Chronic Viral Infections Can Affect Human Immunity In A Similar Way to Aging.

Artist's depiction of Hepatitis C (HCV). Credit: iStock

New research conducted from Buck Institute and Stanford University shows that the lasting impact of chronic viral infections on the human immune system has similarities to the impacts of aging.

The immune responses of three groups of people were monitored:

1. Those who were aging,

2. Those on long-term antiretroviral therapy to treat HIV, and

3. Those with hepatitis C before and after receiving drug treatment.

What are the similarities?

All groups had some similar results, including:

• an increase in the amount of T cells (a part of the immune system that attacks certain unfamiliar particles) in particular tissues

• the increase of of signal pathways within cells due to inflammation (can happen when the immune system detects infection or tissue injury)

• and the decrease of response to cytokine cells (triggered to regulate immunity) in white blood cells and myeloid cells (special cells in bone marrow that aid in the control of development, tissue repair, etc.)

What is the difference between acute and chronic viruses?

Chronic viral infections are different from infections such as seasonal, or common flus- the latter are called acute viral infections. The human immune system is usually able to build up a response faster, clear the virus, and develop a future immune response if the viral infection is detected in your system again.

Chronic viral infections, including HIV and HCV, infect a person by hosting their cells in a ‘dormant’ way, which can lead to some people not even knowing of their existence. These viruses are treated differently than those acute in nature.

What does this mean in the long-term?

There is some good news- the drug that is used to treat hepatitis C (sofosbuvir) has been found to have partly repaired the sensitivity that cells have to interferon-a.

Interferons are synthetically developed versions of proteins that are made in the human body, and they can be used as drugs to 'boost’ your immune system to aid in the fight of viruses or even cancer.

This means that there is the possibility to interfere with the implications viruses can have on your immune system, but with much more future research.

What are the impacts of COVID-19?

Dr. David Furman, an associate professor at Buck Institute, suggests that bringing certain conclusions about SARS-CoV-2 is yet too early to be determined. Future studies would be necessary to know how “relatively short-lived but vigorous inflammations” like COVID-19 can affect our immune systems in the long-term.

Virus Fact:

Everyone has their own ‘virome’- which is the group of viral infections a person has had during their lifetime. According to Dr. Furman, a person could have been infected by at least 12 to 15 viruses that you were never aware of.