Omicron has become the most infectious variant of COVID yet, even managing to re-infect people who already had COVID. According to researchers in Botswana and Africa, omicron’s ability to spread so easily is due to its 60 genetic mutations, which include 42 changes to its spike proteins.

In class, we learned about a form of endocytosis called receptor-mediated endocytosis. Receptor-mediated endocytosis occurs when ligand bind to receptor proteins on the cell membrane that match their shape. This process triggers the cell to let in the virus in a coated vesicle. In this case, the ligands are the COVID spike proteins are the receptor proteins are called ACE2. The omicron spike protein is shaped like a claw machine. Most antibodies attack the claw fingers, however, omicron keeps its “knuckles” bent to hide the parts the antibodies target. Omicron can also stick out one positively charged finger to grab onto the negatively charged receptor. This electrical attraction in omicron is three to five times greater than that of the delta variant, greatly contributing to its ability to infect the cell.

Researchers also suspect that omicron uses a mechanism unlike previous variants to enter the cell. They believe that omicron uses a backdoor compartment called an endosomes, sorting organelles part of the endomembrane system, and a protein called cathepsin L to drop its genetic material. We discussed in class that the endomembrane system also included vesicles, nuclear envelope, the Golgi body, plasma membrane, and the ER. Through this method, omicron is able to enter the cell without killing it. This is particularly significant as the virus can use the host cell to create even more of the virus to spread. Another mutation that aids the virus is a sugar molecule on the spike protein. This modification makes it difficult for antibodies to attack the virus. For these reasons, omicron has managed to evade very effective vaccines. In one case, it was found that two doses of the Moderna vaccine was only 44% effective at preventing omicron infection between 14-90 days after getting the vaccine, and only 23.5% effective between 3-6 months after getting the vaccine.

I was interested in this topic because I’ve noticed that many of my classmates have gotten infected with COVID recently, even after receiving multiple vaccines or having already being infected with COVID. We can only hope that the next mutations will not lead to a more virulent form of the virus.