The report estimates 11 million people a year are dying from sepsis – more than are killed by cancer.
The researchers at the University of Washington said the “alarming” figures were double previous estimates.
Most cases were in poor and middle income countries, but even wealthier nations are dealing with sepsis.
What is sepsis?
Sepsis is also known as the “hidden killer” because it can be so hard to detect.
It is caused by the immune system going into over-drive. Instead of just fighting an infection, it starts attacking other parts of the body too.
Ultimately it causes organ failure. Even survivors can be left with long-term damage and disability.
Bacteria and viruses that cause diarrhoeal infections or lung diseases are the leading triggers of sepsis.
Why the jump in numbers?
Previous global estimates, which came up with a figure of 19 million cases and 5 million deaths, were based on just a handful of western countries.
This analysis, published in the Lancet and based on medical records from 195 nations, shows there are 49 million cases a year.
The 11 million deaths from sepsis account for one in five of all deaths around the world.
“I’ve worked in rural Uganda, and sepsis is what we saw every single day,” said researcher, assistant professor Kristina Rudd.
“My colleagues treating patients on the ground in low- and middle-income countries every day have been saying this for years, that sepsis is a major problem.
“So in a way I wasn’t actually that surprised – on the other hand I didn’t expect it to be double the previous estimate.”
The good news in this analysis is that cases and deaths have fallen since 1990.
The hope is understanding the true scale of the problem will raise awareness and save more lives.