If you know someone who has had coronavirus and recovered from it, you have likely spoken with them about how the positive aspect of the whole thing is that they now have more immunity to COVID-19 than someone who has never had it.
While that is a silver lining to contracting the virus, it turns out that some people actually have a “head start” when it comes to immunity to the coronavirus– even if they haven’t ever been exposed. A new study shows that some people who were never exposed to coronavirus have helper T cells that are actually capable of recognizing and responding to the COVID-19 virus.
Why could some people have a “head start” against coronavirus?
The study, published last month in the journal Cell, suggests that some people’s immune system actually may have a head start in fighting the novel coronavirus. There were participants in the study who had never been exposed to the virus but still have the helper T cells that help fight off the coronavirus.
According to the researchers, the most likely explanation for some people having a head start when it comes to immunity to coronavirus is due to a phenomenon called cross-reactivity. Cross-reactivity is when helper T cells that actually developed in response to another virus but can react to a similar, but previously unknown, pathogen.
For someone with a headstart in immunity to coronavirus, the T cells may have been leftover from an individual’s previous exposure to a different coronavirus. In this case, the different coronavirus is most likely one of the four that causes the common cold.
“You’re starting with a little bit of an advantage – ahead starts in the arms race between the virus that wants to reproduce and the immune system wanting to eliminate it,” Alessandro Sette, one of the study’s co-authors, told Business Insider, adding that cross-reactive helper T cells could “help generate a faster, stronger immune response.”
How did researchers study this head start?
For this study, Sette and his team examined the immune systems of 20 individuals who previously had the coronavirus and recovered. The team also examines blood samples from 20 people that were collected between 2015 and 2015, which means that there was no chance the people that gave these samples had been exposed to the novel coronavirus.
Examining the 20 confirmed coronavirus patients, the researchers found that every person had the white blood cells that are specifically created to fight the virus as well as the resulting antibodies. This finding is good news for someone who has had the coronavirus and recovered from it.
“The data are suggestive that the average person makes a good immune response and may have immunity for some time,” Shane Crotty, another co-author of the study, told Business Insider.
Of the blood samples collected before the pandemic, 50% had a type of white blood cell called CD4+, which are T cells that help the immune system create antibodies. The researchers found these cells to be capable of not only recognizing the novel coronavirus but also promoting the immune system to fight back immediately.
Crotty also noted that this finding probably meant that the different vaccines that teams are working on should be able to replicate natural immunity.
While this research suggests some may be able to fight the new coronavirus better than others, more research is needed to know how much this cross-reactivity influences the severity of a coronavirus case.
Among the coronavirus patients studied, the researchers searched their blood samples for two types of white blood cells: CD4+ cells and CD8+ cells. The results of this research showed that while the patients were sick, all 20 individuals made antibodies and helper T cells that were capable of recognizing the novel coronavirus and respond to fight it. Additionally, 70% made killer T cells.
These findings suggest that people’s immune systems will able to identify and defend against the new coronavirus in the future.
The researchers were hesitant to speak on the virus 15 years or so down the line, at is extremely new. It is not known whether this immune response is long-lived or not. But given that your immune system reacts to specific events, Sette believes there is a reason for optimism, especially for those patients who had severe cases.
“The immune memory is related to the event. If it’s a strong event, you’ll have a strong memory,” Sette added. “If you almost got run over by a truck, you’ll remember it, but you may not remember the color of the socks you wore yesterday because it’s not a big deal.”
Jennifer Fabiano is an SEO reporter at Ladders.