Jeremy Alfred 
The U.S. Department of Health & Human Services is bringing back the free COVID-19 test kits distributed by USPS. The tests will be available in late September of 2024, though a date has not yet been announced. Under the COVIDtests.gov program, U.S. households will be able to order 4 free COVID-19 testing kits. The program has previously distributed over 900 million tests directly to American households.
Current COVID-19 infection trends
Dominant variants
COVID-19 is caused by the SARS-CoV-2 virus. Currently, the dominant variants of SARS-CoV-2 circulating in the U.S. are the omicron subvariants such as KP.3.1.1 (27.8% of cases), KP.3 (20.1% of cases), and LB.1 (16% of cases).
Trends in the past week (Aug 17-26, 2024)
According to the CDC,
- COVID-19 infection was diagnosed in 2.5% of hospital visits in the past week.
- COVID-19 caused 4.4 hospitalizations per 100,000 people in the general population.
- COVID-19 infection was detected in 18% of COVID-19 Nucleic Acid Amplification Tests (NAATs) in the past week.
As the fall weather approaches and the weather cools down, the rates of respiratory illnesses such as COVID-19 tend to increase.
How at-home testing works
The at-home test quickly indicates if a patient is infected with the SARS-CoV-2 virus. Once COVID-19 infection has set in, and the patient has been experiencing some symptoms for 2-3 days, the nasal secretions inside the nose contain high enough loads of the virus to be detectable by this simple at-home assay.
The appearance of a COVID-19 at-home kit can vary between manufacturers. However, they all have similar contents. Each at-home testing kit contains a collection swab, a test strip encased in a plastic cassette, and a small tube filled with liquid. The swab is used to collect nasal secretion from each nostril. The secretions are washed into the fluid provided with the kit. Depending on the kit, a specific number of drops are then dripped into a reservoir on the strip. The material of the strip makes the sample collected in the fluid spread out along the strip.
As the sample moves along the strip, it comes into contact with two bands:
1. The SARS-Cov-2 antibody band. The first band the sample comes in contact with has an antibody against an antigen on the SARS-CoV-2 virus. The antibody is designed to trap the virus by binding with it. If the virus is present in the sample, it gets attached to the antibody molecules. Once the antibody is bound with the virus, it can be detected as a dark color. If there are enough virus particles in the sample, the whole band turns dark. In most kits, this dark band is called the “T” line, which stands for the test line. This is a positive result indicating that the virus that causes COVID-19 is present in the sample.
If there is no SARS-CoV-2 virus in the sample, or the viral load is too low, the colored band does not develop. This is a negative result indicating that the virus that causes COVID-19 is NOT present in the sample, or the viral loads are too low to be detectable.
2. A control band. The second band the sample comes in contact with is the control band. As the sample moves from the first band to the second, some antibody molecules from the first band dissolve into the sample. The control band has antibodies that detect this antibody. This control band, called the “C” line which stands for the control line, always darkens if the wicking motion of the sample along the test strip is as expected.
Therefore, the appearance of the C-line indicates that the kit is working correctly. If a control line does not develop, there is some problem with the strip, and all results obtained from it should be disregarded.
What if I test negative?
If you test negative, there are two possibilities. You either do not have a COVID-19 infection, or the viral load is too low. An antigen test can be repeated after 3 days. However, if you are vaccinated, the viral load may never rise high enough to be detectable. In that case, a PCR test is recommended. A PCR test is much more sensitive than an antigen test and can detect very low levels of the virus.
COVID-19 PCR or antigen at-home testing
What if I test positive?
If you test positive, it means you have a COVID-19 infection.
- You may quarantine as appropriate.
- You may rest to give your body time to recover.
- You may reconsider travel plans and social engagements with the very old, the very young, and those who may be immunocompromised or take immunocompromising drugs.
- You may report your test results at MakeMyTestCount.org
- You may keep an eye on your symptoms and seek medical attention if you do not feel much better within a week, or if your cough after the infection lingers on for more than a month.
The information provided in our blog posts is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.
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