Both President Donald Trump and first lady Melania Trump say they are experiencing mild symptoms of COVID-19, but doctors say there could still be cause for concern.

The world is now watching what happens next to President Trump after his early morning announcement that he is now one of millions of Americans to contract COVID-19.

According to the White House chief of staff, Trump has experienced mild symptoms. But Trump falls into a high-risk category because of his gender, age and weight.

Northwell Health infectious disease expert Dr. Bruce Hirsch says the next week will be critical.

"The first couple of days of the infection tend to be mild. And what we're very concerned about is sometime around day seven or day eight, some people take a turn," says Hirsch.

Hirsch says some people develop increased inflammation in their body and develop respiratory problems, such as difficulties extracting oxygen from the air getting inside the body and developing severe complications.

"Watching out for that right around a seven or day eight of the infection is a real priority particularly for a person with those risk factors," says Hirsch.

According to a memo released this afternoon by White House officials, Trump's doctor said that as a precaution, the president received a single 8-gram dose of Regeneron's antibody cocktail and completed the infusion without incident.

While Hirsch says about 80% of people who get the virus have a mild case, about 10% of those can still experience weeks or even months of lingering symptoms.