The Department of Health and Human Services, which includes the CDC, has begun an internal review to assess its own mistakes. But outside observers and federal health officials have pointed to four primary issues that together hampered the national response — the early decision not to use the test adopted by the World Health Organization, flaws with the more complex test developed by the CDC, government guidelines restricting who could be tested and delays in engaging the private sector to ramp up testing capacity.

Combined with messaging from the White House minimizing the disease, that fueled a lackluster response that missed chances to slow the spread of the virus, they said.

“There were many, many opportunities not to end up where we are,” Dr. Ashish K. Jha, the director of the Global Health Institute at Harvard, told the AP. “Basically, they took this as business as usual. … And that’s because the messaging from the White House was ‘this is not a big deal, this is no worse than the flu.’ So that message basically created no sense of urgency within the FDA or the CDC to fix it.”