Risk factors and titers of COVID-19 infection in a longitudinal statewide seroepidemiology cohort

BACKGROUND

Virginia is a large state in the USA, yet it remains unclear what percentage of the population has had natural COVID-19 infection and whether risk factors for infection have changed over time.

METHODS

Using a longitudinal cohort, from December 2021-July 2022 we performed follow up serology and a questionnaire on 784 individuals from across Virginia who had previously participated in a statewide COVID-19 seroepidemiology study in 2020. Children were also invited to participate and an additional 62 children also completed the study. Serology was performed using Roche nucleocapsid and spike serological assays.

RESULTS

The majority of participants were white (78.6%), over 50 years old (60.9%), and reported having received COVID-19 vaccine (93.4%). 28.6% had evidence of prior COVID-19 infection (nucleocapsid positive). Reweighted by region, age, and sex to match the Virginia census data, the seroprevalence of nucleocapsid antibodies was estimated to be 30.6% (95% CI: 24.7, 36.6). We estimated that 25-53% of COVID-19 infections were asymptomatic. Infection rates were lower in individuals > 60 years old and were higher in Blacks and Hispanics. Infection rates were also higher in those without health insurance, in those with greater numbers of household children, and in those that reported a close contact or having undergone quarantine for COVID-19. Participants from Southwest Virginia had lower seropositivity (16.2%, 95% CI 6.5, 26.0) than other geographic regions. Boosted vaccinees had lower infection rates than non-boosted vaccinees. Frequenting indoor bars was a risk factor for infection, while frequently wearing an N95 mask was protective, though the estimates of association were imprecise. Infection rates were higher in children than adults (56.5% vs. 28.6%). Infection in the parent was a risk factor for child infection. Spike antibody levels declined with time since last vaccination, particularly in those that were vaccinated but not previously infected. Neutralizing antibody positivity was high (97-99%) for wild type, alpha, beta, gamma, delta, and omicron variants. Neutralizing antibody levels were higher in the follow-up survey compared to the first survey in 2020 and among individuals with evidence of natural infection compared to those without.

CONCLUSIONS

In this longitudinal statewide cohort we observed a lower-than-expected COVID-19 infection rate as of August 2022. Boosted vaccinees had lower infection rates. Children had higher infection rates and infections tracked within households. Previously identified demographic risk factors for infection tended to persist. Even after the omicron peak, a large number of Virginians remain uninfected with COVID-19, underscoring the need for ongoing vaccination strategies.

Assessment of Seroprevalence of SARS-CoV-2 and Risk Factors Associated With COVID-19 Infection Among Outpatients in Virginia

Importance

Data from seroepidemiologic surveys measuring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure in diverse communities and ascertaining risk factors associated with infection are important to guide future prevention strategies.

Objective

To assess the prevalence of previous SARS-CoV-2 infection across Virginia and the risk factors associated with infection after the first wave of coronavirus disease 2019 (COVID-19) infections in the US.

Design, Setting, and Participants

In this statewide cross-sectional surveillance study, 4675 adult outpatients presenting for health care not associated with COVID-19 in Virginia between June 1 and August 14, 2020, were recruited to participate in a questionnaire and receive venipuncture to assess SARS-CoV-2 serology. Eligibility was stratified to meet age, race, and ethnicity quotas that matched regional demographic profiles.

Main Outcomes and Measures

The main outcome was SARS-CoV-2 seropositivity, as measured by the Abbott SARS-CoV-2 immunoglobulin G assay.

Results

Among 4675 adult outpatients (mean [SD] age, 48.8 [16.9] years; 3119 women [66.7%]; 3098 White [66.3%] and 4279 non-Hispanic [91.5%] individuals) presenting for non-COVID-19-associated health care across Virginia, the weighted seroprevalence was 2.4% (95% CI, 1.8%-3.1%) and ranged from 0% to 20% by zip code. Seroprevalence was notably higher among participants who were Hispanic (10.2%; 95% CI, 6.1%-14.3%), residing in the northern region (4.4%; 95% CI, 2.8%-6.1%), aged 40 to 49 years (4.4%; 95% CI, 1.8%-7.1%), and uninsured (5.9%; 95% CI, 1.5%-10.3%). Higher seroprevalence was associated with Hispanic ethnicity (adjusted odds ratio [aOR], 3.56; 95% CI, 1.76-7.21), residence in a multifamily unit (aOR, 2.55; 95% CI, 1.25-5.22), and contact with an individual with confirmed COVID-19 infection (aOR, 4.33; 95% CI, 1.77-10.58). The sensitivity of serology results was 94% (95% CI, 70%-100%) among those who reported receiving a previous polymerase chain reaction test for COVID-19 infection. Among 101 participants with seropositive results, 67 individuals (66.3%) were estimated to have asymptomatic infection. These data suggested a total estimated COVID-19 burden that was 2.8-fold higher than that ascertained by PCR-positive case counts.

Conclusions and Relevance

This large statewide serologic study estimated that 2.4% of adults in Virginia had exposure to SARS-CoV-2, which was 2.8-fold higher than confirmed case counts. Hispanic ethnicity, residence in a multifamily unit, and contact with an individual with confirmed COVID-19 infection were significant risk factors associated with exposure. Most infections were asymptomatic. As of August 2020, the population in Virginia remained largely immunologically naive to the virus.

Fluorene-containing tetraphenylethylene molecules as lasing materials

A series of star‐shaped oligofluorene molecules, each containing a TPE core, have been specifically designed and produced to show effective aggregation‐induced emission (AIE). Each molecule differs either in the number of fluorene units within the arms (e.g., 1 or 4, compounds 4 and 5), or the terminal group positioned at the end of each arm (e.g., H, TMS, or TPA, compounds 4, 6, and 7). Although they are all poor emitters in solution phase they become efficient yellow‐green luminogens in the condensed state. Their AIE properties were investigated in THF/H₂O mixtures, with each molecule exhibiting a clear emission enhancement at specific water contents. An all‐organic distributed feedback (DFB) laser was fabricated using compound 4 as the gain material and exhibited an average threshold energy fluence of 60 ± 6 μJ/cm² and emission in the green region. Furthermore, piezofluorochromism studies on a thin film of this material displayed a linear dependence of the amplified spontaneous emission (ASE) peak position on applied pressure, indicating potential applications as lasing‐based pressure sensors. © 2016 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 734–746

Development of cell-based immunoassays to measure type I collagen in cultured fibroblasts

Excessive deposition of type I collagen by activated fibroblasts is a hallmark of scarring and fibrotic pathologies. Quantitation of collagen I at the protein level is paramount to measure functionally relevant changes during pathological remodeling of the extracellular matrix. We describe two new cell-based assays to directly quantify the amount of collagen I incorporated into the extracellular matrix of primary human lung fibroblasts. Utilizing a monoclonal antibody specific to native human collagen I, we optimized conditions and parameters including incubation time, specificity and cell density to demonstrate dose-dependent induction of collagen I by transforming growth factor beta, as measured by in-cell enzyme linked immunosorbent assay. The results obtained by this assay were mimicked by an "In situ Quantitative Western Blot" on cultured cells using the same antibody. Results from these assays were comparable to those obtained with a commercial assay for collagen I N-propeptide, which is an index of collagen formation. These assays have been optimized for a 96-well format and provide a novel and useful approach for screening of anti-fibrotic agents in vitro. The assays described here also offer a significant improvement in throughput and specificity over conventional methods that primarily measure soluble collagen.

Potential involvement of BMP receptor type IB activation in a synergistic effect of chondrogenic promotion between rhTGFbeta3 and rhGDF5 or rhBMP7 in human mesenchymal stem cells

Chondrogenic promotion by rhGDF5 with or without rhTGFbeta3 was studied in pellet culture of human mesenchymal stem cells (HMSCs). A synergy between rhGDF5 and rhTGFbeta3 was observed in promoting chondrogenesis. rhBMP2, rhBMP6, rhBMP7 and rhTGFbeta1 were further tested and showed the same effect. To explore the mechanism, the expression of TGFbetatype I and II receptors, ALK5, ALK2, ALK3, ALK6, TGFbetaRII, BMPRII, ActRII was studied. ALK6 showed increase by the rhTGFbeta1 or rhTGFbeta3 treatment. ALK6 protein expression also showed increase by rhTGFbeta3. rhTGFbeta1/rhTGFbeta3 induced ALK6 up-regulation was inhibited by SD-208, a TGFbeta type I receptor inhibitor. Chondrogenesis by rhTGFbetal/rhTGFbeta3 or the combination between rhTGFbetal/rhTGFbeta3 and rhGDF5 also was diminished by SD-208. SMAD1/5/8 phosphorylation in nascent human mesenchymal stem cells (HMSCs) was stimulated weakly by rhGDF5 but strongly by rhBMP7. The rhGDF5 stimulated SMAD1/5/8 phosphorylation was enhanced by rhTGFbetal/rhTGFbeta3 but inhibited by SD-208. The rhBMP7 stimulated SMAD1/5/8 phosphorylation did not show influence by rhTGFbeta3 and SD-208. Our results indicated the potential involvement of ALK6 activation by rhTGFbetas in the synergy between rhTGFbetas and rhBMPs.

The pharmacokinetics of erythropoietin in the cerebrospinal fluid after intravenous administration of recombinant human erythropoietin

OBJECTIVES

Erythropoietin (EPO) was originally described as a regulator of erythropoiesis. Recently, synthesis of EPO and expression of the EPO receptor (EPO-R) have been reported for the central nervous system (CNS). The potential use of EPO to prevent or reduce CNS injury and the paucity of information regarding its entry into the human CNS led us to examine the pharmacokinetics (PK) of recombinant human EPO (r-HuEPO) in the serum and cerebrospinal fluid (CSF).

METHODS

Four patients with Ommaya reservoirs were enrolled to facilitate serial CSF sampling. R-HuEPO was given intravenously (IV) in single doses of 40,000 IU or 1,500 IU/kg and in multiple doses of 40,000 IU daily for 3 days.

RESULTS

The EPO concentrations in the CSF increased after a period of slow equilibration. Linear first-order distribution kinetics were observed for serum and CSF. The concentration of EPO in the CSF was proportional to the serum concentration of EPO and the permeability of the blood-brain barrier (BBB), as determined by the albumin quotient (QA=[albumin] CSF/[albumin] serum). A rise in the CSF concentration was seen as early as 3 h after IV administration. Peak levels (C(max)) were reached between 9 h and 24 h. After a single dose of 1,500 IU/kg, the Cmax in the CSF ranged from 11 mIU/ml to 40 mIU/ml, and the ratios of CSF/serum Cmax ranged from 3.6x10-4 to 10.2x10-4. The terminal half-life (t1/2) values of EPO in serum and CSF were similar. The t(1/2) of r-HuEPO in the CSF ranged from 25.6 h to 35.5 h after a single dose of 1,500 IU/l. Using these parameters a PK model was generated that predicts the concentration-time profile of EPO in the CSF.

CONCLUSIONS

We report that r-HuEPO can cross the human BBB and describe for the first time the PK of EPO in the CSF after IV administration. Our data suggest that the concentration-time profile of EPO in the CSF can be predicted for individual patients if the serum concentration of EPO and the Q(A) are known. This information may be useful in the design of clinical trials to explore the potential therapeutic effects of EPO during CNS injury.

The Erythropoietin Receptor and Its Expression in Tumor Cells and Other Tissues

Erythropoietin (EPO) is the primary regulator of erythropoiesis, stimulating growth, preventing apoptosis, and promoting differentiation of red blood cell progenitors. The EPO receptor belongs to the cytokine receptor superfamily. Although the primary role of EPO is the regulation of red blood cell production, EPO and its receptor have been localized to several nonhematopoietic tissues and cells, including the central nervous system (CNS), endothelial cells, solid tumors, the liver, and the uterus. The presence of EPO receptors and the possibility of EPO signaling in these tissues and cells have led to numerous studies of the effects of EPO at these sites. In particular, expression of EPO and the EPO receptor in cancer cells has generated much interest because of concern that administration of recombinant human erythropoietin (rHuEPO) to patients with breast and other cancer cells expressing the EPO receptor may promote tumor growth via the induction of cell proliferation or angiogenesis. However, evidence supporting a growth-promoting effect has been inconclusive. Moreover, several preclinical studies have shown a beneficial effect of EPO on delaying tumor growth. Further, it is conceivable that increased expression of EPO could reduce tumor hypoxia and ameliorate the deleterious effects of hypoxia on tumor growth, metastasis, and treatment resistance. On the other hand, EPO has also been shown to produce an angiogenic effect in vascular endothelial cells in vitro. However, there is no evidence that these effects occur in vivo to promote tumor growth. EPO and EPO receptors are expressed in neural tissue, and they are upregulated there by hypoxia. Animal studies have shown that administration of epoetin alfa (an rHuEPO) reduces tissue injury due to ischemic stroke, blunt trauma, and experimental autoimmune encephalomyelitis. These findings suggest that epoetin alfa may provide a therapeutic benefit in patients with stroke, trauma, epilepsy, and other CNS-related disorders. Clearly, further study of EPO and the EPO receptor in nonhematopoietic tissue is warranted to determine the potential therapeutic usefulness of rHuEPO as well as to determine the signaling pathway responsible for its effect in vivo.

Human recombinant erythropoietin significantly improves tumor oxygenation independent of its effects on hemoglobin

Tumor oxygenation is known to be an important predictive/prognostic marker in a variety of tumors, including cervix, head/neck, sarcoma, non-small cell of the lung, and breast. Tumor oxygenation is influenced by many interactions, including oxygen delivery (angiogenesis, permeability, and HgB) and consumption (metabolic and growth rates). This study randomized 30 nonanemic, female Fischer 344 rats into three treatment arms to examine the effects of recombinant human erythropoietin (EPO) on R3230 rodent mammary carcinoma oxygenation. The three treatment arms were: (a) placebo; (b) EPO after tumor implantation (2000 units/kg/SQdose, M/W/F for six doses); and (c) EPO before tumor implantation (2000 units/kg/SQdose, M/W/F for six doses). Tumors were implanted in the hindflank, and in vivo oxygenation was measured at day 22 after implantation using the Oxylite system (Oxford Optronix, Oxford, England). An average of 180 measurements/animal were performed. On day 22, median tumor volume was 399 mm(3) (range: 65-950 mm(3)), and no differences in tumor volume were seen between treatment arms. Mean hematocrit was equal between arms at therapy initiation but were significantly higher for both arms receiving EPO at day 22 (placebo versus Arm B versus Arm C; Wilcoxon P = 0.052). EPO-treated tumors had significantly less hypoxic measurements when compared with either the placebo or those receiving EPO before implantation. These data confirm that tumor oxygenation in nonanemic individuals may be improved through the administration of EPO, and this improvement appears to be independent of HgB effects.

Pharmacokinetic and pharmacodynamic modeling of recombinant human erythropoietin after intravenous and subcutaneous dose administration in cynomolgus monkeys

The pharmacokinetics (PK) and pharmacodynamics (PD) of recombinant human erythropoietin (rHuEpo) were investigated in monkeys. A two-compartment model with dual input and nonlinear disposition could adequately characterize the PK of rHuEpo upon three intravenous and six s.c. administrations. The kinetic model suggests rapid zero-order absorption of part of the s.c. dose (35%) followed by a slow first-order entry through the lymphatics. The s.c. treatments caused a delayed dose-dependent rise in reticulocyte numbers peaking between 100 and 200 h and returning to baseline by 300 to 400 h. This was followed by steady rises in red blood cell (RBC) and hemoglobin counts. A physiological catenary model based on a life span concept with rHuEpo stimulating the production of two cell populations (progenitor cells and erythroblasts) was applied. The model could adequately describe the reticulocyte responses upon the various s.c. treatments, giving estimates of maturation times for cells in the various stages of differentiation including the early progenitor cells (70.4 h), erythroblasts (15.0 h), and reticulocytes (141.6 h) that are close to the literature reported values. An Smax of 3.13 was estimated indicating a moderate maximum stimulation of erythropoiesis, whereas the SC50 was 842 IU/l. The model was used to effectively predict the increases in RBC and hemoglobin counts as well. In conclusion, the physiological PK/PD model developed could adequately describe the time course of rHuEpo effects, yielding realistic estimates of cell life span parameters.

The effect of cumulative dosing on the analgesic potency of morphine in mice

Opioid analgesic potency can be evaluated using cumulative dosing, in which subjects are repeatedly administered a drug and tested after each dose until a criterion effect is reached. Although many laboratories use cumulative dosing, the effects of varying the starting dose and the magnitude of the increment dose on morphine analgesia (tail flick) in mice have not been evaluated. In experiment 1. mice were injected with the same starting dose [0.5 mg/kg subcutaneously (SC)] and 30 min later were tested for analgesia. Mice that were not analgesic were administered an increment dose (0.5, 1.0, 2.0, 2.5, or 3.0 mg/kg) and retested. The process was continued until all mice were analgesic. There was a significant effect of increment dose on morphine potency, with the relative potency increasing as the increment dose was increased. In experiment 2, different starting doses (0.5, 1.0, 2.0, or 3.0 mg/kg) were used with a constant increment dose of 1.0 mg/kg. There was a significant effect of starting dose on the potency of morphine, with the relative potency increasing as the starting dose increased. To determine if increment and starting dose affect tolerance estimates, mice were implanted SC with a 25- or 75-mg morphine or placebo pellet for 7 days and then tested using cumulative dose-response. Changes in the increment dose significantly affected the degree of tolerance for mice implanted with a 25-mg morphine pellet but not for mice implanted with a 75-mg morphine pellet. Changes in the starting dose did not significantly alter estimates of tolerance. Overall, these data indicate that the starting dose and increment dose can impact on morphine's potency determined by cumulative dosing protocols. Furthermore, estimates of tolerance can be affected by dosing parameters in the cumulative dosing protocol. These results suggest that cumulative dosing procedures should be standardized across experiments.

Phosphorylation of a Ras-related GTP-binding protein, Rap-1b, by a neuronal Ca2+/calmodulin-dependent protein kinase, CaM kinase Gr

A neuron-specific Ca2+/calmodulin-dependent protein kinase, CaM kinase Gr, phosphorylates selectively a Ras-related GTP-binding protein (Rap-1b) that is enriched in brain tissue. The phosphorylation reaction achieves a stoichiometry of about 1 and involves a serine residue near the carboxyl terminus of the substrate. Both CaM kinase Gr and cAMP-dependent protein kinase, but not CaM kinase II, phosphorylate identical or contiguous serine residues in Rap-1b. The rate of phosphorylation of Rap-1b by CaM kinase Gr is enhanced following autophosphorylation of the protein kinase. Other low molecular weight GTP-binding proteins belonging to the Ras superfamily, including Rab-3A, Rap-2b, and c-Ha-ras p21, are not phosphorylated by CaM kinase Gr. The phosphorylation of Rap-1b itself can be reversed by an endogenous brain phosphoprotein phosphatase. These observations provide a potential connection between a neuronal Ca2(+)-signaling pathway and a specific low molecular weight GTP-binding protein that may regulate neuronal transmembrane signaling, vesicle transport, or neurotransmitter release.

Living until death: adolescents with cancer

The diagnosis and treatment of cancer in adolescents produce changes in their activities, relationships, and concerns. This case study explores these changes and formulates an approach to help such adolescents live meaningfully as they experience their illness.