Great VACCINE Expectations

Refocusing our expectations to align with what the vaccine is designed to do

Dec 13, 2021

Last Thursday — December 9 — was the 42nd anniversary of when the Global Commission for the Certification of Smallpox Eradication declared that smallpox had in fact been eradicated from the world. For public health professionals, the eradication (read: global elimination) of smallpox is our claim to fame; we love to talk (read: boast) about how smallpox is no more. The epidemiologists who were responsible for the vaccination campaign are our heroes. In public health, we talk about smallpox eradication with the same energy, excitement, and ownership as a 1970s Pittsburgh Steelers fan talks about the 4 Superbowl wins. Smallpox eradication is a victory shared by all of us! We did it.

To commemorate the smallpox eradication anniversary last week (which is the first and only time a disease has been eradicated), many calls to action were made on social media urging people to get their COVID vaccine so that we can eradicate the SARS-CoV-2 virus, too. This got me thinking about our vaccine expectations…

What are our vaccine expectations? Should they be great expectations?

Vaccines are “one tool in our toolbox.” They are not a magical fix to end the pandemic. As depicted here (in what could be the next great novel), vaccines must be combined with other tools, namely masking and some physical distance (or some quality HVAC or time together outside).

Managing our vaccine expectations (ensuring that they are realistic) is important as we enter year 2 of the pandemic. Knowing what vaccines can and cannot do will help us to manage our pandemic expectations (read: help reduce our COVID-anxiety) and may help us have meaningful conversations with individuals who have not yet been vaccinated.

Ultimately, the COVID-19 vaccines have a dual purpose —-

The vaccines were designed to create sustained immunity for the vaccinated individual to protect them from severe disease caused by (any variant of) the SARS-CoV-2 virus.
The vaccines are intended to infuse immunity throughout our population/communities (aka herd immunity1), which will further slow the spread of disease from person to person.

Vaccines were always intended to be used in tandem with other mitigation strategies. And vaccines were always intended to be a community action, meaning we need a large proportion of the population (upwards of 90%) to be vaccinated in order to receive the benefits of herd immunity.

Vaccines are one tool in our toolbox to slow the spread of COVID-19.

We cannot expect a vaccination effort in the middle of the COVID-19 pandemic to lead to the eradication of the disease.

Instead, we use vaccines in combination with other mitigation strategies (testing, isolation, quarantine, masking, and avoiding large crowds), to slow the spread of disease. Simultaneously, as we increase the number of individuals who are vaccinated, we can add the benefits of herd immunity to our toolbox of ways to slow the spread of COVID-19. Ultimately, our goal is to get to a place where to spread of the disease has slowed (significantly) and is predictable.

Here are some realistic (and detailed) vaccine expectations —

First, eradicating (global elimination of disease) COVID-19 through a vaccination campaign is unrealistic. And making comparisons between smallpox and COVID just doesn’t work. It is sort of like the Sesame Street sketch “One of These Things Is Not Like the Others” —

Pictured here starting in the upper left-hand corner and moving clockwise are the Alpha, Delta, and Beta variants of the SARS-CoV-2 virus. In the lower left-hand corner is the smallpox virus. Obviously, smallpox is not like the others. Several key characteristics of smallpox made it a candidate for eradication. Unfortunately, the SARS-CoV-2 virus does not have these characteristics in common with smallpox.

Though both are infectious diseases caused by a virus, several key characteristics of smallpox made it an excellent candidate for eradication. Unfortunately, the SARS-CoV-2 virus does not have these characteristics in common with smallpox.

Smallpox is caused by the variola virus. It is spread from person to person in several different ways — through the air (like COVID) and through skin-to-skin contact or contact with contaminated clothing and bedding. Approximately 30% of people who contract smallpox die of smallpox. It is a pretty awful disease. Fun fact: there is evidence that smallpox was spreading as early as 1157 BCE; the mummified remains of Egyptian Pharaoh Ramses V (who died in 1157 BCE) show the telltale pockmarks of smallpox on his skin.

Several key characteristics of the smallpox virus itself allowed for a successful vaccination-eradication campaign —

Smallpox does not have an animal or insect reservoir (a place where an infectious agent lives and multiplies). Meaning the virus cannot jump to or hide in another species and hang out for a time and then be transmitted back to humans. The only known reservoir is human beings.
By the time the smallpox vaccination campaign began (1967), the smallpox virus was not evolving (read: no new variants or strains were arising). The virus had reached peak fitness or its peak capacity to reproduce in humans. Therefore, the risk of the virus continuing to evolve into a new variant that could escape vaccine immunity was really, really, really low.
Smallpox is easy to diagnose. The pocks themselves are distinctive and you cannot hide an infection, as pocks appear all over the hands and face. Additionally, the disease has a distinctive smell. No laboratory test is needed for diagnosis.
The incubation period of smallpox is 10-14 days (meaning there are nearly two weeks between when an individual is exposed to the virus and when they will begin to show symptoms). And there is NO asymptomatic spread of disease. An individual cannot transmit smallpox to another individual until they have the telltale symptoms of smallpox.
An individual can be vaccinated during the incubation period and they will not develop smallpox. This allowed the vaccinators who were part of the global eradication campaign to identify a case (which was super easy because of the distinctive pockmarks) and then vaccinate their close contacts and the contacts of those close contacts (a technique we call ring vaccination).

Unfortuneately, the SARS-CoV-2 virus does not share any of these viral characteristics with smallpox. The SARS-CoV-2 virus has several animal reservoirs (one hypothesis about the evolution of Omicron is that the virus snuck into an animal reservoir and then spilled back over into human). The SARS-CoV-2 virus continues to evolve; Omicron, Omicron, Omicron. And the disease COVID-19, caused by the virus, requires a diagnostic test to confirm infection; many of the symptoms of COVID-19 are shared with other viral infections. And then there is the incubation period. The incubation period of COVID-19 is only average 4-6 days. Additionally, there is evidence that individuals can spread COVID-19 while they are asymptomatic. AND it takes about 14 days for the body to build immunity post-vaccination.

We should NOT be expecting eradication of the SARS-CoV-2 virus.

We need to reframe our expectations. We need to reframe our conversations.

Vaccines are a tool in our toolbox. Vaccines combined with masking, staying home while sick, and avoiding crowded spaces are a way to slow the spread of COVID-19. And when I say “slow the spread,” I mean we are decreasing the transmission of the SARS-CoV-2 virus from one person to the next. The goal here is to stop the virus from transmitting to the next person because outside of the human body (or an animal) the virus will die. We want to prevent the virus from moving from one set of lungs to another. Stop it dead in its invisible, suspended in the air tracks!

For me, the goal is to slow the spread of COVID-19 until the disease becomes endemic (which is defined as having a constant and predictable presence in a population). What does this look like? That is still to be determined. But a recent article in The Atlantic captures the current pandemic moment perfectly —

“We are truly living through unprecedented times. SARS-CoV-2 is the first virus modern science has ever seen emerge and march toward global endemicity. We’ve never watched this process play out before in such detail. We won’t know what endemic COVID looks like until we get there. But we do have to figure out how to live with the coronavirus, now and into the future.”

I believe figuring out how to live with COVID-19 means using all the tools in our toolbox to slow the spread of disease. And the next goal is to increase the number of people who are vaccinated because reaching herd immunity would make our toolbox that much bigger and would help us to further slow the spread of disease.

Our conversations with individuals who are unvaccinated or denying the pandemic, should focus on slowing the spread of disease, which can be done through vaccinations combined with other mitigation strategies.

We need to refocus our great vaccine expectations.

We get vaccinated to slow the spread of disease and to decrease the likelihood that we will develop a severe infection that will require hospitalization. We are aiming for a world in which COVID-19 is predictable, where our hospitals are not overrun, and where the number of new cases per days is orders of magnitude lower than it is today.

We can have great vaccine expectations, but let us all be sure to define what we mean by great and communicate with confidence (and backed by evidence) what those great expectations actually are.

Do you have further questions?

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