Four questions the US must answer concerning COVID-19

Second, where did the mainstream imported cases in the US come from? How many infections has the US exported to the world?

New York Governor Andrew Cuomo recently said that the coronavirus that hit New York State did not come from China but Europe. After the epidemic broke out in China, the US soon issued a travel ban on all people coming from China, yet the country did not close its doors to Europe until mid-March, giving the virus the opportunity to sneak into the US from Europe.

Also in March, Australian prime minister said that the US was the country of origin for most of the novel coronavirus cases in Australia.

US politicians are saying that China spread the virus to the US. Could they clarify how many patients were imported cases from China, and how many came from other countries? Why didn't the US government prevent this large number of infections from entering and spreading in the US? How many cases has the US spread to the world?