Current Testing and New Strains of COVID-19
Every virologist will tell you that the first rule of a virus is that they survive through mutation. As viruses continue to seek out new hosts and find fewer and fewer, they are forced to mutate in an effort to infect a larger group. This behavior is occurring with the COVID-19 virus and scientists are scrambling to try to study each new strain as they are discovered. COVID-19 is one of the many coronavirus types, named for the spikes on their surface that are crown-like. Mutations in the COVID-19 virus include genetic changes in these spikes. Each time this virus mutates there has been growing public concern regarding the testing abilities to accommodate the changes and properly detect the presence of the virus. Thus far, testing abilities have kept up in the detection process.
As of this writing there have been quite a few COVID-19 variants reported around the world and it’s anticipated that as time progresses, there will be more:
- COVID-19 B.1.1.7 identified in the United Kingdom in the fall of 2020 spreads more quickly and easily. U.K. scientists reported in Jan. 2021 that they believe this variant may be associated with an increased risk of death but more research is required. Since the time of the discovery, the variant is detected in many other countries.
- COVID-19 B.1.351 identified in South Africa in Oct., 2020 and while discovered independently of the B.1.1.7, it shares some of the same mutations. Cases of the B.1.351 have been reported in Jan., 2021 in the U.S.
- COVID-19 P.1 identified in Brazil in a routine screening in Jan. 2021 from travelers at a Japanese airport. Concern over P.1 is that it contains new mutations that may affect antibodies to recognize it. Cases of P.1 were first detected at the end of Jan. 2021 in the U.S.
Vaccines and the Immune System
To understand how we can fight the variants we need to know how the current vaccines work against COVID-19. Vaccines are designed to help the immune system recognize specific proteins that exist in the outer coating of the virus. The 2-dose vaccines begin the process with the first dose, but it takes time for the buildup of antibodies. Vaccines stimulate the immune system to take action through the creation of antibodies as well as other areas of the immune system. The specific antibodies can be easily measured in blood samples. Research has shown a significant antibody increase in the first few weeks after the first vaccine dose and then a heightened response within a week or so after the second dose when it peaks and then falls slightly over the following four months.
In yet another immune response is longer term and a bit more difficult to gauge. This response involves the T-cells, which are inside the tissues and have a drastic effect in the limitation of infections and the memory B-cells that exist in bone marrow and can quickly transform into cells that produce antibodies as long as they “remember” the virus that is attacking. Little is known on the amount of time that it takes for these cells to step up to the battle; however, what is known is that they also can morph over time. Scientists are stating that there just isn’t enough data (yet) to make realistic predictions of this behavior.
How Tests Detect COVID-19
The way that COVID-19 testing is done is to identify specific proteins and/or genetic code of the virus in samples from patients that exhibit symptoms. The two major tests used for COVID-19 are PCR (polymerase chain reaction) and LFTs (lateral flow tests). The PCR tests are the most accurate testing method for the emerging variants as they take samples as a nasopharyngeal swab in the upper respiratory system and thus far, none of the variants have escaped detection. The PCR test selects the virus’ most conserved areas of the genome as opposed to the potentially changing spike region that binds to receptors.
The PCR tests that are used don’t have the ability to differentiate between SARS-CoV-2 and SARS-CoV because they are around 80% identical.
The LFT testing may not be quite as accurate as the PCR testing, but they also don’t work the same. LFTs function in the same way as a pregnancy test; using a liquid sample from a patient that is placed on an absorbent pad that contains elements that have a direct reaction with the SARS-CoV-2 virus. A majority of the LFT tests are based on the more stable nucleocapsid protein as opposed to the spike protein and has less likelihood of being affected by any COVID-19 variant.
Variants, Testing and Vaccines
It has already been shown that anyone that has tested positive for COVID-19 and received the first vaccine dose remains susceptible to getting the virus during the waiting period between the first and second dose. Individuals that have received the first dose of a vaccine must continue to wear masks, practice social distancing, and avoid large crowd gatherings or be around anyone that is symptomatic. As new variants enter the social structure, these rules remain the same and anyone that experiences symptoms between the two doses should be tested for COVID-19.
Scientists are testing the current vaccines against each variant that appears. The vaccines that have been developed have been designed to have the body generate immune responses to multiple areas of the virus, so the good news is that a single mutation is highly unlikely to cause a vaccine to lack effectiveness. Even in the case where the antibodies that have been created through immunization might not be able to recognize a single SARS-CoV-2 element, they will still have the ability to recognize the other elements and cause a reaction to them.
It is theorized that the number of COVID-19 mutations may eventually be great enough to cause vaccine evasion in the same way that the flu makes sufficient changes. In this case, there will probably only be a requirement for a booster vaccination to address these mutations.