Vaccines vs. Antibody Therapy

Vaccines vs. Antibody Therapy

The United States is currently locked in an intense race between scientists developing treatments for SARS-CoV-2 versus the rise of COVID-19 outbreaks across the United States. The pandemic represents a significant threat to the livelihood of Americans, having already surpassed five million documented COVID-19 cases and claiming over 150,000 lives [1]. While numerous forms of COVID-19 therapies are currently in the works, the most widely considered include the traditional vaccine and the more novel antibody therapy [2].  

Vaccines work by introducing a weakened form of the virus or bacteria into the body of the inoculated individual and then stimulating an immune response against the mild infection. The introduction of these antigens, which typically consist of a protein from the surface of the microbe, or a weakened or inactivated form of the microbe, induces the formation of antibodies and memory B and T lymphocytes that remain in the body following infection. This process is known as active immunity, where the immune systems of inoculated individuals are “trained” to effectively recognize and respond to a specific antigen. If the individual were to contract the infection again, the individual’s immune system would have the immunological memory from the initial infection to launch into a faster and more robust response. 

Vaccinations are a preventative measure, and it typically takes around two weeks for the body to develop an immunological memory from the initial inoculation. Depending on the vaccine, multiple doses over a sustained period of time may be necessary in order to ensure long-lasting protective immunity. The duration of protective immunity varies from vaccine to vaccine, but can last anywhere between a couple of years to an entire lifetime. Booster shots are sometimes given to the individual in order to retain immunological memory [3]. 

Antibodies are proteins that bind to antigens, and aid in fighting infections by inactivating or destroying foreign substances that cause infection. Antibodies must be specific to the antigen in order for binding to occur, so the human body is capable of synthesizing a great diversity of antibodies. In antibody therapy, blood is taken from patients who have successfully fought off an infection [4]. Antibody producing B-cells are extracted from their blood and then genetically sequenced to create monoclonal antibodies, antibodies that are specific to only one type of antigen. These monoclonal antibodies are injected intravenously into a patient to help fight off an on-going infection. Unlike vaccines, antibody therapy is a form of passive immunity, as the body is given the tools to fight off the current infection, but not put through the “training.” Though antibody therapy works immediately upon injection, monoclonal antibodies only circulate in the body from weeks to months. For those that are currently infected, or are immunocompromised and unable to receive a vaccine, antibody therapy serves as a powerful short-term treatment [5]. 

In the light of the ongoing pandemic, vaccines and antibody therapy are two promising solutions being developed by scientists to combat COVID-19. While both treatments stimulate the individual’s immune system to better fight off infection, the mechanisms by which they do so are distinct.  

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  1. Elbakri A, Nelson PN, Abu Odeh RO. The state of antibody therapy. Hum Immunol. 2010;71(12):1243-1250. doi:10.1016/j.humimm.2010.09.007