Ask Answers: Everything We Know About the COVID-19 Vaccine

By Kate BoveLast Updated Sep 16, 2020 1:22:37 PM ET
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Photo Courtesy: Juan Mabromata/AFP/Getty Images

Editor’s Note: As we’ve witnessed since March, information regarding the COVID-19 pandemic is constantly changing — and the latest on the vaccine is no exception. While we aim to keep our articles as up-to-date as possible, please be sure to check the CDC’s website as well for the latest news.


When it comes to the novel coronavirus, there’s a clear demarcation between the before and after. As the COVID-19 pandemic continues in the United States, it’s becoming increasingly difficult to see (or hope for) an endpoint. After all, is there really a measurable stopping point when it comes to this life-altering virus? While it’s clear we won’t be "going back to normal" post-pandemic, a widely available COVID-19 vaccine will certainly help us regain some sense of normalcy, especially when it comes to sharing public spaces safely.

So, how close are we to having a successful vaccine? And what does the vaccine timeline look like? We’ll answer those burning questions and more here, so be sure to check back frequently for updates.

How Is the Vaccine Being Developed?

As you may have heard, the U.S. government recently enacted Operation Warp Speed, and despite its sci-fi name, the plan has a very real goal: to develop a vaccine and deliver 300 million doses by January 2021. Vaccinologists have since told CNN that this timeline is wildly unrealistic. In the meantime, we’re being bombarded with new treatment possibilities on the daily (some more promising than others), including the Food and Drug Administration’s (FDA) aim to use convalescent plasma and the anti-inflammatory corticosteroid dexamethasone, which is often used to treat conditions like asthma.

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Photo Courtesy: Chandan Khanna/AFP/Getty Images

Although other governments may not have the snappy, Star Trek-sounding moniker for their vaccine production efforts, it’s clear that scientists around the globe, from those employed by biotech and pharmaceutical companies to those staffing research universities like Oxford, are working around the clock to develop a workable vaccine in record time. According to the University of Michigan’s Michigan Medicine branch, more than 100 potential vaccines have been winnowed down to just a handful of promising, trial-ready prospects. In a recent issue of the Journal of the American Medical Association, writers outlined the five leading vaccine contenders:

  • 1) Moderna (mRNA-1273): A vaccine that uses messenger RNA as a delivery mechanism (more on that later).
  • 2) BioNTech, Fosun Pharma and Pfizer: Another messenger RNA-based vaccine.
  • 3) Merck, Sharpe & Dohme and the International AIDS Vaccine Initiative: A vaccine that uses a recombinant vesicular stomatitis virus vector.
  • 4) Johnson & Johnson/Janssen Pharmaceuticals: A vaccine that utilizes a replication-defective human adenovirus 26 vector.
  • 5) AstraZeneca and the University of Oxford: A vaccine that uses a replication-defective simian adenovirus vector.

A variety of options sounds promising, but these vaccines also come with some potentially confusing lingo. So, let’s quickly breakdown the differences between these leading vaccines:

  • What is an adenovirus and why is it being used? To put it simply, adenoviruses are viruses capable of causing the common cold. Michigan Medical School’s associate professor of internal medicine and microbiology and immunology, Adam Lauring, M.D., Ph.D., explains that, "For years, people have been using these viruses to deliver DNA, which are instructions for proteins. For the COVID-19 vaccine, researchers swap in a gene from SARS-CoV-2. When the vaccine is given to someone, the modified cold virus makes the SARS-CoV2 protein, which stimulates the immune response."
  • Is it better to use a human or a simian adenovirus? While Johnson & Johnson/Janssen Pharmaceuticals is using a human adenovirus, AstraZeneca and the University of Oxford are tapping into a simian (or monkey) adenovirus. Lauring explains that companies aim to "find a virus that not a lot of people have been exposed to before." If it’s a virus someone has already had, their immune system would likely attack and destroy the vaccine. Needless to say, some companies turn to monkeys for this reason, although neither adenovirus is more effective, per se.
  • What is a recombinant vesicular stomatitis virus, and why is it being used? To put it simply, it’s a virus that primarily infects livestock, like horses and cows, and, much like the adenoviruses mentioned above, this modified virus delivers instructions for the SARS-CoV-2 protein into cells. According to Lauring, this method worked wonders for fighting Ebola.
  • What are mRNA-based vaccines? Think back to high school biology, and you may recall that DNA is the gene, and RNA provides protein-making instructions. Needless to say, instead of using a virus vector to deliver protein-making instructions, this method just sends along the instructions.

What Is the Timeline for Vaccine Testing and Distribution?

While it’s exciting to hear news about vaccine development and clinical trials, we definitely shouldn’t put the horse before the cart, so to speak. "We might have vaccines in the clinic that are useful in people within 12 or 18 months," University of Wisconsin-Madison virologist Dave O’Connor told online journal nature. "But we’re going to need to improve on them to develop second- and third-generation vaccines."

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Photo Courtesy: Christoph Schmidt/Picture Alliance/Getty Images

So far, results have been decidedly mixed: Some vaccine trials have helped small animals, like mice, stave off the virus, while other trials have seen some symptom mitigation in human and simian subjects. All of this to say, nothing is fully promising, but researchers are clearly moving in the right direction. An article on Reference points out that CDC guidelines require "vaccines pass through six general stages of development: exploratory, pre-clinical, clinical, regulatory review and approval, manufacturing, and quality control. ...It’s not unusual for a vaccine to take 10 to 15 years to complete all the phases under normal circumstances."

On August 24, CNN reported that Dr. Anthony Fauci believes that despite attempts to fast-track a vaccine, it should be proven to be both safe and effective before it’s distributed. This may seem like common sense, but with November 3 approaching fast, the president has been accused of using the vaccine (or the promise of one) as a political prop. "We would hope that nothing interferes with the full demonstration that a vaccine is safe and effective," Dr. Fauci told CNN.


Compounding the issue of fast-tracking is the fact that AstraZeneca, a multinational pharmaceutical company that's been working with Oxford on developing a vaccine, made the decision in early September to delay its third-phase trial of testing. Citing safety concerns, the company paused all trials to "allow an independent committee to review the safety data" after one of the participants developed signs of a potential adverse reaction. While this pause is part of the typical protocol during any routine trial for a vaccine, it's an important reminder that similar speed bumps may prolong the length of time it takes for a safe COVID vaccine to reach the public.

Outside of the U.S., 172 economies are poised to participate in COVAX, a global initiative co-led by the World Health Organization (WHO) that aims to provide equitable access to safe and effective COVID-19 vaccines. "Equal access to a COVID-19 vaccine is the key to beating the virus and paving the way for recovery from the pandemic," said Swedish Prime Minister Stefan Löfven. "This cannot be a race with a few winners." As COVAX highlights, pre-vaccine prep is a must, especially since it’s all a waiting game for now.


In addition, early September saw nine of the leading vaccine developers in Europe and the U.S., including Pfizer, Merck, Moderna, AstraZeneca and GlaxoSmithKline, make an "historic uphold the integrity of the scientific process as they work towards potential global regulatory filings and approvals of the first COVID vaccines." This comes in response to a statement from the head of the FDA that it would be acceptable to bypass normal approval processes in an effort to get a vaccine out to the public faster. But vaccine developers are standing firm in their commitment to creating a safe, effective and thoroughly tested vaccine because they're unwilling to compromise safety and the vaccine's efficacy — particularly when the health consequences for doing so remain unknown.