article Spring 2021

COVID-19: What We Know and What We Don’t

By Brianna Foth

Scientists have learned a lot about COVID-19 in the last few months but understanding its full impact on the human body will require several more years of research.

Photo by: Jason Leonardo

“The new normal.”  

Over the last year, Americans have been forced to grapple with a number of new realities: wearing masks, going to school online, and getting together with friends over Zoom.  It may feel like, after a year of people in white coats frantically collecting samples to study under the microscope, we should know everything about the virus by now.  But the truth?  There’s a lot we do know, but a lot we still don’t.  Here’s what we know so far, and what scientists are still trying to figure out.

What we know: COVID-19 has made a lot of people very sick.

So far, there have been over 29 million cases of COVID-19 in the United States, and over 500 thousand deaths.  These numbers are staggering considering that the United States saw its first few COVID-19 cases just a little over a year ago.  Although the number of new cases each day has decreased since it reached a peak on January 8th, the CDC reports that there are still an average of 5 thousand new people being hospitalized with COVID-19 every day.  Those who do become infected—particularly those who are older or have another condition such as diabetes or heart disease—are at risk of developing serious complications such as pneumonia, acute respiratory distress syndrome (ARDS), or acute respiratory failure.  According to a report published by the World Health Organization (WHO), approximately 10-15% of COVID-19 cases progress to severe disease.

What we know: Novel coronavirus is markedly different from past viruses.

Novel coronavirus, officially known as SARS-CoV-2, is one of seven types of coronavirus, including those that caused the severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) outbreaks in 2003 and 2012 respectively.  The other types include those that can cause the common cold.  Unlike the other coronavirus types, novel coronavirus had not been seen in humans before 2019, meaning that those who become infected do not have antibodies prepared to fight the virus.  This allows the virus to cause more cellular damage than other viruses are capable of, which means that it triggers a more severe inflammatory response from the body.  This is what’s especially dangerous about the virus: if the inflammatory response is strong enough, it can trigger cytokine release syndrome or a “cytokine storm.”  This happens when the immune system floods the bloodstream with inflammatory proteins called cytokines.  They can kill tissue and damage organs, which is what leads to the severe illnesses that can ultimately lead to death.  Even if someone survives such a severe inflammatory response, they can be left with significant damage to the heart muscle, lung tissue, and even to the brain and nervous system.

The novel coronavirus is also different from the influenza virus, which is what causes the common flu each year.  Whereas a person infected with the flu typically develops symptoms 1 to 4 days after becoming infected, a person infected with novel coronavirus can develop symptoms anywhere from 2 to 14 days after becoming infected.  This means that a person infected with novel coronavirus may spend a considerable amount of time going about life as normal before realizing they’re even infected.  This makes the novel coronavirus much more easily spread than other viruses.

Photo by: Jason Leonardo

What we don’t know: What are the long-term health effects of a COVID-19 infection?

Most people infected with COVID-19 experience mild symptoms and typically recover after 2 to 6 weeks.  However, some cases can result in prolonged illness, with symptoms that persist for weeks or even months.  In a phone study published by the CDC, the most common symptoms reported to persist for more than 2 weeks were coughing, fatigue, congestion, shortness of breath, and loss of taste or smell.  Scientists now refer to this condition of prolonged symptoms or health impairment as “post-acute sequelae of COVID-19,” or “PASC”.  In December 2020, Congress approved $1.15 billion in funding over four years for the NIH to study the prolonged health effects of a COVID-19 infection.

After the SARS outbreak of 2003, similar studies were conducted to assess the long-term health effects of severe acute respiratory syndrome.  One such study found that 52% of the people studied had persistent impairment of exercise capacity and health status 2 years after recovering from SARS, and 22% of them still had not returned to work at the time of the study.  Until the NIH is able to conduct similar studies for SARS-CoV-2, it will be difficult to predict what the long-term effects of this new coronavirus will be. Just as we couldn’t have predicted that chickenpox would lead to shingles, it’s unlikely that we’ll know what the long-term health effects of COVID-19 will look like until many years down the road.

The world has had to endure a lot of hardship over the last year, and it will still take some time before things finally start to return to a sense of normalcy.  But one thing that can be counted on is that scientists around the world are learning more every day about how COVID-19 works and how it can be stopped—so that if and when a new disease outbreak happens, we’ll be ready.

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