Although there are variables by health status and age, the mortality of COVID-19 is about 10 times greater than a seasonal flu virus, said Anthony Fauci, MD, head of the National Institute of Allergy and Infectious Diseases (NIAID) at the National Institutes of Health (NIH).

“The stated mortality [of COVID-19], when you look at all the data, is about 3%, but I think if you count all the cases that are minimally symptomatic or asymptomatic, that probably brings the mortality rate down to somewhere around 1%,” Fauci said in recent testimony before Congress. “People always say the flu does this, the flu does that. The flu has a mortality of 0.1%. This has a mortality 10 times that.”

That is not a comforting calculation when you consider that a particularly bad flu season take 2017-2018 as the most recent example killed 60,000 people and caused more than 800,000 hospitalizations.1 Applying Fauci’s tenfold estimated mortality rate means the potential death toll of COVID-19 is more than half a million people in the United States. On the other hand, when looking at the 2011-2012 influenza season, there were 12,000 deaths, the least over the last decade. Based on Fauci’s formula, the range of COVID-19 death rates extrapolated from these two influenzas could vary from 120,000 to 600,000 deaths in the United States. The Centers for Disease Control and Prevention (CDC) declined to comment on such modeling estimates or clarify whether it is working from one of its own.

Regardless, Fauci’s considerable reputation and experience in infectious diseases makes him an authority on these matters, and he has become the voice of calm reason in the federal response to the pandemic. The scale of the COVID-19 pandemic is starting to become clear, as public health officials try to underscore the severity of the threat without setting off a panic.

Conspiracy theories about how COVID-19 originated and whether it is some kind of bioweapon are not helpful in this effort. All evidence suggests that the new coronavirus came from bats through an animal source to humans, much as did its predecessors, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).

“I think we need to speak out often and loudly about how much nonsense this is,” Fauci testified. “This is not new with coronavirus. There are always conspiracy theories when there is a new disease that people are afraid of. I have to say that about 37 years ago, I sat in this room trying to explain to the committee then that HIV [human immunodeficiency virus] was not a virus that was developed by the CIA [Central Intelligence Agency] to essentially eliminate certain populations. It’s crazy, but this is what happens when you have outbreaks. There is a lot of misinformation.”

Vaccine Misunderstandings

In that regard, Fauci painstakingly explained again why a vaccine would not be available in the near term, emphasizing it would be more like one year to a year and a half.

“I want to clear up misunderstandings,” he said. “Right now, the technology we have has allowed us to go from the time the sequence of a virus was put into the public database to the time we can actually stick a candidate into the arm — the fastest we have ever done. I expect that at least one of these vaccine candidates will likely go into clinical trials in a phase 1 study within two months or maybe even six weeks. That would be a record. However, that is not a vaccine.”

Rather, three more months of testing will be needed to determine if the vaccine is safe. Past vaccine debacles have shown that if you don’t get a vaccine right, people will lose faith in the system, and the resulting mistrust could undermine herd immunity to all manner of vaccine-preventable diseases.

“If you show it is safe, you’ve got to put it into a phase 2 trial to show that it works,” Fauci said. “There are medical, ethical, and other considerations. We would be giving this to normal [healthy] people to prevent infection. So, you must be sure. The edict of medicine is, first do no harm.”

It is more likely that treatment of COVID-19 will be available first, with the antiviral remdesivir one of the top candidates under research currently.

“It is being tested in a large trial in China and is also being tested here in the United States in an NIH-sponsored trial,” Fauci said. “We should know within a period of several months whether this particular drug works. If it does, the implementation of that would be almost immediate. I can’t guarantee that it or other drugs in the pipeline will work, but the timetable for a treatment is different than a timetable for a vaccine.”

There has been much discussion whether COVID-19 would fade out in the warmer months, possibly returning later as a seasonal virus.

“When the weather gets warmer, as will happen in March, April, and May, you will inevitably see a marked diminution of influenza,” Fauci said. “The same holds true for other respiratory viruses — including some of the common cold coronaviruses. This could happen with [COVID-19], but we don’t know. This is a brand-new virus, with which we have no experience. So even though the concept is that when warm weather comes, many respiratory viruses diminish, we have no guarantee at all that this is going to happen with this virus.”

Asymptomatic Spread?

There are several other unanswered questions about the novel coronavirus, including whether it can spread in the absence of symptoms. There are reports from China of asymptomatic patients with COVID-19 infecting healthcare workers and people in the community.

“[A] patient undergoing surgery in a hospital in Wuhan infected 14 healthcare workers even before fever onset,” researchers in China reported.2

Another case cited in the paper was a patient who traveled from Shanghai to attend a meeting in Germany and was asymptomatic until the flight back to China. Two of the patient's close contacts were infected, and another two people at the meeting acquired the coronavirus without close contact. In addition, the authors cited an asymptomatic 10-year-old boy who was found to have unusual lung images and markers of the disease in his blood.

“These findings warrant aggressive measures (such as N95 masks, goggles, and protective gowns) to ensure the safety of healthcare workers during this COVID-19 outbreak,” the authors reported.

Unrecognized cases are thought to have contributed to spread in Chinese hospitals, as more than 3,000 healthcare workers have suspected or confirmed novel coronavirus infections.2

It is not completely clear whether children generally remain asymptomatic or do not acquire the coronavirus, but there are few cases reported in pediatrics.

“A group that we would have expected to have poor outcomes — if we used influenza as a guide — is children,” says Amber M. Vasquez, MD, MPH a member of the CDC’s COVID-19 response team. “But based on limited data so far, symptoms of COVID-19 and the clinical course appear to be milder in children. Of [a group of] 44,000 cases in China, only about 2% were less than 20 years old, and no deaths were reported among those less than 10 years old.”

Of course, there are always outliers in any outbreak, and children certainly have been infected with COVID-19.

“What I still don’t totally understand is the lack of detectable infections in children, as well as the lack of any degree of serious disease,” Fauci said. “In some of the [case] reports, there wasn’t even a single identified case of a person less than 15 years old, which seems almost unbelievable. They have to be getting infected. Why they are not developing clinical disease is really interesting. This is something we really need to study because it will certainly tell us something about a correlative immune protection.”


  1. CDC. Disease burden of influenza. Reviewed Jan. 10, 2020.
  2. Chang D, Xu H, Rebaza A, et al. Protecting health-care workers from subclinical coronavirus infection. Lancet Respir Med 2020;8:e13. doi: 10.1016/S2213-2600(20)30066-7