The Omicron variant of the coronavirus has caused a global surge in Covid-19 infections. The highly mutated strain is believed to bypass existing vaccines and deliver a stronger infection to the host.
However, despite living with someone with Covid-19, some people do not contract the virus. How can this be?
A new study explores this angle, claiming that these people may have been exposed to other coronaviruses in the past, allowing them to make memory immune cells — called T cells. They offer higher protection against Covid-19.
“Cross-reactive immune responses to SARS-CoV-2 were observed in pre-pandemic cohorts and suggested to help protect the host,” said the study, published in the journal Nature, which examined 52 Covid-19 household contacts to capture their immune responses. The idea is to capture the immune response at the earliest time point after exposure to the Sars-CoV-2 virus.
Viruses from the coronavirus family, while causing different diseases, share some common characteristics, the researchers noted.
Their shared structural similarities enable immune cells that recognize one type of coronavirus to recognize the other, the study said.
Blood of all 52 household contacts was tested on days one to six. The researchers found higher levels of memory T cells in samples from people who tested negative for Covid-19 PCR than those who tested positive.
The researchers said the T cells they measured targeted not only the spike protein part of the virus, but also the nucleocapsid, the core part of the virus that stores its genetic material.
Meanwhile, earlier this week, an infectious disease expert said that vaccinated and unvaccinated people experience different Omicron symptoms.
Complete News Source : Hindustan Times
