Infection expert explains 4 factors that make Covid-19 way more lethal than the flu

In the past week, a series of rapid events have challenged the nation and the scientific communication of coronavirus. On Thursday, President Trump announced that he and First Lady Melania were infected with Covid-19. The next day he was taken to Walter Reed National Military Medical Center for treatment.

Then, on Tuesday morning, after being treated with the steroid dexamethasone and a five-day course of remdesivir, President Trump returned to the White House. He is still infectious.

Rather than be sobered by his own infection, the President continued a repeated pattern of downplaying the disease. Trump wrote on Twitter, "Don't be afraid of Covid-19. Don’t let it dominate your life.” He went on to equate the novel coronavirus to seasonal influenza on Twitter and Facebook. This comparison is inaccurate at best, and dangerous at worst, experts tell Inverse.

Facebook deleted Trump's post, while Twitter hid the message behind a warning about "spreading misleading and potentially harmful information."

"Covid-19 and influenza are two distinct infectious diseases, caused by different viruses," Lisa Maragakis, senior director of infection prevention at the Johns Hopkins Health System, tells Inverse.

While both are serious diseases, placing the flu and Covid-19 in the same category ignores four key distinguishing factors, Maragakis says:

• Mortality rate
• The diseases' physical effects
• Immunity
• Vaccine and treatment options

"There are some similarities and overlap among the presenting symptoms of the two infections, but there are also important differences," Maragakis says. "Estimates show that the mortality rate of Covid-19 is approximately 10 times higher than that of the flu."

As flu season progresses and we stare down a possible "twindemic," understanding these major differences between the flu and Covid-19 is crucial. Armed with this knowledge, we can take steps to minimize the risk of coming down with either illness, Maragakis explains.

"Anything that confuses the public or undermines their confidence in the public health guidelines is extremely dangerous," she says.

"We need consistent public health messaging to encourage everyone to practice the basic infection prevention measures that will control not only Covid-19 transmission but also influenza and other respiratory viruses. These are masking, physical distancing, hand hygiene, and staying home when you have symptoms."

The difference between coronavirus and the flu

One of Trump's core messages is that the flu is similarly lethal to Covid-19, yet we don't close public spaces or institute lockdowns in response — a precaution that, when it comes to Covid-19, public health experts and some politicians advocate for.

However, despite what Trump says, seasonal influenza is far less lethal than Covid-19, according to national data collected by the Centers for Disease Control: Each year, between three to 11 percent of the U.S. population becomes infected and develops flu symptoms. Influenza routinely kills between 12,000 and 61,000 people in the United States annually.

Meanwhile, Covid-19 has already killed more than 200,000 people in the US since January. More Americans have died from Covid-19 than the previous five flu seasons combined.

"Covid-19 has a mortality rate that is many times higher than most seasonal strains of influenza," Maragakis explains. The flu has a mortality rate of 0.1 percent, while Covid-19 has an estimated one percent mortality rate.

Furthermore, while some of the initial symptoms of Covid-19 and the flu are the same — coughing, fatigue fever, muscle aches — the novel coronavirus is known to damage and stress other bodily systems the flu typically does not. Growing evidence suggests Covid-19 can jeopardize brain and heart health, as well as gut function.

"Covid-19 has also proven to have different types of effects on other organ systems beyond the respiratory illness it causes," Margakis says. "For instance, it increases the chance of clotting disorders and can cause heart, kidney, and neurological changes as well."

Another of the major differences between Covid-19 and the flu is the fact that Covid-19 recently emerged as a novel coronavirus. That means few people's immune systems are prepared to combat it. The same is not true of the flu.

"Influenza viruses circulate year after year and, therefore, most people have at least some degree of immunity or protection against the virus, even if they aren’t completely immune to the different strains that circulate in a given year," Maragakis says.

"In contrast, the vast majority of the world's population has little to no immunity to SARS-CoV-2, the virus that causes COVID-19, because it is a brand new virus."

We also understand how to prepare for the flu, and treat it: Each year, epidemiologists, physicians, and scientists work to predict which influenza strain will hit during flu season and develop an annual flu shot to reduce the public’s risk of getting sick. While the shot isn’t perfect, it is our best defense against the flu.

Between 2018 to 2019, the flu shot prevented an estimated 4.4 million infections and more than 3,500 influenza-associated deaths.

"We have a safe and effective vaccine against influenza, as well as several effective antiviral medications that can be administered by mouth to prevent or treat the illness [influenza]," Maragakis says. "We do not yet have a vaccine against SARS-CoV-2 and the medications that have shown some efficacy must be given by the intravenous route to patients with disease that is severe enough to cause them to be hospitalized."

Facing the future — Even though these pivotal differences set the flu and Covid-19 apart, as flu season and Covid-19 pandemic converge it will be "quite difficult" to distinguish Covid-19 from influenza and other respiratory viruses based on symptoms alone, Maragakis says.

"We are heading into the fall and winter months when people will gather and conduct more of their activities indoors where we know the risk of respiratory viral transmission is highest," Maragakis says.

"We see that SARS-CoV-2, much like the earlier SARS-CoV-1, tends to be transmitted in large 'super-spreader' events where one person can transmit the virus to many other people, especially when they gather indoors without appropriate masks, distancing or good ventilation."

It's also possible people will become infected with both viruses, and the hospitals will be flooded with an influx of ill patients. To avoid this dual-threat and getting sick, people should stay vigilant about public health precautions and get the flu vaccine.

"It will also be important this year to stay home and seek medical evaluation for even mild symptoms so that we can continue to perform testing, contact tracing, and isolation to get the pandemic under control," Maragakis advises.