How vaccines work against new COVID-19 variants, according to a Chattanooga doctor

Q: Is it true the COVID-19 vaccine can possibly prevent new variants of the virus from emerging?

A: COVID-19 vaccines play a crucial role in preventing the emergence of new variants of the virus by reducing the spread of the virus and limiting opportunities for it to mutate. Here’s how COVID-19 vaccines contribute to preventing the emergence of new variants:

Reducing transmission: Vaccines help prevent the spread of the virus by reducing the number of infections. When a significant portion of the population is vaccinated, the virus has fewer opportunities to infect new individuals. This reduced transmission means fewer chances for the virus to replicate and mutate.

Lowering viral load: Even if vaccinated individuals do get infected, the vaccines often reduce the severity of the disease. People with milder symptoms are less likely to shed large amounts of virus, which reduces the viral load in the community. A lower viral load is associated with a lower chance of new mutations occurring.

Herd immunity: When a large percentage of a population is immune to a virus, either through vaccination or prior infection, the virus struggles to find new hosts to infect. This concept, known as herd immunity, limits the virus’s ability to spread and mutate. COVID-19 vaccines contribute to building herd immunity.

Reducing selective pressure: Mutations in viruses often arise due to selective pressure. If a virus faces immune responses that can partially neutralize it (such as from previous infections or incomplete immunity), the virus may mutate to evade these responses. Vaccines provide a stronger and more consistent immune response, reducing the selective pressure for the virus to mutate.

Blocking severe disease: Vaccines not only prevent infections but also significantly reduce the risk of severe disease and hospitalization. This is important because severe cases of the disease provide more opportunities for the virus to replicate and potentially mutate.

Global vaccination efforts: By ensuring a significant portion of the global population is vaccinated, we can reduce the overall prevalence of the virus worldwide. This limits the virus’s chances to spread, replicate and mutate in different parts of the world.

Despite these positive effects, it’s important to note that no preventive measure is foolproof. Variants can still emerge due to the virus’s natural ability to mutate. Some variants might have characteristics that allow them to spread more easily, evade immune responses to some extent or cause more severe disease. Monitoring and studying these variants is crucial to adapting vaccine strategies and public health measures as needed.

Dr. Mark Anderson is an infectious disease specialist with CHI Memorial Infectious Disease Associates and is a member of the Chattanooga-Hamilton County Medical Society.