: We reviewed 1169 cases and determined the variant type of 482 specimens: 77 specimens were original strain, 119 "Delta", 165 "Omicron". The original strain was detected during the third and fourth quarters of 2020. The Delta variant appeared during the second quarter of 2021, whereas Omicron appeared in the fourth quarter of 2021. Conclusions: Prospectively tracking SARS-CoV-2 variants in a university population and a hospital system, utilizing a low-cost, high-throughput PCR assay, was feasible. Local variant monitoring remains important to inform prevention and control efforts among university and clinical settings.

Trust in science and scientists among university students, staff, and faculty of a large, diverse university in Los Angeles during the COVID-19 pandemic, the Trojan Pandemic Response Initiative.

BACKGROUND: Mistrust in science and scientists may adversely influence the rate of COVID-19 vaccination and undermine public health initiatives to reduce virus transmission. METHODS: Students, staff and faculty responded to an email invitation to complete an electronic survey. Surveys included 21-items from the Trust in Science and Scientists Inventory questionnaire. Responses were coded so higher scores indicated a higher trust in science and scientists, A linear regression model including sex, age group, division, race and ethnicity, political affiliation, and history of COVID-19, was used to determine variables significantly associated with trust in science and scientists scores at the p < 0.05 level. RESULTS: Participants were mostly female (62.1%), Asian (34.7%) and White (39.5%) and students (70.6%). More than half identified their political affiliation as Democrat (65%). In the final regression model, all races and ethnicities had significantly lower mean trust in science and scientists scores than White participants [Black ([Formula: see text]= -0.42, 95% CI: -0.55, -0.43, p < 0.001); Asian ([Formula: see text]= -0.20, 95% CI: -0.24, -0.17, p < 0.001); Latinx ([Formula: see text]= -0.22, 95% CI: -0.27, -0.18, p < 0.001); Other ([Formula: see text]= -0.19, 95% CI: -0.26, -0.11, p < 0.001)]. Compared to those identifying as Democrat, all other political affiliations had significantly lower mean scores. [Republican ([Formula: see text] =-0.49, 95% CI: -0.55, -0.43, p < 0.0001); Independent ([Formula: see text] =-0.29, 95% CI: -0.33, -0.25, p < 0.0001); something else ([Formula: see text] =-0.19, 95% CI: -0.25, -0.12, p < 0.0001)]. Having had COVID-19 ([Formula: see text]= -0.10, 95% CI: -0.15, -0.06, p < 0.001) had significantly lower scores compared to those who did not have COVID-19. CONCLUSION: Despite the setting of a major research University, trust in science is highly variable. This study identifies characteristics that could be used to target and curate educational campaigns and university policies to address the COVID19 and future pandemics.

Quantification of Severe Acute Respiratory Syndrome Coronavirus 2 Binding Antibody Levels To Assess Infection and Vaccine-Induced Immunity Using WHO Standards.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binding antibody (Ab) levels following vaccination or natural infection could be used as a surrogate for immune protection if results of serological assays were standardized to yield quantitative results using an international standard. Using a bead-based serological assay (Luminex xMAP), anti-receptor binding domain (anti-RBD) Ab levels were determined for 1,450 participants enrolled in the Los Angeles Pandemic Surveillance Cohort (LAPSC) study. For 123 participants, SARS-CoV-2 binding antibody unit (BAU) levels were also quantified using WHO standards and then compared to the semiquantitative results. Samples were chosen to represent the range of results and time from vaccination. Antibody levels and decay rates were then compared using unadjusted and adjusted linear regression models. The linear range of the assay used in this study was determined to be 300 to 5,000 mean fluorescence intensity units (MFI). Among the fully vaccinated groups (vaccinated only and vaccinated with past infection), 84.8% had anti-RBD MFI values above the linear range of >5,000 MFI, and 33.8% had values of >15,000 MFI. Among vaccinated participants with past infection (hybrid immunity), 97% had anti-RBD values of >5,000 MFI and 70% (120/171) had anti-RBD values of >15,000 MFI. In the subgroup quantified using the WHO control, BAU levels were significantly higher than the semiquantitative MFI results. In vaccinated participants, Ab decay levels were similar between infected and noninfected groups (P = 0.337). These results demonstrate that accurate quantitation is possible if standardized with an international standard. BAU can then be compared over time or between subjects and would be useful in clinical decision making. IMPORTANCE Accurate quantification of SARS-CoV-2-specific antibodies can be achieved using a universal standard with sample dilution within the linear range. With hybrid immunity being now common, it is critical to use protocols adapted to high Ab levels to standardize serological results. We validated this approach with the Los Angeles Pandemic Surveillance Cohort by comparing the antibody decay rates in vaccinated participants and vaccinated infected participants.

Correlates of COVID-19 vaccination status among college students.

Objectives: Despite the widespread availability of COVID-19 vaccines in the United States, vaccine hesitancy remains high among certain groups. This study examined the correlates of being unvaccinated among a sample of students attending a single university (N = 2900) during the spring and summer of 2021, when the campus had been closed for over a year and students were preparing to return to in-person learning. Methods: Students responded to an email invitation and completed electronic surveys. Results: In multivariable logistic regression analyses, students were more likely to be unvaccinated if they were African American, identified with any political affiliation other than Democrat, were undergraduates or international students, had not traveled outside the Los Angeles during the pandemic, and/or had previously been ill with COVID-19. Conclusion: Findings indicate that culturally resonant educational interventions, and possibly vaccine requirements, are needed to promote vaccination among university students.

Serum antioxidant status and mortality from influenza and pneumonia in US adults.

OBJECTIVE: We examined the association between serum antioxidant status and mortality from influenza and pneumonia in US adults. DESIGN: Serum concentrations of antioxidants included vitamin C, vitamin A, vitamin E, sum of α- and ß-carotene, ß-cryptoxanthin, lutein + zeaxanthin and lycopene. We computed total antioxidant capacity (TAC) as a measure of composite antioxidant status in serum. Survey-weighted Cox proportional hazard models were used to compute hazard ratios (HR) and 95 % CI comparing quartiles of each antioxidant and TAC. SETTING: Data from the US National Health and Nutrition Examination Survey (NHANES)-III. PARTICIPANTS: A total of 7428 NHANES-III participants ≥45 years of age. RESULTS: With a weighted-median follow-up of 16·8 years, 154 participants died from influenza/pneumonia. After adjustment for covariates, serum vitamin C, the sum of α- and ß-carotene and TAC were nonlinearly associated with influenza/pneumonia mortality, with the statistically significant smallest HR at the third quartile v. the first quartile (HR = 0·38 (95 % CI: 0·19, 0·77), 0·29 (0·16, 0·51) and 0·30 (0·15, 0·59), respectively). HR comparing the fourth v. the first quartiles were weaker and nonsignificant: 0·57 (95 % CI: 0·27, 1·17), 0·70 (0·41, 1·19) and 0·65 (0·31, 1·35), respectively. Serum lycopene had a monotonic association with influenza/pneumonia mortality (HR = 0·43 (95 % CI: 0·23, 0·83) comparing the fourth v. the first quartile, Pfor trend = 0·01). CONCLUSIONS: The current study suggests that antioxidant intake as reflected by serum concentrations may reduce mortality risk from influenza or pneumonia in the US general population. These findings warrant further confirmation in other populations with different settings (e.g. a shorter-term association with influenza infection).

COVID-19 booster vaccine attitudes and behaviors among university students and staff in the United States: The USC Trojan pandemic research Initiative.

Although authorized mRNA COVID-19 vaccines (BNT162b2 by BioNTech/Pfizer and mRNA-1273 by Moderna) significantly reduce morbidity and mortality, recent evidence suggests that immunity wanes over time, and that a booster dose could further reduce COVID-19 transmission and severe illness. However, research examining attitudes on booster willingness in diverse populations is needed. This study examined COVID-19 booster vaccine attitudes and behaviors among university students and staff in the fall of 2021. In our sample, 96.2% of respondents indicated willingness to get a COVID-19 booster shot at least once per year. In both bivariate and multivariate analyses higher trust in science was associated with having higher odds of booster willingness. Those who identify as Black, on average, reported trusting science less than other racial/ethnic groups. Our findings demonstrate high willingness to receive a COVID-19 booster shot and highlight the importance of educational messages and initiatives that focus on building trust in science to increase willingness to get the COVID-19 booster. More research is needed to better understand the impact of cultural beliefs on booster willingness and vaccine hesitancy. This understanding will help determine what messages and populations to target to increase booster willingness in the future.

Factors associated with parents' willingness to vaccinate their children against COVID-19: The LA pandemic surveillance cohort study.

Background: Children age 5-11 became eligible for COVID-19 vaccination in November 2021 in the United States, but vaccine uptake in this age group remains low. Understanding reasons why parents are hesitant to vaccinate their children may provide critical insights to help protect children from COVID-19 infection. This study examines factors associated with parents' willingness to vaccinate their children. Methods: We conducted a cross-sectional survey focusing on the Los Angeles County adult residents between March and June 2021. Our analytic sample focused on a subgroup of participants who self-report having a child. Predictors included parents' vaccination status and beliefs about COVID-19. We used multivariable logistic regression analysis and calculated the predicted probabilities of parents' willingness to vaccinate their children. Results: Parents (n = 401) who worried about catching the virus, had trust in vaccine development and the COVID-19 vaccine approval process, and vaccinated against COVID-19 were more likely to be willing to vaccinate their children. Socio-economic, racial and ethnic differences were no longer statistically significant in the adjusted model. Predicted probabilities of parents who were willing to vaccine their children were 55% among the vaccinated and 36% among the unvaccinated. Conclusions: Parents' intent to vaccinate their children is influenced by their perceived severity of the pandemic, trust in the vaccine development process, and their vaccination status, which can be the potential drivers of hesitancy to vaccinate their children.

Characteristics associated with COVID-19 vaccination status among staff and faculty of a large, diverse University in Los Angeles: The Trojan Pandemic Response Initiative.

Objective: This study examined characteristics associated with being unvaccinated among a sample of university staff and faculty prior to university campus reopening for in-person learning in 2021. Methods: Staff and faculty responded to an email invitation to complete an online survey. Survey questions included demographic data (race/ethnicity, age, sex), COVID-19 knowledge and behaviors, employment specific data including division and subdivision (healthcare vs. non-healthcare related division); and self-reported vaccination status. A multivariable logistic regression analysis was performed to determine significant characteristics associated with the likelihood of being unvaccinated for COVID-19. Results: Participants identifying as Asian and Asian American (aOR = 1.44, 95% CI: 1.06, 1.96), Hispanic/Latinx (aOR = 1.73, 95% CI: 1.21, 2.49) or Multicultural/Other (aOR = 1.72, 95% CI: 1.24, 2.38) had greater odds of being unvaccinated compared to Non-Hispanic White participants. Other characteristics associated with greater likelihood of being unvaccinated included working as a university staff member (vs. faculty) (aOR = 1.69, 95% CI: 1.24. 2.30), decrease in income (aOR = 1.34, 95% CI:1.05, 1.71), inability to work remotely (aOR = 1.48, 95% CI:1.13, 1.93) and not traveling outside of the Los Angeles area (aOR = 1.46, 95% CI: 1.16, 1.83). Political affiliation as an Independent (aOR = 1.39, 95% CI:1.04, 1.85) or as something else (aOR = 3.84, 95% CI: 2.72, 5.41) were more likely to be unvaccinated compared to participants identifying as Democrat. Conclusions: Several factors associated with racial and social disparities may delay the uptake of COVID-19 vaccination. This study highlights the need for targeted educational interventions to promote vaccination among university staff and faculty.

Did prioritizing essential workers help to achieve racial/ethnic equity in early COVID-19 vaccine distribution? The LA pandemic surveillance cohort study.

BACKGROUND: Most US states and counties prioritized essential workers for early access to COVID-19 vaccines due to their heightened occupational risk. Racial/ethnic groups most impacted by COVID-19 are overrepresented among essential workers. This study estimates the effects of prioritizing essential workers on racial/ethnic equity in COVID-19 vaccination. METHODS: Survey data were collected from 5500 Los Angeles County adult residents in March and April 2021. Multivariate regression models were used to assess marginal changes in probabilities of vaccination attributable to essential worker status by race/ethnicity. These probabilities were multiplied by population proportions of essential workers in each racial/ethnic group to estimate the effects of prioritizing essential workers on vaccine equity in the population. RESULTS: While Latinos (24.9%), Blacks (22.4%), and Asians (21.4%) were more likely to be prioritized essential workers than Whites (14.3%), their marginal gains in vaccine uptake due to their essential worker status did not significantly differ from that of Whites. At the population-level, prioritizing vaccines for essential workers increased the probabilities of vaccination by small and similar amounts among Asians (5.3%; 95% confidence interval [CI]: 3.3%, 7.5%), Blacks (4.0%; 95% CI: 1.7%, 6.5%), Latinos (3.7%; 95% CI: 2.3%, 5.1%), and Whites (2.9%; 95% CI :1.9%, 3.9%). CONCLUSIONS: Prioritizing essential workers did not provide proportionally greater early vaccine uptake benefits to racial/ethnic groups that were disproportionately affected by COVID-19. Early prioritization of essential workers during vaccine campaigns is an important but insufficient strategy for reducing racial/ethnic disparities in early vaccine uptake. Additional strategies addressing access and trust are needed to achieve greater equity in vaccine distribution.

Environmental Cadmium and Mortality from Influenza and Pneumonia in U.S. Adults.

BACKGROUND: Environmental cadmium exposure is widespread. In humans, cadmium is poorly excreted, triggers pulmonary inflammation, reduces pulmonary function, and enhances lung injury by respiratory syncytial virus. OBJECTIVES: We examined the association of cadmium burden with mortality related to influenza or pneumonia. METHODS: This prospective analysis of the National Health and Nutrition Examination Survey (NHANES) included 7,173 and 8,678 participants ≥45 years of age enrolled in NHANES-III and NHANES 1999-2006, respectively. Associations were evaluated between cadmium and mortality from influenza or pneumonia during a median follow-up of 17.3 y (NHANES-III, based on creatinine-corrected urine cadmium) and 11.4 y (NHANES 1999-2006, based on blood cadmium). Survey-weighted Cox proportional hazard models were used to compute hazard ratios (HRs) comparing the mortality of individuals at the 80th vs. the 20th percentile of cadmium concentrations. RESULTS: In NHANES-III, after adjustment for sex, race/ethnicity, education, body mass index, serum cholesterol, hypertension, and NHANES phase (or cycle), the HR comparing influenza or pneumonia mortality among participants with creatinine-corrected urinary cadmium in the 80th vs. 20th percentile was 1.15 (95% CI: 1.05, 1.26; p=0.002) in the population as a whole and 1.27 (95% CI: 1.12, 1.43; p=0.002) among never smokers. In NHANES 1999-2006, adjusted HRs for the 80th vs. 20th percentile of blood cadmium were 1.14 (95% CI: 0.96, 1.36; p=0.15) for the overall population and 1.71 (95% CI: 0.95, 3.09; p=0.07) in never smokers. DISCUSSION: Among middle-aged and older adults in the United States, higher cadmium burdens are associated with higher mortality from influenza or pneumonia. This raises the possibility that cadmium may worsen outcomes from COVID-19 infections. https://doi.org/10.1289/EHP7598.