# Transmission of CoV-2 and the Impact of Spike Protein Evolution

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2024 · $566,583

## Abstract

PROJECT SUMMARY
SARS-CoV-2 has led to unprecedented disruptions to society, killing more than 6 million people worldwide. It is
a respiratory virus whose main mode of transmission is via respiratory droplets and aerosols. Social distancing
and vaccines have greatly decreased the rate of infection and transmission. Despite these efforts, SARS-CoV-
2 transmission has continued. Moreover, different variants of concern, harboring signature mutations in the virus
attachment Spike protein, have emerged. How these changes affect transmission of SARS-CoV-2 in naïve,
infected and immunized individuals is not known. The transmission bottleneck is defined as the number of unique
virus particles that establish an infection in the recipient host. This number is important as it determines the rate
of evolution of the virus and the immune threshold required for protection from infection. This application will use
barcoded or tagged SARS-CoV-2 to quantify how many virus particles establish an infection in the recipient host.
We will use the Syrian hamster SARS-CoV-2 airborne transmission model to define how the innate and adaptive
immune response in the donor and recipient host effect the number of unique transmission events. Using
genetically modified hamsters that are deficient in their type I or III interferon response will be used to measure
the role of innate immunity on SARS-CoV-2 transmission to the upper respiratory tract (URT) and subsequent
dissemination of the virus to lower respiratory tract (LRT). Transmission and dissemination of SARS-CoV-2 will
also be quantified in recipient animals that were previously infected with SARS-CoV-2, immunized with mucosal
and systemic COVID-19 vaccines, or received neutralizing IgG and IgA antibodies. Finally, this application will
measure the impact of immune escape on the transmission bottleneck in immune recipients. Fundamental
insights into respiratory virus transmission and dissemination, transmission bottleneck and defining correlates of
protection in the URT and LRT will inform future vaccine efforts against respiratory viruses.

## Key facts

- **NIH application ID:** 10874383
- **Project number:** 5R01AI169022-02
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Adrianus CM Boon
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $566,583
- **Award type:** 5
- **Project period:** 2023-07-01 → 2027-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10874383

## Citation

> US National Institutes of Health, RePORTER application 10874383, Transmission of CoV-2 and the Impact of Spike Protein Evolution (5R01AI169022-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10874383. Licensed CC0.

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