Coronavirus. Testing 1-2-3
It was barely six weeks ago on March 1st, that the CDC claimed that only 15 Americans were sick with the coronavirus. Clearly this was an illusion and the virus was already everywhere. Some estimates say that there were already 10,000 Americans that had been infected. Now here in mid-April and we just passed 600,000 cases of infection and close to 24,000 deaths here in the U.S. In these confusing times important questions about testing and statistical analysis should be paramount in understanding what is going on. New York seems to be the epicenter for infections in the U.S., but New York has also tested 13x more people on a per capita basis than any other state. California, with its large population base has completed fewer tests per capita than the country’s next five largest states. We can’t be getting clear data if smaller states such as Massachusetts and Washington are showing high outbreaks due to wider testing, and more populous states such as Texas and California show less of an outbreak with less testing. Clearly, testing is the heart of the problem regarding an analysis of what exactly our country has been dealing with and how we can move forward without fear.
The standard recommended testing utilizes a long nasal turbinate swab test to the nasopharyngeal area (the back of the nasal cavity) which is then tested for the virus’s RNA by a method called PCR (polymerase chain reaction) that can pick up genetic material of the virus. In most circumstances, results come back within 8-24 hours. Abbott labs has a device that has a much quicker turnaround time. In as little as 5 minutes a positive can be determined and within 13 minutes a negative. No test is 100% accurate, the nasal turbinate test even when performed correctly by a medical professional has an accuracy rate like the Rapid Influenza Diagnostic Tests (RIDTs) which run about 50%-70% accurate. More than 70 companies have signed up to sell serology tests or “at home antibody tests” which typically use a finger-prick of blood on a test strip to identify people who either have the virus or has developed immunity to it. Rutgers University just got FDA approval for a simple saliva test they developed that can be done to see if you are infected or over your infection.
Antibody testing is a common analysis in the testing in many diseases such as HIV, Epstein Barr virus, Lyme disease, etc. Presently, there is only one company Cellex that has received authorization from the FDA for their serology test to measure IgM and IgG antibodies and gives results in 15-20 minutes. It is not an in-home test. It requires a traditional lab for interpretation. All serology tests look for IgM and IgG antibodies specific to the coronavirus. IgM is present when there is an active infection in place. IgG is usually present when the body is no longer in the active phase but has now moved into a resistant phase and is producing antibodies to a previous infection. Unfortunately, because coronavirus is a new virus, there is an uncertainty that 1. IgG antibodies don’t preclude an ongoing infection. 2. Whether the IgG antibodies will give assurance of immunity and safety for any reinfection. And 3. There are anywhere from 2-8 or as many as 40 different mutations of the Covid-19 virus depending on the source you read, which may explain why some people are experiencing mild reactions and others more severe. So far, even in the virus’s most divergent strains, scientists have only found 11 base pair changes in its 30,000 base pairs. Humans, by comparison, have more than 3 billion. The question then becomes if we have an IgG immunity to one strain, is it similar enough to have IgG immunity to all strains?
From all indications that answer is probably yes. From the successful use of plasma transfusions from recovered patients, it appears that IgG antibodies are probably being transferred no matter the strain and conferring immune support for very sick coronavirus patients. This is a therapy I mentioned in last month's newsletter. It has been used successfully throughout our history, such as the Spanish flu pandemic in 1918, where it was reported that transfusions obtained from survivors may have contributed to a 50% reduction in death among severely ill patients. In 1934, a measles outbreak at a Pennsylvania boarding school was halted when serum harvested from the first infected student was used to treat 62 fellow students. Only three of the 62 students developed measles, and all were mild cases.
Testing would give a clearer view of how widespread the disease has been in the population. Because many people who are asymptomatic and not currently getting tested, an antibody test could help determine the number of people who were infected but did not become ill. Italy is reportedly considering antibody testing to determine which of its civilians would be allowed to go back to work. Those who have been exposed have IgG immunity could be used to donate plasma to those with severe infections. There are numerous legitimate companies that are offering at-home testing for determining IgM and IgG exposure. The FDA needs to hurry up and separate the chaff from the wheat and give us the opportunity to find out which companies are offering legitimate testing in this area.
Lastly, those who are being admitted to the hospitals with corona infections are showing very low pulse oximeter readings. This is a simple test that measures oxygen saturation in the red blood cells with a finger monitor. Normally pulse oximeter readings are in the 95-100% range. Covid-19 patients are being admitted with pulse oximeter readings in the low 70s% or even lower and are indicative of hypoxia, which is characteristic of severe pneumonia. The emergency room doctors across the nation are often prescribing ventilators which means sedating the patient and intubating a patient’s trachea where the ventilator can breathe for the patient to increase the amount of oxygen to the lungs and other vital organs. While ventilators can save many lives there might be instances where a ventilator’s pressure delivering oxygen can injure either the air sacs or the lungs or cause cognitive damage to an elderly patient from prolonged sedation. This could happen to anyone of any age who is struggling to breathe and is concomitantly activating immune responses to a severe infection. As this pandemic is unfolding many doctors are noticing that the Covid-19 patients can have hypoxic readings and none of the usual gasping of impairment that would be expected for those readings because their blood levels of carbon dioxide remain low. This suggests that the lungs are still accomplishing the critical job of removing carbon dioxide even if they’re struggling to absorb oxygen. This is more characteristic of altitude sickness than pneumonia.
There are iconoclastic doctors speaking out such as Sohan Japa, an internal medicine physician at Boston’s Brigham and Women’s Hospital who is saying “I think we have to be more nuanced about who we intubate.” “Delivering oxygen through nasal canula, or CPAP machines may be all that is necessary to bring up low oxygen levels in patients” according to Dr. Lakshman Swamy of Boston Medical Center, “but in terms of avoiding aerosolizing the virus more negative pressure rooms would be needed”. Scott Weingart a critical care physician in New York said, “their oxygen levels look awful, but many can speak in full sentences, don’t report shortness of breath, and have no signs of heart or other organ abnormalities that hypoxia can cause”. Dr. Cameron Kyle-Sidell an emergency medical doctor in Brooklyn said, “They look like they have altitude sickness more than pneumonia”. All of this is collaborating what Dr. Wu Feng observed while an intensive care doctor in China for 12 years and who worked with Covid-19 patients for two months in a Wuhan ICU. He observed strange symptoms among these patients such as high tolerance for hypoxia, unlike typical viral pneumonia cases. Dr. Feng found that 60% of the patient’s oxygen saturation could be improved by using oxygen with a reservoir bag. In more severe cases, a nasal cannula and an oxygen mask would work.
Hopefully, as more data is collected in the coming weeks' refinements in care will improve the devastating mortality statistics that we are seeing on the daily news.