Rxivist logo

Rxivist combines biology preprints from bioRxiv and medRxiv with data from Twitter to help you find the papers being discussed in your field. Currently indexing 166,413 papers from 691,615 authors.

Most tweeted biology preprints, last 24 hours

*There are gaps in historical Twitter data, most notably in spring 2020. This may result in some preprints appearing with less tweets than they should.

71 results found. For more information, click each entry to expand.

1: Increased risk of infection with SARS-CoV-2 Beta, Gamma, and Delta variant compared to Alpha variant in vaccinated individuals
more details view paper

Posted 24 Nov 2021

Increased risk of infection with SARS-CoV-2 Beta, Gamma, and Delta variant compared to Alpha variant in vaccinated individuals
35 tweets medRxiv epidemiology

Stijn P. Andeweg, Harry Vennema, Irene Veldhuijzen, Naomi Smorenburg, Dennis Schmitz, Florian Zwagemaker, SeqNeth Molecular surveillance group, RIVM COVID-19 Molecular epidemiology group, Arianne B. van Gageldonk-Lafeber, Susan JM Hahne, Chantal Reusken, Mirjam J. Knol, Dirk Eggink

The extent to which severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOC) break through infection- or vaccine-induced immunity is not well understood. Here, we analyze 28,578 sequenced SARS-CoV-2 samples from individuals with known immune status obtained through national community testing in the Netherlands from March to August 2021. We find evidence for an increased risk of infection by the Beta (B.1.351), Gamma (P.1), or Delta (B.1.617.2) variants compared to the Alpha (B.1.1.7) variant after vaccination. No clear differences were found between vaccines. However, the effect was larger in the first 14-59 days after complete vaccination compared to 60 days and longer. In contrast to vaccine-induced immunity, no increased risk for reinfection with Beta, Gamma or Delta variants relative to Alpha variant was found in individuals with infection-induced immunity.

2: The SARS-CoV-2 Delta variant is poised to acquire complete resistance to wild-type spike vaccines
more details view paper

Posted 23 Aug 2021

The SARS-CoV-2 Delta variant is poised to acquire complete resistance to wild-type spike vaccines
9 tweets bioRxiv microbiology

Yafei Liu, Noriko Arase, Jun-ichi Kishikawa, Mika Hirose, Songling Li, Asa Tada, Sumiko Matsuoka, Akemi Arakawa, Kanako Akamatsu, Chikako Ono, Hui Jin, Kazuki Kishida, Wataru Nakai, Masako Kohyama, Atsushi Nakagawa, Yoshiaki Yamagishi, Hironori Nakagami, Atsushi Kumanogoh, Yoshiharu Matsuura, Daron M Standley, Takayuki Kato, Masato Okada, Manabu Fujimoto, Hisashi Arase

mRNA-based vaccines provide effective protection against most common SARS-CoV-2 variants. However, identifying likely breakthrough variants is critical for future vaccine development. Here, we found that the Delta variant completely escaped from anti-N-terminal domain (NTD) neutralizing antibodies, while increasing responsiveness to anti-NTD infectivity-enhancing antibodies. Although Pfizer-BioNTech BNT162b2-immune sera neutralized the Delta variant, when four common mutations were introduced into the receptor binding domain (RBD) of the Delta variant (Delta 4+), some BNT162b2-immune sera lost neutralizing activity and enhanced the infectivity. Unique mutations in the Delta NTD were involved in the enhanced infectivity by the BNT162b2-immune sera. Sera of mice immunized by Delta spike, but not wild-type spike, consistently neutralized the Delta 4+ variant without enhancing infectivity. Given the fact that a Delta variant with three similar RBD mutations has already emerged according to the GISAID database, it is necessary to develop vaccines that protect against such complete breakthrough variants.

3: Durability of SARS-CoV-2 Antibodies from Natural Infection in Children and Adolescents
more details view paper

Posted 24 Nov 2021

Durability of SARS-CoV-2 Antibodies from Natural Infection in Children and Adolescents
7 tweets medRxiv pediatrics

Sarah E Messiah, Frances A Brito, Harold W Kohl, Stacia M DeSantis, Melissa A Valerio-Shewmaker, Jessica A Ross, Ashaf Yaseen, Steven H Kelder, Shiming Zhang, Onyinye S Omega-Njemnobi, Michael O Gonzalez, Leqing Wu, Eric A. Boerwinkle, David Lakey, Jennifer A Shuford, Stephen Pont

Background. Recent data suggest the SARS-CoV-2 Delta (B.1.617.2) variant is more transmissible among children compared to the Alpha (B.1.1.7) variant. The true incidence and longitudinal presence of antibody response to SARS-CoV-2 infection is not known, however. We provided estimates of antibody response using Texas Coronavirus Antibody REsponse Survey (Texas CARES) data, a prospective population-based seroprevalence project designed to assess antibody status over time among the general population throughout the state. Methods. In October 2020 Texas CARES began enrolling adults (aged 20-80 years) and children (aged 5-19 years). Participants were offered a series of three SARS-CoV-2 antibody tests over 6-8 months, or every 2-3 months that includes the immunoassay for detection of antibodies to the SARS-CoV-2 nucleocapsid protein (Roche N-test). Descriptive characteristics and COVID-19 infection-related symptom status was determined by questionnaire at the time of enrollment and prior to each successive blood draw. This analysis included participants ages 5-to-19 years old who have completed all three antibody assessments. Results. From our sample (n=159; mean age 12.5 years, SD 3.6), 96% of those with evidence of nucleocapsid antibodies at baseline assessment continued to have antibodies > six months later (mean 7.0 months, SD 0.97). There was no difference in the presence of antibodies by symptom status (asymptotic versus symptomatic) or severity (mild-moderate versus severe), sex, age group, or body mass index group (underweight, healthy weight, overweight, obesity) over the three antibody measurement timepoints. Conclusions. These results suggest that infection-induced antibodies persist and thus may provide some protection against future infection for at least half a year. 57.9% of the sample were negative for infection-induced antibodies at their third measurement point, suggesting a significant proportion of children have still not acquired natural infection.

4: Sampling the conformational landscapes of transporters and receptors with AlphaFold2
more details view paper

Posted 22 Nov 2021

Sampling the conformational landscapes of transporters and receptors with AlphaFold2
5 tweets bioRxiv biophysics

Diego del Alamo, Davide Sala, Hassane Mchaourab, Jens Meiler

Equilibrium fluctuations and triggered conformational changes often underlie the functional cycles of membrane proteins. For example, transporters mediate the passage of molecules across cell membranes by alternating between inward-facing (IF) and outward-facing (OF) states, while receptors undergo intracellular structural rearrangements that initiate signaling cascades. Although the conformational plasticity of these proteins has historically posed a challenge for traditional de novo protein structure prediction pipelines, the recent success of AlphaFold2 (AF2) in CASP14 culminated in the modeling of a transporter in multiple conformations to high accuracy. Given that AF2 was designed to predict static structures of proteins, it remains unclear if this result represents an underexplored capability to accurately predict multiple conformations and/or structural heterogeneity. Here, we present an approach to drive AF2 to sample alternative conformations of topologically diverse transporters and G-protein coupled receptors (GPCRs) that are absent from the AF2 training set. Whereas models generated using the default AF2 pipeline are conformationally homogeneous and nearly identical to one another, reducing the depth of the input multiple sequence alignments (MSAs) led to the generation of accurate models in multiple conformations. In our benchmark, these conformations were observed to span the range between two experimental structures of interest, suggesting that our protocol allows sampling of the conformational landscape at the energy minimum. Nevertheless, our results also highlight the need for the next generation of deep learning algorithms to be designed to predict ensembles of biophysically relevant states.

5: Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission - a prospective cohort study in England
more details view paper

Posted 24 Nov 2021

Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission - a prospective cohort study in England
4 tweets medRxiv epidemiology

Samuel Clifford, Pauline Waight, Jada Hackman, Stephane Hue, Charlotte M Gower, Freja CM Kirsebom, Catriona Skarnes, Louise Letley, Jamie Lopez Bernal, Nick Andrews, Stefan Flasche, Elizabeth Miller

Background: The ability of SARS-CoV-2 vaccines to protect against infection and onward transmission determines whether immunisation can control global circulation. We estimated effectiveness of BNT162b2 and ChAdOx1 vaccines against acquisition and transmission of the Alpha and Delta variants in a prospective household study in England. Methods: Adult index cases in the community and their household contacts took oral-nasal swabs on days 1, 3 and 7 after enrolment. Swabs were tested by RT-qPCR with genomic sequencing conducted on a subset. We used Bayesian logistic regression to infer vaccine effectiveness against acquisition and transmission, adjusted for age, vaccination history and variant. Findings: Between 2 February 2021 and 10 September 2021 213 index cases and 312 contacts were followed up. After excluding households lacking genomic proximity (N=2) or with unlikely serial intervals (N=16), 195 households with 278 contacts remained of whom 113 (41%) became PCR positive. Delta lineages were 4.6 times (95% Credible Interval: 1.5 - 20.1) more transmissible than Alpha; contacts older than 18 years were 2.0 times (1.4 - 3.3) more likely to acquire infection than children. Effectiveness of two doses of BNT162b2 against transmission of Delta was 31% (-3%, 61%) and 42% (14%, 69%) for ChAdOx1, similar to their effectiveness for Alpha. Protection against infection with Alpha was higher than for Delta, 71% (12%,95%) vs 24% (-2%, 64%) respectively for BNT162b2 and 26% (-39%, 73%) vs 14% (-5%, 46%) respectively for ChAdOx1. Interpretation: BNT162b2 and ChAdOx1 reduce transmission of the Delta variant from breakthrough infections in the household setting though their protection against infection is low. Funding: This study was funded by the UK Health Security Agency (formerly Public Health England) as part of the COVID-19 response.

6: Long distance migration is a major factor driving local adaptation at continental scale in Coho Salmon
more details view paper

Posted 22 Nov 2021

Long distance migration is a major factor driving local adaptation at continental scale in Coho Salmon
3 tweets bioRxiv evolutionary biology

Quentin Rougemont, Amanda Xuereb, Xavier Dallaire, Jean-Sebastien Moore, Eric Normandeau, Eric B. Rondeau, Ruth Withler, Donald Van Doornik, Penelope Crane, Kerry Naish, John-Carlos Garza, Terry Beacham, Ben F. Koop, Louis Bernatchez

Inferring the genomic basis of local adaptation is a long-standing goal of evolutionary biology. Beyond its fundamental evolutionary implications, such knowledge can guide conservation decisions for populations of conservation and management concern. Here, we investigated the genomic basis of local adaptation in the Coho salmon (Oncorhynchus kisutch) across its entire North American range. We hypothesized that extensive spatial variation in environmental conditions and the species homing behavior may promote the establishment of local adaptation. We genotyped 7,829 individuals representing 217 sampling locations at more than 100,000 high-quality RADseq loci to investigate how recombination might affect the detection of loci putatively under selection and took advantage of the precise description of the demographic history of the species from our previous work to draw accurate population genomic inferences about local adaptation. Results indicated that genetic differentiation scans and genetic-environment association analyses were both significantly affected by variation in recombination rate as low recombination regions displayed an increased number of outliers. By taking these confounding factors into consideration, we revealed that migration distance was the primary selective factor driving local adaptation and partial parallel divergence among distant populations. Moreover, we identified several candidates SNP associated with long distance migration and altitude including a gene known to be involved in adaptation to altitude in other species. The evolutionary implications of our findings are discussed along with conservation applications.

7: Shedding of Infectious SARS-CoV-2 Despite Vaccination
more details view paper

Posted 31 Jul 2021

Shedding of Infectious SARS-CoV-2 Despite Vaccination
3 tweets medRxiv infectious diseases

Kasen K Riemersma, Brittany E Grogan, Amanda Kita-Yarbro, Peter Halfmann, Anna Kocharian, Kelsey R Florek, Ryan Westergaard, Allen Bateman, Gunnar E Jeppson, Yoshihiro Kawaoka, David H O'Connor, Thomas C Friedrich, Katarina M Grande

The SARS-CoV-2 Delta variant is highly transmissible and contains mutations that confer partial immune escape. We compared RT-PCR cycle threshold (Ct) data from 699 test-positive anterior nasal swab specimens from fully vaccinated (n = 310) or unvaccinated (n=389) individuals. We observed low Ct values (<25) in 212 of 310 fully vaccinated (68%) and 246 of 389 (63%) unvaccinated individuals. Testing a subset of these low-Ct samples revealed infectious SARS-CoV-2 in 15 of 17 specimens (88%) from unvaccinated individuals and 37 of 39 (95%) from vaccinated people. To determine whether infectious virus titers differed in vaccinated and unvaccinated persons, we performed plaque assays on an additional set of 48 samples with Ct <25, finding no difference in infectious virus titer between groups.

8: A human coronavirus evolves antigenically to escape antibody immunity
more details view paper

Posted 18 Dec 2020

A human coronavirus evolves antigenically to escape antibody immunity
3 tweets bioRxiv microbiology

Rachel Eguia, Katharine HD Crawford, Terry Stevens-Ayers, Laurel E Kelnhofer-Millevolte, Alexander L. Greninger, Janet A Englund, Michael J. Boeckh, Jesse D Bloom

There is intense interest in antibody immunity to coronaviruses. However, it is unknown if coronaviruses evolve to escape such immunity, and if so, how rapidly. Here we address this question by characterizing the historical evolution of human coronavirus 229E. We identify human sera from the 1980s and 1990s that have neutralizing titers against contemporaneous 229E that are comparable to the anti-SARS-CoV-2 titers induced by SARS-CoV-2 infection or vaccination. We test these sera against 229E strains isolated after sera collection, and find that neutralizing titers are lower against these "future" viruses. In some cases, sera that neutralize contemporaneous 229E viral strains with titers >1:100 do not detectably neutralize strains isolated 8-17 years later. The decreased neutralization of "future" viruses is due to antigenic evolution of the viral spike, especially in the receptor-binding domain. If these results extrapolate to other coronaviruses, then it may be advisable to periodically update SARS-CoV-2 vaccines.

9: Favipiravir for treatment of outpatients with asymptomatic or uncomplicated COVID-19: a double-blind randomized, placebo-controlled, phase 2 trial
more details view paper

Posted 24 Nov 2021

Favipiravir for treatment of outpatients with asymptomatic or uncomplicated COVID-19: a double-blind randomized, placebo-controlled, phase 2 trial
3 tweets medRxiv infectious diseases

Marisa Holubar, Aruna K Subramanian, Natasha Purington, Haley Hedlin, Bryan Bunning, Katharine Walter, Hector Bonilla, Athanasia Boumis, Michael Chen, Kimberly Clinton, Liisa Dewhurst, Carol Epstein, Prasanna Jagannathan, Richard Kaszynski, Lori Panu, Julie Parsonnet, Elizabeth Ponder, Orlando Quintero, Elizabeth Sefton, Upinder Singh, Luke Soberanis, Henry Truong, Jason Andrews, Manisha Desai, Chaitan Khosla, Yvonne Maldonado

Background: Favipiravir is an oral, RNA-dependent RNA polymerase inhibitor with in vitro activity against SARS-CoV2. Despite limited data, favipiravir is administered to patients with COVID-19 in several countries. Methods: We conducted a phase 2 double-blind randomized controlled outpatient trial of favipiravir in asymptomatic or mildly symptomatic adults with a positive SARS-CoV2 RT-PCR within 72 hours of enrollment. Participants were randomized 1:1 to receive placebo or favipiravir (1800 mg BID Day 1, 800mg BID Days 2-10). The primary outcome was SARS-CoV2 shedding cessation in a modified intention-to-treat (mITT) cohort of participants with positive enrollment RT-PCRs. Using SARS-CoV2 deep sequencing, we assessed the impact of favipiravir on mutagenesis. Results: From July 8, 2020 to March 23, 2021, we randomized 149 participants with 116 included in the mITT cohort. The mean age was 43 years (SD 12.5) and 57 (49%) were women. We found no difference in time to shedding cessation by treatment arm overall (HR 0.76 favoring placebo, 95% confidence interval [CI] 0.48 - 1.20) or in sub-group analyses (age, sex, high-risk comorbidities, seropositivity or symptom duration at enrollment). We observed no difference in time to symptom resolution (initial: HR 0.84, 95% CI 0.54 - 1.29; sustained: HR 0.87, 95% CI 0.52 - 1.45). We detected no difference in accumulation of transition mutations in the viral genome during treatment. Conclusions: Our data do not support favipiravir use at commonly used doses in outpatients with uncomplicated COVID-19. Further research is needed to ascertain if higher doses of favipiravir are effective and safe for patients with COVID-19.

10: PerSVade: Personalized Structural Variation detection in your species of interest
more details view paper

Posted 23 Nov 2021

PerSVade: Personalized Structural Variation detection in your species of interest
2 tweets bioRxiv bioinformatics

Miquel Angel Schikora-Tamarit, Toni Gabaldon

Structural variants (SVs) like translocations, deletions, and other rearrangements underlie genetic and phenotypic variation. SVs are often overlooked due to difficult detection from short-read sequencing. Most algorithms yield low recall on humans, but the performance in other organisms is unclear. Similarly, despite remarkable differences across species genomes, most approaches use parameters optimized for humans. To overcome this and enable species-tailored approaches, we developed perSVade (personalized Structural Variation Detection), a pipeline that identifies SVs in a way that is optimized for any input sample. Starting from short reads, perSVade uses simulations on the reference genome to choose the best SV calling parameters. The output includes the optimally-called SVs and the accuracy, useful to assess the confidence in the results. In addition, perSVade can call small variants and copy-number variations. In summary, perSVade automatically identifies several types of genomic variation from short reads using sample-optimized parameters. We validated that perSVade increases the SV calling accuracy on simulated variants for six diverse eukaryotes, and on datasets of validated human variants. Importantly, we found no universal set of optimal parameters, which underscores the need for species-specific parameter optimization. PerSVade will improve our understanding about the role of SVs in non-human organisms.

11: The BNT162b2 mRNA vaccine against SARS-CoV-2 reprograms both adaptive and innate immune responses
more details view paper

Posted 06 May 2021

The BNT162b2 mRNA vaccine against SARS-CoV-2 reprograms both adaptive and innate immune responses
2 tweets medRxiv infectious diseases

F. Konstantin Föhse, Büsranur Geckin, Gijs J. Overheul, Josephine van de Maat, Gizem Kilic, Ozlem Bulut, Helga Dijkstra, Heidi Lemmers, S. Andrei Sarlea, Maartje Reijnders, Jacobien Hoogerwerf, Jaap ten Oever, Elles Simonetti, Frank L van de Veerdonk, Leo A.B. Joosten, Bart Haagmans, Reinout van Crevel, Yang Li, Ronald P. van Rij, Corine GeurtsvanKessel, Marien I. de Jonge, Jorge Domínguez-Andrés, Mihai G. Netea

The mRNA-based BNT162b2 vaccine from Pfizer/BioNTech was the first registered COVID-19 vaccine and has been shown to be up to 95% effective in preventing SARS-CoV-2 infections. Little is known about the broad effects of the new class of mRNA vaccines, especially whether they have combined effects on innate and adaptive immune responses. Here we confirmed that BNT162b2 vaccination of healthy individuals induced effective humoral and cellular immunity against several SARS-CoV-2 variants. Interestingly, however, the BNT162b2 vaccine also modulated the production of inflammatory cytokines by innate immune cells upon stimulation with both specific (SARS-CoV-2) and non-specific (viral, fungal and bacterial) stimuli. The response of innate immune cells to TLR4 and TLR7/8 ligands was lower after BNT162b2 vaccination, while fungi-induced cytokine responses were stronger. In conclusion, the mRNA BNT162b2 vaccine induces complex functional reprogramming of innate immune responses, which should be considered in the development and use of this new class of vaccines.

12: Fibroblastic reticular cells provide a supportive niche for lymph node-resident macrophages
more details view paper

Posted 24 Nov 2021

Fibroblastic reticular cells provide a supportive niche for lymph node-resident macrophages
2 tweets bioRxiv immunology

Joshua D'Rozario, Konstantin Knoblich, Mechthild Luetge, Christian Perez Shibayama, Hung-Wei Cheng, Yannick O Alexandre, David Roberts, Joana Campos, Jillian Astarita, Emma Dutton, Muath Suliman, Alice E Denton, Shannon J Turley, Richard L Boyd, Scott Mueller, Burkhard Ludewig, Tracy Heng, Anne L Fletcher

The lymph node (LN) is home to resident macrophage populations that are essential for immune function and homeostasis. The T cell paracortical zone is a major site of macrophage efferocytosis of apoptotic cells, but key factors controlling this niche are undefined. Here we show that fibroblastic reticular cells (FRCs) are an essential component of the LN macrophage niche. Macrophages co-localised with FRCs in human LNs, and murine single-cell RNA-sequencing revealed that most reticular cells expressed master macrophage regulator CSF1. Functional assays showed that CSF1R signalling was sufficient to support macrophage development. In the presence of LPS, FRCs underwent a mechanistic switch and maintained support through CSF1R-independent mechanisms. These effects were conserved between mouse and human systems. Rapid loss of macrophages and monocytes from LNs was observed upon genetic ablation of FRCs. These data reveal a critically important role for FRCs in the creation of the parenchymal macrophage niche within LNs.

13: SARS-CoV-2 mRNA Vaccination-Associated Myocarditis in Children Ages 12-17: A Stratified National Database Analysis
more details view paper

Posted 08 Sep 2021

SARS-CoV-2 mRNA Vaccination-Associated Myocarditis in Children Ages 12-17: A Stratified National Database Analysis
2 tweets medRxiv epidemiology

Tracy Beth Hoeg, Allison Krug, Josh Stevenson, John Mandrola

Objectives: Establishing the rate of post-vaccination cardiac myocarditis in the 12-15 and 16-17-year-old population in the context of their COVID-19 hospitalization risk is critical for developing a vaccination recommendation framework that balances harms with benefits for this patient demographic. Design, Setting and Participants: Using the Vaccine Adverse Event Reporting System (VAERS), this retrospective epidemiological assessment reviewed reports filed between January 1, 2021, and June 18, 2021, among adolescents ages 12-17 who received mRNA vaccination against COVID-19. Symptom search criteria included the words myocarditis, pericarditis, and myopericarditis to identify children with evidence of cardiac injury. The word troponin was a required element in the laboratory findings. Inclusion criteria were aligned with the CDC working case definition for probable myocarditis. Stratified cardiac adverse event (CAE) rates were reported for age, sex and vaccination dose number. A harm-benefit analysis was conducted using existing literature on COVID-19-related hospitalization risks in this demographic. Main outcome measures: 1) Stratified rates of mRNA vaccine-related myocarditis in adolescents age 12-15 and 16-17; and 2) harm-benefit analysis of vaccine-related CAEs in relation to COVID-19 hospitalization risk. Results: A total of 257 CAEs were identified. Rates per million following dose 2 among males were 162.2 (ages 12-15) and 94.0 (ages 16-17); among females, rates were 13.0 and 13.4 per million, respectively. For boys 12-15 without medical comorbidities receiving their second mRNA vaccination dose, the rate of CAE is 3.7-6.1 times higher than their 120-day COVID-19 hospitalization risk as of August 21, 2021 (7-day hospitalizations 1.5/100k population) and 2.6-4.3-fold higher at times of high weekly hospitalization risk (2.1/100k), such as during January 2021. For boys 16-17 without medical comorbidities, the rate of CAE is currently 2.1-3.5 times higher than their 120-day COVID-19 hospitalization risk, and 1.5-2.5 times higher at times of high weekly COVID-19 hospitalization. Conclusions: Post-vaccination CAE rate was highest in young boys aged 12-15 following dose two. For boys 12-17 without medical comorbidities, the likelihood of post vaccination dose two CAE is 162.2 and 94.0/million respectively. This incidence exceeds their expected 120-day COVID-19 hospitalization rate at both moderate (August 21, 2021 rates) and high COVID-19 hospitalization incidence. Further research into the severity and long-term sequelae of post-vaccination CAE is warranted. Quantification of the benefits of the second vaccination dose and vaccination in addition to natural immunity in this demographic may be indicated to minimize harm.

14: High-quality reference genome for an arid-adapted mammal, the banner-tailed kangaroo rat (Dipodomys spectabilis)
more details view paper

Posted 23 Nov 2021

High-quality reference genome for an arid-adapted mammal, the banner-tailed kangaroo rat (Dipodomys spectabilis)
2 tweets bioRxiv genomics

Avril M. Harder, Kimberly KO Walden, Nicholas J. Marra, Janna R. Willoughby

Kangaroo rats in the genus Dipodomys are found in a variety of habitat types in western North America, including deserts, arid and semi-arid grasslands, and scrublands. Many Dipodomys species are experiencing strong population declines due to increasing habitat fragmentation, with two species listed as federally endangered. The precarious state of many Dipodomys populations, including those occupying extreme environments, make species of this genus valuable subjects for studying the impacts of habitat degradation and fragmentation on population genomic patterns and for characterizing the genomic bases of adaptation to harsh conditions. To facilitate exploration of such questions, we assembled and annotated a reference genome for the banner-tailed kangaroo rat (D. spectabilis) using PacBio HiFi sequencing reads, providing a more contiguous genomic resource than two previously assembled Dipodomys genomes. Using the HiFi data for D. spectabilis and publicly available sequencing data for two other Dipodomys species (D. ordii and D. stephensi), we demonstrate the utility of this new assembly for studies of congeners by conducting inference of historic effective population sizes (Ne) and linking these patterns to the species' current extinction risk statuses. The genome assembly presented here will serve as a valuable resource for population and conservation genomic studies of Dipodomys species, comparative genomic research within mammals and rodents, and investigations into genomic adaptation to extreme environments and changing landscapes.

15: Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections
more details view paper

Posted 25 Aug 2021

Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections
2 tweets medRxiv infectious diseases

Sivan Gazit, Roei Shlezinger, Galit Perez, Roni Lotan, Asaf Peretz, Amir Ben-Tov, Dani Cohen, Khitam Muhsen, Gabriel Chodick, Tal Patalon

Background: Reports of waning vaccine-induced immunity against COVID-19 have begun to surface. With that, the comparable long-term protection conferred by previous infection with SARS-CoV-2 remains unclear. Methods: We conducted a retrospective observational study comparing three groups: (1)SARS-CoV-2-naive individuals who received a two-dose regimen of the BioNTech/Pfizer mRNA BNT162b2 vaccine, (2)previously infected individuals who have not been vaccinated, and (3)previously infected and single dose vaccinated individuals. Three multivariate logistic regression models were applied. In all models we evaluated four outcomes: SARS-CoV-2 infection, symptomatic disease, COVID-19-related hospitalization and death. The follow-up period of June 1 to August 14, 2021, when the Delta variant was dominant in Israel. Results: SARS-CoV-2-naive vaccinees had a 13.06-fold (95% CI, 8.08 to 21.11) increased risk for breakthrough infection with the Delta variant compared to those previously infected, when the first event (infection or vaccination) occurred during January and February of 2021. The increased risk was significant (P<0.001) for symptomatic disease as well. When allowing the infection to occur at any time before vaccination (from March 2020 to February 2021), evidence of waning natural immunity was demonstrated, though SARS-CoV-2 naive vaccinees had a 5.96-fold (95% CI, 4.85 to 7.33) increased risk for breakthrough infection and a 7.13-fold (95% CI, 5.51 to 9.21) increased risk for symptomatic disease. SARS-CoV-2-naive vaccinees were also at a greater risk for COVID-19-related-hospitalizations compared to those that were previously infected. Conclusions: This study demonstrated that natural immunity confers longer lasting and stronger protection against infection, symptomatic disease and hospitalization caused by the Delta variant of SARS-CoV-2, compared to the BNT162b2 two-dose vaccine-induced immunity. Individuals who were both previously infected with SARS-CoV-2 and given a single dose of the vaccine gained additional protection against the Delta variant.

16: No Significant Difference in Viral Load Between Vaccinated and Unvaccinated, Asymptomatic and Symptomatic Groups Infected with SARS-CoV-2 Delta Variant
more details view paper

Posted 29 Sep 2021

No Significant Difference in Viral Load Between Vaccinated and Unvaccinated, Asymptomatic and Symptomatic Groups Infected with SARS-CoV-2 Delta Variant
2 tweets medRxiv infectious diseases

Charlotte B. Acharya, John Schrom, Anthea M Mitchell, David A Coil, Carina Marquez, Susana Rojas, Chung Yu Wang, Jamin Liu, Genay Pilarowski, Leslie Solis, Elizabeth Georgian, Maya Petersen, Joseph DeRisi, Richard Michelmore, Diane Havlir

We found no significant difference in cycle threshold values between vaccinated and unvaccinated, asymptomatic and symptomatic groups infected with SARS-CoV-2 Delta. Given the substantial proportion of asymptomatic vaccine breakthrough cases with high viral levels, interventions, including masking and testing, should be considered for all in settings with elevated COVID-19 transmission.

17: Rab11 endosomes coordinate centrosome number and movement following mitotic exit
more details view paper

Posted 11 Aug 2021

Rab11 endosomes coordinate centrosome number and movement following mitotic exit
2 tweets bioRxiv cell biology

Nikhila Krishnan, Maxx Swoger, Michael Bates, Judy Freshour, Peter Fioramonti, Alison Elise Patteson, Heidi Hehnly

The last stage of cell division involves two daughter cells remaining interconnected by a cytokinetic bridge that is cleaved in a process called abscission. During pre-abscission, we identified that the centrosome moves in a Rab11-dependent manner towards the cytokinetic bridge in human cells grown in culture and in an in vivo vertebrate model, Danio rerio (zebrafish). Rab11-endosomes are dynamically organized in a Rab11-GTP dependent manner at the centrosome during pre-abscission and this organization is required for the centrosome protein, pericentrin, to be enriched at the centrosome. Using zebrafish embryos, we found that reduction in pericentrin expression or optogenetically disrupting Rab11-endosome function inhibited centrosome movement towards the cytokinetic bridge and abscission resulting in daughter cells prone to being binucleated and/or having supernumerary centrosomes. These studies suggest that Rab11-endosomes contribute to centrosome function during pre-abscission by regulating pericentrin organization resulting in appropriate centrosome movement towards the cytokinetic bridge and subsequent abscission.

18: Population based estimates of comorbidities affecting risk for complications from COVID-19 in the US
more details view paper

Posted 02 Apr 2020

Population based estimates of comorbidities affecting risk for complications from COVID-19 in the US
2 tweets medRxiv epidemiology

Mary L. Adams, David L. Katz, Joseph Grandpre

We used 2017 Behavioral Risk Factor Surveillance System (BRFSS) data (N=444,649) to estimate the proportion of US adults who report comorbidities that suggest heightened risk of complications from COVID-19. Co-morbidities included cardiovascular disease, chronic obstructive pulmonary disease (COPD), diabetes, asthma, hypertension, and/or cancer other than skin, based on data from China. Overall 45.4% (95% CI 45.1-45.7) of adults reported any of the 6 comorbidities, increasing from 19.8% (19.1-20.4) for ages 18-29 years to 80.7% (79.5-81.8) for ages 80+ years. State rates ranged from 37.3% (36.2-38.5) in Utah to 58.7% (57.0-60.4) in West Virginia. Rates also varied by race/ethnicity, health insurance status, and employment. Excluded were residents of nursing homes or assisted living facilities. Although almost certainly an underestimate of all adults at risk due to these exclusions, these results should help in estimating healthcare needs for adults with COVID-19 complications living in the community. Article Summary LineOverall, 45.4% of US adults were estimated to be at heightened risk of COVID-19 complications due to co-morbidities, increasing from 19.8% for ages 18-29 years to 80.7% for ages 80+ years, with state-to-state variation.

19: COVID-19 vaccines dampen genomic diversity of SARS-CoV-2: Unvaccinated patients exhibit more antigenic mutational variance
more details view paper

Posted 05 Jul 2021

COVID-19 vaccines dampen genomic diversity of SARS-CoV-2: Unvaccinated patients exhibit more antigenic mutational variance
2 tweets medRxiv infectious diseases

Michiel JM Niesen, Praveen Anand, Eli Silvert, Rohit Suratekar, Colin Pawlowski, Pritha Ghosh, Patrick J Lenehan, Travis Hughes, David Zemmour, John C OHoro, Joseph D Yao, Bobbi S Pritt, Andrew Norgan, Ryan T Hurt, Andrew D Badley, AJ Venkatakrishnan, Venky Soundararajan

Variants of SARS-CoV-2 are evolving under a combination of immune selective pressure in infected hosts and natural genetic drift, raising a global alarm regarding the durability of COVID-19 vaccines. Here, we conducted longitudinal analysis over 1.8 million SARS-CoV-2 genomes from 183 countries or territories to capture vaccination-associated viral evolutionary patterns. To augment this macroscale analysis, we performed viral genome sequencing in 23 vaccine breakthrough COVID-19 patients and 30 unvaccinated COVID-19 patients for whom we also conducted machine-augmented curation of the electronic health records (EHRs). Strikingly, we find the diversity of the SARS-CoV-2 lineages is declining at the country-level with increased rate of mass vaccination (n = 25 countries, mean correlation coefficient = -0.72, S.D. = 0.20). Given that the COVID-19 vaccines leverage B-cell and T-cell epitopes, analysis of mutation rates shows neutralizing B-cell epitopes to be particularly more mutated than comparable amino acid clusters (4.3-fold, p < 0.001). Prospective validation of these macroscale evolutionary patterns using clinically annotated SARS-CoV-2 whole genome sequences confirms that vaccine breakthrough patients indeed harbor viruses with significantly lower diversity in known B cell epitopes compared to unvaccinated COVID-19 patients (2.3-fold, 95% C.I. 1.4-3.7). Incidentally, in these study cohorts, vaccinated breakthrough patients also displayed fewer COVID-associated complications and pre-existing conditions relative to unvaccinated COVID-19 patients. This study presents the first known evidence that COVID-19 vaccines are fundamentally restricting the evolutionary and antigenic escape pathways accessible to SARS-CoV-2. The societal benefit of mass vaccination may consequently go far beyond the widely reported mitigation of SARS-CoV-2 infection risk and amelioration of community transmission, to include stemming of rampant viral evolution.

20: Effectiveness of Ivermectin-Based Multidrug Therapy in Severe Hypoxic Ambulatory COVID-19 Patients
more details view paper

Posted 07 Jul 2021

Effectiveness of Ivermectin-Based Multidrug Therapy in Severe Hypoxic Ambulatory COVID-19 Patients
2 tweets medRxiv infectious diseases

Sabine Hazan, Sonya Dave, Anoja W. Gunaratne, Sibasish Dolai, Peter A McCullough, Robert Clancy, Thomas J Borody

Ivermectin is a safe, inexpensive and effective early COVID-19 treatment validated in 20+ RCTs. Having developed combination therapies for Helicobacter pylori, we tested various COVID-19 combinations and describe the most effective. In 24 consecutive COVID-19 subjects with high risk features, hypoxia and untreated moderate-severe symptoms averaging 9 days, we trialed this novel combination comprising ivermectin, doxycycline, zinc, and Vitamins D and C. It was highly effective. All subjects resolved symptoms in 11 days on average, and oxygen saturation improved in 24hrs (87.4% to 93.1%, p=0.001). Hospitalizations and deaths were significantly fewer (p<0.002 or 0.05, respectively) than in background-matched controls from the CDC database. Triple combination therapy is safe and effective even in moderate-severe patients with hypoxia treated in the outpatient setting.

Previous page 1 2 3 4 Next page

PanLingua

News