COVID – THE NUMBERS
By Bill Feyerabend.-
Numbers always seem so definitive. You see a weekly total of, say, 273 new COVID cases and 12 deaths.
But are the numbers exact? Are they useful? Let’s review the history.
Beginning in Wuhan, China in December, 2019, there was a growing wave of people in hospitals who were dead in 5 or 10 days from respiratory or kidney failure or blood clots. That was it. That was the initial knowledge.
Quickly doctor’s pieced together a list of symptoms. By January the disease had a name, COVID 19, and a list of symptoms: a fever, cough and shortness of breath. And a rapid health crisis or death. By May the list of symptoms had expanded to include a fever – although that could vary from weak to extreme, cough, loss of appetite, fatigue, shortness of breath and mucus coughed up from the lungs. More variable symptoms included muscle and joint pain, nausea, vomiting and diarrhea. Less common symptoms were sneezing, runny nose, and sore throat and skin lesions. Patients also sometimes complained of chest tightness, heart palpitations and changes to the senses of smell and taste.
Every year there is a flu. Here is a list of symptoms of the ‘regular’ 2019 flu: fever, cough, fatigue, sore throat, muscle and body aches, vomiting and diarrhea.
Add in some real world complications like allergies and you can see how an overworked medical system focused on constantly trying to save lives may have miscounted COVID numbers based on symptom diagnoses. The total number is the sum of individual decisions made in a state, country and around the world by regular people with regular abilities trying to judge a highly variable disease with symptoms comparable to the common flu. Even death is not a good diagnostic tool. Typically 10-30,000 people die each year in the US alone of the regular flu.
Surely testing is the answer to getting a solid number. The first tests were available in late January and only on an extremely limited basis. Now there are tests becoming more commonly available, but beware that each method has its weaknesses and each results in a measureable percentage of false values, both false positive and false negative. The lesson for everyone is that if you have a test run and the result is really important, run it again.
There are two ways to test for COVID. The first is to test for the virus itself and the second is to test for the antibodies the body produces when it is exposed to the virus.
The virus test methods are RT-PCR, isothermal nucleic acid amplification and antigen. Those are big names for techniques that test for the virus’ genetic material or molecular structure. Google each of these for false negatives and false positives and you will get very technical and difficult to understand papers investigating false results from the methods. In addition, sampling with a swab has two problems. First, the sample can be so diluted by saliva or sinus runoff that it is not meaningful. Second, the results depend on how much time has passed since the person was infected. After the first week, the virus can disappear down the throat into the lungs. One solution is to sample deep in the airway with a suction catheter, but that is not feasible for casual testing. Contamination can also be a problem when you have a person in a real life environment collecting by swabs and then sending those for analyses.
Antibody tests are run on blood samples and there are many on the market now, including ones which have not been verified. Also, antibodies might not show up in the body for weeks after infection, making the method ineffective for results immediately after infection.
The very first tests were not available in the US until late January when the US had only a handful of cases. Testing is still ramping up with supply quantity and quality issues. At this time only 6% of the US population has been tested and that is weighted towards those with symptoms. With all the issues, testing can still provide useful information.
Like when did the disease first hit the US? Based on symptoms, the US had only a few cases in late January. A man who had just returned from China tested positive on January 19. More interesting, it autopsy testing showed two California people with no travel history died of COVID on February 6 and 12 and it now thought that the disease was in Colorado between January 20 and 30. There are people who think they had it in November or December, but that has not been confirmed by testing and it can be tricky judging by current symptoms, let alone remembered symptoms from months ago.
The other thing testing does is show that people can be without symptoms (asymptomatic) while spreading the disease to others. The Chinese first reported that in January. In early April, the Center for Disease Control said that up to 25% of people with COVID might not have symptoms but were spreading the disease. Iceland at that time said that 50% of its people with COVID had no symptoms. The estimates of asymptomatic COVID cases range from 25% to as high as 80%. When they are sick, people tend to act that way and accept staying home and doing other things like washing their hands. When they feel well, people go about their life normally, spreading COVID if they are asymptomatic.
So you can begin to understand why it is so difficult to get a precise number of COVID cases. The symptoms are so variable and so like other causes and the medical system was overwhelmed dealing with sick people. And no tests are perfect, testing is still way behind and it has tended towards those with symptoms. Still, a number can be useful. One lady said that she did not see what all the drama was about because people die every year from the flu. She is correct – 10,000 to 30,000 people. Whether the number is 101,348 or 103,296, knowing the magnitude allows you to judge how much importance to put on the opinion of that lady and others like her.
