The COVID-19 virus contains a gene that makes copies of itself. Those copies, or mutants, can become more or less infectious, or cause different symptoms. Some mutations make the virus better at infecting people or spread faster. Others help the virus avoid detection by people’s immune systems or tests for the virus. The concern is that variants with these advantages could increase the number of infections and severity of illness.
CDC tracks COVID-19 variants by collecting samples from infected people. The genetic sequences of these viruses are analyzed to identify the types that are circulating. Scientists use this information to determine whether the FDA-approved and authorized vaccines, treatments and diagnostic tests will work against the new variants. Variants that have changed enough to influence infection rates are designated as “Variants of Interest,” or VOC, or “Variants of Concern,” or VOC.
Omicron has now overtaken Delta as the most common circulating variant. Omicron and its sub-variants have a tendency to evade antibodies, increasing the potential for breakthrough infections in fully vaccinated people.
Several mutations have been identified in the viral spike protein, which is found on the surface of coronaviruses and helps them attach to host cells and enter them. These mutations are being tracked by scientists who are avidly tracking variants with clinical implications. Specifically, Omicron and its sub-variants possess convergent mutations in hotspot regions that confer extreme immune-evasive properties, leading to reduced neutralization by antiviral mAbs. This underscores the need for alternative therapeutic approaches that target host proteins instead of viral ones.