key: cord-1046674-u50x5uj2
authors: Stauft, Charles B.; Selvaraj, Prabhuanand; Lien, Christopher Z.; Starost, Matthew F.; Wang, Tony T.
title: Long‐term immunity in convalescent Syrian hamsters provides protection against new‐variant SARS‐CoV‐2 infection of the lower but not upper respiratory tract
date: 2022-02-28
journal: J Med Virol
DOI: 10.1002/jmv.27641
sha: ac3e5b168b77ed75af0e03459aca3329e57dcf8b
doc_id: 1046674
cord_uid: u50x5uj2

COVID‐19 vaccines provide high levels of protection against severe disease and hospitalization due to severe acute respiratory syndrome‐related coronavirus 2 (SARS‐CoV‐2) infection. Vaccination may be less effective in preventing shedding of infectious viruses from otherwise immune patients. In this study, we describe breakthrough infections and shedding of infectious viruses in convalescent hamsters without significant replication in the lower respiratory tract following reinfection by Alpha and Delta variants despite high levels of circulating antibodies in sera. Using convalescent hamsters with long‐term immunity (up to 1 year) following infection by ancestral SARS‐CoV‐2, we can model aspects of recurring COVID‐19 in the context of preexisting immunity.

The ongoing plague of COVID-19 is perhaps the bestdocumented pandemic in human history and the first major threat to global public health to emerge during the age of big data. Almost real-time sequencing of clinical isolates and the availability of this information has led to a wealth of information about viral evolution. Variants of concern continue to emerge and are identified as severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) spreads and adapts to its new hosts.

Although some beta coronaviruses such as MERS and SARS-CoV-1 were responsible for outbreaks of severe disease, then either faded away or contained, others have become endemic. As SARS-CoV-2 begins to contend with vaccination programs and naturally acquired immunity, infections and deaths continue to occur. Aged Syrian Hamsters recapitulate many aspects of COVID-19 in humans 1,2 including upper respiratory tract (URT), lower respiratory tract (LRT) replication, pathology, and resistance to subsequent infection. 2 postinfection as described previously 9 according to an animal protocol approved by the Food and Drug Administration IACUC. The hamsters were tested for neutralizing antibodies by a 50% plaquereduction neutralization assay 10 just before challenge. A summary of the hamsters used in this study is presented in Table S1 .

To compare the ability of Alpha and Delta variants to cause breakthrough infections, convalescent hamsters with long-term immunity 

The authors declare no conflict of interests. 

Data sharing is not applicable to this article as no new data were created or analyzed in this study.

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Long-term immunity in convalescent Syrian hamsters provides protection against new-variant SARS-CoV-2 infection of the lower but not upper respiratory tract