# Deep sequencing SARS-CoV-2 samples from New Mexico to interrogate immunological selection on genetic variants

> **NIH NIH P20** · NEW MEXICO STATE UNIVERSITY LAS CRUCES · 2021 · $734,660

## Abstract

Although vaccination has blunted the impact of the SARS-CoV-2 pandemic in several countries, the future impact
of this virus will depend on its transmissibility, virulence, and ability to evade naturally-acquired and vaccine-
mediated immunity. All three phenotypes are currently in flux due to the evolution and spread of novel SARS-
CoV-2 variants of concern. Importantly, all of these variants rose to prominence prior to widespread
vaccination. Thus, while some may be the product of immune-mediated selection, they did not evolve in response
to vaccination per se, and we know next to nothing about whether and how vaccination imposes selection on
SARS-CoV-2. To close this knowledge gap, the proposed research will address the question: Do vaccinated
study participants still acquire the SARS-CoV-2 virus, and if so, what variants do they carry? We
hypothesize that vaccine-mediated immunity may impose selection on variants in one of three ways: (i) between-
host selection in which vaccinees are more likely to be infected by variants pre-adapted for immune escape,
(ii) within-host selection in which novel variants with capacity for immune escape first evolve in individual
vaccinees, and may then be transmitted to vaccinated or unvaccinated individuals, or (iii) a combination of
within- and between host selection. Furthermore, we hypothesize that vaccine-mediated immunity will impose
stronger selection on SARS-CoV-2 than naturally-induced immunity or mAb therapy. Inferring patterns of
within-host selection requires data on within-host population variation, but to date, studies of within-host
populations of SARS-CoV-2 have been largely neglected in favor of consensus sequences. Thus, we will obtain
residual material from SARS-CoV-2 positive samples from the following groups: (1) ≥ 100 individuals infected at
least 5 days and any interval thereafter following vaccination, (2) ≥50 individuals being treated with mAbs, (3)
200 to 400 persistently infected individuals testing positive at least 5 days following an initial positive test, and
(4) the first positive test from 100 individuals testing positive early in the pandemic, to represent a control group
that is likely at an early point in their first infection. These samples will be provided by Tricore labs from
individuals tested in New Mexico. RNA extracted from samples will be subject to both Illumina and PacBio
sequencing; data from both approaches will be used to detect consensus variants, indels, and intra-host
single-nucleotide variants (iSNVs) at frequencies >2%, and the longer-read Pac Bio data will be used to
assess linkage between mutations, facilitating detection of recombination, e.g. (20), and mixed-variant
infections (co-infection). These data will be used to quantify intra-host diversity and selection, frequency of
common, sub-consensus mutations, convergent evolution of high-risk mutations present in VOC. Phylogenetic
association of iSNVs will also be analyzed. Novel mutations that fall with...

## Key facts

- **NIH application ID:** 10381048
- **Project number:** 3P20GM103451-21S1
- **Recipient organization:** NEW MEXICO STATE UNIVERSITY LAS CRUCES
- **Principal Investigator:** SHELLEY LUSETTI
- **Activity code:** P20 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $734,660
- **Award type:** 3
- **Project period:** 2001-09-30 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10381048

## Citation

> US National Institutes of Health, RePORTER application 10381048, Deep sequencing SARS-CoV-2 samples from New Mexico to interrogate immunological selection on genetic variants (3P20GM103451-21S1). Retrieved via AI Analytics 2026-06-11 from https://api.ai-analytics.org/grant/nih/10381048. Licensed CC0.

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