It is true the second wave of the 1918 Influenza pandemic was the most deadly, but it did not happen due to lifting of quarantine.
A Facebook post warning “humanity should never allow a repeat of the same mistake in 1918” has been shared thousands of times on Facebook.
The post reads “The most severe pandemic in history was the Spanish Flu of 1918. It lasted for 2 years, in 3 waves with 500 million people infected and 50 million deaths. Most of the fatalities happened in the 2nd wave. The people felt so bad about the quarantine and social distancing measures that when they were first lifted, the people rejoiced in the streets without abandon. In the coming weeks, the 2nd wave occurred, with tens of millions dead.”
The claims in the post about 1918 are a mixture of accurate and inaccurate.
The 1918 influenza outbreak or the “Spanish flu” spread across the world in between 1918 and 1919, and is generally believed to have infected 500 million people and killed 50 million, making it the deadliest pandemic of modern times, (the black death is thought to have killed more.)
It is also correct to say most of the fatalities happened in the second wave of the virus. The graph shown in the post is a commonly used graphic when talking about the three waves of the Spanish flu. We believe it shows weekly influenza mortality figures for England and Wales, rather than global figures—it appears to come from this scientific paper, which in turn adapted it from this 1927 book, which sourced the data from a 1920 report by the General Register Office.
However, it’s incorrect to say the lifting of quarantine and social distancing measures was what led to the second wave. In reality, across the world, public health measures greatly varied, with parades still being held in Autumn 1918, at the height of the second wave. In the US, quarantine measures were implemented during the second wave.
The reason why there was a second wave of the flu is still debated, but is usually more associated with broader public health policy failures, and issues related to the war, such as soldiers travelling across Europe. Some suggest that the virus may have mutated into a deadlier strain between the first and second wave, but this remains uncertain.
The post might be referring to an infamous incident that happened with a parade in Philadelphia during the 1918 pandemic, although again, this didn’t happen because of quarantine being lifted. We wrote about that outbreak here.
This article is part of our work fact checking potentially false pictures, videos and stories on Facebook. You can read more about this—and find out how to report Facebook content—here. For the purposes of that scheme, we’ve rated this claim as partly false because there was an extremely deadly second wave of the 1918 flu, but not due to quarantine being lifted.