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At least 19 recordsLinked to original sources
PubMed2026

Synonymous mutations in essential genes infrequently produce fitness effects in human cell lines.

The assumption that synonymous mutations are fitness-neutral is central to many foundational results in the fields of genetics, genomics, evolutionary biology, and medicine. However, recent results suggest synonymous mutations have pervasive and strong fitness effects. These vigorously debated studies in non-human model systems have even suggested that the proportion of synonymous mutations and their fitness effect sizes are similar to non-synonymous mutations. To probe the fitness effect of synonymous mutations, we utilized recent advances in base editing to test 8558 potential synonymous mutations in 128 highly essential genes in human cell lines. Importantly, our library design excluded splice-proximal sites, ensuring a direct test of codon-level synonymous effects independent of splicing disruption. We find that synonymous mutations rarely have fitness effects on growth, occurring around 37.9-fold (95% CI: 22.16-81.48-fold) less frequently than missense mutations. In this experimental context, these findings demonstrate that synonymous mutations impact cellular fitness far less frequently than missense mutations. These results deviate from earlier reports of widespread synonymous fitness effects in yeast, yet they align with recent prime editing data observed in other human cell lines.

Humans↗
PubMed1992

Nonsynonymous polymorphic sites in the apolipoprotein (apo) A-IV gene are associated with changes in the concentration of apo B- and apo A-I-containing lipoproteins in a normal population.

The aims of this study were to detect polymorphic sites in the apolipoprotein (apo) A-IV gene, to establish their frequencies, to determine potential haplotypes, and to investigate the role of these polymorphisms in lipid metabolism. A sequencing study of four individuals led to the identification of two synonymous mutations (codons 9 and 54) and three nonsynonymous mutations (Val-8----Met, Gln360----His, and Thr347----Ser) and of a VNTR polymorphism within a series of three or four CTGT repeats in the noncoding region of exon 3. Frequencies of these polymorphisms were determined in 291 students by using naturally occurring (BstEII for the synonymous mutation in codon 54, HinfI for Thr347----Ser, and Fnu4HI for Gln360----His) or artificially introduced restriction-enzyme cutting sites (BstEII for the synonymous mutation in codon 9 and MamI for Val-8----Met), subsequent to PCR amplification. The four-base deletion/insertion polymorphism and its localization cis or trans to the mutations in codons 347 and 360 were studied by direct sequencing of PCR-amplified DNA from 87 students. Frequencies of the rarer alleles were .007 for apo A-IV-8:Met, .04 for the synonymous mutation in codon 9, .14 for the synonymous mutation in codon 54, .16 for apo A-IV347:Ser, .07 for apo A-IV360:His, and .39 for the four-base of insertion. Apo A-IV360:His in all cases was cis-localized to the (CTGT)3 repeat and apo A-IV347:Thr; and apo A-IV347:Ser was cis-localized to the (CTGT)4 repeat and apo A-IV360:Gln. Four haplotypes formed from these three polymorphic sites were thus found. The apo A-IV347:Ser allele was associated both with significantly lower plasma apo B concentrations in both sexes and with significantly lower LDL-cholesterol concentrations in men. Heterozygous carriers of apo A-IV360:His exhibited significantly higher concentrations of LDL-cholesterol and lower Lp(a) concentrations, compared with apo A-IV360:Gln homozygotes. We could not confirm the previously reported association of apo A-IV360:His with elevated HDL-cholesterol concentrations. In the population, the Val-8----Met polymorphism was not associated with significantly different lipid concentrations, but in a family study the Met-8 allele was associated with lower HDL-cholesterol and higher LDL-cholesterol concentrations. In conclusion, our results indicate an important role of the apo A-IV gene locus in the metabolism of apo B and, to a lesser extent, apo A-I containing lipoproteins.

Adult↗
PubMed2024

A novel splice-altering TNC variant (c.5247A > T, p.Gly1749Gly) in an Chinese family with autosomal dominant non-syndromic hearing loss.

BACKGROUND: This study aims to analyze the pathogenic gene in a Chinese family with non-syndromic hearing loss and identify a novel mutation site in the TNC gene. METHODS: A five-generation Chinese family from Anhui Province, presenting with autosomal dominant non-syndromic hearing loss, was recruited for this study. By analyzing the family history, conducting clinical examinations, and performing genetic analysis, we have thoroughly investigated potential pathogenic factors in this family. The peripheral blood samples were obtained from 20 family members, and the pathogenic genes were identified through whole exome sequencing. Subsequently, the mutation of gene locus was confirmed using Sanger sequencing. The conservation of TNC mutation sites was assessed using Clustal Omega software. We utilized functional prediction software including dbscSNV_AdaBoost, dbscSNV_RandomForest, NNSplice, NetGene2, and Mutation Taster to accurately predict the pathogenicity of these mutations. Furthermore, exon deletions were validated through RT-PCR analysis. RESULTS: The family exhibited autosomal dominant, progressive, post-lingual, non-syndromic hearing loss. A novel synonymous variant (c.5247A > T, p.Gly1749Gly) in TNC was identified in affected members. This variant is situated at the exon-intron junction boundary towards the end of exon 18. Notably, glycine residue at position 1749 is highly conserved across various species. Bioinformatics analysis indicates that this synonymous mutation leads to the disruption of the 5' end donor splicing site in the 18th intron of the TNC gene. Meanwhile, verification experiments have demonstrated that this synonymous mutation disrupts the splicing process of exon 18, leading to complete exon 18 skipping and direct splicing between exons 17 and 19. CONCLUSION: This novel splice-altering variant (c.5247A > T, p.Gly1749Gly) in exon 18 of the TNC gene disrupts normal gene splicing and causes hearing loss among HBD families.

Adult↗
PubMed2025

SARS-CoV-2 genomic diversity and within-host evolution in individuals with persistent infection in the UK: an observational, longitudinal, population-based surveillance study.

BACKGROUND: Persistent SARS-CoV-2 infections in hospitalised immunocompromised individuals are known to facilitate accelerated within-host viral evolution, potentially contributing to the emergence of highly divergent variants. However, little is known about the evolutionary dynamics and transmission risks of persistent infections in the general population. We aimed to characterise the within-host evolution of SARS-CoV-2 during persistent infections identified through a large community surveillance study. METHODS: We used data from the Office for National Statistics COVID-19 Infection Survey (ONS-CIS), a large-scale, longitudinal, population-based surveillance study conducted in the UK from April, 2020, to March, 2023. For this analysis, we focused on infections with high viral load (cycle threshold &#x2264;30) and available genome sequences, from seven major SARS-CoV-2 lineages (alpha, delta, BA.1, BA.2, BA.4, BA.5, and XBB). ONS-CIS participants were randomly selected from the general population and tested regularly by RT-PCR, regardless of symptoms. We defined persistent infections as those with sustained or rebounding high viral RNA titres for 26 days or longer. We examined associated host characteristics and used raw sequence data to identify de novo mutations and estimate within-host synonymous and non-synonymous evolutionary rates across the SARS-CoV-2 genome. FINDINGS: Between Nov 2, 2020, and March 21, 2023, we identified 576 persistent infections with at least two sequences, including 11 alpha, 106 delta, 102 BA.1, 204 BA.2, 16 BA.4, 133 BA.5, and 4 XBB. Persistent infections were more common in males than females (p<0&#xb7;0001) and individuals older than 60 years (p=0&#xb7;0027). The median within-host genome-wide evolutionary rate was 7&#xb7;9&#x2009;&#xd7;&#x2009;10-4 substitutions per site per year (IQR 7&#xb7;0-9&#xb7;0&#x2009;&#xd7;&#x2009;10-4), with high inter-individual variability driven largely by non-synonymous mutations, particularly in the N-terminal and receptor-binding domains of the spike protein. Longer infection duration was associated with higher evolutionary rates, while no associations were found with age, sex, vaccination status, previous infection, or virus lineage. We found no clear evidence of transmission beyond the first month of infection in any of the 84 persistent infections lasting 56 days or longer. In total, we identified 379 recurrent mutations, including many with known or predicted negative fitness effects and low prevalence at the population level, as well as de novo reversions to the Wuhan-Hu-1 reference sequence, which were likely under positive selection within those individuals. INTERPRETATION: This study highlights the heterogeneous nature of within-host SARS-CoV-2 evolution in individuals with persistent infection in the community. Notably, a small subset of persistent infections with high viral loads underwent accelerated viral evolution or recurrently acquired hallmark mutations found in novel variants. In addition, onward transmission from a persistent infection during the later stages of infection is likely to be rare. These insights have important implications for prioritising genomic surveillance and managing patients with persistent infections. FUNDING: Department of Health and Social Care.

Humans↗
PubMed2026

Wastewater-based sequencing of respiratory syncytial virus to investigate lineage dynamics and antigenic site mutations: a retrospective genomic epidemiology study.

BACKGROUND: Respiratory syncytial virus (RSV) infections pose a substantial health burden, particularly for clinically vulnerable populations such as infants and older adults. Although novel immunoprophylactic interventions show promise in providing protection, many countries may not have robust surveillance systems to monitor circulating RSV lineages and detect mutations that might reduce the effectiveness of these new interventions. We aimed to assess the diversity and temporal dynamics of circulating RSV lineages in urban populations through amplicon-based sequencing and analysis of wastewater extracts. METHODS: In this prospective observational wastewater-based genomic surveillance study, 32 raw influent 24-h composite samples were collected during the 2022-23 and 2023-24 RSV seasons from both Zurich and Geneva, Switzerland. We applied an RSV subtype-specific amplicon-based sequencing approach to obtain RSV-A and RSV-B sequences from all 64 samples. Mutations relative to reference genomes were identified at positions with read depth above 30. Relative abundances of RSV lineages were estimated from frequencies of lineage-signature mutations, present in greater than 90% of publicly available sequences of that lineage. FINDINGS: Relative abundances of RSV-B (2022-23) and RSV-A (2023-24) lineages were estimated over the two RSV seasons. During the 2022-23 season, the RSV-B B.D.E.1 lineage prevailed in both cities. In the 2023-24 season, multiple RSV-A lineages cocirculated, including A.D.1, A.D.3, A.D.5, and their sub-lineages. Identification and frequency estimation of mutations showed low-frequency, non-synonymous mutations in antigenic sites on the fusion gene of both RSV-A and RSV-B, some of which have not been reported in clinical sequences. The primary outcome was identification and relative abundance of RSV lineages in wastewater samples. INTERPRETATION: These findings show the potential of wastewater-based genomic surveillance to identify and track circulating RSV lineages and clinically relevant mutations. As novel RSV immunoprophylaxis measures are introduced in upcoming RSV seasons, wastewater-derived genomic RSV data provide a valuable baseline for understanding RSV diversity and future viral evolution under increased immunological pressure. FUNDING: This study was funded by the Swiss National Science Foundation and in part by the National Institute Of Allergy And Infectious Diseases of the National Institutes of Health. Funding for sample collection and processing was provided by the Swiss Federal Office of Public Health.

Humans↗
PubMed2025

Characterisation of a persistent SARS-CoV-2 infection lasting more than 750 days in a person living with HIV: a genomic analysis.

BACKGROUND: People who are immunocompromised can develop persistent SARS-CoV-2 infections. Several viral mutations accumulated during the course of such persistent infections have also been observed in prominent variants of concern (VOCs). Here, we characterise persistent infection and viral evolution of SARS-CoV-2 lasting more than 750 days in a person with advanced HIV-1 infection. METHODS: Between March, 2021, and July, 2022, eight clinical specimens were collected from a person living with HIV, neither receiving antiretroviral therapy nor virally suppressed, and presumed to have been initially infected with SARS-CoV-2 in mid-May, 2020. Viral RNA was extracted from each swab and an amplicon-based sequencing approach was used for genomic analysis of SARS-CoV-2. Variable sites were characterised at the consensus and subconsensus levels, and phylogenetic tools were applied to analyse viral evolution. Publicly available SARS-CoV-2 sequences from GenBank were leveraged to contextualise our sequenced samples and identify any potential evidence of transmission. FINDINGS: Genomes formed a monophyletic cluster in the B.1 lineage. 68 consensus and 67 subconsensus single nucleotide variants were observed over the course of infection. The intrahost clock rate remained similar to that of the interhost rate in contemporaneous community sequences (6&#xb7;74&#x2009;&#xd7;&#x2009;10-4 [95% credible interval 5&#xb7;05&#x2009;&#xd7;&#x2009;10-4 to 8&#xb7;54&#x2009;&#xd7;&#x2009;10-4] substitutions per site per year vs 6&#xb7;11&#x2009;&#xd7;&#x2009;10-4 [5&#xb7;54&#x2009;&#xd7;&#x2009;10-5 to 6&#xb7;66&#x2009;&#xd7;&#x2009;10-4]). Mutations grouped into two distinct subpopulations present throughout infection. 10 non-synonymous mutations in the spike protein gene were at positions in common with those defining the omicron lineage (BA.1 or BA.2), of which nine were present before November, 2021. Nine of 18 substitutions present throughout infection were rare in online databases, suggesting a lack of long transmission chains descending from this individual. INTERPRETATION: Convergent SARS-CoV-2 evolution, both in and outside the spike protein, observed in this study suggests parallels with the evolutionary process leading to emergence of the omicron VOC. The inferred absence of onward infections might indicate a loss of transmissibility during adaptation to a single host. Our results underscore the importance of appropriate treatment to cure persistent SARS-CoV-2 infections and monitoring them to understand how mutations contribute to viral adaptation. FUNDING: National Institute of General Medical Sciences of the National Institutes of Health, Centers for Disease Control and Prevention, the National Institute of Allergy and Infectious Diseases, MassCPR, and Morris Singer Foundation.

Humans↗
PubMed1992

Homology among Escherichia coli K1 and K92 polysialytransferases.

The neuS-encoded polysialytransferase (polyST) in Escherichia coli K1 catalyzes synthesis of polysialic acid homopolymers composed of unbranched sialyl alpha 2,8 linkages. Subcloning and complementation experiments showed that the K1 neuS was functionally interchangeable with the neuS from E. coli K92 (S. M. Steenbergen, T. J. Wrona, and E. R. Vimr, J. Bacteriol. 174:1099-1108, 1992), which synthesizes polysialic acid capsules with alternating sialyl alpha 2,8-2,9 linkages. To better understand the relationship between these polySTs, the complete K92 neuS sequence was determined. The results demonstrated that K1 and K92 neuS genes are homologous and indicated that the K92 copy may have evolved from its K1 homolog. Both K1 and K92 structural genes comprised 1,227 bp. There were 156 (12.7%) differences between the two sequences; among these mutations, 55 did not affect the derived primary structure of K92 polyST and hence were synonymous with the K1 sequence. Assuming maximum parsimony, another estimated 17 synonymous mutations plus 84 nonsynonymous mutations could account for the 70 amino acid replacements in K92 polyST; 36 of these replacements were judged to be conservative when compared with those of K1 polyST. There were no changes detected in the first 146 5' or last 129 3' bp of either gene, suggesting, in addition to the observed mutational differences, the possibility of a past recombination event between neuS loci of two different kps clusters. The results indicate that relatively few amino acid changes can account for the evolution of a glycosyltransferase with novel linkage specificity.

Amino Acid Sequence↗
PubMed1986

The rate with which spontaneous mutation alters the electrophoretic mobility of polypeptides.

Studies of a Japanese population, involving a total of 539,170 locus tests distributed over 36 polypeptides, yielded three presumptive spontaneous mutations altering the electrophoretic mobility of the polypeptide. This corresponds to a mutation rate of 0.6 X 10(-5) per locus per generation. The a priori probability that undetected discrepancies between legal and biological parentage might in our test system result in an apparent electrophoretic mutation in this population is calculated to be only 0.3 X 10(-7) per locus per generation. Since electrophoresis only detects about half of the amino acid substitutions due to mutations of nucleotides, the corrected rate for mutations causing amino acid substitutions in polypeptides is 1.2 X 10(-5) per locus per generation. With allowance for synonymous mutations and those resulting in stop codons, the total mutation rate for nucleotide changes in the exons encoding a polypeptide becomes approximately equal to 1.8 X 10(-5) per locus per generation. When the present observations are combined with all of the other available data concerning mutation resulting in electrophoretic variants, the electrophoretic rate drops to 0.3 X 10(-5) per locus per generation, the total locus rate drops to roughly 1.0 X 10(-5), and the nucleotide rate drops to 1 X 10(-8). Even with this lower estimate, given approximately equal to 2 X 10(9) nucleotides in the haploid genome and an average of 10(3) exon nucleotides per polypeptide encoded, the implication, if these exon rates can be generalized, is of approximately equal to 20 nucleotide mutations per gamete per generation. This estimate of the frequency of "point" mutations does not include small duplications, rearrangements, or deletions resulting from unequal crossing-over, transcription errors, etc.

Child↗
PubMed2026

The distribution of fitness effects of nonsynonymous mutations varies phylogenetically across animals.

The distribution of fitness effects (DFE) describes the selection coefficients of newly arising mutations and fundamentally influences population genetic processes. However, the extent and mechanisms of differences in the DFE for non-synonymous mutations have not been systematically investigated across species with divergent phylogenetic histories and ecologies. Here, we inferred the DFE in natural populations of 11 animal (sub)species, including humans, mice, fin whales, vaquitas, wolves, collared flycatchers, pied flycatchers, halictid bees, Drosophila, and mosquitoes. We found that mammals have a higher proportion of strongly deleterious mutations (defined as s&#x2264;-0.01; 22% to 47% in mammals; 0.0% to 5.4% in insects and birds) and a lower proportion of weakly deleterious mutations than insects and birds. Further, the DFE co-varies with phylogeny, such that the mean mutation effects are more similar in closely related species (Pagel's &#x3bb; = 0.84, P&#x2009;=&#x2009;0.01). Next, we investigated whether various summary statistics of the DFE were related to variation in life-history traits across these organisms. We found some support for genome size, body mass, and long-term effective population size being correlated with the DFE. Overall, our findings are consistent with predictions derived independently from the Fisher's Geometric Model (FGM), which defines organismal complexity as the number of phenotypes under selection. FGM predicts that mutations are more deleterious in complex organisms, while strongly deleterious mutations occur more frequently in smaller populations. Our study demonstrates strong phylogenetic signal in the evolution of a fundamental population genetics parameter, and proposes that, through mechanisms of epistasis, long-term population size and organismal complexity could be underlying variation in the DFE across animals.

Journal Article↗
PubMed2026

Epistasis and the changing fitness landscapes of SARS-CoV-2.

Since its emergence in late 2019, millions of SARS-CoV-2 genomes have been generated as part of global efforts to monitor the evolution and spread of the virus. This unprecedented volume of data provides a unique opportunity to study viral evolution at unparalleled resolution. In particular, individual genomic sites can be observed to have mutated independently thousands of times. These mutation counts have been used to estimate site-specific mutation rates and fitness effects for most mutations across the viral genome. Here, we use these data to investigate how the landscape of mutational fitness costs has changed over the course of the pandemic. SARS-CoV-2 evolution over the past 6 years has been characterized by the emergence of distinct variants separated by long branches corresponding to evolutionary saltations involving up to 50 mutations. We compare inferred fitness landscapes of the Spike protein across these variants and find that shifts in the estimated effects of non-synonymous mutations are linked to genetic differences between them. Sites with altered fitness costs are enriched near positions where the genetic backgrounds differ. To explain the observed changes, we introduce a model with pairwise epistatic interactions between mutations and residues that differ between variants. This model is able to explain about half of the variance in the shifts of fitness effects and suggests that each mismatch between variants substantially alters mutation effects at typically 1 to 3 additional positions.

SARS-CoV-2↗
PubMed1992

A germ line mutation within the coding sequence for the putative 5-phosphoribosyl-1-pyrophosphate binding site of hypoxanthine-guanine phosphoribosyltransferase (HPRT) in a Lesch-Nyhan patient: missense mutations within a functionally important region probably cause disease.

Lesch-Nyhan syndrome caused by a complete deficiency of hypoxanthine guanine phosphoribosyltransferase (HPRT) is the result of a heterogeneous group of germ line mutations. Identification of each mutant gene provides valuable information as to the type of mutation that occurs spontaneously. We report here a newly identified HPRT mutation in a Japanese patient with Lesch-Nyhan syndrome. This gene, designated HPRT Tokyo, had a single nucleotide change from G to A, as identified by sequencing cDNA amplified by the polymerase chain reaction. Allele specific oligonucleotide hybridization analysis using amplified genomic DNA showed that the mutant gene was transmitted from the maternal germ line. This mutation would lead to an amino acid substitution of Asp for Gly at the amino acid position 140 located within the putative 5-phosphoribosyl-1-pyrophosphate (PRPP) binding region. Missense mutations in human HPRT deficient patients thus far reported tend to accumulate in this functionally active region. However, a comparison of the data suggested that both missense and synonymous mutations can occur at any coding sequence of the human germ line HPRT gene, but that a limited percentage of all the missense mutations cause disease. The probability that a mutation will cause disease tends to be higher when the missense mutation is within a functionally important sequence.

Amino Acid Sequence↗
PubMedDate not supplied

[Molecular bases of evolution].

The general notions of the theory of evolution are listed. The unity of the "engineering principles" of the living nature is emphasized. The generalists and specialists species are discussed. The estimation of their evolution rates must be different if it is expressed by the number of species or by the morphological changes. The principles of "protein engineering" of the organisms and the role of metals in protein evolution are discussed. It is suggested that in the presence of ions of transition metals and zinc the Fox's proteinoids can possess more specific forms of enzymatic activity. In the evolution of language the horizontal transfer plays a much more important role than in the biological evolution. However in this case also the initial basis of the language remains. The random drift is considered and it is shown that in concordance with the neutralist theory there are no grounds to replace the calculation of the rates of mutational changes per time unity by the calculation per generation. The molecular drive is the main source of the evolutionary novelties. The drive is connected with drift. The synonymic mutations and the mutations in non-functional DNA are evolutionary important. The future mathematical theory of evolution must be based on the theory of Markov's chains with the stochastic matrix changing along the chain and containing the set of the non-diagonal members equal to zero. The results obtained in the theory of ontogeny are presented. The evolution of species is the evolution of ontogenies, the formation of the molecular theory of evolution can be possible only on the basis of the molecular theory of ontogeny. The internal causes of extinction of species reduce the accumulation of neutral and pseudo-neutral mutations.

Animals↗
PubMed2025

Comparative Genomic Analysis of Six Mycoplasma Gallisepticum Strains: Insights into Genetic Diversity and Antibiotic Resistance.

Mycoplasma gallisepticum (MG) is a significant pathogen that causes respiratory diseases, which have had a substantial economic impact on the poultry industry. Despite the resistance of MG to antibiotics, it is imperative to identify genetic diversity in order to develop countermeasures. In this study, the genomes of six MG strains were examined to gain deeper insights into the mutations. The data pertaining to Variant Annotation and Mutation Analysis using SnpEff, along with the calculation of mutation rates as the ratio of total mutations to the length of the genomic regions analyzed, were thoroughly examined. The comprehensive evaluation yielded a total of 25,942 variants across the six strains, underscoring substantial genetic diversity. Notably, strain S6 exhibited a preponderance of frameshift mutations. A notable finding was the presence of a mutation in the MsbA gene shared by all six strains. Furthermore, five of the six strains, with the exception of strain F99 Lab, exhibited a mutation at position 5158, which impacts a multidrug transport system. Notably, strain ATCC exhibits a distinctive mutation at position 942, while strain S6 displays a unique mutation at position 6855, which is linked to efflux ABC transporter components. Furthermore, a substantial degree of genetic variation was observed among the CrmA, GapA, and vlhA genes among the various strains. High-impact changes, such as insertions and deletions, exhibited a higher frequency in CrmA, particularly in strain S6. Conversely, nonsynonymous variations demonstrated a heightened prevalence in GapA, particularly in strain F99 Lab. The vlhA gene exhibited a spectrum of effects, ranging from synonymous mutations to high-impact mutations such as stop-gains and frameshifts, particularly in strains k5111a and k4602. The functional variations observed among the strains can be attributed to these mutations, which have the potential to alter gene expression or protein function. Furthermore, substantial mutations in the dxr and rpoC genes were associated with antibiotic resistance. These mutations underscore the ongoing evolutionary adaptations of M. gallisepticum. Consequently, there is an imperative for the revision of treatment protocols and the formulation of targeted vaccines to regulate resistance within the poultry industry.

Mycoplasma gallisepticum↗
PubMed2025

Impact of High-Titer Convalescent Plasma on Clinical and Virologic Outcomes Among Veterans Hospitalized With SARS-CoV-2 Infection: VA CoronavirUs Research and Efficacy Studies-1 (VA CURES-1).

In the initial absence of proven therapies, empirical COVID-19 convalescent plasma (CCP) was rapidly introduced for individuals hospitalized for COVID-19. Seventy-five participants were randomized from November 2020 to June 2021 in a double-blind, multi-site, placebo-controlled, randomized trial (VA CURES-1) evaluating the impact of CCP vs. saline in Veterans hospitalized with COVID-19 with hypoxemia. The composite primary outcome was acute hypoxemic respiratory failure or all-cause death by Day 29. We analyzed clinical outcomes, nasal viral RNA, plasma cytokines and viral evolution over time. Among 40 participants receiving saline and 35 receiving CCP with high neutralizing titers (median 1:1420), the percent reaching the primary outcome was similar (10%), as were time to clinical recovery and to nasal viral clearance. By whole genome sequencing, viral molecular complexity evolved pre- to posttreatment more frequently in recipients of saline vs. CCP (4 of 7 (57.1%) vs. 1 of 4 (25%), respectively), based on numbers of mixed allele positions. Numbers of amino acid-changing, non-synonymous mutations in the spike protein were greater in saline vs. CCP recipients. Both outcomes suggested purifying selection (reduced overall viral infection complexity) following CCP. In conclusion, convalescent plasma showed no significant clinical impact but may influence SARS-CoV-2 complexity. Trial Registration: ClinicalTrials.gov Identifier: NCT04539275.

Aged↗