Dr. Lostroh, Tell us what a pandemic is and why COVID-19 was designated one.
Good morning, everybody. I'll try to answer your questions today as they come in.
Vickie, thanks for getting us started. A pandemic is an outbreak of an infectious disease that is widespread. "Widespread" is a relative term; COVID-19 was designated a pandemic because of community spread in multiple countries. My source for this answer is the World Health Organization.
Hi, everybody. According to the CDC, washing your hands with soap and water is very effective. Wash your hands as you normally do, after bathroom and before preparing or eating food. Wash them extra when you return from going out of your home. Of course, it is best to minimize going out of your home at this point. My source for this information is CDC.
I'm getting questions about "close contact." CDC uses this definition: staying within six feet of someone for a prolonged period of time. "Prolonged" is a bit to vague for my taste, so I think that probably means on the order of 6-8 hours a day. But that is a guess on my part. Another type of close contact would be if someone coughed directly on you.
I like to read two sources for reliable up-to-the-day news about COVID-19. These are statnews.com and https://www.nature.com/news. The second link is news written for scientists but I think much of the reporting on COVID-19 is accessible to the general public.
When thinking about whether an infection will spread or not, we use the number of healthy people who will be infected by a sick person as an index of how much the infection will spread. This “basic reproduction number” is derived from epidemiology research and can be used in mathematical models that work like weather forecasting in that they use quantifiable parameters and past experience to predict the future with mathematical equations.
A documented, published calculation for the basic reproduction number for COVID-19 is 2.28, which was derived from studying the population confined to the infamous Diamond Princess cruise ship and published in a peer-reviewed scientific journal on February 22, 2020. This basic reproduction number is twice as high as that of seasonal influenza and about 80-90% of the value for measles. So, we might expect about twice as many people will catch nCoV-2019 as catch seasonal influenza. Other more recent calculations based on different populations, mostly in China, range from 1.4-4.0.
Thanks Phoebe for putting some numbers to this that we can understand.
I hope someone replies to these posts or makes their own comments.
The majority of COVID cases are mild (81% of 44,000 cases), according to the Chinese CDC. When thinking about how dangerous an infection is, we calculate something called the case fatality rate. The case fatality rate is the percent of sick people who die from an infection. Using data from the Chinese CDC again, we know that the case fatality rate depends on age.
The case fatality rates in China by age may not apply to the U.S. but they are the best information we have. Here they are. They have been published in a Chinese journal called Chinese CDC Weekly.
I'm just over 2 months 'til 80, so I'll take the 8%.
The case fatality rate is also affected by pre-existing conditions, according to the same source. People with chronic heart disease, diabetes (especially untreated), chronic respiratory diseases, high blood pressure, and cancer are at greater risk of dying from COVID-19.
Does it make any difference if one's underlying condition is controlled by meds, for example, hypertension, but normal BP if controlled by meds. Diabetes, but A1C in normal range if controlled by meds. Also, I note the virus uses ACE2 as well as TMPRSSR host cell factors. Does it matter if you are taking an ACE inhibitor to control BP as opposed say to a calcium channel blocker ?
The Council on Hypertension strongly recommend that physicians and patients should continue treatment with their usual anti-hypertensive therapy because there is no clinical or scientific evidence to suggest that treatment with ACEi or ARBs should be discontinued because of the Covid-19 infection."(https://www.escardio.org/Councils/Council-on-Hypertension-(CHT)/News/position-statement-of-the-esc-council-on-hypertension-on-ace-inhibitors-and-ang).
I am not a doctor, just a scientist. But I would always recommend talking to a doctor before making any decisions about changing medications.
The reason it's very important for everyone in the US to stay home for a few weeks is that we don't have enough tests to test everybody and find out who has it and who doesn't. People can spread the virus for an average of 3 days before they get any symptoms at all, and the infection can be caught from a contaminated surface or from aerosols in the air, even after someone sick has left the room (source, CDC and Emerging Infectious Diseases).
Because we can't test everybody and isolate only people who have it, we have to interrupt the transmission chain by limiting exposure to other people. People who get only mild infections can spread the infection and might not even realize they have it. So even if you feel well, it is best for our entire population, especially people >70 years old or with chronic heart or lung conditions or cancer, if you just stay home and limit your time in public venues. Sources: CDC, Emerging Infectious Diseases.
In the US and China, we are testing chloroquine (an old malaria drug) and Remdesivir in clinical trials. Source: PANTHR at DHS.gov.
Have you seen the pre-print in Cell that is titled: "SARS-CoV-2 Cell Entry Depends on ACE2 and TMPRSSSR2 and is Blocked by a clinically Proen Protease Inhibitor" It is fascinating work by various German scientists. Apparently, it indicates that TMPRSS2 is dispensible for development and homeostatis, and constitutes an attractive drug target. Camostat mesylate, which blocks its activity is approved in Japan but for an unrelated use.
I'm going to take a 120-minute break, until 3:15 p.m. Eastern Daylight Savings Time. Take care.
What are the pre-existing health risk factors that I should be aware of?
Hi, everybody. Lyn, thank you for the question. The Chinese experience provides the best data with large numbers. From those observations, the pre-existing health conditions that could make it worse are cardiovascular (heart) disease, diabetes (especially untreated/undiagnosed), chronic respiratory diseases (COPD, probably others), high blood pressure, and cancer. The risk of having an infection with life-threatening symptoms also increases with age.
Source is Chinese CDC Weekly summarized in a document from US DHS
Wow, so people with those health conditions should stay home?
Hi, Lyn, thanks for speaking up. I am not a medical doctor. But from my years of reading research papers in epidemiology and medicine and teaching about epidemics, everyone should stay home. I mean everyone. Every single person. People with those conditions should avoid close contact with everyone. Family and neighbors who do not have pre-existing conditions should shop for those who do and leave packages outside the house. "Close contact" means being within 6 feet of someone for a prolonged period of time, like hours. Someone who is infectious might not know it because they can be asymptomatic for an average of 3 days, but for as long as 24 days. This is all so hard, I know.
If you have a pre-existing condition, you can always call and ask your doctor if you should self-isolate.
Maybe we could use this forum to get cracking on phone trees to make sure everyone has someone checking in on them and no one is running out of necessities. Does anyone know of organizations in Colorado who are doing this? Or does someone want to volunteer? Please don't post your phone number on this public site, but contact Vickie at Pillar, or brainstorm here about how we can help each other.