As governors across the U.S. consider when exactly to reopen state economies amid the coronavirus outbreak, a former White House health official warns that large gatherings likely could not safely resume until at least the fall of 2021.

Dr. Ezekiel Emanuel, who served as special advisor for health policy to the director of the White House Office of Management and Budget during the Obama administration, told a recent New York Times panel that “restarting the economy has to be done in stages... Larger gatherings — conferences, concerts, sporting events — ... I think those things will be the last to return. Realistically we’re talking fall 2021 at the earliest.”

Dr. Emanuel, who is currently Vice Provost for Global Initiatives and chair of the Department of Medical Ethics and Health Policy at the University of Pennsylvania, added that the overall experience is “going to be this roller coaster, up and down. The question is: When it goes up, can we do better testing and contact tracing so that we can focus on particular people and isolate them and not have to reimpose shelter-in-place for everyone as we did before?”

‘Too soon to rest on our laurels’

Emanuel, who has also cast doubts on the effectiveness of the use of an anti-malarial drug against the coronavirus due to the lack of sufficient data, is not alone in advising caution.

Dr. Tom Tsai, an assistant professor at the Harvard Global Health Institute, also stressed the need to think about other safeguards in place before reopening the economy.

[See also: Ex-Obama adviser Dr. Emanuel explains what it will take for America to return to ‘full normalcy’]

“A lot of these early signs are encouraging … but it’s still too soon to rest on our laurels,” Tsai said on Yahoo Finance’s The Ticker. “The data from New York showing that yes, we may be at the peak, but it’s not a rapid fall off the peak back to normal.”

Tsai advised testing and social distancing to continue until there is “definitive data” that the pandemic is over.

“There are going to be multiple recurrences that occur throughout the summer,” Tsai said, adding that “we still have to keep our eye on the ball and be vigilant as those cases resurface because the data from the other countries have shown that once we lift these quarantine measures, then the chances of community transmission increase.”

According to a separate study by Harvard — unaffiliated with Tsai — coronavirus cases could surge again during the winter. To prevent that, the authors wrote, “prolonged or intermittent social distancing may be necessary into 2022” unless “critical care capacity is increased substantially or a treatment or vaccine becomes available.”

‘The ultimate solution... is to create a vaccine’

The timing of a coronavirus vaccine is the centerpiece to the puzzle of opening the economy, as its emergence is considered by many as an early indicator of the end of the outbreak.

“We’re looking around the world. As they relax the economic controls, the virus flares back up again,” Federal Reserve Bank of Minneapolis President Neel Kashkari said on CBS’s Face the Nation recently. “We could have these waves of flareups, controls, flareups and controls until we actually get a therapy or a vaccine. I think we should all be focusing on an 18-month strategy for our health care system and our economy.”

“The ultimate solution, the only thing that really lets us go back completely to normal and feel good about sitting in a stadium with lots of other people, is to create a vaccine,” billionaire Bill Gates said last week. “And not just take care of country, but take that vaccine out to the global population so that we have vast immunity and this thing, no matter what, isn’t going to spread in large numbers.”

Emanuel told the New York Times panel that “we’re going to end up with an immunity passport, probably an electronic one,” noting that conservative estimates for the future show “10 to 20 million Americans being infected and therefore most likely being immune for some amount of time. That is a very powerful cohort that you don’t want just sitting at home on the sidelines, if you can restart parts of the economy with them.”

Aarthi Swaminathan is a reporter for Yahoo Finance.

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