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COVID-19: Facts and figures
This column was written on the evening of March 9, with all data coming in as of the reports for that date. This is a swiftly changing situation. The information herein was compiled from a variety of official, reliable sources including the World Health Organization (who.int) and the Centers for Disease Control (cdc.gov).
The COVID-19 viral pandemic – by the facts and numbersCOVID-19 is a novel (new) coronavirus that emerged in late 2019. The outbreak began in Wuhan City, which is the capital city of Hubei province, China. This large city has a population of 11 million. At the time of writing this (March 9, 2020), there are 80,904 reported cases in China, with 3,123 deaths. Globally there are total of 109,577 cases and 3,809 deaths with reports from 104 countries. The United States is reporting 423 cases and 19 deaths with reports from 35 states.
What is a coronavirus?Coronaviruses are a family of virus pathogens that can cause mild to severe disease responses. Other examples of coronaviruses include: Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS). COVID-19 is novel, or new, because this is the first time this strain has been seen in humans. The surface elements of these viruses resemble a crown when imaged and this is where the descriptive category name comes from.
Zoonotic?Like both SARS and MERS, COVID-19 is listed as zoonotic, which refers to pathogens that are transmitted between animals and humans. It has been determined that SARS jumped from civet cats to humans and MERS jumped from a Dromedary camel. COVID-19 has a likely origin of “a wet animal market” although the exact animal host is not yet officially listed.
SymptomsAlso similar to SARS and MERS, COVID-19 has been causing respiratory illness that ranges from mild to severe to life-threatening. Symptoms include fever, dry coughing, and shortness of breath. Hospitalized patients are being monitored for fever-control and some have been put on respirators via intubation. Death rates are higher in the elderly, those with underlying respiratory conditions, and those with compromised immune systems. A vaccine for COVID-19 is in development but will likely not be ready for 12-18 months. COVID-19 is now considered a pandemic (globally widespread and being transmitted from person to person).
Illness and death ratesDeath rates are calculated by dividing the number of reported deaths by the number of total cases. That puts the average global death rate, as of today, at 3.4 percent. This number will almost certainly fluctuate wildly, because we are at the beginning edge of a pandemic, and eventually go down, because the denominator (number of total cases) will certainly go up as there is increased testing. South Korea is the country that has done the most widespread testing and their calculated death rate from COVID-19 has been as low as 0.7 percent. A confounding factor is that many individuals can have the virus but show no symptoms. This is officially known as an asymptomatic carrier. Early estimates have suggested that on average 20 percent of infected persons will have symptoms in a severe category and may require significant interventions including hospitalization. This number is calculated similarly to the death rate and thus is subject to volatility and is likely to diminish as we push more into this pandemic. The take-home is that predictive calculations will become more reliable as more data are added.
How does COVID-19 compare to other epidemics?The seasonal flu is caused by influenza viruses, and there are many different strains which vary from year to year. On average, the flu death rates are in the range of 0.1 percent. The SARS epidemic landed on a death rate of approximately 9.6 percent and MERS was calculated at 35 percent. With COVID-19 sitting now at 3.4 percent but perhaps dropping as low as 0.7 percent, this virus is likely to be much more widespread but not as deadly as those other recent coronavirus outbreaks. Similar also to SARS and MERS, death rates are higher among the elderly but basically zero for children. Data out of China are suggesting the death rates for ages 80+ could be as high as 15 percent. Individuals who have cardiovascular disease, diabetes, hypertension, or respiratory conditions all have death rates between 5 and 10 percent. In addition, males have a slightly higher death rate than females. Again, these data are specific to China and cultural differences play a part here. For example, about 52 percent of Chinese men smoke compared to only about 3 percent of Chinese women. This alone could help to explain the gender difference due to this disease.
OutlookA vaccine for COVID-19 is in development but won’t be ready for 12-18 months. In the meantime, countries are struggling to identify and contain the outbreak as well as treat the ill. The biggest concern is an over-burden on the healthcare infrastructure. One potential hope is that the timing of expansion of COVID-19 infections in the United States will coincide with the drawdown of seasonal flu. It is currently not known if this virus will have a seasonal component, in other words it is not clear whether or not it will subside as the northern hemisphere comes into summer. There are cases in southern hemisphere countries where it is now late summer, so seasonality may not be likely for COVID-19. In fact, the buzz around the biology circles I’m chatting with predicts a noticeable impact to healthcare systems and daily life plus local economies in late March through at least mid-April.
Shannon Lee, PhD, is a Glen Ellen resident and an instructor in the Biology Department at Sonoma State University. She has been a science educator for 20 years having taught previously at UCLA and California State University Northridge.