NEWS YOU CAN USE: Coronavirus Is Very Different From the Spanish Flu of 1918. Here’s How.

In 1918, the world was a very different place, even without the disruptive influence of World War I. Doctors knew viruses existed but had never seen one — there were no electron microscopes, and the genetic material of viruses had not yet been discovered. Today, however, researchers not only know how to isolate a virus but can find its genetic sequence, test antiviral drugs and develop a vaccine.

In 1918, it was impossible to test people with mild symptoms so they could self-quarantine. And it was nearly impossible to do contact tracing because the flu seemed to infect — and panic — entire cities and communities all at once. Moreover, there was little protective equipment for health care workers, and the supportive care with respirators that can be provided to people very ill with coronavirus did not exist.

With a case fatality rate of at least 2.5 percent, the 1918 flu was far more deadly than ordinary flu, and it was so infectious that it spread widely, which meant the number of deaths soared.

Researchers believe the 1918 flu spared older people because they had some immunity to it. They theorize that decades earlier there had been a version of that virus, one that was not as lethal and spread like an ordinary flu. The older people living in 1918 would have been exposed to that less lethal flu and developed antibodies. As for children, most viral illnesses — measles, chickenpox — are more deadly in young adults, which may explain why the youngest were spared in the 1918 epidemic.

Regardless of the reason, it was a disaster for life expectancy, which plummeted. In 1917, life expectancy in the United States was 51 years. It was the same in 1919. But in 1918, it was just 39 years.

The new coronavirus tends to kill older people and those with underlying medical conditions, and it does not seem to kill children. All of which means it will have far less effect, if any, on life expectancy.

To riff off Salena Zito, treat this coronavirus seriously but not hysterically.