• Barbara Johnson, MD

COVID-19. What You Need to Know. Part 1.

Updated: Mar 23


The COVID-19 pandemic is an emerging and rapidly evolving situation and information today may be outdated next week. But I will try to keep you updated with current information emerging from the CDC as well as from experts in the field. It is very important that you understand this virus, your risks and what you can do today to protect yourself, your family and your community.


The information that I will be providing about the Coronovirus is from Dr. Nashan Zhong, MD, PhD who was instrumental in the discovery of SARS-CoV in 2003 and in helping to control the current outbreak of COVID-19 in China since January. This remarkable physician and scientist has been working with researchers at Harvard since February to identify biomarkers and in the development of vaccines and antiviral therapies. This information provided by Dr. Zhong and others working daily with patients is of critical value today to understand best how to avoid getting ill from the virus, spreading the virus and recovering quickly.


What is COVID-19 and How it Infects Your Body


SARS-CoV-2 is the name of the virus that causes the COVID-19 disease. COVID-19 stands for Coronavirus Disease 2019.


The original SARS in 2003 is called SARS-CoV. The similarity in the genome is between SARS-CoV and SARS-CoV 2 is 80% and the mode of infection is also very similar with only a few differences in amino acids. Both use the ACE2 (Angiotensin-converting enzyme 2) receptor as its host receptor. To infect a human host, viruses must be able to gain entry into individual human cells.



The virus binds to ACE2 which is expressed in the kidneys, GI tract, blood vessels and importantly the lungs. After binding to the ACE2 receptor in the lungs, the virus infects the pneumocytes, replicates and damages that cell. This cellular damage can lead to profuse alveolar damage with fluid filling up the lungs. Some patients present with diarrhea and vomiting due to ACE2 receptors in the GI tract.


Studies have shown that with COVID-19 it is not the immune response that is critical but the cellular damage that occurs due to the viral infiltration and replication. Thus, boosting your immune system is not the answer although supporting cellular health is important



Transmission of the Virus and Symptoms


Direct transmission is still the most common route which is why standard precautions are still valuable. Avoid crowded public places, avoid touching and shaking hand, avoid touching your face and wash hands frequently. Carry a bottle of hand sanitizer with you to use after going to the grocery store or other public buildings.




Slide from Dr. Zhong


Asymptomatic patients can be a carrier of the virus and transmit it to others, but this is not a common means of infection.


The Ro (reproductive number) represents how rapidly the disease spreads. This number keeps changing but is believed to be between 1.5 and 3.5. The common flu is 1.3 and SARS CoV1 was 2.


Infants and children were infected in China, but symptoms were mild. None advanced to more serious conditions.


Pregnant women infected with COVID-19 were rigorously tested. The cord blood, placenta and infants were all tested, and no virus was found.


The infection rate on the Diamond Princess cruise was high. Out of 3,711 passengers and crew members, 709 tested positive for the virus which is a 19.1% rate of infection. Of those with a positive test, 50% were 60 and over. This elevated infection rate reinforces the need to stay out of crowded public places with close contact.


Another very important question is whether recovered patients who show + RNA remain contagious. The reports from China is that this is doubtful due to the high levels of IgG antibodies which prevents recurrent infection.



Incubation period, which is time between exposure and onset of symptoms, varies from 2 days to as long as 14.

The aver age is 4 days. There were a few but very rare cases of almost 20 days of incubation period.



Most of the symptoms very similar to flu. Fever very common but many did not get a fever until after admission to the hospital. Cough, shortness of breath, sore throat, fatigue and fever are the most common symptoms. Congestion is usually not a problem. When the virus moves into the lungs, it causes pneumonia and possible progression to ARDS (Aute Respiratory Distress Syndrome) requiring oxygen and intubation.


It is also being noted that many patients are having heart issues such as cardiomyopathy.


How Dangerous is the COVID-19


The slide below was published in JAMA (Journal of the American Medical Association). Key take away is that 81% of documented cases were mild with 5% being critical and 2.3% death rate. The majority of individuals who advanced to critical were over the age of 70.





Death rate for critically ill patients is 49% but only 2.3% progress to critical cases.

Currently the World Health Organization (WHO) estimates the fatality rate to be around 3.4% but this rate may change. For comparison, the case fatality rate for SARS-CoV1 was 9.6% and MERS 34.4%.


80% who died in China were over the age of 60 and 75% of them ad pre-existing health conditions.


Continue onto Part 2.








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