Why Does It Take So Long to Make a Vaccine? (2:55)
May 5, 2020 — 11 a.m. EST
When will a vaccine for coronavirus disease 2019 (COVID-19) be developed? It’s one of the most commonly asked questions these days. Tired of social distancing and economic shutdown, many people are wondering when a vaccine will finally come and save the day.
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Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, has repeatedly said that a vaccine is at least 12–18 months away. Others have suggested it may come even sooner than this. However, while it would definitely be useful to have a vaccine sooner rather than later, one thing is clear: We shouldn’t rush the process.
Vaccines are incredible. Ever since its discovery in 1796, vaccines have changed the world, making it so we no longer have to worry about many of the communicable diseases that once plagued humans. Today, there are vaccines for 26 diseases in use in the United States, and getting vaccinated is a normal part of life for most people. But, despite the prevalence of vaccines, actually developing one is a long and arduous task. From the initial research to the widespread distribution to the general public, the whole process typically takes upwards of 10 years. The reason for this is because there are two very important things every vaccine has to be: safe and effective. If a vaccine is safe but not effective, there’s no point in using it. And if it’s effective but not safe, a vaccine could end up doing more harm than good.
In the United States, all vaccines must gain approval from the U.S. Food and Drug Administration (FDA). To do this, vaccine candidates go through a series of phases of research. First, researchers need to decide what they are going to make the vaccine out of. Then, they need to actually produce that substance before testing it on animals. If it is safe, the vaccine candidate is administered to increasing numbers of human subjects in clinical trials, all the while assessing its efficacy and safety. If at any point the vaccine candidate turns out not to be one of these things, it is abandoned.
Each of these steps typically takes months to years — and for good reason. Side effects may not always show up right away, so the only way to make sure they aren’t occurring is to follow test subjects for a long time. Similarly, immunity to the infectious agent may not last, so it’s important to see if the beneficial effects of a vaccine are still present months to years after the vaccine is given. Without any of this data, it’s impossible to predict what the outcome of vaccinating an entire population could be.
People who are pushing for an abbreviated development schedule for COVID-19 see a few parts of this process that could be made more efficient. For example, the phases of clinical trials could overlap instead of occurring sequentially. And building the factories that will eventually mass-produce the vaccine can be done before clinical trials end. That being said, there are certain steps that simply can’t happen any faster — and that’s why it’s unlikely there will be a vaccine earlier than 12 to 18 months from now.
The good news is that there are over 70 vaccine candidates that are currently being investigated for COVID-19, some of which have already begun phase 1/phase 2 clinical trials in humans. Additionally, the World Health Organization (WHO) has called for collaboration between everyone seeking to develop a vaccine, in the hopes that working together brings about a solution faster.
The bad news is that there’s no guarantee any of these vaccine candidates will actually end up working. Historically, there is a low success rate for vaccine candidates, with significant drop-off every step of the way. (One study found that a vaccine in the preclinical phase has only a 6% chance of ever making it to market.) Especially since there is still so much we don’t know about the virus that causes COVID-19, it’s possible that none of the candidates currently being tested will make it.
And this last point makes for an interesting possibility; while it’s nice to set an abbreviated timeline and suggest a vaccine will be available in 12 to 18 months, the harsh truth is, it’s possible a vaccine will never be developed. While there are many communicable diseases that do have a vaccine (e.g. measles, polio, and the flu), there are also many that don’t (e.g. HIV, herpes, and hepatitis C). This isn’t because nobody has tried; some diseases just aren’t as easy to vaccinate for as others.
To figure out if it’s even possible to create a vaccine for a coronavirus (the cause of COVID-19), we can look at what’s been done in the past. During previous coronavirus outbreaks (such as the SARS outbreak of 2002–2004 and the MERS outbreak of 2012–2013), vaccine candidates were studied, but ultimately no vaccines were ever made (this was partially due to lack of interest and funding). Scientists have also never developed a vaccine for the common cold (which is sometimes caused by a coronavirus). On top of this, certain coronaviruses have even been shown to experience vaccine enhancement of disease. This is a situation in which the vaccine can actually make the disease worse. With this track record, it’s understandable why making a COVID-19 vaccine is a difficult endeavor.
COVID-19 has changed the world more than SARS or MERS ever did, so it’s unlikely interest and funding will run out. The amount of resources that are currently being poured into vaccine development is encouraging, and time will tell how effective those efforts have been. What is sure, is that we have a lengthy vaccine development process for a reason. Before injecting the entire population with a pharmaceutical, we want to make sure we know as much about it as possible. However long it takes, it’s clear researchers will remain committed to their quest to find a vaccine that is safe and effective.