A conceptual framework to model social determinants of COVID-19 vaccination uptake among underserved homeless populations

Background

 Homeless people have a higher risk of COVID-19 infection, linked to several social, economic and environmental determinants, frequent comorbidities, obstacles to exercising their constitutional social and health rights, poor medical cover, and insufficient use of the healthcare system. Data on COVID-19 vaccine uptake and its main determinants are lacking for this underserved population.

Objectives

 To construct and test a conceptual framework to model structural social determinants of COVID-19 vaccine uptake among underserved homeless populations, and to test this model to identify the determinants of COVID-19 vaccine uptake on the homeless population living in two metropolitan areas in France.

Methods

 We implemented a multicenter cross-sectional survey from 15/11/2021 to 22/12/2021 in homeless adults in the city of Marseille and in the greater Paris area. Persons sheltered in migrant worker hostels or in emergency social shelters, members of the COVID HOMELESS cohort study in Marseille, and Travelers living in traditional housing were all eligible. A standardized face-to-face questionnaire was administered to the participants where they lived in various languages by trained interviewers. We used structural equation modeling to analyze the structural social determinants of COVID-19 vaccine uptake, the latter defined as receiving at least one dose.

Results

 The participation rate was 64 %, accounting for 3811 participants. There were three main factors associated with greater vaccine uptake: i) opportunity, which included having a personal general practitioner (β = 0.05, p < 0.05), healthcare cover (β = 0.05, p < 0.05), and somebody to accompany the participant for medical appointments (β = -0.04, p < 0.05); ii) motivation, which included attitudes towards vaccination (β = 0.55, p < 0.05), press- and poster-based information (β = 0.03, p < 0.05), and vaccination history (β = 0.03, p < 0.05); iii) type of housing (β = 0.13, p < 0.05) and housing stability (β = 0.04, p < 0.05).

Conclusion

 Our results highlight that housing exclusion is a structural social determinant of COVID-19 vaccine uptake in homeless people in France. They also underline the role which opportunity and motivation play in improving uptake in this underserved homeless population.

Factors associated with vaccine adherence among an underserved population: the adult Travellers in Nouvelle-Aquitaine, France

BACKGROUND

A measles epidemic affected the Nouvelle-Aquitaine region from November 2017 to May 2018 with clusters among Travellers. This indicates that measles vaccination rates among Travellers remain lower than in the general population. The objective of this study was to estimate the 'declarative vaccination' against measles, mumps and rubella (MMR) and to propose a conceptual framework to help identify determinants of MMR vaccination uptake among adult Travellers in Nouvelle-Aquitaine in 2019-20.

METHODS

A cross-sectional study using random sampling was performed and included 612 adult Travellers from 1 November 2019 to 31 March 2020. A conceptual framework to model vaccination adherence was tested among this underserved population by using structural equation modelling. This model included five latent variables: health literacy, attitudes toward preventive measures, stigma, accessibility to care and perceived needs and five measured variables: information received on vaccination, perception of barriers, support for administrative documents, social support and housing conditions.

RESULTS

Individuals who did not answer all the questions linked to the variables included in the model were excluded, thus 347 adults were included in the final sample. The declared vaccination rate against MMR was 74.0%, and 72.4% of the participants were favorable to vaccination. Vaccination adherence was significantly correlated with favorable attitudes toward preventive measures such as having a history of MMR vaccination and not having already refused a recommended vaccine and finally satisfactory information received on vaccination.

DISCUSSION

To improve vaccination adherence, health authorities should lean on personal history with vaccination and on transmitting information on vaccination.

Health status, healthcare use and child MMR vaccination coverage in Travellers according to their environmental and living conditions in Nouvelle-Aquitaine, France, 2019-2022

BACKGROUND

The poor health status of underserved populations is compounded by low vaccination uptake, leading to a greater risk of epidemics. On October 2017, a measles outbreak started in the southwest of France among under-vaccinated social groups, including Travellers. We aimed to describe the health status, healthcare use and child measles-mumps-rubella (MMR) vaccination coverage in Travellers according to their environmental and living conditions.

METHODS

A cross-sectional study with a three-stage random sample design was conducted between October 2019 and March 2022 in the Nouvelle-Aquitaine region in France. Trained social workers administered face-to-face questionnaires to collect data on adults and children. Anthropometric measurements, vaccination records and data using an environmental exposure questionnaire were also collected.

RESULTS

The participation rate was high (73.6%), with 1030 adults and 337 children included. Concerning the adults, 36.6% had obesity, 14.4% reported diabetes, 24.7% hypertension and 14.4% major depression. The prevalence of major depression was significantly higher in adults living in precarious and unauthorized housing than in those with adequate housing (19.8 vs. 14.7%, P = 0.03). With regard to children, 45.3% had full (i.e. 2-dose) MMR vaccination coverage at 24 months and 17.9% had obesity. Finally, 74.5% of the households experienced housing insecurity, and 22.2% did not have a supply of drinking water.

CONCLUSION

Traveller children and adults faced deleterious environmental and living conditions potentially affecting their health, healthcare use and vaccination coverage. These results demonstrate the need for urgent interventions for underserved populations which take into account their specific needs.

Activities at risk of lead exposure and lead poisoning in children of travellers' families in charente, France

Background

-A study to assess lead exposure of traveller children aged from 9 months to 18 years old was conducted in Charente-France between 2017 and 2019.

Methods

A face-to-face questionnaire was administered to each participating family (N = 78). Blood samples were collected, and in case of lead poisoning, an environmental survey of soil, dust and water samples was also performed.

Results

-Among the 100 children, they were 39 girls and 61 boys. Among them, 40 suffered from lead poisoning (Blood Lead Level ≥50 μg/L). Being a boy aged between 11 and 14 years old, and participating in lead exposure at-risk activities were significantly associated with higher mean blood lead level.

Conclusion

-The high levels of lead detected advocate the reinforcement of lead poisoning screening for all children in the traveller population.

Synthesis and biological evaluation of novel 2 (4`-hydroxynaphthyl) chromen-4-one as a CK2 inhibitor

Protein kinase CK2 is a potential drug target for many diseases including cancer, inflammatory disorders, Alzheimer's disease, Parkinson's disease and viral infections. Significant efforts have been made for the discovery of potent inhibitors of this enzyme. Herein, we report on the synthesis, characterization, and biological evaluation of novel flavonoid compounds as CK2 inhibitors. The tested compounds were 2 (4`-hydroxynaphthyl) chromen-4-one which is a naphthyl backbone flavonoid with an IC50 value of 0.45±0.059 μM and 2(4-hydroxyphenyl)-4H-chromen-4-one a phenyl based derivative with an IC50 value of 0.33±0.048 μM. Cell viability was tested using MCF-7 cells. Both compounds were able to reduce the cell viability around 50 % in concentration of 100 μM after 48 h. Molecular modeling studies were performed to understand the binding mode of both compounds.

Computational prediction of new CYP17 inhibitors based on pharmacophore modeling, virtual screening and docking approach

17α-Hydroxylase/C17-20-lyase (P450 17, CYP 17) is an important enzyme in the androgen biosynthesis and inhibitors of this enzyme can be used for the treatment of prostate cancer. With the aim of developing new inhibitors for the target enzyme, we generated a structure-based pharmacophore model to further explain the binding requirements for human CYP17 inhibitors. Seven common features of steroidal CYP17 inhibitors were determined using MOE software. This pharmacophore model was then used to search the Cambridge Structural Database (CSD) with the aim of developing more potent and selective CYP17 inhibitors by identifying new hits. We were able to identify 36 structures as possible active CYP17 inhibitors. Docking studies for the selected compounds from the database were also performed and the best three compounds were chosen as possible hits.

Synthesis and biological evaluation of 2,6-di(furan-3-yl)anthracene-9, 10-dione as an inhibitor of human protein kinase CK2

Protein kinase CK2 is an emerging target for the therapeutic intervention in human diseases, in particular in cancer. Inhibitors of this enzyme are at current in clinical trials indicating its drug ability. Here we report on the synthesis of two derivatives of 2,6-diaryl-anthracene-9,10-dione, one of them, 2,6-di(furan-3-yl)anthracene-9,10-dione (3), turned out to be active towards CK2, and ATP competitive with an IC50 value of 2.35 μM and a K(i) value of 1.26 μM. Molecular modeling studies were performed to explain the binding affinity of compound 3 in comparison to emodin. These indicated that unlike emodin, compound 3 was not able to perform a hydrogen bond with Lys68, although the compound fits well in the active site of human CK2α, which explains the difference in the measured affinity between those two compounds.

Chlorpyrifos exposure and biological monitoring among manufacturing workers

AIM

To use biological monitoring data to evaluate the soundness of job based exposure classifications.

METHODS

The authors studied 52 chlorpyrifos manufacturing workers and 60 referent workers to compare chlorpyrifos exposure estimations from job titles and work areas to urinary excretion of 3,5,6 trichloro-2-pyridinol (TCP), a metabolite of chlorpyrifos. Work history records and industrial hygiene monitoring data were used to establish cumulative interim exposure. Chlorpyrifos exposure during the study year was assessed biologically by urinary excretion of TCP.

RESULTS

Exposure as measured by three urinary TCP samples was significantly higher among the chlorpyrifos workers (188 microg/l) than it was for the referent subjects (7 microg/l). Urinary TCP also correlated well with specific exposure categories of negligible (0.73-1.98 mg/m3 days), low (1.99-4.91 mg/m3 days), and moderate (4.92-15.36 mg/m3 days). The weighted Kappa coefficient was 0.80 (95% CI 0.72 to 0.87) for the mean TCP over the study period.

CONCLUSIONS

The estimates of chlorpyrifos exposure based on job classifications and industrial hygiene measurements were significantly related to urinary TCP excretion, indicating that the ambient estimates are useful for providing exposure estimates among chlorpyrifos manufacturing workers.

Synthesis and evaluation of steroidal hydroxamic acids as inhibitors of P450 17 (17 alpha-hydroxylase/C17-20-lyase)

With the aim of developing new inhibitors of 17 alpha-hydroxylase/C17,20-lyase (P450 17, CYP 17), two steroidal hydroxamic acids (compounds 2 and 3) were synthesized and evaluated as inhibitors of CYP 17. The synthesis was performed using carboxylic acids as starting material to give acid chlorides which were reacted with N,N,O-tris(trimethylsilyl) hydroxylamine. Using microsomal fractions of human and rat testes and progesterone as a substrate, both compounds moderately inhibited the human and rat enzyme.

Synthesis and evaluation of novel steroidal oxime inhibitors of P450 17 (17 alpha-hydroxylase/C17-20-lyase) and 5 alpha-reductase types 1 and 2

17 alpha-Hydroxylase/C17-20-lyase (P450 17, CYP 17) and 5 alpha-reductase are the key enzymes in androgen biosynthesis and targets for the treatment of prostate cancer and benign prostatic hyperplasia. In the search of inhibitors for both enzymes, 23 pregnenolone- or progesterone-based steroids were synthesized bearing an oxime group connected directly or via a spacer to the steroidal D-ring. Tested for inhibition of human and rat P450 17, some pregnenolone (9, 11, 14) and a series of progesterone compounds (17-20) turned out to be highly active inhibitors of the human enzyme. The most active compound was Z-21-hydroxyiminopregna-5, 17(20)-dien-3 beta-ol (9) showing K(i) values of 44 and 3.4 nM for the human and rat enzymes, respectively, and a type II UV-difference spectrum indicating a coordinate bond between the oxime group and the heme iron. In contrast to the pregnenolones which showed no inhibition of 5 alpha-reductase isozymes 1 and 2, the progesterones 16, 17, 20, 21, and 23 showed marked inhibition, especially toward the type 2 enzyme. Compounds 17 and 20 were identified as potent dual inhibitors of both P450 17 and 5 alpha-reductase. Tested for selectivity, the most potent P450 17 inhibitors 9, 10, and 14 showed no or only marginal inhibition of P450 arom, P450 scc, and P450 TxA(2). Selected compounds were tested for inhibition of the target enzymes using whole-cell assays. Compounds 9-11 strongly inhibited P450 17 being coexpressed with NADPH-P450 reductase in E. coli cells, and 16, 20, and 23 markedly inhibited 5 alpha-reductase expressed in HEK 293 cells. Tested for in vivo activity, 9 (0.019 mmol/kg) decreased the plasma testosterone concentration in rats after 2 and 6 h by 57% and 44%.

Mid-infrared (5-12-microm) and limited (5.5-8.5-microm) single-knob tuning generated by difference-frequency mixing in single-crystal AgGaS2

We describe tunable 5-12-microm mid-infrared generation in single-crystal silver gallium sulfide (AgGaS(2)), from nonlinear optical difference-frequency generation. Signal and idler waves obtained from a Nd:YAG laser-pumped LiNbO(3) optical parametric oscillator (OPO) were mixed in AgGaS(2) crystal to yield difference-frequency waves. For the efficient generation of difference frequency, an unstable resonator was employed as the OPO to reduce output beam divergence. A maximum difference-frequency power of 95 microJ/pulse was obtained near 7.5 microm for a 1-cm-long AgGaS(2) crystal. Spectral noncritical phase matching within a specific tuning range was also investigated that permitted limited single-knob tuning (5.5-8.5 microm) of the difference-frequency generator.

Difference Frequency Generation of 5-18 mum in a AgGaSe(2) Crystal

Mid-infrared radiation in the 5-18-mum range has been obtained by difference frequency generation in a AgGaSe(2) crystal by pumping with the output of a type I LiNbO(3) optical parametric oscillator (OPO). Here we suggest the use of a LiTaO(3) retarder to achieve an orthogonal state of polarization between OPO outputs that are necessary for efficient pumping of a AgGaSe(2) crystal. Several tens of kilowatts of peak power near 8 mum and continuously tunable operation in the above range have been obtained.

Pharmacokinetics, absolute bioavailability, and absorption characteristics of lamivudine

Lamivudine is a novel cytosine nucleoside analog, reverse transcriptase inhibitor that has shown activity against human immunodeficiency virus (HIV) types 1 and 2 and hepatitis B virus in vitro. This study was conducted to compare the absolute bioavailability, pharmacokinetics, and absorption characteristics of oral solution, 100-mg capsule, and 100-mg tablet formulations of lamivudine with those of intravenous lamivudine. Twelve patients with HIV were enrolled in a single-center, randomized, open-label, four-way cross-over study. Treatment arms consisted of 100 mg intravenous lamivudine (administered over 1 hour), 100 mg oral lamivudine (1 mg/mL), a 100-mg capsule, and a 100-mg tablet, each followed by a 3- to 14-day washout period. Serial blood samples over 24 hours were obtained after each dose administration. Serum concentration data were analyzed to determine pharmacokinetic parameter estimates including area under the curve (AUC), terminal half-life (t1/2), mean residence time (MRT) for each formulation, systemic clearance, oral clearance, and apparent volume of distribution (Vd). Absolute bioavailability and in vivo mean absorption time (MAT) and mean dissolution time (MDT) were calculated for the oral formulations. Deconvolution techniques were used to calculate the input rate for the oral solution, capsule, and tablet. The two one-sided t test was used to determine bioequivalency among oral formulations with respect to logarithmic transformed estimates of AUC and maximum peak concentration (Cmax). Mean (CV) systemic clearance and Vdss after intravenous administration of lamivudine were 22.6 L/h (15%) and 99 L (28%), respectively; mean t1/2 ranged from 8.41 to 9.11 hours for all formulations; and MRT ranged from 4.42 to 5.77 hours for all formulations. Mean absolute bioavailability ranged from 86% to 88% for the oral solution, capsule, and tablet. All oral formulations were considered bioequivalent for AUC and Cmax. The MAT was 1.32 hour for the oral solution, and MDT was 0.03 and -0.11 hours for the capsule and the oral solution, respectively. The oral formulations of lamivudine examined in this study demonstrated acceptable bioavailability for oral administration. The solid oral formulations (capsule and tablet) show rapid dissolution properties with an absorption rate similar to or exceeding those observed with the oral solution. This suggests that dissolution is not an important factor for the rate of absorption of lamivudine. The use of deconvolution techniques using PCDCON provides valuable insight into the absorption characteristics of lamivudine.