The world cowered in fear as polio claimed lives and the ability of infants and children to walk and breathe in the early 1950s. The grotesque iron lung was used to help patients breathe, and the comparison to today’s ventilator is not lost on us, is it?
For those baby boomers who remember those days—and the epidemic year of 1953—the savior appeared in the form of medical researcher Dr. Jonas Salk, the talented doctor who developed a vaccine to prevent polio. The disease had been around for decades and struck hardest at children by causing paralysis and death.
President Franklin Roosevelt developed polio in 1921 and was left partially paralyzed. He promoted early efforts to find a prevention. One such researcher was Salk at the University of Pittsburgh who received a grant in 1948 to study polio.
Dr. Salk announced the success of his vaccine, after others had tried and failed to create immunity, on national radio in 1953. He had tested his vaccine on himself and his family and on former polio patients.
As school kids, we lined up for our shots, went back to school, and life went on.
Until now with COVID-19. The vaccine development process doesn’t work like it did in Salk’s day.
As the COVID-19 pandemic ensnares the world, the news becomes increasingly ominous as hopes for a vaccine to prevent the disease—as Salk’s did for polio—become more desperate.
Although the frequency of new cases in some areas has decreased, emerging data from Russia and selected countries shows an alarming escalation of this nightmare. Unemployment in the United States has reached levels previously only seen in the Great Depression, and as much as we want to return to life as we knew it, we won’t without a life-saving medical breakthrough in treatment and prevention.
Oh, yes, there is an expectation that at some point a vaccine will be available. Salk’s vaccine took years to develop with rudimentary testing. Today’s vaccine will undergo rigorous testing before being rolled out to the general population. The goal is to develop a vaccine that is safe and effective.
Here is a short course in vaccine development 101.
You have heard talk about three phases of clinical trials. This explanation may help you understand how that works in medicine's search for a vaccine.
In a Phase 1 clinical trial, a potential vaccine (or any drug) is assessed for safety. The research question is this: Is this drug safe for humans? And in what dose?
Up to 100 healthy volunteers receive an injection or a product might be delivered through the nasal passages as a spray. The investigators carefully assess these patients for side effects and try to determine what is the highest dose that is safe for humans. There are careful analyses of blood in these volunteers for kidney and liver function, and there is keen attention to any other side effects such as skin or heart conditions. Even death.
Once a safe upper limit is determined, the researchers move to Phase 2. Know that many vaccines in the pipeline are first tested on cells in test tubes and then on animals such as monkeys before they ever get to Phase 1. And many drugs never move past this phase at all.
Phase 2 studies typically focus on several hundreds of volunteers to address the short-term and common side effects of the vaccine such as pain at the injection site, redness and any other unusual observations. There are also detailed analyses of blood to see if the vaccine is creating an immunity in the trial participants.
You have watched endless drug commercials interrupting your favorite TV shows. You hear a long list of potential side effects. The presumption is that the drug or vaccine has caused those side effects in the volunteers in these drug trials. If the vaccine is deemed safe enough, the trials move into Phase 3. Some drugs never move past this phase.
During Phase 3, there are clear indications about the safety of the vaccine as well as knowledge of the side effects (acceptable or not), so the vaccine is given to thousands of individuals, and their experiences are compared with individuals who do not get the vaccine. Again, researchers take careful note of side effects and unanticipated complications. Imagine the logistical challenge of tracking these volunteers and recording their experiences. Some drugs never go into full production after this phase.
But a promising vaccine that makes it through all phases and shows safety (doesn’t kill people) and creates immunity (prevents the disease for which it was developed) will herald a new Dr. Salk moment.
Please take note of the phase of a clinical drug trial when you hear or read about vaccine development. Promising substances that work in five monkeys or even forty-five adults are nowhere near being injected into your arm anytime soon.
As the pandemic accelerates, especially in face of loosening of social restrictions, and as the economy deteriorates, there is increasing pressure to fast-track the vaccine development program. Fast-tracking would be a mistake.
If this regulatory pathway is not deliberate, conscientious, and detailed—as the three-phase trials are designed to be—there can be serious harm to large populations of people. And this explains why some experts anticipate a minimum of two years before a COVID-19 vaccine might be proven safe—and hopefully effective.
