DALLAS (NEXSTAR) — When the coronavirus currently sweeping the world was first identified, many comparisons were made between COVID-19 and the flu. Doctors treating patients during the current coronavirus pandemic say the comparison simply isn’t accurate.

Dr. Roberto Cosentini works at the main hospital of the city of Bergamo, the area in Italy hardest hit by the new coronavirus. He explained to UK broadcaster Sky News that COVID-19 the disease caused by the virus, is nothing like the flu.

Consentini says it’s like severe pneumonia and that some 50 to 60 patients are coming in every day in a serious condition, placing a massive strain on the stretched health system.

A respiratory therapist who has treated COVID-19 patients in New Orleans spoke to non-profit newsroom ProPublica about his experience treating the virus. ProPublica withheld the therapist’s name and employer to prevent potential retaliation. He admits he initially thought the disease was over-hyped.

“Reading about it in the news, I knew it was going to be bad, but we deal with the flu every year so I was thinking: Well, it’s probably not that much worse than the flu. But seeing patients with COVID-19 completely changed my perspective, and it’s a lot more frightening.”

The therapist said he’s been running ventilators for the sickest COVID-19 patients. According to him, many of his patients are relatively young, in their 40s and 50s, and have minimal, if any, preexisting conditions in their charts.

“It first struck me how different it was when I saw my first coronavirus patient go bad. I was like, holy s—, this is not the flu. Watching this relatively young guy, gasping for air, pink frothy secretions coming out of his tube and out of his mouth.”

For most people, the coronavirus causes only mild or moderate symptoms, such as fever and cough. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia.

The vast majority of people recover from the new virus.

According to the World Health Organization, people with mild illness recover in about two weeks, while those with more severe illness may take three to six weeks to recover.

Anaesthetist Dr Lorenzo Grazioli of Bergamo, Italy had a message for other countries currently facing increasing numbers of cases: “What I would suggest is just shut down to stop all the outbreak and not come in this kind of situation, that is very, very difficult to manage,” he told Sky.

Grazioli said he is used to working under strain and making difficult choices about critical patients but he admits he has never been so stressed in his life.

“When you are arrive at this point, you realize that you are not enough,” he said, adding we are 100 anaesthetists here and we are doing our best, but maybe it is not enough.”

(The Associated Press contributed to this report.)