Developing a new vaccine is a process that typically takes years, but the urgent need for a COVID-19 vaccine has pushed officials and researchers to find ways of shortening that timeline. 

What You Need To Know

  • The condensed timeline for a COVID-19 vaccine raises questions over whether a vaccine can be proven safe and effective

  • Typically, a vaccine takes a couple of years to work through the pre-clinical trial stage

  • Then, it moves forward to a phase one clinical trial, followed by phases two and three

  • The full clinical trial process usually takes as little as five or as many as 20 years to work through, but for the coronavirus vaccine, the Food and Drug Administration has created a “fast forward” option called Operation Warp Speed

The condensed timeline, however, raises questions over whether a vaccine can really be proven safe and effective in such a short amount of time. 

Usually a virus is studied for two or more years before a vaccine candidate is even created.

Because SARS-CoV-2 , the virus that causes COVID-19, is similar in many ways to previous coronaviruses like SARS and MERS, researchers had a head start on some of this research.

Another advantage researchers have in developing a coronavirus vaccine, is that the virus’ genome information was shared almost immediately, allowing scientists around the world to begin work on a vaccine right away. With more than 200 coronavirus vaccines in development around the world, the odds of finding a safe and effective candidate are much higher. 

Typically, it takes a couple of years to work through the pre-clinical trial stage. This involves testing the vaccine candidate on tissue cultures and animals.

Then, it moves forward to a phase one clinical trial, in which researchers test the safety and efficacy of the potential vaccine on a small group of human participants — usually fewer than 100.

If all goes well, the vaccine candidate advances to a phase two trial. During phase two, scientists expand the pool to several hundred participants. 

Candidates that perform well in phase two, then progress to phase three trials, involving thousands of volunteers. 

The full clinical trial process usually takes as little as five or as many as 20 years to work through, but for the coronavirus vaccine, the Food and Drug Administration has created a “fast forward” option called Operation Warp Speed. 

Under the new process, vaccine candidates are still required to progress through each stage of the development process, and meet safety and efficacy benchmarks. To shorten the timeline, Operation Warp Speed relies on two main changes.

Instead of waiting until phase three trials are completed to send the data to the FDA, researchers are sending in results on a rolling basis, allowing FDA officials to approve a vaccine much sooner. Some researchers have even been approved to run phases one and two trials simultaneously.

The other big change is that manufacturing of the most promising vaccine candidates can now begin even before phase three trials are complete. Normally, the risk of the financial loss if the vaccine ultimately does not receive approval would make this unrealistic, but with substantial government aid backing the race to find a vaccine, this change means the vaccine can be distributed to the public almost immediately after approval.

Of course, even with this expedited timeline, finding a safe and effective vaccine is still a lengthy process. Unexpected side effects can delay the trials or even take a particular vaccine candidate out of the running all together.  

So how will they determine if a vaccine is safe and effective? 

A diverse phase three trial is key. A vaccine that performs well in young people may not be as effective in the elderly. A pre-existing health condition may put someone at risk of a serious complication. 

If no severe side-effects are reported in phase three, the vaccine is deemed safe.

Even after the vaccine is approved, officials will continue to monitor recipients and record any adverse reactions. 

In order to be considered effective, the FDA says, a vaccine should protect at least 50 percent of recipients from infection or severe illness. 

Trying to decipher the results of a clinical trial may be overwhelming. Public confidence in the process has been low, with fears that a vaccine will be pushed out before it's really safe.

With that in mind, scientists around the world are calling on the companies developing the vaccines to offer greater access to trial results — allowing independent experts to evaluate the data and build public confidence in the process. 

Ultimately experts say when a vaccine becomes available, talk to your doctor about the type of protection it might offer, potential side effects, and whether there are risks to you based on your age or health conditions.