4 surprising reasons scientists think asymptomatic coronavirus cases are so common

N95 masks.
(Image credit: John Moore/Getty Images)

The coronavirus is a serious, often-deadly pathogen, yet the Centers for Disease Control and Prevention estimates 40 percent of all cases are asymptomatic. In some isolated outbreaks in prisons and food processing plants where thousands of people contracted COVID-19, as many as 94 percent of infected individuals presented no symptoms. The Washington Post spoke to experts and suggested four possible reasons as to why, though it's important to note the research in all cases is in early stages.

T-Cells: T-cells, a type of white blood cell that generally provides longer-lasting immunity than antibodies, may be the key to understanding resistance. One research group found that, among uninfected blood samples donated to a blood bank between 2015 and 2018, a "remarkable" 40 to 60 percent recognized the coronavirus, suggesting some people may have an immune response based on memory of other, less potent coronaviruses.

Vaccines: The Mayo Clinic is studying whether vaccines for other pathogens can protect against the virus, as has been proven in other situations. Seven types of vaccines given one, two, or five years in the past were found to be associated with a lower rate of coronavirus infection, particularly pneumonia and polio vaccines.

Subscribe to The Week

Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.

SUBSCRIBE & SAVE
https://cdn.mos.cms.futurecdn.net/flexiimages/jacafc5zvs1692883516.jpg

Sign up for The Week's Free Newsletters

From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.

From our morning news briefing to a weekly Good News Newsletter, get the best of The Week delivered directly to your inbox.

Sign up

Allergies: Scientists have noted children with asthma and allergies surprisingly don't seem to be at high risk of developing serious cases of COVID-19. One theory is that those children have a reduced number of ACE2 receptors, the protein the virus latches onto before replicating inside the body. Without those receptors, the virus' chance of causing damage could decrease, meaning allergies may offer protection in this case.

Masks: Masks are discussed as a preventative measure, but they may contribute to more mild infections, as well. The most direct evidence of this theory is a comparison of two cruise ships. On the Diamond Princess, where masks weren't used, 47 percent of the positive cases were asymptomatic, whereas an Antarctic-bound Argentine cruise ship that had a similar outbreak, but provided masks to all passengers and crew, saw an 81 percent asymptomatic rate. Read more at The Washington Post.

To continue reading this article...
Continue reading this article and get limited website access each month.
Get unlimited website access, exclusive newsletters plus much more.
Cancel or pause at any time.
Already a subscriber to The Week?
Not sure which email you used for your subscription? Contact us