COVID-19: What is Viral load?

After more than two years into the COVID-19 global pandemic, you have probably heard the terms “viral load” or “viral dose,” but you may still not be clear about what they mean and why they should be something you should pay attention to. In the simplest terms, a viral load is how much of a virus you are carrying in your body.

Your viral load is important because the more of a virus you are carrying, the more likely you are to share it with those around you. So, if a virus reproduces more quickly, more of it will be in your lungs, mucus or sweat, making it more infectious to others.

How Viral Load Is Measured

In order to understand what is so important about the viral load, it is first important to know how it is measured. A viral load test quantifies the amount of genetic material, normally the RNA, in the blood of a patient. The standard metric for viral load is number of copies per milliliter of blood.

There are three main kinds of tests for measuring viral load:

  1. Reverse transcription-polymerase chain reaction (RT-PCR) test—the RT-PCR test is ideal for samples with low quantities of genetic material. The test amplifies the targeted mRNA of the virus, making it detectable even if the virus is present in minute quantities. This is considered one of the most sensitive and accurate methods for measuring the viral load.
  2. Branched chain DNA (bDNA) assay—the bDNA test measures the amount of nucleic acid molecules in a sample. This test can accurately measure the concentration of virus from 500 to 10 million molecules. This is an easy-to-use test with good reliability.
  3. Nucleic acid sequence-based amplification (NASBA) tests—the NASBA test is a moderately reliable test that can be performed much more rapidly than other viral load tests. It also does not require expensive thermocycling equipment.

Although it is important to get an accurate viral load measurement, you should keep in mind that this figure can change over time and depending on what part of the body the sample was taken.

Why It Is Important to Know the Viral Load

There are many reasons why knowing your viral load is important, but perhaps the primary reason is that it indicates how likely you are to become sick. In most cases of viral infection, the symptoms worsen as the virus multiplies. So, if the viral load tapers off, you are more likely to feel better and recover.

Secondly, the amount of virus is a good predictor of how infectious a patient is. A higher viral load means there is more virus in and on their bodies, making it more likely that some of those virus particles can be transmitted to someone else.

It is also important to note that the “infectious dose” is also relevant to this discussion. The infectious dose is the amount of virus that the patient was initially exposed to. It is believed that, in at least some kinds of infectious illnesses, the amount of initial virus may help predict the severity of the illness. This is because too much of the virus can overwhelm the immune system.

How Viral Load Can Be Lowered

If you do get infected with a disease like COVID-19, you want to lower your viral load so that your body can fight off the virus.  This begins with limiting the infectious dose or the amount of virus you are initially exposed to. This is best achieved by wearing a mask and maintaining social distance, as well as consistently washing your hands.

You want to minimize your exposure to sources of the virus which is other people. So, you want to avoid large gatherings or crowded indoor spaces with limited ventilation. In crowded spaces, you can be exposed to multiple infectious people or even the same sick person’s viruses several times. This can lead to a higher viral load that can overwhelm your immune system.

This overwhelming viral load can be fatal in COVID-19 patients because the immune system generates an oversized response. This includes inflammation of tissue in the lungs which is intended to fight off the virus but also curtails breathing.

Once the infection has taken root, however, it is considerably more difficult to lower your viral load. The most effective way is to take good care of your body. You want to cut out bad habits that can weaken your immune system or tax your body like smoking, drinking alcohol or coffee. You want to sleep as much as possible to help your immune system fight off the illness.

The most important way to reduce the viral load if infected is to get vaccinated beforehand. Many of the available vaccines are quite successful boosting the immune system so that even a heavy dose of virus is insufficient to produce an infection. A vaccine primes the immune system so that it readily recognizes the viral pathogen and applies defenses more rapidly.

There are some new antiviral therapies for COVID-19. The first therapy approved for the treatment of COVID-19 is remdesivir. Remdesivir must be given in a hospital because it is an infusion into the vein. One study found that the drug could lower the risk of hospitalization or death by 87 percent.

In late 2021, the FDA approved the oral antiviral drug Paxlovid to treat COVID-19. Paxlovid has been recommended for use in mild or moderate cases of COVID-19 that may progress to more severe symptoms. If given in the first five days of symptom onset, Paxlovid has been clinically shown to lower the likelihood of hospitalization or death by 88 percent.

Article written by: Dr. Robert Moghim – CEO/Founder Colorado Pain Care

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