The multiple waves of a pandemic - restrictions are lifted too soon and reimposed

In 1918, a new respiratory virus invaded the human population and killed between 50 million and 100 million people — adjusted for population, that would equal 220 million to 430 million people today. 

Most pandemics have multiple waves. The 1918 Spanish flu had 3 waves with the 2nd wave being the most deadly and the worst one. 

There were 3 different waves of illness during the pandemic, starting in March 1918 and subsiding by summer of  1919. The pandemic peaked in the U.S. during the second wave, in the fall of 1918. This highly fatal second wave was responsible for most of the U.S. deaths attributed to the pandemic.

In 1918 many cities imposed restrictions, lifted them too soon, then reimposed them. Covid-19’s average incubation period is more than double influenza’s, so compliance may have to be sustained for months, and openings and closings may also have to be repeated. Again, if the public is going to comply over time, they will have to be led, inspired or compelled.

Second wave starting in Asia

Countries in Asia are facing new waves of coronavirus infections after lockdowns lift. The same could happen in the rest of the world.

The 11-week coronavirus lockdown in Wuhan, China, ended Wednesday, allowing residents to leave their homes for periods of time with clearance from a government-sanctioned app.

Shops are beginning to open again, and people are leaving the city en masse. Schools remain closed, and residents are still encouraged to stay home as much as possible, but some people are beginning to congregate in the streets for conversation or games.

First, a small number of residents who were under lockdown could still have the virus when restrictions lift but not know they're sick. Those people could then spread it, starting a new wave of infections.

The latter seems to have sparked a surge of new infections in Hong Kong.

Second, international travelers could bring the virus back into the country.

"What happened in Wuhan and now what's happened in north Italy is not the peak of an epidemic. That's about a month away from the peak," he said. "They are still facing now, most likely, a second wave in one to two months' time. So are they going to shut down again?"

New waves could lead to multiple shutdowns

Along with barring foreigners from entering, some jurisdictions in China have already reimposed business closings shortly after lifting them.

Chinese scientists and health experts had previously downplayed the threat of another domestic wave of coronavirus infections, however.

"For me, a second outbreak (of coronavirus), a domestic outbreak in China, wouldn't be a great concern," Cao Wei, the deputy director of the Department of Infectious Diseases at the Peking Union Medical College Hospital, told Reuters on March 18.

Souces: 

The Single Most Important Lesson From the 1918 Influenza

1918 Pandemic Influenza: Three Waves

Countries in Asia are facing new waves of coronavirus infections after lockdowns lift. The same could happen in the rest of the world.