The US, Brazil and others lifted lockdowns early. These charts show just how deadly that decision was

Patience in lifting coronavirus restrictions is paying off all over the world, but lifting lockdowns too early can have deadly consequences.

A CNN analysis of policies across 18 nations has shown that most of the countries that have now been designated by the European Union as having the epidemic under control only started easing their regulations after seeing sustained drops in daily new cases of Covid-19.

In contrast, three of the four countries with the world's highest death tolls and case counts -- the United States, Brazil and India -- have either never properly shut down or started reopening before their case counts begun to drop.

The EU formally agreed a set of recommendations of 15 countries it considers safe enough to allow their residents to travel into its territory on Tuesday. To get on the list, countries have to check a number of boxes: their new cases per 100,000 citizens over the previous 14 days must be similar to or below that of the EU, and they must have a stable or decreasing trend of new cases over this period in comparison to the previous 14 days.

The bloc will also consider what measures countries are taking, such as contact tracing, and how reliable each nation's data is.

The list includes Algeria, Australia, Canada, Georgia, Japan, Montenegro, Morocco, New Zealand, Rwanda, Serbia, South Korea, Thailand, Tunisia, Uruguay. China, where the virus originated, is also on the list, but the EU will only offer China entry on the condition of reciprocal arrangements.

An examination of the coronavirus response in the 14 countries shows they have one key thing in common. Despite economic pressure, the vast majority refused to ease social distancing measures while their case counts were still going up. And when they did lift their lockdowns, they did it in a careful, phased manner.

Scientists say lockdowns have likely prevented hundreds of millions of infections around the world. A modeling study published in the scientific journal Nature last month estimated that by early April, shutdown policies saved 285 million people in China from getting infected, 49 million in Italy and 60 million in the US.