Health care workers and those in other front-line, highly vulnerable sectors will likely benefit the most as new tests come on the market to determine whether a person has had the coronavirus.

The big picture: Serological testing, along with diagnostic testing and contact tracing, is one of the basic tools public health experts say are key to managing the pandemic.

Serological tests identify the antibodies a patient's body produces when it fights this strain of the coronavirus. They test for past infections, not current ones.

• Some people likely contracted the coronavirus but didn't feel sick, or weren't able to get a diagnostic test. Serology tests will confirm whether they had it. And on a larger scale that will provide more information about where the virus spread, the real number of cases and the actual death rate from the virus.

Yes, but: "People just think this is the solution, that this is finally the thing, that everybody is going to have immunity passports ... and I am very skeptical of this for a variety of reasons," said Ashish Jha, professor of global health at the Harvard T.H. Chan School of Public Health.

• "It's going to have limited utility outside of hotspot cities and outside of professions where you're going to see higher exposure," former Food and Drug Administration commissioner Scott Gottlieb told me.

Between the lines: Enthusiasm for serology tests as a way to help get people back to work is rooted in the belief that if you have antibodies for the virus in your system, you're immune from catching it again.

• But we don't actually know whether that's true, or how strong that immunity might be.
• And though the basic science is well-established, some officials, including Anthony Fauci, have cautioned the new tests haven't yet been proven to work well.

Serology testing will be most useful in hotspots like New York City, Detroit, New Orleans and Miami — areas where a larger percentage of the population has been infected.

• And if the antibodies these tests detect do end up conferring immunity, the tests will be primarily helpful for workers who are at a particularly high risk of spreading the virus — including health care workers, first responders, grocery store workers and people who work with the elderly.

The bottom line: The value here is in understanding the virus' true spread and helping the highest-risk workplaces operate more safely — not as any kind of universal, nationwide get-back-to-normal permit.

Go deeper: The next coronavirus test we need

The coronavirus and lockdowns have brought us tons of "who'd have thought?" developments, from the easing of air pollution to the shift to telemedicine, the resurgence of phone calls, and crazes for jigsaw puzzles and bread baking.

Why it matters: Society has become a lab experiment for what happens — economically, culturally, politically — when commerce and socializing are all but banned. The surprise effects we are witnessing may stick around for some time, Axios' Jennifer Kingson reports.

Driving the news: The severe disruptions to our lives have taken all sorts of turns, from dire to comic — and there's no end in sight.

• For many people, the "new normal" involves a bombardment of tragic news about death, illness and loss, punctuated by escapism (Netflix binges, Chef Boyardee dinners), teleworking or telestudying, and waiting for unemployment and stimulus checks.

Burgeoning unemployment and household financial troubles are raising stress levels for Americans, with consequences that could last for years, says Amy Zalman, CEO of Prescient, a future-oriented consultancy, and professor at Georgetown University.

• "The ground is being laid for terrible psychological disorders and stressed families," Zalman tells Axios.
• Among Zalman's top picks for unforeseen trends around COVID-19: The rise of virtual doctor's visits, the unleashing of people's creativity around face masks, the advent of "smart toilets" that may one day be able to detect the disease, and the demise of the handshake.

Go deeper.

Anthony Fauci told CBS News Wednesday it's "possible to shave a couple of months off" his earlier projection that it would take 12–18 months until a novel coronavirus vaccine would be widely available.

The federal government plans to release guidelines on Thursday for reopening parts of the U.S. economy, President Trump said at Wednesday's White House coronavirus briefing.

Protesters assembled at the state Capitol on Wednesday in response to Michigan Gov. Gretchen Whitmer's stringent stay-at-home order, NBC News reports.

It's taken less than two weeks to reach the $349 billion cap for small business loans for the coronavirus stimulus.

Former President Jimmy Carter criticized President Trump's decision to withhold U.S. funding from the World Health Organization Wednesday, calling it "the only international organization capable of leading the effort to control the virus."

New York Gov. Andrew Cuomo compared scaling up testing and contact tracing to the degree necessary to reopen the economy during the coronavirus pandemic to "trying to get Apollo 13 back to Earth 220,000 miles, 50 years ago."

The federal government will pay $100, instead of the standard $51, for any commercial coronavirus test that is run through a highly automated lab machine. These include machines made by Abbott, Roche, Hologic, Cepheid and NeuMoDx, among others.

UnitedHealth Group CEO Dave Wichmann told Wall Street analysts Wednesday that deferred non-urgent visits at hospitals and clinics are "offsetting COVID-19 costs," which helped the health insurance and services giant register a $3.4 billion first-quarter profit and temporarily keep its 2020 profit projections intact.

The Bill and Melinda Gates Foundation pledged $150 million for its coronavirus relief efforts on Wednesday, on top of $100 million committed in February.

Germany will begin a "gradual" and "very careful" loosening of its coronavirus lockdown next week, though social distancing rules will remain in place through at least May 3, Chancellor Angela Merkel said Wednesday.

Israeli Prime Minister Benjamin Netanyahu rejected a request from U.K. Foreign Secretary Dominic Raab to allow ventilators to be exported from Israel to the U.K., Israeli officials tell Israel's Channel 13 News' Barak Ravid.

World Health Organization Director-General Tedros Adhanom Ghebreyesus said at a press briefing Wednesday that he "regrets" President Trump's decision to halt U.S. funding, pointing out that the coronavirus is not the only health crisis that the group works to combat.

Ground and air ambulances are frequent sources of surprise out-of-network bills, and those charges “were substantially greater than in-network prices," according to new research published in Health Affairs.

The bottom line: Three out of every four ambulance sirens you hear right now, in the middle of a pandemic, come with an average surprise bill of $450 for the person inside, Axios' Bob Herman writes.

Scientists are calling for a better biosecurity system to govern lab experiments involving potentially dangerous viruses, Axios' Bryan Walsh reports.

Why it matters: COVID-19 has clearly demonstrated the tremendous human and economic damage even a relatively mild but new virus can wreak. With researchers increasingly able to create far more lethal pathogens in a lab using new gene engineering tools, science needs to rethink oversight for such experiments.

Background: A Washington Post article by Josh Rogin this week reignited speculation that the novel coronavirus could have originated in a Wuhan lab that had been studying bat coronaviruses.

• There's no hard evidence that's the case, and the vast majority of scientists believe COVID-19 originated in animals before crossing over to human beings.

But, but, but: The Wuhan lab had come under criticism in the past for conducting research that involved engineering a hybrid pathogen that contained parts of a bat coronavirus and parts of a SARS virus.

• Such research is becoming more common around the world as scientists use new genetic tools in the lab to try to understand how viruses might evolve in the wild.
• That's a challenge for biosecurity policies.

In a piece in the journal Science, Tufts University researcher Sam Weiss Evans and his colleagues argue the field needs to rethink biosecurity governance.

• Because new technologies could give rise to new threats, Evans believes scientists need to adopt a strategy of experimentation around biosecurity, rather than getting locked into firm categories of what is and isn't allowed.

A majority of people say they would resume at least some level of normal activities if the federal government announced a re-opening, a new survey from CivicScience provided first to Axios shows.

• The percentage who say they would restart activities has climbed since last month when 42% of respondents said they would choose to remain in quarantine, Axios' Dion Rabouin reports.

Why it matters: An economic recovery is much more dependent on people's willingness to go out and spend money than it is on whether the government has issued a proclamation.

• Even if orders are given to re-open businesses across the country, the economy will stay mired in recession if a significant number of Americans are still too scared to leave their homes.

Go deeper: America isn't prepared to reopen the economy

It's well-known that the coronavirus targets the lungs, but evidence suggests that the virus may also cause heart inflammation, acute kidney disease, neurological problems, blood clots, intestinal damage and liver issues, the Washington Post reports.

Why it matters: The treatment for each patient will vary depending on which organs are being attacked, and the myriad symptoms of the virus have already made treatment complicated.

• Nearly half of the coronavirus patients who are hospitalized have signs of kidney damage, and intensive care units in New York are treating so much kidney failure that they're running low on personnel and supplies.

What they're saying: "The question is, is it kind of behaving like a hybrid of different viruses?" Brennan Spiegel, co-editor in chief of the American Journal of Gastroenterology, told the Post. "What we're learning is, it seems anyway, that this virus homes in on more than one organ system."