Infectious Disease Specialist Dr. Sheryl Henderson
talks about COVID-19
Getting the Facts on COVID-19
|Dr. Sheryl Henderson, a specialist in pediatric infectious diseases,
completed a fellowship at Emory University, which is in proximity to the
U.S. Centers for Disease Control.
viruses for a long time.
“There are a few that have been circulating around humans for many years that we’ve known about that mainly cause a cold,” Henderson said. “It’s a respiratory
virus. Based on that it means it causes sneezing, and coughing. It can affect the lungs sometimes. But it is in the same class. In general, it shares most of the same
DNA and it is a similar structure. But if people remember the SARS back in 2003-2004, that was also a corona virus. It did not get into this country. It was fairly well
contained. But it was a significantly serious virus related to the corona virus and caused a high mortality among people. COVID is actually the official name for it. It
is basically the second SARS virus.
Because of its highly infectious nature that has caused it to spread rapidly, the scientific community has been playing catch-up on the specific nature of this corona
virus and how to prevent it. Things have been evolving rapidly and so the information on prevention has rapidly evolved as well.
“If someone is infected with the virus, the virus is in a sneeze or a cough,” Henderson said. “It kind of lives in the respiratory track. So if someone sneezes or
coughs, the most efficient transmission is for little droplets that are carrying this virus to land in the mouth, in the nose or on the eyes of someone standing close to
them. That’s where many of the recommendations for ‘cover your cough’ comes from. The other place it can land is that when someone sneezes or coughs, the
droplets fall within 3-6 feet. That’s where the distance comes from. It can land on surfaces nearby. If one person sneezes or coughs, it lands on a table. Another
person comes by and puts their hand on that table and puts their hand to their face, that is another means of transmitting the virus through the eyes, the nose and
the mouth. That’s why we have the recommendation to not touch your face. That’s how that comes about.”
And it is because of the droplets that we need to keep our hands sanitized.
“We get a lot of recommendations for handwashing with soap and water for 20 seconds,” Henderson said. “If someone is sick and they sneeze into their hands,
they should wash their hands immediately. You should wash your hands as you are out and about and touching things that you aren’t normally touching or there are
a lot of people around who may have touched the surfaces. Washing hands and using hand sanitizer if it is available is very prudent. Some of the early
recommendations were do not shake hands. That’s another reason. Someone is infected. They rub their nose and then turn around and shake someone’s hand. That’
s another way that the virus can be transmitted.”
And while the measles and corona virus can both be spread through coughing and sneezing, they actually get transmitted in different ways.
“One of the big questions early on was whether or not the virus was airborne,” Henderson said. “There are some viruses like measles that can actually stay in the
air current for a while. That is considered to be airborne. Someone who has measles can put the virus in the air and leave the room and the virus still lingers. And
that is not the corona virus. When we talk about transmission, measles is airborne. Corona virus and most of the respiratory viruses like influenza are borne
through droplets. They attach to droplets that fall fast.”
And as the scientific community developed an understanding of that, the recommendations have changed from “Don’t shake hands” to “Stay six feet away” which
is how far droplets could disperse through a sneeze or a cough.
Some people, including President Trump, pointed to the “low” mortality rate of COVID-19 a month ago and said that the flu killed many more Americans. While it is
true that influenza may kill 39,000 to 69,000 in a given year, the flu season lasts for approximately six months. COVID-19 deaths near the beginning of March stood
at 44. As of April 7, there have been 11,816 deaths in the U.S. It is accelerating. And this has led to such drastic measures as stay at home measures. There is a lot
of uncertainty right now. And uncertainty leads to fear.
“There are several reasons that we fear COVID-19,” Henderson said. “One is that it is more easily transmittable. There is a formula of how many people one
infected person will infect if they are standing within a certain distance for a certain period of time. It is greater for the Corona Virus than it is for influenza. One
person can infect more people. It’s a difference of around 1.5 to 3. But if you think about it that way, if one person infects three people, each of those people go out
and infect another 2-3 people, the numbers of people who are infected grow faster. One of the biggest concerns is the speed at which the numbers of people
infected can happen. Another thing is that people can have the virus and not know it. They don’t have the symptoms, so they may not be as likely to protect the
others. It’s important for people to act as if they have it and say, ‘I’m going to stay a distance away. I might have it and be healthy, but I don’t want to infect the other
There is also fear because by all indications — short of complete scientific studies — COVID-19 has a higher mortality rate with some guessing 10 times that of
“Another reason is how severe the infections are and the higher mortality rate,” Henderson said. “Overall, until we know exactly how many people are infected, we
can’t get a true mortality rate. But it is definitely higher. And as you can see just looking at New York and Italy, people are much sicker. And the combination of how
sick people get and how rapidly it can spread and it can spread without people knowing it is spreading can overwhelm the healthcare system.”
Part 1 of 2
By Jonathan Gramling
For the past 25 years, Dr. Sheryl Henderson, a pediatric infectious disease specialist
with the UW-Madison School of Medicine and Public Health. She’s been in the field for
over 25 years and did a fellowship at Emory University in Atlanta where she got an
understanding on how the U.S. Centers for Disease Control — also based in Atlanta —
tracks diseases looking at the large-scale in how transmission occurs.
Henderson and the staff at UW Hospital and the medical school have been putting in
extra time as they treat present cases and prepare for any eventuality during the
COVID-19 pandemic. COVID-19 stands for COVID-19 stands for COronaVIrus Disease-
While for most of us COVID-19 is a strange new virus that suddenly appeared and has
taken the world by storm, Henderson and her colleagues have known about corona