By Hagop Kantarjian, M.D.
Nonresident Fellow in Health Policy, Baker Institute
Mary Alma Welch, MMSc
The COVID-19 world pandemic continues to spread. As of March 24, 2020, the total number of COVID-19 infected people is 400,000+, up from 230,000 only five days ago, the date of the previous Baker Institute blog in our ongoing series. The number of deaths has almost doubled in five days, from 9,500 to 17,000+ (mortality rate 4%). In the United States, the number of infections is close to 50,000 (up from 300 on March 6, 2020), and the number of deaths 600 (mortality rate 1.2%). The infection rates in the U.S. and the world are following the early trends in China, with an increased prevalence of 33% daily. So the number of infected cases doubles every three days (actually increases by 2.3 fold every three days). If we do the math, one case today will increase to 32 cases in 15 days. Let us put this in context. By April 7, 2020, the number of COVID-19 infections in the United States will be around 32 times greater (50,000 x 32), or about 2.5 million cases. The number of deaths will increase to 30,000 (2.5 million x 1.2% mortality)! In Texas (number of cases today 900; number of deaths 10, likely a delay in reporting), the numbers in two weeks could be as high as 30,000 infections and 400 deaths. These figures may be even higher as Texas starts wider COVID-19 screening and because of the delayed cancelation of large public events (at times sources of outbreaks) like the Houston Rodeo, closed only March 11, and a reasonable city lock-down started March 16, 2020. So no one should be surprised or panic as the figures roll out.
The first cases of COVID-19 were reported in China on November 17, 2019. With intense screening and restrictive measures, the spread in China subsided by early March 2020, three to four months later. Following the China model, other countries controlled well the pandemic spread: South Korea, Hong Kong, Taiwan, Singapore, and Australia. Taiwan, an island of 23 million but an international hub close to China, implemented travel restrictions from China, and other internal isolation and containment measures. As of March 24, 2020, Taiwan reported only 215 cases of COVID-19 (two deaths). South Korea (population 51 million) implemented early and broad COVID-19 testing (10,000 tests daily) in addition to restrictive isolation: so far 9,000 are infected (infection rate less than 1%) and 120 have died (mortality rate 1.3%). Others countries such as Italy, Spain and France did not fare well. The differences in infection rates among countries are related to three key factors: 1) early recognition of COVID-19 as a serious pandemic; 2) early development and widespread use of COVID-19 testing; and 3) the extent of societal protective measures (city-wide lockdowns, social distancing and canceling large public events, among others).
The status and control of COVID-19 in the U.S. is still uncertain. And it is possible that different regions of the U.S. may have different outcomes. The first case in the U.S. was reported on January 16, 2020, almost simultaneously with the first case in South Korea. The U.S. was late in COVID-19 testing due to issues in developing the test by the U.S. Centers for Disease Control and Prevention (CDC). This is now up and running. Infection and mortality rates in the U.S. and the world may depend on factors inherent to different geographies and cultures. The amount of social contact is more in Italy and Spain than in Japan. Recent data suggest that warm and humid weather can suppress COVID-19, as happens with seasonal influenza. Some cities have high density populations, unavoidable crowding (mass transportation, subways), cold and dry weather, and more influx from affected areas (tourism). These cities appear to be more prone to be epicenters of COVID-19, and we already see the examples of New York, Seattle, San Francisco and Chicago. These cities are already preparing for, or are in the midst of, the COVID-19 massive surge, which is overwhelming medical infrastructures (hospital beds, intensive care unit beds, respirators, health care workers). Activation of the Defense Production Act may be needed to secure the necessary medical supplies (ventilators, testing kits, personal protective equipment).
How about Houston and Texas? Our cities are more spread out, have lower population densities, and have a warm and humid climate. So the impact may be less. Still, we should prepare for the worst while hoping for the best. Perhaps for once we will be thankful for our hot and humid weather.
Other modifying factors rely on the decisions made in the U.S.: 1) restrictive societal measures; 2) wider COVID-19 testing; 3) optimal medical infrastructures that can absorb and accommodate COVID-19 surges in different cities (and thus reduce mortality rates); 3) rapid development of safe and effective vaccines (human trials started early March); 4) and development of effective anti-COVID-19 drugs.
Why are mortality rates different in various countries, ranging from 1% to 3%-4%? Older age is definitely associated with higher mortality rates. Wider COVID-19 screening will bring down the true mortality rate to its realistic range. What is unclear is the potential effect of smoking on COVID-19 associated mortality. COVID-19 kills through damaging the lungs. Smoking, which compromises the lungs, is more common in China (over 65% of adult men; much less among women) and in some European countries (Italy, Spain). Smoking is less common in the U.S. (14% of adults).
COVID-19 is highly contagious. It can survive in air droplets for up to three hours. Some experts question the validity of this conclusion. For now, masks should be worn by COVID-19 infected people (to prevent infecting others); health care workers in contact with proven COVID-19 infected patients should wear N95 masks. Others do not have to wear masks or hoard them. COVID-19 lives on inert surfaces for several hours (copper, four hours; cardboard, 24 hours; plastic and stainless steel, two to three days). A person infected with COVID-19 can have no symptoms for three to seven days, and many have no or mild symptoms. The clinical disease and infectivity last another one or two weeks. We do not know if COVID-19 will recur in several waves, and if a second wave will have a more virulent virus (like with the Spanish influenza) or a less virulent one (as is more common with viruses). We do not know if COVID-19 is seasonal (subsiding in warmer weather and recurring in the cold season).
Can previous viral epidemics inform us about COVID-19? The 1918-1920 pandemic “Spanish flu” developed in three waves over two years, infected a third of the world population (500 million of 1.5 billion ) and caused the death of 50 million (range 20-100 million; estimated mortality rate 10% over the three waves). Most of the deaths were in the second wave. But there were no vaccines or antibiotics then. COVID-19 has a lower mortality rate and may or may not recur. If it does, based on current progress, effective and safe vaccines and new drugs to treat the virus will hopefully be available. So the long-term health-care impact of the COVID-19 pandemic will be much less severe. However, the long-term economic impact may be worse. The economic impact of the 1918-20 Spanish influenza was closely intertwined with post-World-War I consequences, so it cannot be assessed as a stand-alone event. Today, the world is interconnected, economies are global and depend on many industries that did not exist in 1920: oil, global tourism, transportation, aviation, sports, technology, health care and entertainment.
The CDC has produced different models to predict the effects of COVID-19. But these models are only as good as the assumptions used to develop them. They estimate infection rates of 20% to 60%, and mortality rates of 0.5% to 4%. These produce vastly different numbers. The Diamond Princess Boat cruise COVID-19 closed box experience can enlighten us. Of some 3,300 crew members and passengers, 712 were infected (21%) and 10 died (1.4%). These figures could represent the best infection and mortality rates estimates for the U.S., but they occurred under optimal conditions of isolation, comprehensive testing and medical management. Based on these estimates, the first COVID-19 wave may infect 69 million Americans and cause the death of almost a million. These figures need to be considered as Americans deliberate the value of restrictions on individual freedoms versus societal obligations (minimizing the COVID-19 effects on the most vulnerable Americans).
Broader COVID-19 testing beyond the strict CDC criteria is needed. From the Chinese experience, we now know that about 7-18% have mild infections (may infect others) with symptoms that do not meet the CDC screening criteria. These are the individuals who now propagate the virus spread most. Despite the slow start, the U.S. now screens 8,000 people daily. But capacity must be ramped up quickly to enable screening of even 30,000+daily, if needed.
One additional note regarding Houston, home to one of the largest medical centers in the world. These hospitals care for patients highly vulnerable to COVID-19. Health care workers in contact with patients should be tested under different criteria (minor symptoms and/or periodically) than the strict CDC ones, in order to protect their patients, and their families and social circles.
In summary, based on the known facts about COVID-19, we are still cautiously optimistic, particularly if all the “ifs” are realized soon. This view is shared by a few others, but not many. The next month will better clarify the COVID-19 picture.
About the authors:
Hagop Kantarjian, M.D., is a medical oncologist and a nonresident in health policy fellow at the Baker Institute. His opinions do not reflect those of his institution affiliation
Mary Alma Welch, MMSc, is a physician assistant. Her opinions do not reflect those of her institution affiliation.
Map courtesy of Johns Hopkins Center for Systems Science and Engineering: https://bit.ly/2UxXzXK