The Spanish flu ravaged the world more than a century ago, and made its mark as one of the world's deadliest pandemics, by causing an estimated 50 million deaths worldwide.
From 1918 to 1919, 675- thousand people died in the U.S.
And as of this week, Covid-19 deaths in the U.S. has surpassed that figure with more than 680-thousand deaths.
"The fact that Covid-19 deaths have surpassed the Spanish flu death toll in the U.S. in the 21st century when medical systems, vaccines, and hygiene are much more advanced than a hundred years ago, should tell how threatening this pandemic is."
The world's Covid-19 death toll is still some way behind that of the Spanish flu.
But to judge the danger of the disease by the sheer number of deaths would be an unfair comparison.
Rather, we'd have to look at the mortality rates, one expert says.
"The Spanish flu had an estimated mortality rate of 2.5 percent. The world's mortality rate for Covid-19 is around 2 percent. So just looking at the fatality rates, Covid-19 and the Spanish flu bear a lot of similarities. "
Meanwhile, the World Health organization late last month listed another variant of interest, the Mu variant.
"The Mu variant is found in around 40 countries, but there's no evidence yet of whether it trumps the Delta variant in transmissibility."
A recent report by WHO shows that the variant makes up only point-1 percent of Covid-19 cases worldwide, but has already grown to almost 40 percent of Colombia's cases.
Scientists say the Mu carries a spike gene mutation similar to Beta, a strain that has shown some ability to evade vaccines, so they're still weighing up how concerned they should be of the new strain.
Kim Yeon-seung, Arirang News