Immunology experts at Duke-NUS Medical School in Singapore have found patients who previously had colds caused by viruses related to COVID-19, called betacoronaviruses, could have immunity against the deadly disease. The experts also suggested the strain of the cold could help provide protection for up to 17 years. Betacoronaviruses, specifically OC43 and HKU1, cause common colds but also severe chest infections in the oldest and youngest patients.
They share many genetic features with the coronaviruses COVID-19, MERS and SARS, all of which pass from animals to humans.
The scientists in the study found evidence that some immunity may be present for many years due to the body’s “memory” T-cells from attacks by previous viruses that bear a similar genetic make-up – such as the common cold.
T-cells are a type of white blood cell and form part of the immune system’s second line of defence to any viral attack.
They find and destroy infected cells and seen as vitally important for developing immunity to a virus.
The experts found patients who recovered from the deadly lung virus SARS in 2003 showed immune responses to key proteins found in COVID-19.
Researchers said: “These findings demonstrate that virus-specific memory T-cells induced by betacoronavirus infection are long-lasting, which supports the notion that Covid-19 patients would develop long-term T-cell immunity.
“Our findings also raise the intriguing possibility that infection with related viruses can also protect from or modify the pathology caused by SARS-Cov-2 [the strain of coronavirus that causes COVID-19].”
The study took blood from 24 patients who had recovered from COVID-19, 23 who had become ill from SARS and 18 who had never been exposed to either SARS or COVID-19.
Scientists found that half of the patients in the group with no exposure to either COVID-19 or SARS had T-cells which showed an immune response to the betacoronaviruses, COVID-19 and SARS.
This suggested patients’ immunity developed after exposure to common colds caused by betacoronavirus or possibly from other as yet unknown pathogens.
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