Washington, DC, August 25, 2020 --  

The rapid spread of coronavirus amongst young Americans may cause them to reach herd immunity before everyone else. Once this happens, they'll stop giving the disease to the rest of us.

The dead bodies were overflowing morgues in Philadelphia when October began. A shortage of coffins saw police collect cadavers wrapped in cloth from the city's neighborhoods and pile them in wagons like cordwood.¹ The year was 1918, and the deadly flu pandemic that ripped through the city had effects far more terrifying than what we see today. But even before the bodies could be buried, an amazing thing happened: infection and death rates plummeted. By the end of October, life was returning to normal. The disease had burned through most potential victims, slowing the spread dramatically.

Could the same thing happen in 2020?

Most infectious disease specialists don't think so, saying herd immunity will only be reached when 80 percent of people are immune (although some think it could be significantly lower). As infectious as the coronavirus is -- with some evidence of airborne spread in specific conditions -- it is not nearly as infectious as the 1918 influenza strain. Influenza is commonly spread through airborne particles, making it spread far more easily and quickly.

Because coronavirus is less infectious, the current pandemic won't burn out quickly as happened in 1918. Conventional wisdom is that we must use vaccines to reach herd immunity to break the pandemic. The vaccines must be highly effective (dubious) and most everyone must be willing to take that vaccine (more dubious still), and we must have production capacity to get the to most everybody on earth. Under the best of conditions, this whole process could take a year or more.

But what if the experts are missing something?

While most people have been stuck at home, wearing masks, and staying six feet away from their friends, not everybody has been so pious. Photos of maskless young people frolicking in bars, on beaches, and at house parties have filled the news and fueled older Americans to shake their fists with anger. A survey in June found that 69 percent of teens report they do not engage in pure social distancing.² Behavior of adults under 40 wasn't much better.

This bad behavior has been partly behind the rise in cases this summer, test results show the disease has started disproportionately affected the young. But test results are nearly worthless to tell what's going on amongst America's youth. Few people without symptoms ever bother to get tested for coronavirus, and most young people don't get symptoms. One study showed that 79 percent of 10 to 19 year-olds are asymptomatic when infected.³

Young people have far more interaction with others than older people. They congregate in large groups of friends, hang out in bars and fill the hallways of schools and classrooms. They dominate jobs such as servers, cashiers and the like that bring them into contact with others both in and outside their age group. As a result, once they reach herd immunity it will have a disproportionate effect on the spread of disease to the rest of us.

Herd immunity amongst Americas youth might act as a firewall that causes the pandemic to peter out.

To be sure, there are absolutely no numbers to prove this is happening -- it is impossible to get them. Antibody tests to measure those who have been infected are notoriously unreliable in the best of conditions, and are worthless a few months after infection. They generally can't detect cases so mild that antibodies were never produced. How close are America's youth to herd immunity? There is absolutely no way to know.

But the very same thing was true in 1918. Nobody knew what was happening. They saw the pandemic get worse and worse. Then, all of a sudden, it was over.

Even if we get a similar surprise in 2020, it won't be the end of the coronavirus any more than the end of the 1918 pandemic was the end of influenza. Flareups will continue in communities and subgroups without herd immunity. Mutations might create a new strain that causes people to get infected again. But all these caveats will also be true once we finally manage to get a highly effective vaccine to most people around the world.

Once enough people are immune, either through a vaccine or through infection and recovery, life can start returning to normal. The longer we wait for effective vaccines, the more likely it is we will never need them.

Related Web Columns:

Sunk by the Flunkies, June 30, 2020

Notes:

1. Barry, John M., The Great Influenza, The Story of the Deadliest Pandemic in History, 2004

2. JAMA Pediatrics, Attitudes and Psychological Factors Associated With News Monitoring, Social Distancing, Disinfecting, and Hoarding Behaviors Among US Adolescents During the Coronavirus Disease 2019 Pandemic, June 29, 2020

3. Nature Medicine, Age-Dependent Effects in the Transmission and Control of COVID-19 Epidemics, June 16, 2020