Estimating protection afforded by prior infection in preventing reinfection: Applying the test-negative study design.

The COVID-19 pandemic has highlighted the need to use infection testing databases to rapidly estimate effectiveness of prior infection in preventing reinfection ($P{E}_S$) by novel SARS-CoV-2 variants. Mathematical modeling was used to demonstrate a theoretical foundation for applicability of the test-negative, case-control study design to derive $P{E}_S$. Apart from the very early phase of an epidemic, the difference between the test-negative estimate for $P{E}_S$ and true value of $P{E}_S$ was minimal and became negligible as the epidemic progressed. The test-negative design provided robust estimation of $P{E}_S$ and its waning. Assuming that only 25% of prior infections are documented, misclassification of prior infection status underestimated $P{E}_S$, but the underestimate was considerable only when >50% of the population was ever infected. Misclassification of latent infection, misclassification of current active infection, and scale-up of vaccination all resulted in negligible bias in estimated $P{E}_S$. The test-negative design was applied to national-level testing data in Qatar to estimate $P{E}_S$ for SARS-CoV-2. $P{E}_S$ against SARS-CoV-2 Alpha and Beta variants was estimated at 97.0% (95% CI: 93.6-98.6) and 85.5% (95% CI: 82.4-88.1), respectively. These estimates were validated using a cohort study design. The test-negative design offers a feasible, robust method to estimate protection from prior infection in preventing reinfection.

Evaluation of antioxidant, anti-inflammatory, anticancer activities and molecular docking of Moringa oleifera seed oil extract against experimental model of Ehrlich ascites carcinoma in Swiss female albino mice.

The current research intended to evaluate the antitumor properties of Moringa oleifera oil extract (MOE). Fifty-six female Swiss albino mice were employed in this study. Animals were assigned into four groups: control (C) group, moringa oil extract (MOE) group administered (500 mg/kg b. wt) MOE daily via gavage, Ehrlich ascites carcinoma (EAC) group and EAC group administered daily with (500 mg/kg b.wt) MOE for two weeks (EAC/MOE). The results showed that MOE significantly ameliorated the EAC increase in body weight and reduced the EAC cell viability. In addition, they upgraded the levels of hepatic and renal functions, inflammatory cytokines, oxidative stress markers and EAC-induced hepatic and renal histopathological changes. Treatment of EAC with MOE induced antitumor, anti-inflammatory and antioxidant effects and normalized most of the tested parameters besides the histopathological alterations in both renal and hepatic tissues. HPLC for the MOE identified Cinnamic acid, Ellagic acid, Quercetin, Gallic acid, Vanillin and Hesperidin as major compounds. The molecular docking study highlighted the virtual binding of the identified compounds inside the GSH and SOD proteins, especially for Quercetin which exhibited promising binding affinity with good interactive binding mode with the key amino acids. These results demonstrate that the antitumor constituents of MOE against EAC induced oxidative stress and inflammation by preventing oxidative damage and controlling EAC increase.

Effects of previous infection, vaccination, and hybrid immunity against symptomatic Alpha, Beta, and Delta SARS-CoV-2 infections: an observational study.

BACKGROUND: Protection against SARS-CoV-2 symptomatic infection and severe COVID-19 of previous infection, mRNA two-dose vaccination, mRNA three-dose vaccination, and hybrid immunity of previous infection and vaccination were investigated in Qatar for the Alpha, Beta, and Delta variants. METHODS: Six national, matched, test-negative, case-control studies were conducted between January 18 and December 18, 2021 on a sample of 239,120 PCR-positive tests and 6,103,365 PCR-negative tests. FINDINGS: Effectiveness of previous infection against Alpha, Beta, and Delta reinfection was 89.5% (95% CI: 85.5-92.3%), 87.9% (95% CI: 85.4-89.9%), and 90.0% (95% CI: 86.7-92.5%), respectively. Effectiveness of two-dose BNT162b2 vaccination against Alpha, Beta, and Delta infection was 90.5% (95% CI, 83.9-94.4%), 80.5% (95% CI: 79.0-82.0%), and 58.1% (95% CI: 54.6-61.3%), respectively. Effectiveness of three-dose BNT162b2 vaccination against Delta infection was 91.7% (95% CI: 87.1-94.7%). Effectiveness of hybrid immunity of previous infection and two-dose BNT162b2 vaccination was 97.4% (95% CI: 95.4-98.5%) against Beta infection and 94.5% (95% CI: 92.8-95.8%) against Delta infection. Effectiveness of previous infection and three-dose BNT162b2 vaccination was 98.1% (95% CI: 85.7-99.7%) against Delta infection. All five forms of immunity had >90% protection against severe, critical, or fatal COVID-19 regardless of variant. Similar effectiveness estimates were observed for mRNA-1273. A mathematical model accurately predicted hybrid immunity protection by assuming that the individual effects of previous infection and vaccination acted independently. INTERPRETATION: Hybrid immunity, offering the strongest protection, was mathematically predicted by assuming that the immunities obtained from previous infection and vaccination act independently, without synergy or redundancy. FUNDING: The Biomedical Research Program and the Biostatistics, Epidemiology, and the Biomathematics Research Core, both at Weill Cornell Medicine-Qatar, Ministry of Public Health, Hamad Medical Corporation, Sidra Medicine, Qatar Genome Programme, Qatar University Biomedical Research Center, and Qatar University Internal Grant ID QUCG-CAS-23/24-114.

Biphasic calcium phosphate doped with zirconia nanoparticles for reconstruction of induced mandibular defects in dogs: cone-beam computed tomographic and histopathologic evaluation.

The present study aimed to evaluate osteogenic potential and biocompatibility of combining biphasic calcium phosphate with zirconia nanoparticles (4Zr TCP/HA) compared to biphasic calcium phosphate (TCP/HA) for reconstruction of induced mandibular defects in dog model. TCP/HA and 4Zr TCP/HA scaffolds were prepared. Morphological, physicochemical, antibacterial, cytocompatibility characterization were tested. In vivo application was performed in 12 dogs where three critical-sized mandibular defects were created in each dog. Bone defects were randomly allocated into: control, TCP/HA, and 4Zr TCP/HA groups. Bone density and bone area percentage were evaluated at 12 weeks using cone-beam computed tomographic, histopathologic, histomorphometric examination. Bone area density was statistically increased (p < 0.001) in TCP/HA and 4Zr TCP/HA groups compared to control group both in sagittal and coronal views. Comparing TCP/HA and 4Zr TCP/HA groups, the increase in bone area density was statistically significant in coronal view (p = 0.002) and sagittal view (p = 0.05). Histopathologic sections of TCP/HA group demonstrated incomplete filling of the defect with osteoid tissue. Doping with zirconia (4Zr TCP/HA group), resulted in statistically significant increase (p < 0.001) in bone formation (as indicated by bone area percentage) and maturation (as confirmed by Masson trichrome staining) compared to TCP/HA group. The newly formed bone was mature and organized with more trabecular thickness and less trabecular space in between. Physicochemical, morphological and bactericidal properties of combining zirconia and TCP/HA were improved. Combining zirconia and TCP/HA resulted in synergistic action with effective osteoinduction, osteoconduction and osteointegration suggesting its suitability to restore damaged bone in clinical practice.

Enhanced Graphene Oxide Electrical Properties for Thin-Film Electronics Using an Active/Shrinkable Substrate.

The advances in material science along with the development of fabrication techniques have enabled the realization of thin-film-based electronics on active substrates. This has substantially enhanced and supported the deployment of electronic devices in several emerging applications with flexible functionality. In this work, we report a novel fabrication of graphene oxide (GO)-based memristor devices on an active/shrinkable substrate. The standard lithography process is used to fabricate planar Au-rGO-Au devices on a polymer substrate that has the ability to shrink at a certain temperature (i.e., 170 °C). Upon heating, the devices are shrunk to 50% of their original size. A detailed electrical characterization has been carried out to study the switching behavior of the fabricated devices before and after shrinking. The results prove that upon shrinking, the device preserves its switching ability with enhanced electrical parameters (i.e., switching voltage). Also, material characterization performed for the deposited GO on the active substrate shows improved properties of the GO film due to the enhanced arrangement of GO flakes after shrinking. The novel approach proposed in this work provides new insights into and offers the ability to scale thin-film electronics postfabrication and thus overcome some of the device scaling challenges due to manufacturing limitations. It also unfolds a new path for the realization of GO-based electronic devices with improved electrical properties, which is a crucial aspect of the development of highly flexible and lightweight green electronics.

Parasitological and histopathological studies to the effect of aqueous extract of Moringa oleifera Lam. leaves combined with praziquantel therapy in modulating the liver and spleen damage induced by Schistosoma mansoni to male mice.

This study assessed the effectiveness of an aqueous extract of Moringa Oleifera Lam. leaves (MOL) alone or in combination with praziquantel (PZQ) drug targeting-infected mice with Schistosoma mansoni-induced liver and spleen damage. Mice were divided into eight groups control mice group treated orally with saline. PZQ group: non-infected mice treated orally with 300 mg/kg bwt PZQ three consecutive days. MOL group: non-infected mice treated orally with 150 mg/kg bwt MOL extract for 15 days. PZQ/ MOL group: non-infected mice treated orally with 300 mg/kg bwt PZQ for three consecutive days and 150 mg/kg bwt MOL extract for 15 days. IF group: infected mice with 100 cercariae/mouse of the Egyptian strain of S. mansoni. IF/PZQ group infected mice with S. mansoni cercariae and treated orally with 300 mg/kg bwt PZQ for three consecutive days. IF/MOL group: infected mice with S. mansoni cercariae treated orally with 150 mg/kg bwt MOL extract for 15 days. IF/PZQ +MOL group: infected mice with S. mansoni cercariae treated orally with 300 mg/kg bwt PZQ for three consecutive days and 150 mg/kg bwt MOL extract for 15 days. Blood, liver, spleen, worm, and eggs were collected at the end of the experimental period. Treatment of infected mice with MOL and PZQ together significantly reduced the number of ova/g tissue and eliminated the parasites. In addition, the liver and spleen of infected mice showed less histopathological alteration and immunohistochemical expression of nuclear factor kappa ß (NF-Kß). We can conclude that MOL extract combined with PZ has a curative effect on S. mansoni infection and helped to lessen its pathological effects.

Acute Kidney Injury Among Patients with Multi-Drug Resistant Infection: A Study from Jordan.

Background: Acute kidney injury (AKI) is a well-known complication for hospitalized patients. Sepsis and various infections play a significant role in increasing the incidence of AKI. The present study evaluated the risk for Multidrug-resistant (MDR) infections and its effect on the incidence of AKI, hospitalization, need for dialysis, and mortality. Methods: In a retrospective study design, data were collected from all adult patients with a positive multi-drug resistant culture who were admitted to King Abdullah University Hospital (KAUH). Records of 436 patients were reviewed between January 2017 - December 2018 with at least one year of follow-up. Results: The mean age was 57.3 years (SD± 23.1), and 58.5% were males. The most common source of positive cultures was sputum, with 50% positive cultures. The incidence of AKI was 59.2%. The most isolated microorganism was Acinetobacter baumannii (76.8%), followed by Pseudomonas aeruginosa (14.9%).On multivariate analysis, age (OR 1.1, 95% CI 1.1-1.2, P=0.001), HTN (OR 1.8, 95% CI 1.0-3.3, P=0.02), DM (OR 1.1, 95% CI 0.6-1.9, P=0.69) and the use of Foley catheter on chronic bases (OR 4.3, 95% CI 2.6-6.8, P<0.0001) were strong predictors of AKI. Among patients with AKI, 74.4% died compared to 44.4% among non-AKI patients (p<0.001). Conclusion: In patients with MDR, AKI incidence, hospitalization, and mortality were high. Early detection and addressing the problem may decrease bad outcomes, and health education for reducing antibiotic abuse is needed to lower MDR.

The Biological, Histopathological, and Parasitic Abundance of Oreochromis niloticus Inhabiting Two Different Freshwater Canals.

The current study aimed to assess the impact of metal pollution in water on parasitic abundance, biology, and histopathological characteristics of Oreochromis niloticus in two different freshwater habitats in the Al Sharkia government. The fish were collected from the Mueweis canal area (A) which received industrial wastewater from factories and the San El-Hagar area (B) which received agricultural and domestic wastewater. Parasitic abundance and histopathological changes in the liver and gonads were inspected. The total prevalence of parasitic infection was at the highest percentage in area B correlated with metals present in the water, in addition to severe histopathological damage to the liver and the gonads. The prevalence of parasites for different examined fish ranges from 50% for parasites in the San El-Hagar canal and 4.17% for parasites in the Muwies canal, seasonally. There were positive relationships between Fe or Zn or Mn concentrations with parasite abundance in tilapia fish collected from the San Hagar canal. Several histopathological alterations were detected in the liver and gonads of O. niloticus collected from the two canals located in the Al Sharkia province. It was concluded that the uncontrolled inputs of agricultural and domestic wastes highly altered the O. niloticus health status and the prevalence of the parasites in the investigated two areas.

Covid-19 Vaccine Protection among Children and Adolescents in Qatar.

BACKGROUND: The BNT162b2 vaccine against coronavirus disease 2019 (Covid-19) has been authorized for use in children 5 to 11 years of age and adolescents 12 to 17 years of age but in different antigen doses. METHODS: We assessed the real-world effectiveness of the BNT162b2 vaccine against infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among children and adolescents in Qatar. To compare the incidence of SARS-CoV-2 infection in the national cohort of vaccinated participants with the incidence in the national cohort of unvaccinated participants, we conducted three matched, retrospective, target-trial, cohort studies - one assessing data obtained from children 5 to 11 years of age after the B.1.1.529 (omicron) variant became prevalent and two assessing data from adolescents 12 to 17 years of age before the emergence of the omicron variant (pre-omicron study) and after the omicron variant became prevalent. Associations were estimated with the use of Cox proportional-hazards regression models. RESULTS: Among children, the overall effectiveness of the 10-µg primary vaccine series against infection with the omicron variant was 25.7% (95% confidence interval [CI], 10.0 to 38.6). Effectiveness was highest (49.6%; 95% CI, 28.5 to 64.5) right after receipt of the second dose but waned rapidly thereafter and was negligible after 3 months. Effectiveness was 46.3% (95% CI, 21.5 to 63.3) among children 5 to 7 years of age and 16.6% (95% CI, -4.2 to 33.2) among those 8 to 11 years of age. Among adolescents, the overall effectiveness of the 30-µg primary vaccine series against infection with the omicron variant was 30.6% (95% CI, 26.9 to 34.1), but many adolescents had been vaccinated months earlier. Effectiveness waned over time since receipt of the second dose. Effectiveness was 35.6% (95% CI, 31.2 to 39.6) among adolescents 12 to 14 years of age and 20.9% (95% CI, 13.8 to 27.4) among those 15 to 17 years of age. In the pre-omicron study, the overall effectiveness of the 30-µg primary vaccine series against SARS-CoV-2 infection among adolescents was 87.6% (95% CI, 84.0 to 90.4) and waned relatively slowly after receipt of the second dose. CONCLUSIONS: Vaccination in children was associated with modest, rapidly waning protection against omicron infection. Vaccination in adolescents was associated with stronger, more durable protection, perhaps because of the larger antigen dose. (Funded by Weill Cornell Medicine-Qatar and others.).

Protection against reinfection with SARS-CoV-2 omicron BA.2.75* sublineage

The BA.2.75* sublineage of SARS-CoV-2 B.1.1.529 (omicron) variant escapes neutralizing antibodies. We estimated effectiveness of prior infection in preventing reinfection with BA.2.75* using a test-negative, case-control study design. Effectiveness of prior pre-omicron infection against BA.2.75* reinfection, irrespective of symptoms, was 6.0% (95% CI: 1.5-10.4%). Effectiveness of prior BA.1/BA.2 infection was 49.9% (95% CI: 47.6-52.1%) and of prior BA.4/BA.5 infection was 80.6% (95% CI: 71.2-87.0). Effectiveness of prior pre-omicron infection followed by BA.1/BA.2 infection against BA.2.75* reinfection was 56.4% (95% CI: 50.5-61.6). Effectiveness of prior pre-omicron infection followed by BA.4/BA.5 infection was 91.6% (95% CI: 65.1-98.0). Analyses stratified by time since prior infection indicated waning of protection since prior infection. Analyses stratified by vaccination status indicated that protection from prior infection is higher among those vaccinated, particularly among those ...

Heavy metals and parasitological infection associated with oxidative stress and histopathological alteration in the Clarias gariepinus.

The goal of this study was to assess the harmful effects of heavy metal accumulation on Clarias gariepinus (catfish) in two different polluted areas in the Al Sharkia governorate and assess the impact on oxidative stress and histological changes. The results revealed a highly significant difference in heavy metal levels in the water and inside fish tissues (liver and gonads) between the two sites. The total prevalence of parasitic infection was at the highest percentage in area B, in addition to severe histopathological damage to the liver and the gonads. Findings show that the total prevalence of parasitic infection is associated with uptake of metals, depleted antioxidant activity, and incidence of lipid peroxidation in tissue.

Effectiveness of the BNT162b2 vaccine against SARS-CoV-2 infection among children and adolescents in Qatar

BackgroundThe BNT162b2 COVID-19 vaccine is authorized for children 5-11 years of age and adolescents 12-17 years of age, but in different dose sizes. We assessed BNT162b2 real-world effectiveness against SARS-CoV-2 infection among children and adolescents in Qatar. MethodsThree matched, retrospective, target-trial, cohort studies were conducted to compare incidence of SARS-CoV-2 infection in the national cohort of vaccinated individuals to incidence in the national cohort of unvaccinated individuals. Associations were estimated using Cox proportional-hazards regression models. ResultsEffectiveness of the 10 {micro}g dose for children against Omicron infection was 25.7% (95% CI: 10.0-38.6%). It was highest at 49.6% (95% CI: 28.5-64.5%) right after the second dose, but waned rapidly thereafter and was negligible after 3 months. Effectiveness was 46.3% (95% CI: 21.5-63.3%) among those aged 5-7 years and 16.6% (-4.2-33.2%) among those aged 8-11 years. Effectiveness of the 30 {micro}g dose for adolescents against Omicron infection was 30.6% (95% CI: 26.9-34.1%), but many adolescents were vaccinated months earlier. Effectiveness waned with time after the second dose. Effectiveness was 35.6% (95% CI: 31.2-39.6%) among those aged 12-14 years and 20.9% (13.8-27.4%) among those aged 15-17 years. Effectiveness of the 30 {micro}g dose for adolescents against pre-Omicron infection was 87.6% (95% CI: 84.0-90.4%) and waned relatively slowly after the second dose. ConclusionsPediatric vaccination is associated with modest and rapidly waning protection against Omicron infection. Adolescent vaccination is associated with stronger and more durable protection, perhaps because of the larger dose size. Age at such young age appears to play a role in determining vaccine protection, with greater protection observed in younger than older children or adolescents.

Protection of SARS-CoV-2 natural infection against reinfection with the BA.4 or BA.5 Omicron subvariants

This study estimates the effectiveness of previous infection with SARS-CoV-2 in preventing reinfection with Omicron BA.4/BA.5 subvariants using a test-negative, case-control study design. Cases (SARS-CoV-2-positive test results) and controls (SARS-CoV-2-negative test results) were matched according to sex, 10-year age group, nationality, comorbid condition count, calendar week of testing, method of testing, and reason for testing. Effectiveness was estimated using the S-gene "target failure" (SGTF) infections between May 7, 2022-July 4, 2022. SGTF status provides a proxy for BA.4/BA.5 infections, considering the negligible incidence of other SGTF variants during the study. Effectiveness was also estimated using all diagnosed infections between June 8, 2022-July 4, 2022, when BA.4/BA.5 dominated incidence. Effectiveness of a previous pre-Omicron infection against symptomatic BA.4/BA.5 reinfection was 15.1% (95% CI: -47.1-50.9%), and against any BA.4/BA.5 reinfection irrespective of symptoms was 28.3% (95% CI: 11.4-41.9%). Effectiveness of a previous Omicron infection against symptomatic BA.4/BA.5 reinfection was 76.1% (95% CI: 54.9-87.3%), and against any BA.4/BA.5 reinfection was 79.7% (95% CI: 74.3-83.9%). Results using all diagnosed infections when BA.4/BA.5 dominated incidence confirmed the same findings. Sensitivity analyses adjusting for vaccination status confirmed study results. Protection of a previous infection against BA.4/BA.5 reinfection was modest when the previous infection involved a pre-Omicron variant, but strong when the previous infection involved the Omicron BA.1 or BA.2 subvariants. Protection of a previous infection against BA.4/BA.5 was lower than that against BA.1/BA.2, consistent with BA.4/BA.5s greater capacity for immune-system evasion than that of BA.1/BA.2.

Effects of Previous Infection and Vaccination on Symptomatic Omicron Infections.

BACKGROUND: The protection conferred by natural immunity, vaccination, and both against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with the BA.1 or BA.2 sublineages of the omicron (B.1.1.529) variant is unclear. METHODS: We conducted a national, matched, test-negative, case-control study in Qatar from December 23, 2021, through February 21, 2022, to evaluate the effectiveness of vaccination with BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna), natural immunity due to previous infection with variants other than omicron, and hybrid immunity (previous infection and vaccination) against symptomatic omicron infection and against severe, critical, or fatal coronavirus disease 2019 (Covid-19). RESULTS: The effectiveness of previous infection alone against symptomatic BA.2 infection was 46.1% (95% confidence interval [CI], 39.5 to 51.9). The effectiveness of vaccination with two doses of BNT162b2 and no previous infection was negligible (-1.1%; 95% CI, -7.1 to 4.6), but nearly all persons had received their second dose more than 6 months earlier. The effectiveness of three doses of BNT162b2 and no previous infection was 52.2% (95% CI, 48.1 to 55.9). The effectiveness of previous infection and two doses of BNT162b2 was 55.1% (95% CI, 50.9 to 58.9), and the effectiveness of previous infection and three doses of BNT162b2 was 77.3% (95% CI, 72.4 to 81.4). Previous infection alone, BNT162b2 vaccination alone, and hybrid immunity all showed strong effectiveness (>70%) against severe, critical, or fatal Covid-19 due to BA.2 infection. Similar results were observed in analyses of effectiveness against BA.1 infection and of vaccination with mRNA-1273. CONCLUSIONS: No discernable differences in protection against symptomatic BA.1 and BA.2 infection were seen with previous infection, vaccination, and hybrid immunity. Vaccination enhanced protection among persons who had had a previous infection. Hybrid immunity resulting from previous infection and recent booster vaccination conferred the strongest protection. (Funded by Weill Cornell Medicine-Qatar and others.).

Effect of prior infection, vaccination, and hybrid immunity against symptomatic BA.1 and BA.2 Omicron infections and severe COVID-19 in Qatar

BACKGROUNDProtection offered by five different forms of immunity, combining natural and vaccine immunity, was investigated against SARS-CoV-2 Omicron symptomatic BA.1 infection, symptomatic BA.2 infection, BA.1 hospitalization and death, and BA.2 hospitalization and death, in Qatar, between December 23, 2021 and February 21, 2022. METHODSSix national, matched, test-negative case-control studies were conducted to estimate effectiveness of BNT162b2 (Pfizer-BioNTech) vaccine, mRNA-1273 (Moderna) vaccine, natural immunity due to prior infection with pre-Omicron variants, and hybrid immunity from prior infection and vaccination. RESULTSEffectiveness of only prior infection against symptomatic BA.2 infection was 46.1% (95% CI: 39.5-51.9%). Effectiveness of only two-dose BNT162b2 vaccination was negligible at -1.1% (95% CI: -7.1-4.6), but nearly all individuals had received their second dose several months earlier. Effectiveness of only three-dose BNT162b2 vaccination was 52.2% (95% CI: 48.1-55.9%). Effectiveness of hybrid immunity of prior infection and two-dose BNT162b2 vaccination was 55.1% (95% CI: 50.9-58.9%). Effectiveness of hybrid immunity of prior infection and three-dose BNT162b2 vaccination was 77.3% (95% CI: 72.4-81.4%). Meanwhile, prior infection, BNT162b2 vaccination, and hybrid immunity all showed strong effectiveness >70% against any severe, critical, or fatal COVID-19 due to BA.2 infection. Similar levels and patterns of effectiveness were observed for BA.1 and for the mRNA-1273 vaccine. CONCLUSIONSThere are no discernable differences in the effects of prior infection, vaccination, and hybrid immunity against BA.1 versus BA.2. Hybrid immunity resulting from prior infection and recent booster vaccination confers the strongest protection against either subvariant. Vaccination enhances protection of those with a prior infection.

Estimating protection afforded by prior infection in preventing reinfection: Applying the test-negative study design

BackgroundThe Coronavirus Disease 2019 (COVID-19) pandemic has highlighted an urgent need to use infection testing databases to rapidly estimate effectiveness of prior infection in preventing reinfection (PES) by novel variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). MethodsMathematical modeling was used to demonstrate the applicability of the test-negative, case-control study design to derive PES. Modeling was also used to investigate effects of bias in PES estimation. The test-negative design was applied to national-level testing data in Qatar to estimate PES for SARS-CoV-2 infection and to validate this design. ResultsApart from the very early phase of an epidemic, the difference between the test-negative estimate for PES and the true value of PES was minimal and became negligible as the epidemic progressed. The test-negative design provided robust estimation of PES even when PES began to wane after prior infection. Assuming that only 25% of prior infections are documented, misclassification of prior infection status underestimated PES, but the underestimate was considerable only when >50% of the population was ever infected. Misclassification of latent infection, misclassification of current active infection, and scale-up of vaccination all resulted in negligible bias in estimated PES. PES against SARS-CoV-2 Alpha and Beta variants was estimated at 97.0% (95% CI: 93.6-98.6) and 85.5% (95% CI: 82.4-88.1), respectively. These estimates were validated using a cohort study design. ConclusionsThe test-negative design offers a feasible, robust method to estimate protection from prior infection in preventing reinfection.

Evaluating the protective role of Deglycyrrhizinated licorice root supplement on bleomycin induced pulmonary oxidative damage.

The goal of this study was to investigate the protective effect of licorice supplements in a rat model of Bleomycin-induced lung oxidative damage over a duration of one month. The rats were randomly divided into six groups (n = 10 per group). Control group; Bleomycin group (B): rats were IP injected with bleomycin 5 mg/kg twice weekly. Licorice group (L): rats received orally 300 mg/kg licorice extract. Bleomycin and a low dose of Licorice group (BLLG): rats received orally 75 mg/kg licorice daily and injected as the B group. Bleomycin and a middle dose of Licorice group (BMLG): rats received orally 150 mg/kg licorice daily and injected as the Bleomycin group. Bleomycin and a high dose of Licorice group (BHLG): rats received orally 300 mg/kg licorice daily and injected as the Bleomycin group. Treatment with Bleomycin induced inflammation and oxidative damage to the lungs expressed in the disturbance of the measured parameters in the blood serum, the lung tissue, and the broncholavage fluid. In addition to the decreased expression of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and catalase (CAT) in the lung tissues. Bleomycin caused deformative changes in the histopathological and cellular examination of the lungs especially in the alveolar cells and the interstitial space. On the other hand, treated the bleomycin group with different doses of licorice supplement activates the antioxidant defense mechanism and attenuates the oxidative damage and damage induced to the lung. In conclusion, Deglycyrrhizinated licorice root supplement provided strong antioxidant and protective effects on Bleomycin-induced lung damage.