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Modeling SARS-CoV-2 propagation using rat coronavirus-associated shedding and transmission
Caroline J Zeiss1, Jennifer L Asher1, Brent Vander Wyk2
1Department of Comparative Medicine, Yale School of Medicine, New Haven, CT, United States of America.
Plos One
|November 23, 2021
Summary
Even after infection or vaccination, individuals can still shed and transmit SARS-CoV-2. This study modeled viral shedding and transmission in rats, showing ongoing potential for COVID-19 spread.
Area of Science:
- Virology
- Immunology
- Epidemiology
Background:
- Global immunity to SARS-CoV-2 is complex, involving susceptible, infected, and vaccinated individuals.
- Understanding viral shedding and transmission post-re-exposure is crucial for COVID-19 endemic stability.
Purpose of the Study:
- To model how prior natural infection or vaccination affects viral shedding and transmission upon re-exposure using Sialodacryoadenitis Virus (SDAV) in rats.
- To assess the potential for continued SARS-CoV-2 propagation by seropositive individuals.
Main Methods:
- Rats were infected with SDAV via high-risk (direct contact) or low-risk (fomite) exposure.
- Animals were reinfected after 3.7-5.5 months.
- Viral shedding and transmission to naive recipients were monitored.
Main Results:
- Seropositive rats shed virus upon re-exposure, with transmission occurring to 25% of naive contacts from naturally infected animals.
- Vaccinated rats transmitted SDAV to only 4.7% of naive contacts, despite comparable shedding.
- Transmission occurred even with low-level shedding and was not always a prerequisite for spread.
Conclusions:
- Low-level viral shedding in both naturally infected and vaccinated seropositive individuals can propagate infection.
- Results suggest that seropositive individuals (previously infected or vaccinated) may continue to propagate SARS-CoV-2.
