KIU, Main Campus - Vaccines in development around the world are in various stages of testing. While COVID-19 keeps spreading, the world eagerly anticipates a vaccine that could defeat the pandemic.

According to Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, one of the vaccine candidates will be proven safe and effective by the first quarter of 2021.

Meanwhile, the US government is aiding companies, such as Moderna to ramp up development of their candidate vaccines so that they can be rolled out quickly once proven to work safely.

However, many doctors say getting an effective vaccine out by January is a highly ambitious goal. Dr. Larry Corey, an expert in virology, immunology and vaccine development, holds that everything will have to go incredibly perfectly if that's going to happen.

This is because vaccines have to go through multi-phase trials to make sure they're effective and safe. Experts say that a vaccine takes eight to 10 years to develop, and here is how it works;

First, a vaccine is usually tested in animals before humans. If the results are promising, a three-phase trial in humans will begin:

Phase 1: The vaccine is given to a small group of people to assess safety and, sometimes, immune system response. If things go well, researchers move on to:

Phase 2: This phase increases the number of participants -- often into the hundreds -- for a randomized trial. More members of at-risk groups are included. "In Phase II, the clinical study is expanded and the vaccine is given to people who have characteristics (such as age and physical health) similar to those for whom the new vaccine is intended," according to the Centers for Disease Control and Prevention. If the results are promising, the trial moves to:

Phase 3: This phase tests for efficacy and safety with thousands (or tens of thousands) of people. The substantially larger number of participants in this phase helps researchers learn about possible rare side effects of the vaccine.

Therefore, despite the fact that vaccines are critical in helping preventing disease and death, rushing the process could prove fatal as history itself has shown that vaccines developed or distributed in a hurry can lead to unintended consequences.