(CN) — Gutting the theory that economic peril demands the immediate reopening of the United States during the Covid-19 pandemic, health policy experts published a study Thursday that says rushing the process could cost hundreds of billions of dollars in direct medical expenses.

Published ahead of print Thursday afternoon by the journal Health Affairs, the study operates on the estimate that a single case of the disease caused by the novel coronavirus produces about $3,045 in direct medical costs, just during the course of the infection.

If 20% of America were to become infected, “there would be a median of 11.2 million hospitalizations, 62.3 million hospital bed days, and 1.6 million ventilators used, costing $163.4 billion,” the study states.

That number jumps to $654 billion in direct costs — including the use of 6.5 million ventilators and 249.5 million days in hospital beds — if the infection rate is 80%.

What the experience of treating the disease these last several months has shown, however, is that a Covid-19 diagnosis carries with it a range of major complications that require follow-up care and potentially rehospitalization.

“It is important to remember that for a proportion of the people who get infected, health care costs don’t end when the active infection ends,” Bruce Lee, a public health professor and one of the study’s seven co-authors, said in a statement. “This pandemic will have its lasting effects and taking care of those who will suffer continuing problems is one of them.”

In an interview this afternoon, epidemiology professor Lee Riley said the U.S. should heed the data from Asian countries where economic forces began to gradually reopen weeks after the epidemic hit peak levels.

“Some cities like Singapore and Tokyo have seen resurgence after the epidemic was controlled,” said Riley with the University of California, Berkeley. “Other places like Korea and Taiwan have been able to maintain control and the economy is no longer under complete lockdowns.

“The efforts being made in successful Asian countries and identifying high-risk groups in the U.S. all need to be in place in the US before the restrictions are relaxed,” the professor continued. “Once we have these control strategies in place, we can begin to talk about opening up. Otherwise, we may end up going back to where we’ve been. The issue is not just about maintaining versus easing the lockdowns.”

In Thursday’s study, the researchers painstakingly accounted for factors such as the cost of a telephone consult, hospitalization in the intensive care unit, and use of a ventilator, emphasizing that the health care costs add up exponentially when comparing infection rates of 20% versus 50% versus 80% of the population.

“The significant difference in medical costs by attack rate show the value of any strategies that can keep the attack rate as low as possible and, conversely, the potential cost of any ‘herd immunity’ strategies that allow people to get infected,” the study states.

Herd immunity is the epidemiological concept behind vaccination, wherein such a high percentage of the population can’t get the disease that those who can aren’t likely to come in contact with it.

“These strategies consist of allowing people to get infected until herd immunity thresholds are reached and the virus can no longer spread,” said Sarah Bartsch, the study’s lead author. “However, our study shows that such strategies could come at a tremendous cost.”

Like Bartsch and Lee, six of the study’s authors are directors or researchers at the City University of New York’s Public Health Informatics, Computational, and Operations Research team in the Graduate School of Public Health and Health Policy. James McKinnell, a professor and medical doctor who works on infectious disease research at the Harbor-UCLA Medical Center in Los Angeles, is a co-author.

“If the virus is still circulating and the infection rates surge as a result, we have to consider the resulting health care costs,” Lee said in a statement. “Such costs will affect the economy as well because someone will have to pay for them. Any economic argument for reopening the country needs to factor in health care costs.”

Using other diseases like the common flu for context, the study notes that the extensive medical resources that to treat Covid-19 make it a much more expensive undertaking. “The cost on average is four times that of a symptomatic influenza case ($696 in medical costs in 2020 values) and 5.5 times that of a pertussis case ($412–$555 in 2020 values),” the study states.

Bartsch called this yet “more evidence that the Covid-19 coronavirus is very different from the flu.”

To arrive at the cost estimates, the research team developed a computer-simulation model of the U.S. and simulated scenarios wherein varying amounts of people became infected with coronavirus. The model run by researchers simulated infected persons who developed different symptoms over time and then visited clinics, emergency departments, or hospitals in accordance and tracked the resources involved in treatment.

Even in the lowest simulated infection rate of 20 percent, the researchers emphasized that the United States does not have enough ventilators or hospital beds to handle demand.

There are approximately 96,596 intensive care unit beds and 62,000 full-featured mechanical ventilators in the U.S., according to the Society of Critical Care Medicine.

“Of course, the actual capacity used will depend on the timing of when patients need them,” said Bartsch. “But showing that there are orders of magnitude differences between what is currently available and what may be needed is concerning.”

Riley, the Berkeley professor, called it premature to talk about opening the country back up before we understand the data coming in.

One point that he said demands attention is why the country is seeing new cases “well past the incubation period of the disease following the start of social-distancing orders.”

While social-distancing measures are not 100% effective, Riley said it is important to figure out how these cases are happening in a lockdown otherwise meant to stop new transmissions.

“This is something the public health departments need to be getting data on, so that these risk groups can be targeted for more control,” Riley said.