A member of my family who is not in a science or medical field recently asked for my thoughts on the new vaccines in development to combat COVID-19. She, like many Americans, voiced a fear at the prospect of taking a vaccine that felt “rushed.”
She’s not an anti-vaxxer, wants a safe vaccine in theory, but also wanted my take on potential risks associated with the incredible timeline that we’ve watched unfold as Pfizer, Moderna and soon to be several others are completing their clinical trials. My explanation, which I feel could be relevant and informative for a broad population of Americans, is as follows.
To start I’ll say that the development of the COVID-19 vaccines rests on the shoulders of a century of microbiology and immunology research, and on 50 years of concentrated vaccine research and innovation. I understand why people might think that this process has been rushed, because in the past vaccines have taken years to develop, but it actually has not been rushed, at all, with the design of the vaccine or with respect to the safety and efficacy trials (all these phase 1-3 trials).
During the SARS1 (SARS-CoV-1) outbreak 18 years ago, researchers started looking at that virus, and other coronaviruses, and found a really promising vaccine target on the virus cell surface -- which is a protein called spike. That protein is what binds to human cells and leads to an infection.
So about 10 years ago the science wheels started churning out strategies to vaccinate against SARS1. Unfortunately, funding dried up for SARS1 as that virus never made its way to the U.S., so a vaccine didn’t actually get developed. However, the research on the virus and ideas of how to vaccinate against it were already available.
Thankfully SARS2 (SARS-CoV-2, our current situation) uses almost the exact same version of that protein to infect cells and uses the exact same receptor on human cells. Due to these similarities, scientists were able to pick up where they left off, which sped up the process dramatically.
Further, vaccination strategies have improved significantly in the last 10-plus years, particularly in the past couple of years with the mRNA technology that Moderna and Pfizer have utilized. All of these companies basically just took the DNA or RNA backbone of a vaccine that they had already built and plugged in the SARS2 spike protein’s genetic information.
Essentially, they just popped in some new instructions. It is amazing that they could do it so fast, but again, it’s on the shoulders of a century of hard-won knowledge and vaccine trial and error.
That said, the real question is about the human trials. Our country has set up a network of clinical trials with an extremely high bar, particularly with vaccines. The COVID-19 vaccine candidates have not skipped any of the safety trials and measurements necessary, and they haven’t skipped any of the efficacy ones either. It’s been fast in part because people have been so eager to volunteer for the trials, and because the virus has spread like wildfire, infecting a staggering amount of people.
Phase 3 safety and efficacy trials are all based on statistics, and you need a lot of people in the trials to give the amount of statistical power needed to prove that a vaccine will make things better, and not worse, in a significant way. In order to clear the Food and Drug Administration bar to be used on the public it must be significant. In fact, the FDA is requiring at least a 50% protection for approval and pretty much total safety.
Due to the sheer number of people in the current trials and the amount of COVID-19 cases circulating this fall, the statistical power necessary for any kind of conclusion was achieved for Moderna and Pfizer really quickly. They found that there’s been little to no adverse reactions, and both vaccines are in the 90-95% effective ranking, thereby making these some of the best vaccines to date.
As for the questions regarding long term safety – in 10 years will there be major health complications due to the vaccine alone? This will remain an open question until we actually get there, however, these vaccines are not based on live virus and the only thing that gets expressed in our bodies is the spike protein.
It would take more time and immunological descriptions to explain these concepts than an opinion piece could ever do justice but, essentially, the protein will prime our immune system, and then it will disappear forever. Many safe vaccines work just like this, and those do have longitudinal data that show safety out past 10 years or more. Again, we benefit from a wealth of historical vaccine knowledge.
And then lastly, the risk/ benefit scenario is hugely tilted toward vaccination. COVID-19 infection has now been linked not just with acute sickness and death, but with autoimmune diseases, heart failure and many other complications that may emerge years from now. Becoming infected with the actual virus is what worries the medical field for the future long-term scenarios. The benefit from getting the vaccine, which has now been shown to be safe and effective, is a much less risky scenario than contracting the actual virus for long-term health ramifications.
And the greatest benefit of all is that of the collective good. If every individual subscribes to these vaccines, once they’re cleared by the FDA, the world will become safer again. That is, by taking the vaccine you will not only protect yourself from a grave illness, but you also will be actively protecting all the people around you, especially those too immunocompromised to be vaccinated.
Herd immunity can be achieved, and our world can return to a semblance of normalcy, but it relies upon all of us doing our part to make a better world.
See you at the clinic.
Allison M. Weis
Allison Weis, Ph.D., is a microbiology postdoctoral fellow at the University of Utah School of Medicine.