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The #1 Cause of COVID-19, According to Science

Doctors explain what to know about COVID right now.
FACT CHECKED BY Emilia Paluszek

COVID-19 began as a mysterious illness that quickly spread around the globe infecting millions of people and killing over six million worldwide in just over two years. While much still needs to be learned about the virus, experts do know key factors about COVID. Eat This, Not That! Health spoke with doctors who explain the cause of COVID-19, why we're likely to experience another surge and why the virus keeps mutating. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


What Causes COVID?

Two women with protective face masks talking on the city street in safe distance.

Dr. Thomas Gut, D.O., Associate Chair of Medicine at Staten Island University Hospital says, "COVID is caused by a coronavirus variant known as SARS-COV2." 

According to John Hopkins Medicine, "Coronaviruses are a type of virus. There are many different kinds, and some cause disease. A coronavirus identified in 2019, SARS-CoV-2, has caused a pandemic of respiratory illness, called COVID-19. As of now, researchers know that the coronavirus is spread through droplets and virus particles released into the air when an infected person breathes, talks, laughs, sings, coughs or sneezes. Larger droplets may fall to the ground in a few seconds, but tiny infectious particles can linger in the air and accumulate in indoor places, especially where many people are gathered and there is poor ventilation. This is why mask-wearing, hand hygiene and physical distancing are essential to preventing COVID-19."


Why COVID is Likely to Surge Again

Worried nurse sitting in hospital corridor

Dr. Kunal Gurav, M.D., FACC, MBA, ChenMed Medical Director of Cardiology and Regional Chief Clinical Officer for Dedicated Senior Medical Centers in Missouri and Tennessee shares, "Mutations in viruses — including the coronavirus causing the COVID-19 pandemic — are neither new nor unexpected. For example, since flu viruses change often, doctors recommend patients get a new flu vaccine every year, especially patients with underlying health conditions. The reasons COVID-19 is likely to surge again are a significant percent of the population is unvaccinated. Others are not likely to be up to date with future vaccines designed to protect against new and fast- spreading COVID-19 variants. Plus, some communities are becoming less vigilant about masking and social distancing as COVID-19 infection rates drop."


How Many Times Can Someone Get COVID?

Sick young woman lying in the bed covered with blanket

Dr. Gut explains, "It's not known how many times a person can get infected. There are now countless cases of people being infected two or even three times. It is reasonable to expect that a person that has been infected with one strain previously is still at risk of getting infected by a newer strain several months later." 


Why Does COVID Keep Mutating?

Female Lab Research Worker Wearing PPE Holding Test Tube Labelled BA.2

"COVID mutations are a natural process that has been known to occur in other coronavirus strains as well as most other viruses," says Dr. Gut. "Mutations that allow the virus to spread quicker are generally mutations that have a greater chance of spreading and becoming the dominant strain. COVID treatment strategies are still generally similar for all variants. Some medication formulations have been shown to be less effective during more recent variants, which did cause certain medication formulations to be halted. Thankfully, the vaccines have shown very strong protection for recent strains."

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How Long Can COVID Survive in the Air and on Surfaces?

grocery delivery

Dr. Gut states, "COVID has been known to stay in the air for up to 24 hours in areas with poor ventilation. This number can be reduced significantly with ventilation. It's generally accepted that COVID can survive on surfaces for up to three days." 

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What Puts People at Risk for a More Severe Case of COVID?

Senior woman checking her blood glucose level.

Dr. William Lang, Medical Director, WorldClinic shares that several factors increase the risk of someone contracting a serious case of COVID and lists the following reasons: 

  • "Age: The number of deaths among people over age 65 is 97 times higher than the number of deaths among people ages 18-29 years.
  • Cancer: Depending on the type of cancer one has; treatment can suppress the immune system. 
  • Chronic kidney, liver, heart, or respiratory disease
  • Diabetes: Specifically, Type 2 (adult onset) is more of a risk factor than type 1
  • HIV infection
  • Patients with immunologic abnormalities either as a direct result of an immune system disorder or due to treatments (such as steroids) for other conditions.  To a limited extent, pregnancy also falls into this category.
  • Weight issues (risk increases with body mass index)
  • Sedentary people
  • Blood disorders such as thalassemia or sickle cell
  • Smoking
  • Transplant recipients (mainly due to the anti-rejection drugs that blunt the immune system
  • Chronic infectious diseases such as tuberculosis."

How to Stay Safe Out There


Follow the public health fundamentals and help end this pandemic, no matter where you live—get vaccinated or boosted ASAP; if you live in an area with low vaccination rates, wear an N95 face mask, don't travel, social distance, avoid large crowds, don't go indoors with people you're not sheltering with (especially in bars), practice good hand hygiene, and to protect your life and the lives of others, don't visit any of these 35 Places You're Most Likely to Catch COVID.

Heather Newgen
Heather Newgen has two decades of experience reporting and writing about health, fitness, entertainment and travel. Heather currently freelances for several publications. Read more about Heather