An Immune Boost Toward COVID-19 Vaccines

Posted on Aug 18, 2020 in Research & Clinical Trials, Scroll Images

Microscopy image of the novel coronavirus, COVID-19

As the COVID-19 pandemic continues to persist worldwide, few features of the human body have figured as prominently on center stage as the immune system.

How does the immune system respond to viruses?
One function of the human immune system is to inhibit viruses, and prevent them from causing illness. The body has two types of immune response to accomplish this function: innate immunity, which starts within hours of an infection, and adaptive immunity, which develops over days and weeks.

A virus causes an illness by infecting cells in the body and taking control of their genetic material. The virus then instructs these infected cells to reproduce the virus’s genetic code and replicate more viral “soldiers” that fight against our immune system.

The body’s adaptive immune response consists of two types of white blood cells—called T and B cells—that can detect “signals” specific to the virus and assemble a targeted response to it.

T cells identify and kill cells infected by a virus. B cells make antibodies—a kind of protein that blocks viral material from entering our cells and prevents the virus from reproducing.

In case the body may need to fight the same virus again, the body stores T and B cells that helped eliminate the original infection. These “memory cells” help provide us with long-term immunity. How long is long-term? Antibodies produced in response to a common, seasonal virus last for approximately one year. But the antibodies generated in response to a measles infection, for example, can provide lifelong protection.

Antibodies, a critical component of the human immune system

The human immune system and vaccines
Vaccines provide immunity, or protection against a disease without causing the illness. They are made using killed or weakened versions—called antigens—of the disease-causing virus. For some vaccines, genetic engineering is used to make the antigens included in the vaccine.

If you’re administered a vaccine to prevent viral infection, your immune system responds to the vaccine in the same way it would if exposed to the actual virus, by: recognizing the proteins and other components of the vaccine as foreign; making antibodies to “attack” the vaccine, as if it were the actual virus, and; remembering the foreign invader and how to destroy it. This response means if you are exposed to the disease-causing virus again, your immune system can intervene before you get sick.

The science on COVID-19 vaccines
Worldwide, scientists are studying more than 165 vaccines against COVID-19. Thirty are being tested in clinical trials in humans, and three of those are in Phase 3 studies.(1) Vaccines typically require years of research and testing before reaching the marketplace or clinic, but scientists are attempting to develop a safe and effective COVID-19 vaccine by next year if not sooner.

Each of the COVID-19 vaccines being tested use a different method to “attack” the virus and engage the immune system to fight infection. But to date, there are a few common approaches being studied in clinical trials:(1, 2)

1. Genetic vaccines use one or more of the COVID-19 virus’s genes to provoke an immune response, using genetic material called messenger RNA (mRNA) or DNA to produce viral proteins in the body.
2. Repurposed vaccines rely on vaccines already being used to protect humans against other diseases (e.g., tuberculosis) that may also be effective in protecting against COVID-19.
3. Viral vector vaccines use a virus to deliver COVID-19 genes into cells and provoke an immune response. These vaccines typically use viruses that infect animals such as chimpanzees or monkeys to act as the “carrier” that prompts an immune response against COVID-19 in humans.
4. Whole-virus vaccines use a weakened or inactivated version of COVID-19 to spark an immune response.
5. Protein-based vaccines use a COVID-19 protein or its pieces to invoke an immune response against the virus.

Sutter Health anticipates studying a COVID-19 vaccine being tested in humans through a Phase 3 clinical trial. Stay tuned for more news next month! Curious about other research at Sutter? Learn more.

References:

  1. World Health Organization. Accessed Aug. 11, 2020.
  2. The race for coronavirus vaccines: a graphical guide. Nature news feature, April 2020.

Posted by on Aug 18, 2020 in Research & Clinical Trials, Scroll Images | Comments Off on An Immune Boost Toward COVID-19 Vaccines