AP Biology class blog for discussing current research in Biology

Tag: Asymptomatic

Your Genetics May Have Saved You From Getting COVID-19

Were you one of the, what felt like fairly few, people who never got COVID-19 when it seemed like everyone else did? Well, maybe you did and you were asymptomatic with COVID-19. I remember when my whole family was sick with this virus, except for me. I always thought it was just luck, and you might have as well, but what if certain gene mutations can prevent the symptoms of this virus.

In a study done by the National Institute of Health, researchers looked into the genetic variations and how they affected T cells in the immune system. The focus of the study was the human leukocyte antigen complex (HLA). The proteins of these genes prevented people from people feeling symptoms of COVID-19. The proteins of HLA helped the immune system react to the SARS-CoV-2 virus by recognizing the infected cells by presenting pieces of pathogens to the T cells.

HLA-B*2705-peptide in complex with influenza nucleoprotein NP383-391

At the University of California, San Francisco, researchers studied unvaccinated bone marrow donated from The National Marrow Donor Program/Be The Match. Out of 1,428 donors, 136 were asymptomatic for two weeks before and after testing positive COVID-19. The HLA variant, HLA-B*15:01, had a strong association with the asymptomatic donors. The team, along with researchers from La Trobe University in Australia, studied T-cell memory. They found that the T cells in people who had the HLA-B15 gene, and were never exposed to the COVID-19 virus, responded to the NQK-Q8 peptide in the virus and were able to have a faster immune response. Therefore, people who contain the HLA-B15 gene are prone to being asymptomatic to COVID.

In AP Biology we learned about the immune system’s response to viruses, like SARS-CoV-2. We learned that T-cells and Helper T Cells are part of cell-mediated immunity and are crucial for recognizing antigens and releasing cytokines to trigger immune responses. Then, B and T cells create antibodies and cytotoxic cells to kill off the virus. Memory B and T cells are also formed in order to generate a faster immune response if the body is exposed to the same virus again. Therefore, the immune response stimulated when a person contains the HLA-B15 gene is similar to one where the body uses memory cells to fight an infection.

So, have you never caught COVID-19, or are you one of the lucky people to contain the HLA-B15 gene?


Restaurants: A COVID-19 Hotspot

After spending months locked in our homes, eager for social interaction, you may find yourself wanting to justify grabbing a quick bite with a friend despite the risk of COVID-19. However, this MIT Technology Review article proves that not only are restaurants the riskiest location when it comes to the coronavirus, but you are actually four times more likely to catch the virus in a restaurant than in the gym, which is the second most dangerous location.

Safegraph, a company that collects anonymous location data from smartphones, curated a team of epidemiologists, computer scientists, and social scientists from Stanford University and Northwestern University. Together, Safegraph and their new team used smartphone data to predict and understand where most people were catching COVID-19. To do this, researchers tracked nearly 100 million people through their phones in 10 of the biggest US cities from March 1 to May 1, collecting the movements of people going to gyms, grocery stores, restaurants, places of worship, etc. 

After accumulating this smartphone data, they used it to predict the level of risk each location had based on three categories: “how big the venue was, how long people stayed inside it, and how many people were likely to be infectious in the given area.” After comparing their predictions to the official records of cases, it was proven that their new prediction model was accurate. Like one may have already guessed: the smaller the venue is, the longer people stay inside it, and the larger the number of people inside the venue are all of the factors that make a location more dangerous when it comes to catching COVID-19.

Epidemiology has proved that the three factors stated above make someone more susceptible to getting COVID-19 because the virus spreads most prominently through respiratory droplets. These droplets can be spread through breathing, talking, eating, etc. In restaurants, people don’t wear masks, allowing these respiratory droplets to infect everyone around them, as they can land on surfaces as well as drift through the air. Another danger with restaurants and not wearing a mask is being asymptomatic: unknowingly contracting the virus, having no symptoms, and then going to restaurants, where you take your mask off, allowing the virus to spread to all those around you. 

Eating, talking, breathing, and possibly even laughing are almost all guaranteed when going out to eat. However, those are all the primary methods by which respiratory droplets spread. 

If you acquire an asymptomatic or mild coronavirus case, research suggests that your immune system works the same as it normally would for other viruses. When you come in contact with COVID-19, your innate immune system immediately reacts; it is the first line of defense in your immune system and releases a rapid response. This quick response is nonspecific, meaning that it is recognized as simply a pathogen, with minimal specifics. As that rapid response begins, your adaptive immunity begins to develop and form antibodies to fight the specific virus you are infected with. Because this response is more specific to the virus you have, it is also slower acting, which is why viruses take days or weeks to recover from. 

Anyway, going back to the research: Using this new prediction model, the research team simulated different restaurant situations, such as 10% capacity, 50% capacity, and even full capacity. The model suggested that implementing a 20% maximum capacity in restaurants would cut infection rates by 80%. However, from an economic standpoint, a 20% maximum capacity would result in a likely loss of 42% of customers during “peak hours.”

So, it is crucial to think about what is more important: minimizing infection rates or keeping businesses alive? Personally, I think it is necessary to find a balance where people can stay safe, and businesses can remain open, especially small ones. Restaurants have already begun thinking of safe and innovative ways to dine. For example, a restaurant in NYC has an outdoor patio with large, private pods where groups of people can eat out without exposure to the people around them. Though even this system has its loopholes and issues, it is a step in the right direction. 

Will you be going out to eat this week? 

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