Don’t Be a Germophobe
That nagging cold might protect you from something much worse one day.
Note: This article was originally published on Medium.com on August 24, 2020. My account has been deleted (by me) due to Medium’s unfortunate policy of banning authors they do not agree with.
Good news is out there, if you look hard enough. Sometimes it might be in disguise. But it’s there.
Take the country of Sweden. The Swedish government weathered harsh, withering criticism in April over the decision not to lock down, despite rising cases and deaths due to Covid-19. Instead, they continued to ban gatherings over fifty people, and encouraged social distancing. They were predicted to have over 95,000 deaths. They will likely never reach 6,000, and most of these were in long-term care facilities, just like almost everywhere else in the world.
Since April, Sweden’s curve hasn’t flattened, it’s plummeted, with numbers consistently below the average of excess deaths. In the month of August, Sweden has seen very few Covid-related deaths, and cases have dropped precipitously. In contrast, other European countries are seeing a resurgence of cases as they emerge from lock down, along with more severe, long-term economic destruction and increased lock down-related deaths. The same scenario is being played out throughout the world. Where lock downs were the most stringent, the virus has made a comeback. But Sweden, with no forced quarantine, seems to be over the pandemic completely. Life is normal in Stockholm these days.
What happened? One possible answer is that herd immunity has been reached in Sweden, as a result of natural infection. Herd immunity occurs when a significant portion of a population has recovered from an infection, or has been vaccinated, so that a virus is no longer spread efficiently from person to person, due to lack of susceptible hosts. The immune system is a miraculous system of molecules, cells, and tissues that leaves individuals with a memory of past infections and vaccinations, with a specific, targeted protection that prevents disease recurrence. Since no changes were made to Sweden’s mitigation strategy during the pandemic, and yet Covid-19 is becoming increasingly rare, herd immunity seems a viable explanation.
Yet there are some puzzling aspects to this development. Herd immunity to Covid-19 was initially projected to be achieved when 60–70% of individuals within a community recovered from infection. Since the beginning of the pandemic, the prevalence of previous Covid-19 infection has been measured by detection of serum antiviral antibodies. Antibodies are proteins (secreted by immune cells called B cells) that bind viruses, bacteria, or their toxic products, and facilitate their removal and degradation. Antibodies produced in response to an infection may be detected in serum by a simple test. However, it has become clear that some individuals, especially with mild or asymptomatic Covid-19 infection, do not develop lasting serum antibody responses. As a result, antibody sampling studies are not an accurate strategy for estimating the true number of people in a population with immunity to Covid-19.
More importantly, serum antibodies are not among the most important factors that protect from respiratory viral infection. The immune system also has cells called T cells that kill infected cells after recognizing fragments of viral proteins attached to surface molecules shuttled from inside the cell, a process that does not involve extracellular antibodies. Recently, several research groups have published fascinating, groundbreaking studies showing that those who recovered from infection developed strong protective T cell responses specific to Covid-19. This includes asymptomatic infection or people with mild infection that don’t develop long-lasting serum antibodies against the virus and thus aren’t identified by serological testing. Surprisingly, some of the fragments anti-Covid T cells recognized matched fragments from other coronaviruses, like those that cause common colds. More importantly, T cells in samples collected before the pandemic also recognized some of these coronavirus fragments. It is thus possible that previous colds could provide some level of immune protection against Covid-19, possibly resulting in less severe disease. Researchers have been careful to note that overlapping protection has yet to be functionally demonstrated. It is important in scientific research that conclusions are directly supported by data. Yet the implications of the data are obvious and enormous.
T cell protection could explain what is happening in Sweden, and in other places where cases are dropping despite significant differences in mitigation strategies. With lower than expected numbers of people testing positive for anti-Covid antibodies in Stockholm, and consistently mild mitigation measures, something else is preventing viral spread. If enough people have experienced mild or asymptomatic infections that aren’t detectable by antibody tests (possibly facilitated by preexisting T cell protection acquired from other coronavirus infections), then many places could be a lot closer to the end of the Covid-19 pandemic than previously thought.
Of course, like everything else these days, this possibility is becoming heavily politicized. Those that favor collective action with a worldwide technocratic response want to see their worldview validated with evidence of successful mitigation strategies and effective vaccines as the only sure way to reach herd immunity. Those that fear the unintended consequences of harsh worldwide interventions want to see their worldview validated with evidence that forced interventions were ineffective and unnecessary at best, and at worst, enormously destructive. They want to see herd immunity reached despite our failed efforts to contain the virus. That the goal of either worldview is to save lives, albeit by different strategies, seems to be easily lost.
I think there will be long term consequences to the pandemic response. I believe the message that we can gain complete control over the course of a highly infectious respiratory virus is potentially destructive and should be minimized in future pandemics. Even if we demand that our leaders give us the illusion of control, it is still mostly an illusion. We have been living and evolving in a world full of viruses for hundreds of thousands of years. They aren’t going anywhere. We certainly need to understand emerging viruses and learn how to respond more quickly to protect those most vulnerable to severe disease, especially with vaccines. But not every infection is harmful to everyone. The immune system reminds us that what doesn’t kill us makes us stronger. It is a lesson we should remember.
So, if the hysteria surrounding the pandemic is turning you into a germophobe, don’t let it. That nagging cold you try to avoid catching every year just might protect you from something worse one day.
Good news is out there, if you know where to look.