New study shows higher contagion rate than originally estimated
A key indicator of contagion has been revised upward for the COVID-19 virus in a recently released study by researchers with the Los Alamos National Laboratory in New Mexico. The study indicates that COVID-19 may be twice as contagious as previously thought.
Meanwhile, Pennsylvania is the fourth most affected state in the country with 35,684 cases and 1,622 deaths as of Wednesday. In Pennsylvania, 166,851 tests have been conducted – less than 1.3 percent of the state’s population.
As of Tuesday, 2,783 COVID-19 patients were hospitalized across the state with 667 on ventilatory life support. Across the state, 1,472 ventilators were being used, which is about 30 percent of the state’s stockpile of 5,119.
Bucks County had 2,004 confirmed cases, ranking sixth in the commonwealth for confirmed infections behind Philadelphia, Montgomery, Delaware, Lehigh and Berks counties. Bucks County recorded 116 COVID-19 deaths.
Ann D’Antonio, vice president of marketing and communications with Trinity Health Mid-Atlantic, stated that St. Mary Medical Center, which is in the Trinity Health network, evaluates utilization data daily. However, she added, the statistics have not been consistent enough to determine trends.
“We have experienced increases in our ICU-bed utilization and are able to manage this increase within our own facility,” D’Antonio said, adding that the initial phase of a detailed, multi-phase surge plan has been activated due to the increased need for ICU beds.
“We are monitoring the situation very closely, in close coordination with the departments of health and other officials, so we can continue to best adapt to the conditions on the ground,” D’Antonio stated.
According to the Los Alamos study, revised epidemiological equations based upon newly compiled case reports early in the epidemic revealed both a shortened time for cases to double and an increased number of individuals infected by a single person.
The latter is measured by a value known as the basic reproduction number, or R0. A value of 1 means that an infected individual will infect only one other, resulting in a stable, low-level of spread of infection. The R0 of COVID-19 was originally estimated to be 2.2 to 2.7 with a doubling time of six to seven days.
Mathematical modeling of newly compiled case reports early in the epidemic revealed an accelerated doubling rate of two to three days – less than half the time estimated in earlier studies – and an R0 of 5.7 which is more than twice that of the highest previous estimates.
The early release study by the CDC indicates more aggressive action may be needed to slow the spread of the virus, suggesting “early and active surveillance, quarantine, and especially strong social distancing efforts.” The increased R0 significantly raises the threshold of acquired immunity required to break the pandemic, from 55 percent to 82 percent, according to the study.
That means that eight out of every ten people would need immunity through either natural exposure or vaccination in order to contain the epidemic. Exposure, however, has not yet been determined to confer immunity, and a vaccine is likely months away.
Based upon data released by Johns Hopkins as of April 21, global cases have surpassed 2.5 million. The United States has about a third of all infections worldwide at 825,000 cases, outpacing the next four most affected countries combined (Spain, Italy, France and Germany) and four times the number of cases of the second most affected country (Spain).
By contrast, South Korea, which experienced a rise in infections around the same time as the US, has had only 10,683 confirmed cases and 237 deaths. The 2.2 percent mortality rate in South Korea is less than half that of the U.S., which with over 45,000 deaths is 5.4 percent – 120,268 COVID-19 patients are currently hospitalized in the United States.