Now, North Korea, a country that was expected to send athletes to the Olympics, announced it will not take part in the Games.
North Korea said its National Olympic Committee had a meeting in late March and decided not to attend in order to keep its athletes from getting sick.
However, a number of international policy experts think the decision is a way to keep the country closed. North Korea said it has controlled the spread of COVID-19 by closing its borders, banning foreign visitors and sending diplomats home. But those who follow North Korea think that may not be true. The country already has a weak medical system because of international economic restrictions that have limited spending on infrastructure.
Experts say the closed border is making life in North Korea more difficult than necessary for the average person.
Jean H. Lee directs the North Korean program for The Wilson Center, an international policy research center in Washington, D.C.
Jean H. Lee执掌威尔逊中心的朝鲜项目，这是华盛顿特区的一家国际政策研究中心。
In a tweet, she asked if any other country has announced it would not attend the Olympics. She called the move "a political decision...as much as it is a public health concern."
A spokesperson for the South Korean foreign ministry said there is still time for North Korea to reconsider its decision.
Many people thought the 2018 winter Olympics in South Korea was a chance to renew diplomacy with North Korea. The closed-off nation sent 22 athletes, government officials, performers and a 230-member cheering group. Athletes from both North and South Korea marched under a flag with a blue map that symbolized a united Korean land.
The sister of North Korean leader Kim Jong Un also attended the Games.
Experts say North Korea's presence at the 2018 Games helped start discussions between former U.S. President Donald Trump and Kim. The talks, however, have not restarted for more than one year.
In addition, North Korea recently fired test missiles for the first time in one year.
The 2020 Tokyo Summer Olympics were delayed because of the coronavirus health crisis. The Games are scheduled to open on July 23.
I'm Jill Robbins.