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1.
PLoS Global Public Health ; 2(8), 2022.
Article in English | CAB Abstracts | ID: covidwho-2039233

ABSTRACT

Comprehensive data on transmission mitigation behaviors and both SARS-CoV-2 infection and serostatus are needed from large, community-based cohorts to identify COVID-19 risk factors and the impact of public health measures. We conducted a longitudinal, population-based study in the East Bay Area of Northern California. From July 2020-March 2021, approximately 5,500 adults were recruited and followed over three data collection rounds to investigate the association between geographic and demographic characteristics and transmission mitigation behavior with SARS-CoV-2 prevalence. We estimated the populated-adjusted prevalence of antibodies from SARS-CoV-2 infection and COVID-19 vaccination, and self-reported COVID-19 test positivity. Population-adjusted SARS-CoV-2 seroprevalence was low, increasing from 1.03% (95% CI: 0.50-1.96) in Round 1 (July-September 2020), to 1.37% (95% CI: 0.75-2.39) in Round 2 (October-December 2020), to 2.18% (95% CI: 1.48-3.17) in Round 3 (February-March 2021). Population-adjusted seroprevalence of COVID-19 vaccination was 21.64% (95% CI: 19.20-24.34) in Round 3, with White individuals having 4.35% (95% CI: 0.35-8.32) higher COVID-19 vaccine seroprevalence than individuals identifying as African American or Black, American Indian or Alaskan Native, Asian, Hispanic, two or more races, or other. No evidence for an association between transmission mitigation behavior and seroprevalence was observed. Despite >99% of participants reporting wearing masks individuals identifying as African American or Black, American Indian or Alaskan Native, Asian, Hispanic, two or more races, or other, as well as those in lower-income households, and lower-educated individuals had the highest SARS-CoV-2 seroprevalence and lowest vaccination seroprevalence. Results demonstrate that more effective policies are needed to address these disparities and inequities.

2.
Embase; 2022.
Preprint in English | EMBASE | ID: ppcovidwho-338254

ABSTRACT

To inform public health policy, it is critical to monitor COVID-19 vaccine effectiveness (VE), including against acquiring infection. We estimated VE using a retrospective cohort study among repeat blood donors who donated during the first half of 2021, demonstrating a viable approach for monitoring of VE via serological surveillance. Using Poisson regression, we estimated overall VE was 88.8% (95% CI: 86.2–91.1), adjusted for demographic covariates and variable baseline risk. Time since first reporting vaccination, age, race-ethnicity, region, and calendar time were statistically significant predictors of incident infection. Studies of VE during periods of Delta and Omicron spread are underway.

3.
PubMed; 2021.
Preprint in English | PubMed | ID: ppcovidwho-333856

ABSTRACT

Early in the SARS-CoV-2 pandemic, there was a high level of optimism based on observational studies and small controlled trials that treating hospitalized patients with convalescent plasma from COVID-19 survivors (CCP) would be an important immunotherapy. However, as more data from controlled trials became available, the results became disappointing, with at best moderate evidence of efficacy when CCP with high titers of neutralizing antibodies was used early in infection. To better understand the potential therapeutic efficacy of CCP, and to further validate SARS-CoV-2 infection of macaques as a reliable animal model for testing such strategies, we inoculated 12 adult rhesus macaques with SARS-CoV-2 by intratracheal and intranasal routes. One day later, 8 animals were infused with pooled human CCP with a high titer of neutralizing antibodies (RVPN NT 50 value of 3,003), while 4 control animals received normal human plasma. Animals were monitored for 7 days. Animals treated with CCP had detectable levels of antiviral antibodies after infusion. In comparison to the control animals, they had similar levels of virus replication in the upper and lower respiratory tract, but had significantly reduced interstitial pneumonia, as measured by comprehensive lung histology. By highlighting strengths and weaknesses, data of this study can help to further optimize nonhuman primate models to provide proof-of-concept of intervention strategies, and guide the future use of convalescent plasma against SARS-CoV-2 and potentially other newly emerging respiratory viruses. AUTHOR SUMMARY: The results of treating SARS-CoV-2 infected hospitalized patients with COVID-19 convalescent plasma (CCP), collected from survivors of natural infection, have been disappointing. The available data from various studies indicate at best moderate clinical benefits only when CCP with high titer of neutralizing antibodies was infused early in infection. The macaque model of SARS-CoV-2 infection can be useful to gain further insights in the value of CCP therapy. In this study, animals were infected with SARS-CoV-2 and the next day, were infused with pooled human convalescent plasma, selected to have a very high titer of neutralizing antibodies. While administration of CCP did not result in a detectable reduction in virus replication in the respiratory tract, it significantly reduced lung inflammation. These data, combined with the results of monoclonal antibody studies, emphasize the need to use products with high titers of neutralizing antibodies, and guide the future development of CCP-based therapies.

4.
Embase; 2021.
Preprint in English | EMBASE | ID: ppcovidwho-330468

ABSTRACT

Comprehensive data on transmission mitigation behaviors and both SARS-CoV-2 infection and serostatus are needed from large, community-based cohorts to identify COVID-19 risk factors and the impact of public health measures. From July 2020-March 2021, approximately 5,500 adults from the East Bay Area, California were followed over three data collection rounds to investigate the association between geographic and demographic characteristics and transmission mitigation behavior with SARS-CoV-2 prevalence. We estimated the populated-adjusted prevalence of antibodies from SARS-CoV-2 infection and COVID-19 vaccination, and self-reported COVID-19 test positivity. Population-adjusted SARSCoV-2 seroprevalence was low, increasing from 1.03% (95% CI: 0.50-1.96) in Round 1 (July-September 2020), to 1.37% (95% CI: 0.75-2.39) in Round 2 (October-December 2020), to 2.18% (95% CI: 1.48-3.17) in Round 3 (February-March 2021). Population-adjusted seroprevalence of COVID-19 vaccination was 21.64% (95% CI: 19.20-24.34) in Round 3, with Whites having 4.35% (95% CI: 0.35-8.32) higher COVID-19 vaccine seroprevalence than non-Whites. No evidence for an association between transmission mitigation behavior and seroprevalence was observed. Despite >99% of participants reporting wearing masks, non-Whites, lower-income, and lower-educated individuals had the highest SARS-CoV-2 seroprevalence and lowest vaccination seroprevalence. Results demonstrate that more effective policies are needed to address these disparities and inequities.

5.
PubMed; 2020.
Preprint in English | PubMed | ID: ppcovidwho-296875

ABSTRACT

We report very low SARS-CoV-2 seroprevalence in two San Francisco Bay Area populations. Seropositivity was 0.26% in 387 hospitalized patients admitted for non-respiratory indications and 0.1% in 1,000 blood donors. We additionally describe the longitudinal dynamics of immunoglobulin-G, immunoglobulin-M, and in vitro neutralizing antibody titers in COVID-19 patients. Neutralizing antibodies rise in tandem with immunoglobulin levels following symptom onset, exhibiting median time to seroconversion within one day of each other, and there is >93% positive percent agreement between detection of immunoglobulin-G and neutralizing titers.

6.
PUBMED; 2021.
Preprint in English | PUBMED | ID: ppcovidwho-293448

ABSTRACT

Serosurveys are a key resource for measuring SARS-CoV-2 cumulative incidence. A growing body of evidence suggests that asymptomatic and mild infections (together making up over 95% of all infections) are associated with lower antibody titers than severe infections. Antibody levels also peak a few weeks after infection and decay gradually. We developed a statistical approach to produce adjusted estimates of seroprevalence from raw serosurvey results that account for these sources of spectrum bias. We incorporate data on antibody responses on multiple assays from a post-infection longitudinal cohort, along with epidemic time series to account for the timing of a serosurvey relative to how recently individuals may have been infected. We applied this method to produce adjusted seroprevalence estimates from five large-scale SARS-CoV-2 serosurveys across different settings and study designs. We identify substantial differences between reported and adjusted estimates of over two-fold in the results of some surveys, and provide a tool for practitioners to generate adjusted estimates with pre-set or custom parameter values. While unprecedented efforts have been launched to generate SARS-CoV-2 seroprevalence estimates over this past year, interpretation of results from these studies requires properly accounting for both population-level epidemiologic context and individual-level immune dynamics.

10.
Transfusion ; 60(SUPPL 5):276A-277A, 2020.
Article in English | EMBASE | ID: covidwho-1044277

ABSTRACT

Background/Case Studies: Blood donor based serosurveillance is a convenient and cost-effective strategy to monitor the extent of the COVID-19 pandemic and allows the detection of asymptomatic and recovered cases. The RESPONSE (REDS-IV-P Epidemiology, Surveillance and Preparedness of the Novel SARS-CoV-2 Epidemic) study conducted monthly cross-sectional serosurveys of 1000 routinely obtained donor samples in 6 metropolitan regions (see table). Study Design/Methods: Samples were captured monthly from March or April through June 2020. Siteswere selected based on reports of epidemic activity or as low prevalence control regions. Donations from COVID- 19 convalescent plasma donors were excluded. Coded samples, with routinely collected demographic data and zip code of residence, were tested for SARS-CoV-2 antibodies using the Ortho VITROS anti-SARS-CoV-2 S1 Total Ig (data reported below) with planned confirmation of reactivity on Roche Elecsys® NC Anti-SARS-CoV-2 and a pseudovirus-based neutralization assay. Results/Findings: Table 1 shows donor seroreactivity with 95% CI. For all sites, seroreactivity was <1.0% (range 0.1%-0.9%) at the beginning of the surveillance period. Donor seroreactivity in New York City (NYC) was about 10-fold higher in April through June as compared to March and was much higher than in other locations. There were modest increases in seroreactivity over the study timeframe for all other sites. Conclusions: Modest increases in seroreactivity from baseline were found in all sites, with the largest increase in NYC. SARS-CoV-2 antibody testing of routinely obtained blood donor samples allows for detection of asymptomatic and recovered COVID-19 cases and enables future estimation of infection incidence by geographic and other demographic parameters. This approach will be used in a significantly expanded CDC National serosurveillance study involving all 50 states over 18 months.

11.
Transfusion ; 60(SUPPL 5):278A, 2020.
Article in English | EMBASE | ID: covidwho-1043232

ABSTRACT

Background/Case Studies: The efficacy of COVID-19 convalescent plasma (CCP) to treat COVID-19 is hypothesized to be associated with the concentration of neutralizing antibodies (nAb) to SARS-CoV-2. While high capacity, automated serologic assays to detect binding antibodies (bAb) have been developed, complex nAb assays are not easily adaptable to high-throughput testing. We sought to determine the effectiveness of using surrogate bAb signalto- cutoff ratio (S/CO) in predicting nAb titers using a pseudovirus reporter viral neutralization (RVPN) assay. Study Design/Methods: CCP donor serum collected by 3 large US blood collectors was tested with a bAb assay (Ortho Diagnostic VITROS® Anti-SARS-CoV-2 Total, CoV2T) and a nAb RVPN assay. Although EUA approved as a qualitative assay, CoV2T reports a semi-quantitative S/CO. The RVPN assay uses a pseudovirus construct with native S-protein and target cell lines overexpressing ACE2 receptor and TMPRSS2 protease. Serially diluted serum is mixed with SARS-CoV-2 pseudovirus to assess inhibition of viral entry in culture and reported as titers resulting in 50% neutralization of virus infectivity (NT50) by nonlinear regression analysis. CoV2T prediction effectiveness at several S/CO thresholds was evaluated for various RVPN nAb NT50 titers using receiver operating characteristic analysis. Results/Findings: 753 CCP donations were tested with median CoV2T S/CO of 71.2 (range 0.1-919) and median NT50 of 527.5 (range <40 to >10,240). The prevalence of CCP donors with NT50 over various target n-Ab titers were 86% >80, 76% >160, and 45% >640. Increasing CoV2T reactivity threshold reduces sensitivity to predict the target NT50 titer while specificity to identify those below nAb threshold increases for all targeted NT50s (Table 1). As the targeted NT50 is increased from >80 to >640, the positive predictive value falls dramatically while the negative predictive value increases, thus S/CO thresholds are less able to predict donors who have the target NT50 titer but more able to predict those donors who do not meet it. Conclusions: The selection of targeted nAb titer for clinical use will significantly impact availability of CCP for transfusion. Product release with CoV2T assay S/CO thresholds must balance the risk of releasing products below minimum target nAb titer and the cost of false negatives (CCP units below the threshold with adequate nAb titers). A two-step testing scheme may be optimal, with nAb testing performed on CoV2T reactive samples with S/CO values below the release threshold.

12.
Transfusion ; 60(SUPPL 5):276A, 2020.
Article in English | EMBASE | ID: covidwho-1041123

ABSTRACT

Background/Case Studies: SARS-CoV-2 RNA has been detected by PCR in plasma, serum or whole blood specimens from hospitalized patients in studies from multiple countries. For asymptomatic individuals, several reports have described detection of SARS-CoV-2 RNA in plasma in a small number of blood donors, whereas other reports showed no detection of SARS-CoV-2 RNA in whole blood, serum or plasma from asymptomatic individuals including blood donors. No cases of transfusion-transmission of SARS-CoV-2 (or other human coronaviruses) have been reported, nor has virus been isolated from blood samples by tissue culture. We tested residual volumes of donor plasma from mini-pools (MPs) used for routine nucleic acid testing (NAT) screening to determine the frequency of SARS-CoV-2 RNAemia in blood donors in six US metropolitan regions (New York, Seattle, San Francisco, Los Angeles, Boston, Minneapolis). Study Design/Methods: Blood donations collected from 7 March 2020 to 30 June 2020 were tested for SARS-CoV-2 RNA. Donations were tested in plasma MPs of 6 or 16 donations (MP16 format for five regions and MP6 format for Seattle), targeting 500 MPs per region per month, using the Grifols Procleix SARS-CoV-2 transcriptionmediated amplification (TMA) assay on the Procleix Panther system. The test has a 95% limit of detection (LOD) of 16.5 copies/mL (95% CI, 12.8 to 23.6 copies/mL) by probit analysis. A confirmed positive result was defined by the detection of viral RNA upon repeat testing using the same assay and an alternate target region TMA assay (Grifols SARS-CoV-2 confirmatory TMA assay) with comparable sensitivity. Positive MPs were further tested using the Ortho VITROS anti-SARS-CoV-2 Total Ig test to detect antibodies and diluted 4-fold and tested using the Procleix SARS-CoV-2 TMA assay to determine whether the viral load was close to the 95% LOD. Results/Findings: A total of 8,496 MPs16 and 1,998 MPs 6, corresponding to ∼147,000 blood donations, were tested for SARS-CoV-2 RNA. One confirmed positive MP16 sample from a March donation in San Francisco was identified (0.0007% [95% CI 0.000035-0.004%]). The MP was negative for antibody and nonreactive when diluted 4-fold, suggesting a viral load below 1,000 RNA copies/mL in the individual donation. Conclusions: Blood donation MP-NAT indicated that SARS-CoV-2 RNAemia is rare, and when detected the RNA was at low concentration. Although future studies to determine the infectivity of RNA-positive plasma are warranted and in progress, these findings are reassuring with respect to transfusion safety and support current recommendations from WHO and regulatory agencies to not screen donors by NAT.

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