On Immunity
Prioritizing the COVID-19 vaccine for all
My previous post about HERD IMMUNITY sparked great conversations/questions centered around the concept of immunity. This post is in response to those conversations and definitely a follow-up to the herd immunity post. Before diving into definitions and a review of a paper published by researchers at the Cleveland Clinic (that has received a lot of press), I want to reiterate what I have said previously. I stand by these words that I wrote last week —
“While choosing whether or not to get vaccinated is an individual choice - and please read my letter to my daughter about the vaccine if you are not vaccinated yet - everyone who is vaccinated is contributing to the greater good and improving our community’s health. You being vaccinated not only protects you from becoming ill (and potentially dying), but it is also increasing the number of individuals who are immune and may in fact protect someone who is susceptible to the disease from becoming ill.
The COVID vaccine will protect you and will save other lives.
While you might feel invincible against COVID-19, your neighbor may not be. The vaccine is one way to love our neighbors and create healthy communities for all.”
Immunity is the body’s way of resisting/fighting a particular infection. Immunity to a specific disease, like COVID-19, is produced through ANTIBODIES to that disease. Antibodies can be produced in one of two ways — (1) through infection with the actual disease, or (2) through vaccination.
Given that you can produce antibodies following infection with COVID-19, many people have asked why get vaccinated? Why get the vaccine when infection with COVID-19 will result in immunity? To quote Dr. Jennifer Gommerman —
“Choosing the disease over vacciantion is a very bad decision.”
Everyone is vulnerable to COVID-19. We still do not know for sure why some people get very sick and die while others have no symptoms. We do not know how to predict who will become severely ill, need hospitalization, or will die. COVID-19 is no joke - everyone is vulnerable to severe disease and there is no guarantee that you will only suffer minor adverse health effects. For healthy adults 18-35, one in five had chronic health issues for MONTHS following a COVID infection. For those of us over 35, the likelihood of developing long-term health effects post-COVID jumps to 33% (or one in three); I don’t know about you, but I do not want to suffer for months, possibly unable to work or be a mom. If there is a 33% chance of that happening, I am going to do everything in my power to prevent COVID-19 infection (read: I am getting the vaccine!).
Natural immunity is unpredictable. There is a “massive dynamic range” in the immune response of those individuals previously infected with COVID-19; a 200-fold difference in antibody levels exists. This means if you were previously infected, you may have a strong immune response or none whatsoever. You may be able to fight off reinfection or you may get sick a second time and die. There is no way of knowing. With the vaccine, we know the dose/amount that is being given to an individual, and we know that the dose is effective at creating an immune response. The vaccine was created to generate an optimal immune response. The vaccine is a sure thing — it protects you from infection, hospitalization, and death AND that immunity will be sustained over time.
Many people have asked me about the Cleveland Clinic study, Necessity of COVID-19 Vaccination in Previously Infected Individuals, that was posted online (without peer review) on June 5. The media was quick to pick up on the conclusion posed by the authors in the abstract: “individuals who have had SARS-CoV-2 infection are unlikely to benefit from COVID-19 vaccination.” However, the scientific community has been quick to point out several limitations of the study and the Cleveland Clinic was also quick to clarify that this conclusion was inappropriate given the study population, study outcomes, and duration of the study. The Cleveland Clinic states —
“This information could help guide vaccination efforts should there be a shortage of vaccine supply and in countries where the vaccine supply is limited… It is safe to receive the COVID-19 vaccinate even if you have previously tested positive, and we recommend all those who are eligible to receive it.”
Upon review of this article, I saw several limitations (some listed in the paper’s discussion; others were not). A quick breakdown of those limitations is below. I do NOT believe the researchers have the evidence, sample size, or demographic make-up in their study sample to make sweeping conclusions about the vaccine not being necessary for those with a previous infection. I firmly believe that everyone eligible to receive the COVID vaccine should get it NOW.
Review of Necessity of COVID-19 Vaccination in Previously Infected Individuals —
I’d like to start this review of the Cleveland Clinic study by saying that scientific studies need to be looked at as a whole. They are a narrative of the goals, methods, findings, and applications of the study - with a beginning, middle, and end. If we take just a quote, especially ones from the article’s abstract on page #1, we could mischaracterize the findings or support findings that are unsubstantiated by the evidence. Learning to read the scientific literature is so important; in the age of COVID, it is a superpower.
Let’s dive in…
The study included employees at the Cleveland Clinic. These employees are not representative of the general population. They are younger (average age was ~40). And they were all healthy enough to be working. The healthy worker effect states that individuals who are able to get up and work every day will be healthier than those who do not work. In this study, we had a group of participants who were younger and healthier than the American population as a whole. Because of this we cannot apply/generalize the findings of the study to the American population. It is like comparing the effects among a group of oranges (healthy workers) to apples (the entire population - made up of young and old; healthy and sick; able to work and not). Therefore, we cannot apply the results of this study to the general population.
Additionally, the study population was comprised of healthcare providers and those working in a healthcare setting. These individuals are still utilizing personal protective equipment - masks, gloves, face shields, gowns - as well as being required to wash their hands frequently or use hand sanitizer. The conditions in a healthcare setting are not the same as in the “real world” where masking is not universally required, handwashing standards are not enforced, and face shields or gowns are not available for use by all. Again — we cannot apply the results of this study to the general population.
The authors gloss over one of the key findings from their work — 99.3% of all cases of COVID occurred in the group that was unvaccinated and never infected with COVID-19. When I read this, my first thought is “if these folks were vaccinated, cases of disease would have been prevented.” Please let’s focus on that… the majority of those who are being infected with COVID-19 right now are those who are susceptible because they remain unvaccinated in the middle of a pandemic.
During the 5 month study (which is a short study period), only 0.7% of individuals in the vaccinated group were diagnosed with COVID-19. These are vaccine break-through cases. We expect this to occur. There were 0 cases (0%) of COVID in the group that was not vaccinated but had a previous diagnosis with COVID-19. We do not know who was working with whom or if cases of breakthrough infection occurred randomly or among individuals caring for COVID patients in the ICU. We do not know if there was a hospital outbreak, hospital transmission, or a random assortment of cases. It is messy and there are so many factors at play here aside from vaccination status or previous infection. Additionally, there are very few cases in the study among those who were either vaccinated or had a previous diagnosis, and with small numbers there is very little we can do statistically to determine if there is a real difference (read: with small numbers, we CANNOT make sweeping claims that the vaccine is not necessary for those with a previous COVID diagnosis). The authors of the study state this —
“The absence of events precluded accurate or precise estimates of risk.”
The authors do NOT provide evidence that individuals with a previous COVID diagnosis will not benefit from a COVID vaccine. There are no measures of antibody levels; we know next to nothing about the cases (their work environment, contact with patients, or if they were connected to one another through a hospital outbreak). Nor was the study conducted in a “real world” environment that would allow for application to the general public. The study sample was NOT representative of the general population.
I agree with the statement by the Cleveland Clinic (not the authors) in response to the paper being posted online — if there is a vaccine shortage, those without a previous diagnosis should receive the vaccine first. However, given the ample supply of vaccines to date, everyone who is eligible to get the vaccine should do so immediately. This study does not provide evidence that the vaccine is unnecessary for those who were previously diagnosed with COVID.
In conclusion, this post is titled after a great book On Immunity: An Inoculation by Eula Biss. In chapter 3 she poses the following question about vaccines —
“Dracula is as much about this problem, the problem of evidence and truth, as it is about vampires. In proposing that one truth may derail another, it invites an enduring question—do we believe vaccination to be more monstrous than disease?”
Vaccines are NOT monstrous. Vaccines save lives. And in 2021, vaccines are essential to slowing the spread of the SARS-CoV-2 virus.
I will continue to write, teach, answer questions, and advocate for vaccines. And will shout from the rooftops that public health needs to be prioritized. We need to see health in all places and health (prioritized) in all policies.
Excellent analysis, Dr Dawson. Thank You!