Before getting into the T-Cell test topic, I just wanted to mention a few items:
- This week marked the highest one day total in hospitalization in the US in over a month. This is predictably on the heels of an increased number of cases, will likely progress and will soon lead to increased deaths. Probably fewer proportionately, but that is because, as we learn more about how the virus works, we learn how to treat severe disease better. That’s a good thing, but treating the disease is not PREVENTING the disease, which should really be the goal with any condition.
- The predominant strain of SARS-Cov-2 in the US is the British variant. It has now been identified in every state in the Union and is the predominant virus in Canada, not to mention the rest of the world.
- Continuing to vaccinate as well as follow mask and distancing guidelines is crucial to slowing this trend down.
- Covid testing has dropped off dramatically. Partly because staff has been redirected to vaccination and partly due to the false sense of security people are feeling. This is NOT over!
- We are not an island and we do not live in a bubble. Although the US population is getting vaccinated at a significant rate, less than 4% of the world’s population has been vaccinated. We are also privileged and spoiled. 80% of the vaccine is being used by only 10 countries. At least 30 countries have NO vaccine at all. In addition, the number of cases on a worldwide basis is the worst it’s been since the start of the pandemic. As Dr. Osterholm, a covid expert points out, “we are in the darkest hour of this pandemic right now”.
Now, getting on to a new test.
I’ve had numerous patients, friends and even family members comment on how, last Winter, especially early on, they were quite ill with a respiratory infection they were convinced was Covid, however their testing results were negative for Covid. As I like to remind everyone, there are many other pathogens out other than SARS-Cov-2 causing illness. The problem with testing for Covid is that if done too late, there may no longer be any evidence of the virus, determined using antigen tests, or the antibodies we created to combat them, which do wane over time. Also, early on, tests were not as readily available and some were not accurate.
Just as a reminder, there are different tests.
- Nasal swab and spit tests. These can be quick (15 minute results) or take a few days. There are 2 types.
- Antigen tests (measuring actual viral particles) are quick and become negative more reliably within a week or two after being sick.
- Genomic tests (looking for the genetic material from the virus). These can be quick (usually expensive and cash) but usually a few days if done through insurance. They can remain positive for weeks, even months, after infection since the technique involves taking small pieces of genetic material and amplifying it. Not great if you need a negative test for travel after you had, and recovered from Covid, but the most accurate if you are looking for a definitive answer as to whether you had Covid or not.
- Blood tests. These measure the antibodies we develop to the virus. There are 2 types. IgM, the early phase antibodies which wane within 7-10 days, and IgG, which develop towards the end of the first week of infection and stay elevated for months, if not permanently.
Now there is another way to see if you have been exposed to the SARS-COv-2. T-cell testing.
T cells (called “T” because they are created in the thymus gland which is located just deep to the breastbone) and B cells (bone marrow or bursa-derived cells) are the major cellular components of the adaptive immune response, the system which responds to any in vader, whether we have been exposed to them in the past or not. T cells are involved in what is called cell-mediated immunity (relating to the fact that the cells are directly responsible for action), whereas B cells are primarily responsible for humoral immunity (relating to antibody production). Once T or B cells have identified an invader, the cells generate specific responses to eliminate specific pathogens or infected cells. B cells respond to pathogens by producing large quantities of antibodies which then neutralize foreign objects like bacteria and viruses. In response to pathogens some T cells, called T helper cells, produce cytokines, inflammatory compounds that direct the immune response. Overproduction of these cytokines are responsible for the “cytokine storm”, an over reaction leading to multi-organ damage. We have now learned how to minimize this response with medications like steroids. Other T cells, called cytotoxic T cells, produce toxic compounds which kill pathogen-infected cells. Following activation, B cells and T then form memory cells which will “remember” each specific pathogen encountered, and are able to mount a strong and rapid response if the same pathogen is detected again, forever. This is known as acquired immunity. Memory cells are like a fingerprint, unique to each pathogen and never go away. This is also why people who may have had infections with other coronaviruses over the years, may have some degree of innate protection since there may be some overlap in some of the antibodies and memory cells we produce.
The T-Detect COVID Test is a genomic test, polymerase chain reaction (PCR) test, which detects the presence of gene sequences for rearranged T-cell receptors which were formed for specific pathogens, in this case SARS-Cov-2. It’s a blood test.
The first company to licence such a test is Adaptive Technologies. It’s a blood test, not a swab or spit test and costs about $150. Additional fees include blood draws shipping. If all your tests were negative, and you REALLY want to know if you had COvid last year, it may be worth the investment.
Soon, we will have more readily accessible home tests. These can be ones you send away (the genomic tests) or ones you can get an immediate response to (antigen tests) like a pregnancy test. The T-Detect test is a blood test so although you can get it personally, you need to get blood drawn somewhere or have someone come to the house to do it.
Although testing is still important, especially if you plan to travel or get together with people, we should still be focusing on prevention, just like overall health. Primary prevention means we are doing what we can to prevent a disease. In the case of Covid, it’s about careful, protective behavior. In the case of diabetes and heart disease, lifestyle improvements like eating a more plant-centric diet and exercise. Secondary prevention is all the same stuff, except you are trying to prevent a secondary event (like another heart attack or stroke) or prevent the complications of a disease, like kidney failure or amputation with diabetes or a stroke if you already have elevated cholesterol, blood pressure or vascular disease. Our medical system sadly doesn’t focus enough on primary prevention! It’s not “healthcare”, it’s “sick care”.
Although the issue with rising numbers and the variants is disappointing and can lead to despair, we CAN stem the tide. But opening up, behaving irresponsibly and pretending that the pandemic is over is not the way.
MASK UP! It’s still really important. Don’t burn it at some idiotic party.
DISTANCE. 3 feet is not enough.
WASH but don’t overdo it with sanitizers.
VENTILATE.
VACCINATE. Even if you had Covid.
GET HEALTHY!!!
Have a great weekend.
Stay Safe and Be Well.
AC