New evidence that common cold protects against COVID-19 infection

A new study led by researchers at Imperial College London, published in the journal Nature Communications, provides the first evidence of the protective role of pre-existing T cells
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While previous research has shown that other coronavirus-induced T cells can recognize SARS-CoV-2, the new study is the first to examine how the presence of these T cells actually affects whether someone is infected when exposed to SARS-CoV-2

The researchers also said their findings provide a blueprint for a second-generation universal vaccine that could protect against infection by current and future SARS-CoV-2 variants, including Omicron
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The study's lead author, Dr Ria Kundu, from the National Heart and Lung Institute at Imperial, said: "Exposure to the SARS-CoV-2 virus does not always lead to infection, and we have been eager to understand why
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High levels of pre-existing T cells produced during infection with other human coronaviruses, such as the common cold, protect against COVID-19 infection

“While this is an important finding, it is only a form of protection and I would like to stress that no one should rely on it alone
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Instead, the best way to protect yourself from COVID-19 is to be adequately vaccinated Vaccines, including boosters

The study began in September 2020, when most people in the UK were neither infected with SARS-CoV-2 nor vaccinated
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These included 52 people who lived with a patient with PCR-confirmed SARS-CoV-2 infection and were therefore exposed to the virus

52 participants had blood samples collected within 1-6 days of exposure to the virus
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This allowed the researchers to analyze the levels of pre-existing T cells induced by previous common cold coronavirus infections that also cross-recognize proteins from the SARS-CoV-2 virus

The researchers found significantly higher levels of these cross-reactive T cells in the 26 uninfected people compared to the 26 infected people
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These T cells target proteins inside the SARS-CoV-2 virus, rather than the spike protein on the surface of the virus, to prevent infection

Current vaccines do not elicit an immune response to these internal proteins
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Like our pre-existing potent spike protein-targeted vaccines, these internal proteins provide a new vaccine target that could provide durable protection, the researchers say, because T-cell responses last longer than antibody responses, which are will weaken in the next few months

The study's senior author, Professor Ajit Lalwani, Director of the NIH Health Protection Research Centre for Respiratory Infections at Imperial College London, said: " Our study provides the clearest evidence to date that the common cold coronavirus Induced T cells protected against SARS-CoV-2 infection
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These T cells provided protection by attacking proteins inside the virus rather than the spike protein on the surface of the virus

"The spike protein is under intense immune pressure from vaccine-induced antibodies, which drives the evolution of vaccine-evading mutants
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By contrast, we identified far fewer mutations in the internal proteins targeted by protective T cells

The researchers noted several limitations of their study, including that, because of the small size of the study and 88 percent of participants of white European ethnicity, it was not possible for them to model demographic factors
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notes

1. These proteins include the outer surface proteins (spike, membrane, and envelope proteins) on the surface of the SARS-CoV-2 virus, as well as internal proteins, including the nucleocapsid (which wraps viral genetic material) and ORF1 (which SARS-CoV-2 replicates part of the mechanism)
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2. Targeted internal proteins of SARS-CoV-2 include only nucleocapsid and ORF1

Reference: "Cross-reactive memory T cells associate with protection against SARS-CoV-2 infection in COVID-19 contacts" by Rhia Kundu, Janakan Sam Narean, Lulu Wang, Joseph Fenn, Timesh Pillay, Nieves Derqui Fernandez, Emily Conibear, Aleksandra Koycheva, Megan Davies, Mica Tolosa-Wright, Seran Hakki, Robert Varro, Eimear McDermott, Sarah Hammett, Jessica Cutajar, Ryan S.
Thwaites, Eleanor Parker, Carolina Rosadas, Myra McClure, Richard Tedder, Graham P.
Taylor, Jake Dunning and Ajit Lalvani, 10 January 2022, Nature Communications .

DOI: 10.
1038/s41467-021-27674-x