COVID-19 Vaccine

As the new coronavirus continues to spread, people around the world are anxious to know when we might have a vaccine to stop it.

What Would a COVID-19 Vaccine Do?

When you come into contact with viruses or bacteria, your body’s immune system makes antibodies to fight them off.

A vaccine forces your immune system to make antibodies against a specific disease, usually with a dead or weakened form of the germs. Then, if you come into contact with them again, your immune system knows what to do. The vaccine gives you immunity, so you don’t get sick or so your illness is much milder than it otherwise would have been.

A vaccine against COVID-19 would slow its spread around the world. Fewer people would get sick, and more lives could be saved.

How Are Vaccines Developed?

So how long could a COVID-19 vaccine take? More than 100 possible vaccines are in various stages of development around the world, according to the World Health Organization. Some have begun human clinical trials. But certain things can’t be rushed, like how long it takes a person’s immune system to respond to a vaccine or the wait to check for side effects.

Even when researchers find a vaccine that works against the new coronavirus, it could be 12 to 18 months at best before it’s ready for the public. That’s only a fraction of the usual time.

Before any vaccine can be used widely, it must go through development and testing to make sure that it’s effective against the virus or bacteria and that it doesn’t cause other problems. The stages of development generally follow this timeline:

  • Exploratory stage. This is the start of lab research to find something that can treat or prevent a disease. It often lasts 2 to 4 years.
  • Pre-clinical stage. Scientists use lab tests and testing in animals, such as mice or monkeys, to learn whether a vaccine might work. This stage usually lasts 1 to 2 years. Many potential vaccines don’t make it past this point. But if the tests are successful and the FDA signs off, it’s on to clinical testing.
  • Clinical development. This is a three-phase process of testing in humans. Phase I usually lasts 1 to 2 years and involves fewer than 100 people. Phase II takes at least 2 years and includes several hundred people. Phase III lasts 3 or 4 years and involves thousands of people. Overall, the clinical trial process may stretch to 15 years or more. About a third of vaccines make it from phase I to final approval.
  • Regulatory review and approval. Scientists with the FDA and CDC go over the data from the clinical trials and sign off.
  • Manufacturing. The vaccine goes into production. The FDA inspects the factory and approves drug labels.
  • Quality control. Scientists and government agencies keep tabs on the drug-making process and on people who get the vaccine. They want to make sure it keeps working safely.



Coronavirus Vaccine Progress

This version of the coronavirus only surfaced in late 2019, but scientists have gotten a boost from research on similar coronaviruses that cause severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). Efforts to fight those diseases played a role in the record speed of the COVID-19 vaccine trials that are underway.

Some of the vaccines that are now in trials use messenger RNA (mRNA). This is what carries the instructions for making the “spike” protein that lets the virus enter human cells. The mRNA vaccine tells your immune cells to make the protein and act as if they’ve already been infected with the coronavirus, giving you some immunity against it.

Another candidate uses DNA that’s designed to trigger an immune response to the virus.

Several vaccines have weakened versions of the adenovirus, one of the viruses that causes the common cold. It’s been combined with genes from the new coronavirus’ spike protein to trigger your immune system to fight it.

Other vaccines that aren’t yet in clinical trials teach your immune system to target the coronavirus by using versions of the spike protein or the virus itself.

Some of the companies working on vaccines are also looking for ways to ramp up production quickly when the clinical trials find one that works safely. With more than 300 million people in the United States alone, mass vaccination will be a joint effort among several companies and government agencies.

Experts say the coronavirus could turn out to be seasonal, like colds and the flu. A vaccine might not be ready until after the current pandemic is over, but it may be vital if the cycle begins again.

WebMD Medical Reference Reviewed by Brunilda Nazario, MD on August 05, 2020



CDC: “About Coronavirus Disease 2019 (COVID-19),” “Vaccines: The Basics,” “Vaccine Testing and the Approval Process.”

The History of Vaccines: “Vaccine Development, Testing, and Regulation.”

Biostatistics: “Estimation of clinical trial success rates and related parameters.”

Johns Hopkins University HUB: “What Will It Take to Develop a Vaccine for COVID-19?”

JAMA Network: “Characteristics and Important Lessons from the Coronavirus Disease 2019 (COVID-19) Outbreak in China.”

Children’s Hospital of Philadelphia: “Making Vaccines: Process of Vaccine Development.”

White House: “Remarks by President Trump, Vice President Pence, and Members of the Coronavirus Task Force in Press Conference.”

News release, National Institutes of Health.

Science: “Scientists are moving at record speed to create new coronavirus vaccines -- but they may come too late.”

News release, Moderna.

The Lancet: “COVID-19 vaccine development pipeline gears up.”

News release, Inovio.

News release, University of Oxford.

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