April 24, 2020
COVID-19 Is Not the Flu
In less than five months, a tiny string of genetic material, 30,000 base pairs long (compared to 3 billion in our genome), has brought our planet to a standstill. The economic and social damage, the curtailment of education and travel and sports, has been devastating. Central banks are printing trillions of dollars and other currencies to keep our economies clinging to a life preserver. Is this all worth it? There are some who think we are overreacting, and that we should open up the country and go back to normal sooner than later. The main argument they make is that this is “just the flu” and so we should treat it that way, rather than upending our lives.
Superficially, COVID-19 illness is similar to the flu. It is a respiratory illness transmitted by droplets, often spread by coughing and sneezing, and causes fever and fatigue. Like the flu, most people will recover completely within two weeks, and in about 50% of cases experience little or no symptoms. And while most people recover, with both the flu and COVID-19, a small percentage of cases turn out to be fatal.
But a deeper look shows that COVID-19 is most definitely not the flu. Start with fatality. Influenza has a lethality of 1 in a 1,000, and skews toward older people. In addition, flu rarely kills people directly, deaths result from secondary bacterial pneumonias or flair of emphysema or other conditions. COVID-19, on the other hand, triggers a severe viral pneumonia in about 3-5% of patients. This is bad enough to put many of these patients into the hospital to get oxygen until their lungs heal. In about half of those patients the lungs flood with fluid due to inflammation and ARDS, requiring a ventilator and a lengthy ICU stay. At this point, mortality is about 50%. Overall, COVID-19 is ten times deadlier than flu. In addition, we are finding that COVID-19 appears to cause blood clotting, with patients dying from pulmonary embolisms or heart attacks.
Flu is less deadly partly because we can treat it with Tamiflu, and we can treat the bacterial pneumonias that result with antibiotics. We have no treatment for COVID-19. We can also protect people and healthcare workers from flu with vaccines. In 30 years of doing critical care, I have never seen healthcare workers take the precautions with flu patients that we do with COVID-19. While new flu strains appear every year, our immune system does have partial memory from previous flus, giving many of us partial immunity. In addition, flu has lower infectivity than COVID-19. The R0, which defines how infective an organism is, is about twice as high with COVID-19 as flu. Even in a bad flu season, only 10-15% of the public get the flu. But with COVID-19, without social distancing and masks and quarantines, there is no reason to think it would not eventually infect 50% or more of the country. The rapid spread of the virus on cruise ships and aircraft carriers verifies that.
The worst flu season of the last 30 years was 2017-2018. It hit us hard, and local hospitals were stretched thin. ICUs were full, and critically ill patients often waited 24-48 hours in the emergency rooms till a bed opened in ICU. Roughly, 45 million Americans were infected, and about 60,000 died over 5 months. COVID-19 is a totally different beast. If unchecked, it will rapidly overwhelm a region, and send thousands to the ICU. The healthcare system cannot take care of that many patients at once, and in Italy, doctors had to choose who got a ventilator and who didn’t. If we open up the country, we could see Italy replicated in every major city.
With a nation essentially shutdown for several weeks now, we are still seeing over 2,000 people die every day. COVID-19 is now the leading cause of death, surpassing heart disease or cancer. Almost 60,000 will die in April, if we let that continue for a year, we would have 720,000 dead. This is not the flu. Until we have a vaccine, we cannot return to normal. But if we are aggressive and smart and organized, we can get most people eventually back to school and work, especially if we are able to find effective therapies that cut fatalities sharply.
