Towards a post-pandemic future for global pathogen genome sequencing

Estimating the deferred value of pathogen genomic data for secondary use

The COVID-19 pandemic has illuminated the utility of pathogen genomics and highlighted roadblocks to international data sharing. This article describes the deferred value of pathogen genomics data for secondary use using a set of 10,110 assembled genomes of Vibrio cholerae shared via international repositories between 2010 and 2024 as an illustrative representation of a pandemic disease. Trends in the quality, representativeness, and timeliness of data sharing as well as the increasing role of microbiology services as genomic data providers resulting from gradually improving access to sequencing technologies in countries with a high burden of disease were identified. The deferred value of individual and aggregated genomic data was tracked over time and mapped to geographical hot spots of cholera. The time lag between the collection of the samples for V. cholerae cultures and the submission of the genome to an international database remained eight years on average. The data value assessment described here paves the way for the international mobilization of quality microbial genomic data for global health and knowledge discovery.

SARS-CoV-2 Genomic Surveillance from Community-Distributed Rapid Antigen Tests, Wisconsin, USA

In the United States, SARS-CoV-2 genomic surveillance initially relied almost entirely on residual diagnostic specimens from nucleic acid amplification-based tests. However, use of those tests waned after the end of the COVID-19 Public Health Emergency on May 11, 2023. In Dane County, Wisconsin, we partnered with local- and state-level public health agencies and the South Central Library System to continue genomic surveillance by obtaining SARS-CoV-2 genome sequences from freely available community rapid antigen tests (RATs). During August 15, 2023-February 29, 2024, we received 227 RAT samples, from which we generated 127 sequences with >10× depth of coverage for >90% of the SARS-CoV-2 genome. In a subset of tests, lower cycle threshold values correlated with sequence success. Our results demonstrated that collecting and sequencing results from RATs in partnership with community sites is a practical approach for sustaining SARS-CoV-2 genomic surveillance.

Emergence and interstate spread of highly pathogenic avian influenza A(H5N1) in dairy cattle in the United States

Highly pathogenic avian influenza (HPAI) viruses cross species barriers and have the potential to cause pandemics. In North America, HPAI A(H5N1) viruses related to the goose/Guangdong 2.3.4.4b hemagglutinin phylogenetic clade have infected wild birds, poultry, and mammals. Our genomic analysis and epidemiological investigation showed that a reassortment event in wild bird populations preceded a single wild bird-to-cattle transmission episode. The movement of asymptomatic or presymptomatic cattle has likely played a role in the spread of HPAI within the United States dairy herd. Some molecular markers that may lead to changes in transmission efficiency and phenotype were detected at low frequencies. Continued transmission of H5N1 HPAI within dairy cattle increases the risk for infection and subsequent spread of the virus to human populations.

Comprehensive molecular epidemiology of influenza viruses in Brazil: insights from a nationwide analysis

Influenza A and B viruses represent significant global health threats, contributing substantially to morbidity and mortality rates. However, a comprehensive understanding of the molecular epidemiology of these viruses in Brazil, a continental-size country and a crucial hub for the entry, circulation, and dissemination of influenza viruses within South America, still needs to be improved. This study addresses this gap by consolidating data and samples across all Brazilian macroregions, as part of the Center for Viral Surveillance and Serological Assessment project, together with an extensive number of other Brazilian sequences provided by a public database during the epidemic seasons spanning 2021-23. Phylogenetic analysis of the hemagglutinin segment of influenza A/H1N1pdm09, A/H3N2, and influenza B/Victoria-lineage viruses revealed that in 2021 and in the first semester of 2022, the A/H3N2 2a.3 strain was the predominant circulating strain. Subsequently, the A/H3N2 2b became the prevalent strain until October, when it was substituted by A/H1N1pdm09 5a.2a and 5a.2a.1 lineages. This scenario was maintained during the year of 2023. B/Victoria emerged and circulated at low levels between December 2021 and September 2022 and then became coprevalent with A/H1N1pdm09 5a.2a and 5a.2a.1 lineages. The comparison between the vaccine strain A/Darwin/9/2021 and circulating viruses revealed shared mutations to aspartic acid at residues 186 and 225 across all A/H3N2 lineages from 2021 to 2023, altering the charge in the receptor-binding domain. For A/H1N1pdm09, the 2022 consensus of 5a.2a.1 and the vaccine strain A/Victoria/2570/2019 showed 14 amino acid substitutions. Key residues H180, D187, K219, R223, E224, and T133 are involved in hydrogen interactions with sialic acids, while N130, K142, and D222 may contribute to distance interactions based on docking analyses. Importantly, distinct influenza A lineage frequency patterns were observed across Brazil's macroregions, underscoring the regional variations in virus circulation. This study characterizes influenza A and B viruses circulating in Brazil, providing insights into their circulation patterns and dynamics across Brazilian macroregions. These findings hold significant implications for public health interventions, informing strategies to mitigate transmission risks, optimize vaccination efforts, and enhance outbreak control measures.

Optimizing next-generation sequencing efficiency in clinical settings: analysis of read length impact on cost and performance

BACKGROUND

The expansion of sequencing technologies as a result of the response to the COVID-19 pandemic enabled pathogen (meta)genomics to be deployed as a routine component of surveillance in many countries. Scaling genomic surveillance, however, comes with associated costs in both equipment and sequencing reagents, which should be optimized. Here, we evaluate the cost efficiency and performance of different read lengths in identifying pathogens in metagenomic samples. We carefully evaluated performance metrics, costs, and time requirements relative to choices of 75, 150 and 300 base pairs (bp) read lengths in pathogen identification.

RESULTS

Our findings revealed that moving from 75 bp to 150 bp read length approximately doubles both the cost and sequencing time. Opting for 300 bp reads leads to approximately two- and three-fold increases, respectively, in cost and sequencing time compared to 75 bp reads. For viral pathogen detection, the sensitivity median ranged from 99% with 75 bp reads to 100% with 150-300 bp reads. However, bacterial pathogens detection was less effective with shorter reads: 87% with 75 bp, 95% with 150 bp, and 97% with 300 bp reads. These findings were consistent across different levels of taxa abundance. The precision of pathogen detection using shorter reads was comparable to that of longer reads across most viral and bacterial taxa.

CONCLUSIONS

During disease outbreak situations, when swift responses are required for pathogen identification, we suggest prioritizing 75 bp read lengths, especially if detection of viral pathogens is aimed. This practical approach allows better use of resources, enabling the sequencing of more samples using streamlined workflows, while maintaining a reliable response capability.

A retrospective study revealing complex viral diversity and a substantial burden of HPV infection in SARS-CoV-2 positive individuals, Sierra Leone

BACKGROUND

The COVID-19 pandemic has underscored the critical role of sequencing technology in disease control and outbreak response. However, resource limitations and challenging environments often impede such efforts in low and middle-income countries. This study aimed to investigate the spectrum of viral co-infections, particularly with human viral pathogens, in SARS-CoV-2 positive individuals in Sierra Leone using metagenomic sequencing, evaluating the feasibility of utilizing this technology for epidemiological and evolutionary surveillance of pathogens related to public health in low-income environments.

METHODS

We retrospectively collected and analyzed 98 nasopharyngeal swab specimens from SARS-CoV-2 positive individuals in Sierra Leone. Samples were pre-processed locally and transferred to China via FTA cards for metagenomic sequencing, which was performed using the Novaseq platform. The study focused on the identification of nasopharyngeal viruses co-infecting with SARS-CoV-2, with a deeper analysis of significant human viral pathogens such as HPV.

RESULTS

The study identified 22 viral taxa from 20 families, including 4 human viruses. Notably, 19.4% of samples showed HPV co-infection with 34 distinct types, predominantly beta and gamma HPVs. Multiple HPV types were found in individual samples, indicating a high complexity of viral co-infections.

CONCLUSIONS

The identification of a wide range of co-infecting viruses, particularly multiple HPV genotypes, highlights the complexity of viral interactions and their potential implications for public health. These findings enhance our understanding of viral co-infections and provide valuable insights for public health interventions in Sierra Leone. Further research is needed to explore the clinical significance of these findings and their impact on disease outcomes.

Real-time identification of epistatic interactions in SARS-CoV-2 from large genome collections

BACKGROUND

The emergence of the SARS-CoV-2 virus has highlighted the importance of genomic epidemiology in understanding the evolution of pathogens and guiding public health interventions. The Omicron variant in particular has underscored the role of epistasis in the evolution of lineages with both higher infectivity and immune escape, and therefore the necessity to update surveillance pipelines to detect them early on.

RESULTS

In this study, we apply a method based on mutual information between positions in a multiple sequence alignment, which is capable of scaling up to millions of samples. We show how it can reliably predict known experimentally validated epistatic interactions, even when using as little as 10,000 sequences, which opens the possibility of making it a near real-time prediction system. We test this possibility by modifying the method to account for the sample collection date and apply it retrospectively to multiple sequence alignments for each month between March 2020 and March 2023. We detected a cornerstone epistatic interaction in the Spike protein between codons 498 and 501 as soon as seven samples with a double mutation were present in the dataset, thus demonstrating the method's sensitivity. We test the ability of the method to make inferences about emerging interactions by testing candidates predicted after March 2023, which we validate experimentally.

CONCLUSIONS

We show how known epistatic interaction in SARS-CoV-2 can be detected with high sensitivity, and how emerging ones can be quickly prioritized for experimental validation, an approach that could be implemented downstream of pandemic genome sequencing efforts.

SARS-CoV-2 resistance to monoclonal antibodies and small-molecule drugs

Over four years have passed since the beginning of the COVID-19 pandemic. The scientific response has been rapid and effective, with many therapeutic monoclonal antibodies and small molecules developed for clinical use. However, given the ability for viruses to become resistant to antivirals, it is perhaps no surprise that the field has identified resistance to nearly all of these compounds. Here, we provide a comprehensive review of the resistance profile for each of these therapeutics. We hope that this resource provides an atlas for mutations to be aware of for each agent, particularly as a springboard for considerations for the next generation of antivirals. Finally, we discuss the outlook and thoughts for moving forward in how we continue to manage this, and the next, pandemic.