SARS-CoV-2 viral load is associated with risk of transmission to household and community contacts.

BACKGROUND: Factors that lead to successful SARS-CoV-2 transmission are still not well described. We investigated the association between a case's viral load and the risk of transmission to contacts in the context of other exposure-related factors. METHODS: Data were generated through routine testing and contact tracing at a large university. Case viral loads were obtained from cycle threshold values associated with a positive polymerase chain reaction test result from October 1, 2020 to April 15, 2021. Cases were included if they had at least one contact who tested 3-14 days after the exposure. Case-contact pairs were formed by linking index cases with contacts. Chi-square tests were used to evaluate differences in proportions of contacts testing positive. Generalized estimating equation models with a log link were used to evaluate whether viral load and other exposure-related factors were associated with a contact testing positive. RESULTS: Median viral load among the 212 cases included in the study was 5.6 (1.8-10.4) log10 RNA copies per mL of saliva. Among 365 contacts, 70 (19%) tested positive following their exposure; 36 (51%) were exposed to a case that was asymptomatic or pre-symptomatic on the day of exposure. The proportion of contacts that tested positive increased monotonically with index case viral load (12%, 23% and 25% corresponding to < 5, 5-8 and > 8 log10 copies per mL, respectively; X2 = 7.18, df = 2, p = 0.03). Adjusting for cough, time between test and exposure, and physical contact, the risk of transmission to a close contact was significantly associated with viral load (RR = 1.27, 95% CI 1.22-1.32). CONCLUSIONS: Further research is needed to understand whether these relationships persist for newer variants. For those variants whose transmission advantage is mediated through a high viral load, public health measures could be scaled accordingly. Index cases with higher viral loads could be prioritized for contact tracing and recommendations to quarantine contacts could be made according to the likelihood of transmission based on risk factors such as viral load.

Adoption of digital tools in the context of the COVID-19 pandemic in the Region of the Americas - the Go.Data experience.

The COVID-19 pandemic has accelerated the growth of digital health tools. Although a number of different tools exist to support field data collection in the context of outbreak response, they have not been sufficient. This prompted the World Health Organization (WHO) to collaborate with the Global Outbreak Alert and Response Network (GOARN) and GOARN partners to develop a comprehensive system, Go.Data. Go.Data, a digital tool for outbreak response has simplified how countries operationalize and monitor case and contact data. Since the start of the pandemic, WHO and GOARN partners have provided support to Go.Data projects in 65 countries and territories, yet the demand by countries to have documented success cases of Go.Data implementations continues to grow. This viewpoint documents the successful Go.Data implementation frameworks in two countries, Argentina and Guatemala and an academic institution, the University of Texas at Austin.

Comparative Effectiveness of mRNA-based BNT162b2 Vaccine versus Adenovirus Vector-Based Ad26.COV2.S Vaccine for the Prevention of COVID-19 among Dialysis Patients.

BACKGROUND: Studies have demonstrated that mRNA-based SARS-CoV-2 vaccines are highly effective among patients on dialysis. Because individual vaccines may be differentially available or acceptable to patients, it is important to understand comparative effectiveness relative to other vaccines, such those on the basis of adenovirus technologies. METHODS: In this retrospective study, we compared the clinical effectiveness of adenovirus vector-based Ad26.COV2.S (Janssen/Johnson & Johnson) to mRNA-based BNT162b2 (Pfizer/BioNTech) in a contemporary cohort of patients on dialysis. Patients who received a first BNT162b2 dose were matched 1:1 to Ad26.COV2.S recipients on the basis of date of first vaccine receipt, US state of residence, site of dialysis care (in-center versus home), history of COVID-19, and propensity score. The primary outcome was the comparative rate of COVID-19 diagnoses starting in the 7th week postvaccination. In a subset of consented patients who received Ad26.COV2.S, blood samples were collected ≥28 days after vaccination and anti-SARS-CoV-2 immunoglobulin G antibodies were measured. RESULTS: A total of 2572 matched pairs of patients qualified for analysis. Cumulative incidence rates of COVID-19 did not differ for BNT162b2 versus Ad26.COV2.S. No differences were observed in peri-COVID-19 hospitalizations and deaths among patients receiving BNT162b2 versus Ad26.COV2.S, who were diagnosed with COVID-19 during the at-risk period. Results were similar when excluding patients with a history of COVID-19, in subgroup analyses restricted to patients who completed the two-dose BNT162b2 regimen, and in patients receiving in-center hemodialysis. SARS-CoV-2 antibodies were detected in 59.4% of 244 patients who received Ad26.COV2.S. CONCLUSIONS: In a large real-world cohort of patients on dialysis, no difference was detected in clinical effectiveness of BNT162b2 and Ad26.COV2.S over the first 6 months postvaccination, despite an inconsistent antibody response to the latter.

Real-World Effectiveness and Immunogenicity of BNT162b2 and mRNA-1273 SARS-CoV-2 Vaccines in Patients on Hemodialysis.

BACKGROUND: Patients on hemodialysis have an elevated risk for COVID-19 but were not included in efficacy trials of SARS-CoV-2 vaccines. METHODS: We conducted a retrospective, observational study to estimate the real-world effectiveness and immunogenicity of two mRNA SARS-CoV-2 vaccines in a large, representative population of adult hemodialysis patients in the United States. In separate, parallel analyses, patients who began a vaccination series with BNT162b2 or mRNA-1273 in January and February 2021 were matched with unvaccinated patients and risk for outcomes were compared for days 1-21, 22-42, and ≥43 after first dose. In a subset of consented patients, blood samples were collected approximately 28 days after the second dose and anti-SARS-CoV-2 immunoglobulin G was measured. RESULTS: A total of 12,169 patients received the BNT162b2 vaccine (matched with 44,377 unvaccinated controls); 23,037 patients received the mRNA-1273 vaccine (matched with 63,243 unvaccinated controls). Compared with controls, vaccinated patients' risk of being diagnosed with COVID-19 postvaccination became progressively lower during the study period (hazard ratio and 95% confidence interval for BNT162b2 was 0.21 [0.13, 0.35] and for mRNA-1273 was 0.27 [0.17, 0.42] for days ≥43). After a COVID-19 diagnosis, vaccinated patients were significantly less likely than unvaccinated patients to be hospitalized (for BNT162b2, 28.0% versus 43.4%; for mRNA-1273, 37.2% versus 45.6%) and significantly less likely to die (for BNT162b2, 4.0% versus 12.1%; for mRNA-1273, 5.6% versus 14.5%). Antibodies were detected in 98.1% (309/315) and 96.0% (308/321) of BNT162b2 and mRNA-1273 patients, respectively. CONCLUSIONS: In patients on hemodialysis, vaccination with BNT162b2 or mRNA-1273 was associated with a lower risk of COVID-19 diagnosis and lower risk of hospitalization or death among those diagnosed with COVID-19. SARS-CoV-2 antibodies were detected in nearly all patients after vaccination. These findings support the use of these vaccines in this population.

Mental Health Services Data Dashboards for Reporting to Australian Governments during COVID-19.

The Australian Institute of Health and Welfare (AIHW) has been providing support to the Australian Government Department of Health to report on mental health-related data to Australian governments on a frequent basis since April 2020 in the form of COVID-19 mental health services data dashboards. These dashboards feature extensive use of data visualizations which illustrate the change in mental health service use over time as well as comparisons with pre-pandemic levels of service use. Data are included from the Medicare Benefits Schedule (MBS), Pharmaceutical Benefits Scheme (PBS/RPBS), Australian Government-funded crisis and support organizations, and key findings from emerging research. Demand for telehealth, crisis and support organizations and online mental health information services, in particular, have increased during the pandemic. The dashboards incorporate both new and existing data sources and represent an innovative way of reporting mental health services data to Australian governments. The reporting has enabled timely, targeted adjustments to mental health service delivery during the pandemic with improved cooperative data sharing arrangements having the potential to yield ongoing benefits.

Screening Programs for SARS-CoV-2 Infections on a University Campus - Austin, Texas, September 30-November 30, 2020.

Colleges and universities in the United States have relied on various measures during the COVID-19 pandemic to prevent transmission of SARS-CoV-2, the virus that causes COVID-19, including implementing testing programs (1-3). These programs have permitted a safer return to campus for students by identifying infected persons and temporarily isolating them from the campus population (2,3). The University of Texas at Austin (UT Austin) implemented COVID-19 prevention measures in Fall 2020* including the following testing programs: clinic-based diagnostic testing, voluntary community screening, and targeted screening (testing of specific student populations in situations of increased transmission risk). During September 30-November 30, 2020, UT Austin students participated in tests for SARS-CoV-2, which resulted in the detection of 401 unique student cases of COVID-19 from among 32,401 tests conducted.† Among students who participated in one targeted screening program for students attending campus events, 18 (37.5%) of 48 infected students were asymptomatic at the time of their positive test result compared with 45 (23%) of 195 students identified through community testing and nine (5.8%) of 158 students identified through clinic-based testing. Targeted screening also identified a different population of students than did clinic-based and community testing programs. Infected students tested through targeted screening were more likely to be non-Hispanic White persons (chi square = 20.42; p<0.03), less likely to engage in public health measures, and more likely to have had interactions in settings where the risk for SARS-CoV-2 transmission is higher, such as restaurants, gyms, and residence halls. In addition to clinic-based SARS-CoV-2 testing at colleges and universities, complementary testing programs such as community and targeted screening might enhance efforts to identify and control SARS-CoV-2 transmission, especially among asymptomatic persons and disproportionately affected populations that might not otherwise be reached.

Antibody Status, Disease History, and Incidence of SARS-CoV-2 Infection Among Patients on Chronic Dialysis.

BACKGROUND: Although reinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is rare among individuals with few coronavirus disease 2019 (COVID-19) risk factors, the ability of naturally acquired immunity to prevent reinfection among patients with ESKD is not known. METHODS: This prospective study was conducted among adults with ESKD treated with in-center hemodialysis (ICHD) in the United States. Exposure was ascribed on the basis of the presence or absence of IgG against SARS-CoV-2 at baseline, and separately, a history of documented COVID-19 before study entry. Outcomes were assessed after an infection-free period, and were any SARS-CoV-2 infection (i.e., detected by protocolized PCR tests or during routine clinical surveillance), and clinically manifest COVID-19 (consisting of only the latter). RESULTS: Of 2337 consented participants who met study inclusion criteria, 9.5% were anti-SARS-CoV-2 IgG positive at baseline; 3.6% had a history of COVID-19. Over 6679 patient-months of follow-up, 263 participants had evidence of any SARS-CoV-2 infection, including 141 who had clinically manifest COVID-19. Presence of anti-SARS-CoV-2 IgG (versus its absence) at baseline was associated with lower risk of any SARS-CoV-2 infection (incidence rate ratio, 0.55; 95% confidence interval, 0.32 to 0.95) and clinically manifest COVID-19 0.21 (95% confidence interval, 0.07 to 0.67). CONCLUSION: Among patients with ESKD, naturally acquired anti-SARS-CoV-2 IgG positivity is associated with a 45% lower risk of subsequent SARS-CoV-2 infection, and a 79% lower risk of clinically manifest COVID-19. Because natural immunity is incomplete, patients with ESKD should be prioritized for SARS-CoV-2 vaccination, independent of their COVID-19 disease history.

SARS-CoV-2 Antibody Seroprevalence Among Maintenance Dialysis Patients in the United States.

RATIONALE & OBJECTIVE: Reported coronavirus disease 2019 (COVID-19) cases underestimate the actual number of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Patients receiving maintenance dialysis are at high risk for COVID-19 and higher case rates have been reported relative to the general population. To better understand infection patterns, we performed a seroprevalence study among maintenance dialysis patients at a large dialysis organization in the United States. STUDY DESIGN: Cross-sectional. SETTING & PARTICIPANTS: We measured immunoglobulin G antibodies in an institutional review board-approved study of remnant serum samples collected for routine laboratory screenings in a national sample of 12,932 maintenance dialysis patients (May 27 to July 1, 2020). EXPOSURE: State, sex, age, and race. OUTCOMES: Seropositivity; ratio of seropositivity to known COVID-19 case rate. ANALYTIC APPROACH: Seropositivity was calculated overall and by state, sex, age, and race. The ratio of seropositivity to known COVID-19 cases was calculated overall and by state. RESULTS: 747 (5.8%) samples were seropositive. Seroprevalence varied by state and was lowest in Kentucky (1.0%) and highest in New York (23.6%). Seroprevalence was similar among men and women. Among samples from patients younger than 70 years, 6.0% to 6.5% were seropositive; whereas 5.2% and 3.9% of samples from patients aged 70 to 79 and 80 years or older, respectively, were seropositive. Samples from Black and Hispanic patients were 7.3% and 7.7% positive, respectively, compared with 2.8% of samples from White patients. After adjustment, risk differences among racial groups were lower but not eliminated. During the study period, the known COVID-19 case rate was 3.3%. The ratio of seropositivity to known COVID-19 cases was 1.7. LIMITATIONS: Imperfect assay sensitivity; results represent infections occurring before July 2020; deidentification prevented comparison of antibodies to previous COVID-19 status for individual patients; may not generalize to patients dialyzing with other providers or in other countries. CONCLUSIONS: Seroprevalence was 5.8% among dialysis patients as of July 1, 2020. This indicates that the actual number of infections was 1.7 times greater than reported cases. This ratio is lower than reported in the general population, suggesting that there were fewer unknown infections among maintenance dialysis patients.