At the beginning of this time of pandemic, it was interesting to read stories of people on an extended wilderness sojourn as they returned to their normal life. In the several weeks away, they discovered there was nothing normal about the world they had left. They returned to find covid-19, masks, social distancing, sheltering at home, and a world reporting and tracking pandemic.
They also returned to find friends that were budding disease specialists and epidemiologists apart from their usual work and careers well afield from the world of medicine and research. It is good, …to a point… that as a society we are far more conversant on the topics of vaccines, inoculation, immunization, antibodies, immunity, herd immunity, and other. Although it seems to me that there is some softness around the edges of the way we understand and use the words.
For our purposes we’ll treat vaccination/vaccine and inoculation as the same term. Vaccination is the term used for getting a vaccine – that is, actually getting the injection or taking an oral vaccine dose. Immunization refers to the process of both getting the vaccine and becoming immune to the disease following vaccination.
But we can become immune to disease through life. When we are exposed to viruses (bacteria, fungi, or parasites, too) through an infection the immune system creates antibodies and immune cells that inactivate or destroy the specific infectious organism. Assuming the disease does not kill us, if we encounter the same organism in the future, the immune system “remembers” that previous exposure and can mount a defense.
So, an individual can become immune through vaccination and previous exposure.
But not all viruses have vaccines or build immune responses. Consider HIV and dengue – both viruses for which there is no vaccine (and not for lack of trying) and no effective immune responses. Fortunately, Covid-19 is not this type of virus. It belongs to the coronavirus family, and while being new, the track record is that a vaccine will be developed – mostly likely – but it is not likely that it will happen in 2020. But then I am not a researcher.
But what about so-called, herd immunity? When enough of us are immune, then as a community/society we are said to have herd immunity. Herd immunity is an epidemiological concept that describes the condition where a population consists of a large number of people sufficiently immune to a disease so that the infection will not spread within that group. In other words, enough people can’t get the disease – either through vaccination or natural immunity – that the people who are vulnerable are protected because disease does not have enough human carriers to widely spread the disease.
For example, let’s think about mumps. Mumps is a very infectious disease that, while relatively benign, is very uncomfortable and sometimes causes severe life-long complications. It’s also vaccine-preventable, with a highly effective vaccine that has made the disease incredibly rare in the modern age.
Mumps has a basic reproductive rate (R0) of 10-12, which means that in a population which is entirely susceptible – meaning no one is immune to the virus – every person who is infected will pass the disease on to 10-12 people. This means that without vaccination roughly 95 percent of the population gets infected over time. But even with something that is this infectious, there are still some people – 5 percent of the population – who don’t get sick, because once everyone else is immune there’s no one from whom to catch the disease.
We can increase herd immunity by vaccinating, because vaccination makes people immune to infection, but it also stops infected people passing on the disease to everyone that they otherwise would. If we can get enough people immune to the disease, then it will stop spreading in the population.
And that’s herd immunity, in a nutshell. Not a perfect explanation, but it will suffice.
For mumps, you need 92 percent of the population to be immune for the disease to stop spreading entirely. This is what’s known as the herd immunity threshold. COVID-19 is, fortunately, much less infectious than mumps, with an estimated R0 of roughly 3. With this number, the proportion of people who need to be infected in order to stop spreading the disease is lower… but still high, sitting at around 70 percent of the entire population.
Lacking a vaccine, we can achieve herd immunity for Covid-19 when 70 percent of get infected – presuming the once-infected-individual is in fact immune (studies are still out on that one). The working number of people in the United States is 330 million. A 70% infection rate means 230 million or so people need to be infected to achieve herd immunity (lacking an effective vaccine). Of course, I am not recommending this, just running the numbers. There is no consensus on the mortality rate of Covid-19, but for purposes of this discussion assume it is really low 0.5% (the best estimates put COVID-19 infection fatality rate at around 0.5-1 percent.) – that means approximately 1.1 million people in the United State would die from the disease; a catastrophic outcome.
With something like 10 percent of all infections needing to be hospitalized, you’d also see upwards of 23 million people requiring advanced medical care. The has huge implications for the country as well.
Until we have a vaccine, anyone talking about herd immunity as a preventative strategy for COVID-19 is badly misguided. Fortunately, there are other ways of preventing infections from spreading, which all boil down to avoiding people who are sick. And given Covid-19 seems to have asymptomatic carriers, it kinda’ boils down to avoid people.
So, stay home, stay safe, and practice physical distancing as much as possible in these days when there is no vaccine and no herd immunity.
And now we have the protestors who, for their own reasons and rationale, take the position: you can’t tell me what to do. “We have freedom! Don’t tread on me!” Maybe there are of lot of people protesting, or may the news makes it appear as though there are. Regardless of numbers, there is still the rallying cry of “Freedom.”
Over many years I have asked people “What is freedom?” Inevitably the answers are synonymous with “choice.” We can choose to stay home, we can choose to wear a mask or not, maintain distance or not – we can choose because we are free!
About 1,000 years ago, Anselm of Canterbury, in his treatise De Libertate Arbitrii, addressed this very matter. He wrote that if your idea of freedom is simply a matter of choice, then it is a very impoverished sense of freedom. To be truly free is to be unburdened. Unburdened so that there are no obstacles, no barriers, no impediments on your journey to come before God, where you can experience the great paradox. To be truly free is to have no choice at all. To stand before the fountain fullness of divine love pouring into your being…there is no choice. One always chooses love.
What’s love got to do with it? In the New Testament Greek, the Christian ideal of love is not eros, or philos, but agape – a love that is self-sacrificing for the other and is an act of the will. It is as Jesus says in Gethsemane: “not my will but yours be done.” (Luke 22:42) It is this ultimate act of agape, that Jesus chose the redemption of the world over the preservation of his own self.
Or maybe in the language of this article, Jesus chose the safety and protection of the herd over his own wants and desires: “not my will but yours be done.” He was willing to give up his life so that we would be unburdened by sin, so that we would be free.
And what about us? The stakes might just be as high for the herd of our time – life and death. But the simple ask is to wear a mask, to maintain social distancing, to do small things. But to respond with a battle cry of “freedom” is as far, in that moment, from the life of Christ as can be, as you choose one’s self above the safety of the community.
To be in solidarity with the community and to take the small steps of social distancing, wearing masks, and all the rest – that is love – and that is the only immunity we have against Covid-19 here in May of 2020.