As we reach a point in the global pandemic where approximately 25% of Americans have received at least one dose of a COVID-19 vaccine, I have heard discussions relating to a football game. These comments indicate that the first quarter of the contest has been completed, with the home team doing better than anticipated, but still trailing behind a powerful foe.
Building upon this idea, we need to think beyond merely the second quarter to consider the final minutes of this match and, stretching the analogy, to the end of a long and brutal season. Stated another way, I seek to summarize key concerns and opportunities facing COVID-19 vaccines as we look towards what will certainly be a better future.
We cannot – and are not – letting our guard down
A key question, with wide public health implications, pertains to the long-term safety of COVID-19 vaccines. We have all been witness (especially on social media) to speculation about short-term consequences of vaccination, replete with unfounded rumors and conspiracies claiming everything from cardiovascular to reproductive dangers. One of the more insidious claims is that that mRNA vaccines might alter your fundamental genetic material (they cannot).
Thankfully, the three vaccines authorized for emergency use in the United States have a remarkably safe track record, far exceeding the most optimistic view from a year ago. Yes, there have been rare cases of anaphylactic responses in a few individuals who were particularly susceptible to such reactions; thankfully, these can be monitored and managed.
History has taught us that most adverse responses happen soon after vaccination and rarely last more than a few days. A hallmark of COVID-19 immunization is temporary malaise and a minor fever. These responses should be celebrated as an indication the vaccine has worked as intended. Although certainly annoying, this adverse reaction is generally less severe than the side effects of some shingles vaccines.
Nonetheless, we cannot – and are not – letting our guard down. As both an immunologist and a volunteer for one of the vaccine candidates, I can assure you that extensive follow-up is being conducted to remain vigilant for potential unwanted side effects. I volunteered for more than two years of monitoring, including in-person visits to physicians to test for potential problems. There are comparatively few risks for long-term concern but, in full disclosure, the immune system is amazingly powerful and able to cause autoimmune reactions. Yet an analysis of the spike glycoprotein from COVID-19 (which all the vaccines target) does not reveal homology to human proteins, and thus the risk of side-effects is minimal. Nonetheless, we are watching very closely.
Durability and anti-vaxx campaigns
Of greater concern are two fundamental questions for which we currently have no definitive answers. The first pertains to a word that has not, in my opinion, been emphasized enough: durability. This simple word reflects the unresolved question of how long vaccines will protect us against COVID-19. It would be short-sighted to assume that, once immunized, this protection will last forever. All evidence collected to date suggests that the protection is at least six-to-nine months (the time that they have been studied to date). We simply do not know how long the protection will last.
This unknown is particularly salient given what we know about other coronaviruses. There are seven known families of coronaviruses that infect humans. Four contribute to what we collectively refer to as “the common cold”. We do know that individuals infected with any of these four variants are protected from another cold for only about a year. For two other variants, SARS and MERS, which are magnitudes more deadly than SARS-Cov2, survivors seem to have longer-term protection. Yet again, we are limited to only eighteen years of information for SARS and less than of that time for MERS. Therefore, it will be crucial to continue monitoring vaccinated individuals for their ability to respond to a future challenge.
The question of durability is further confounded by the rise of variants. It is natural for viruses to mutate. A high mutation rate will invariably create a risk that some variants might escape the protection conferred by vaccines. Rest assured that such variations will not occur overnight but are more likely to manifest themselves as a gradual erosion of the remarkable efficacy of today’s vaccines. We have been fortunate that all three vaccines authorized for use in the United States confer 100% protection against severe disease and death.
As more and more variants arise, that protection might slowly degrade to 95%, then 90% and so forth. At present, there is no evidence that extant variants of SARS-CoV2 threaten to do so, but it would be naïve to presume this will never happen. Indeed, much focus is being placed upon the development of “booster” vaccines in anticipation these could both extend the durability of a protective immune response and address dangerous variants. Given what we know about SARS-CoV-2, it seems unlikely that we will require annual updates (as we do for influenza). Yet variants will likely arise that will require future boosts. And yes, there will be future aches and pains after we receive these boosters. It is a comparatively small price to pay.
Moreover, there is something we can do about this… and we can do it right now. If there are fewer infected people, the number of mutations (and variants) will proportionally decrease. Returning to the analogy of the vaccination campaign as a football game, what worries me is the fourth quarter. To overcome COVID-19, we must achieve herd immunity, a misunderstood concept that reflects whether a pathogen is present in enough people to spread within a community. For SARS-CoV-2, it seems that something like 80-85% of people will need to be immunized to achieve herd immunity.
Arming ourselves with facts
Looking back on recent history, 80% may prove to be particularly challenging. First, the top-line level of immunization will, in reality, necessarily be higher because some immunized people will not be able to mount a robust immune response, perhaps the consequence of prior treatment for cancer or autoimmune diseases, or simply a consequence of a long life.
The problem will lie with those who reject vaccines. A powerful anti-vaccine movement has been progressively growing. This is not a particularly new phenomenon but has grown in recent years. Indeed, it is a fundamental character trait for our species to question (and often reject) concepts we do not understand.
To win this contest against COVID-19, we must prevail with transparency. This means conveying what we do, and do not, know about the safety, efficacy and durability of vaccines. We must overcome those who seek to buttress and advance the destructive view of anti-vaxxers. We must prepare for honest, fact-based conversations with sceptics. Most of these sceptics are simply afraid and confused, perhaps as a result of our society’s dependence upon a social media unrestricted by fact-checking. These discussions will inevitably frustrate many, but vaccination should be viewed as a selfless act taken to protect our friends, families and neighbors. I am an inveterate optimist and sincerely believe that, when honestly, accurately and respectfully conveyed, rational people will respond accordingly.
Let us therefore all prepare now for what could be our last major hurdle between now and the end of the pandemic: arming ourselves with facts and having honest and constructive conversations with those who are hesitant or opposed to vaccination.
Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the official position of Technology Networks.
About the author
Michael S. Kinch is associate vice chancellor, professor of biochemistry and molecular biophysics, and director of the Centers for Research Innovation in Biotechnology and Drug Discovery at Washington University in St. Louis. He is the author of Between Hope and Fear: A History of Vaccines and Human Immunity, The End of the Beginning: Cancer, Immunity and the Future of a Cure and A Prescription for Change: The Looming Crisis in Drug Development.