The 1918 pandemic transpired in three waves, from the spring of 1918 to the winter of 1919 — ultimately killing 50 million to 100 million people globally. The first wave in the spring of 1918 was relatively mild. A majority of 1918 flu deaths occurred in the fall of 1918 — the second, and worst, wave of the 1918 flu.
Health experts expect Covid-19 infections to increase this winter because the virus that causes Covid-19 is a coronavirus, and other coronaviruses spread more during winter. In wintry, less-humid air, virus-carrying particles can linger in the air longer. Additionally, our nasal membranes are drier and more vulnerable to infection in winter. And as the weather gets colder, we spend more time indoors without sufficient ventilation, which means the virus has a higher likelihood of spreading.
“But, of course, the story that we’re talking about isn’t over yet,” Brown said.
Why the second wave was so deadly
There are several possibilities why the 1918 second wave was so horrible, including a virus that possibly mutated and patterns of human movement and behavior at the time. Winter meant that influenza also spread more and people were indoors more often.
In 1918 flu patients, pneumonia often quickly developed and killed people by the second day. Efforts for the First World War had taken over, so rampant spread was facilitated by troop movements and crowded military camps.
Read More: 1918 pandemic vs. 2020 pandemic: Lessons of the second wave