On Saturday, July 11, the Centers for Disease Control and Prevention issued new guidance saying that about 40% of people who have COVID-19 are likely asymptomatic, meaning they show or display no symptoms. The agency added that "asymptomatic cases are difficult to identify and transmission is difficult to observe and quantify."
The idea of being asymptomatic is a double-edged sword. On a personal level, not having a sore throat, fever or cough, among other symptoms, might be a plus. However, from a public health standpoint, asymptomatic carriers will continue to leave the house and unknowingly contribute to the spread of the virus. The lack of visible symptoms in these individuals makes it hard to isolate and remove them from circulation.
Under the CDC's current best estimate, the transmissibility of the virus from asymptomatic people, in comparison to people with no symptoms, is at 75%. Under the same estimate, the infection fatality ratio of COVID-19 is 0.65%, meaning that 0.65% of people infected with the virus will die.
The basic reproduction number, R0, is a value that denotes the average number of people that one person with COVID-19 is likely to infect. The CDC best estimate places that value at 2.5, meaning that for every person infected with the virus, he or she will infect 2-3 more people.
Yesterday, July 11, Arizona saw a drop in new confirmed cases with 3,038 being reported among nearly 18,000 total tests. Arizona has become one of the global hotspots with recent weekly increases surpassing entire countries on the other side of the world.
Hospital intensive care unit capacity in Arizona continues to hover around 90%, with most recent data showing a total of 174, or 10%, available ICU beds across the state. The use of ventilators across Arizona continues to steadily rise; on June 10, only 38% of ventilators were in use, and on July 10, that number had risen to 51%.
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