# Why are some people not affected by the virus, yet, including me? **URL:** \ **Category:** The Quarantine Zone\ **Tags:** covid-quarantine\ **Created:** [August 23, 2020, 5:40pm UTC](https://boards.straightdope.com/t/why-are-some-people-not-affected-by-the-virus-yet-including-me/918832 "2020-08-23T17:40:39Z")\ **Posts on this page:** 1\ **Showing post:** 3
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [August 23, 2020, 6:11pm UTC](https://boards.straightdope.com/t/why-are-some-people-not-affected-by-the-virus-yet-including-me/918832/3 "2020-08-23T18:11:43Z")
> [@sta3535](#): > > I’m now starting to wonder why a majority of the people that I personally know or work with have not gotten sick from the virus, yet, including me as well, despite following the rules of social distancing and proper mask wearing. You’re surprised that following the scientific guidelines to minimize the chance of catching the virus has worked? In any event, it’s well established that the great majority of people who catch the virus don’t get very sick, or are completely asymptomatic. So you don’t know that you have been virus-free. Why is there so much variance in response to the virus, even after taking into account risk factors like age and other preexisting medical conditions? (1) Genetics. This may include such things as variants in the cell surface proteins that the virus interacts with; blood type has been implicated; and almost certainly HLA haplotype will be a factor, an aspect of the immune system that has evolved to be highly variable in the popluation, for the express purpose of ensuring that a pathogen that can evade one person’s immune system cannot necessarily evade everyone’s immune systems. (2) A significant proportion of the population may have acquired some degree of cell-mediated immunity due to prior exposure to other coronaviruses. > [@Study published in Cell: Long term immunity likely even after antibody levels fade](https://boards.straightdope.com/t/study-published-in-cell-long-term-immunity-likely-even-after-antibody-levels-fade/918464/1): > > A [study](https://www.cell.com/cell/fulltext/S0092-8674(20)31008-4?rss=yes) published in the journal Cell points to a vigorous and lasting immune response even after antibody levels to the virus fade. Researchers examined blood samples from patients who recovered from COVID and found memory T cells in virtually all patients who had recovered from the infection, and many who were merely exposed or who had an asymptomatic infection. A full 100% of samples from those who had a severe infection showed such memory T cells, 87% of those with a mild case, and even 67%… --- _[View the full topic](https://boards.straightdope.com/t/why-are-some-people-not-affected-by-the-virus-yet-including-me/918832)._