Before stay-at-home restrictions can be loosened and states and cities can begin the fragile process of emerging from isolation, public health experts warn that more people must be tested and then isolated through contact tracing to further diminish the virus's spread, while tracking who is healthy enough to go out.

...

Crystal Watson, a senior scholar at the Johns Hopkins Center for Health Security and one of the lead authors of the report, told NBC News on Friday that public health departments of states and territories should be the ones determining how large of a contact tracing workforce will be needed and where it should be focused. And those states, such as New York and Massachusetts, with larger numbers of COVID-19 cases, will need to scale up accordingly.

Public health officials recognize that testing for the coronavirus has been woefully inadequate, and some public health experts have said that testing must be at least doubled or tripled from its current levels to allow for even a partial reopening of America's economy.

Watson said that those discussions for contact tracing need to happen and be implemented first before the reopening of the larger economy. But President Donald Trump has been pressing states with lower cases of the virus to reconsider reopening sooner, and on Thursday unveiled federal guidelines for “the next front in our war, which is called opening up America again.”

“I do think we need to buckle down. Right now, our attention is all over the place,” Watson said. “If we put concerted effort into building [contact tracing] capacity for states, that is what allows us to transition to the next phase to reopen our economy. Without that, we're flying blind.” [NBC News, 4/16/20]

A group of leading health experts on Monday sent a letter to Congress calling for $46.5 billion to expand contact tracing and isolation of infected people in order to safely reopen the economy. 

“We are writing to propose Congress take swift action in upcoming legislation to give states the funding necessary to scale up our nation’s contact tracing ability and support voluntary self-isolation of infected and exposed individuals,” write the 16 health experts, who include former Food and Drug Administration (FDA) Commissioner Scott Gottlieb and former acting administrator of the Centers for Medicare and Medicaid Services (CMS) Andy Slavitt. “This is fundamental to our ability to begin to reopen our economy while continuing to safeguard American lives.”

The letter asks for $12 billion to hire 180,000 new workers who would conduct contact tracing, meaning interviewing infected people to find out who they have been in contact with and then notifying those people so they can self-isolate for 14 days. The experts say this is important until a vaccine is developed.

…

The experts who have signed onto the letter come from both sides of the aisle.

Gottlieb served under President Trump and Slavitt under President Obama. Additional signers include former Senate Majority Leader Bill Frist (R-Tenn.); Mark McClellan, who was head of FDA and CMS under President George W. Bush; Atul Gawande, a prominent health expert and CEO of a joint health venture from Amazon, Berkshire Hathaway and JP Morgan Chase; and Tom Inglesby, director of the Johns Hopkins Center for Health Security. [The Hill, 4/27/20]

The country will need to implement a “robust and comprehensive system” of contact tracing to return Americans to work, reopen schools and ease social distancing guidelines, Johns Hopkins University experts say.

…

Keren Landman, an epidemiologist and journalist, wrote for NPR that she helped a contact tracing effort by the Centers for Disease Control and Prevention during a mumps outbreak in the Midwest, cold-calling residents potentially exposed to the disease with a scripted list of questions from a cubicle office in Atlanta.

“Contact tracing can feel like drudgery, but in an outbreak, it’s vital to public health,” Landman wrote. “During events like the current COVID-19 outbreak, it helps make possible early diagnosis and getting care to people who need it.

The Centers for Disease Control and Prevention is increasing the number of people who can contact trace in the U.S. to carry out a “very aggressive” plan to track coroanvirus, CDC Director Robert Redfield told NPR.

“We are going to need a substantial expansion of public health fieldworkers,” Redfield told NPR.

In an ideal world, that would mean “100,000 new contact tracers,” Anita Cicero, deputy director at the Johns Hopkins Center for Health Security, told The Verge. [The Sacramento Bee, 4/13/20]

The Trump administration's top health officials have voiced support for tracing and tracking symptomatic individuals. Dr. Robert Redfield, the director of the Centers for Disease Control, told NPR the plan to begin reopening the country will have to rely on “very aggressive” contact tracing.

And in an interview with the Associated Press, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, echoed some of the cautions about reopening the country before systems are in place to identify and isolate infected individuals and their contacts.

“We have to have something in place that is efficient and that we can rely on,” Fauci said, “and we're not there yet.” [ABC News, 4/14/20]

In lieu of a vaccine, which might not be widely available for at least a year, and mass testing, public health experts say tracking down sick people and those they might have exposed to the virus will be critical in allowing the public to work, shop and gather in groups again without sparking more outbreaks.

The more restrictions are eased, these experts say, the more contact-tracing workers will be needed.

“The scale at which that is required far supersedes what is available right now at public health departments,” said Emily Toth Martin, a professor of epidemiology at the University of Michigan School of Public Health. [The Wall Street Journal, 4/20/20]

As some governors consider easing social distancing restrictions, new estimates by researchers at Harvard University suggest that the United States cannot safely reopen unless it conducts more than three times the number of coronavirus tests it is currently administering over the next month.

An average of 146,000 people per day have been tested for the coronavirus nationally so far this month, according to the COVID Tracking Project, which on Friday reported 3.6 million total tests across the country. To reopen the United States by mid-May, the number of tests performed every day should be 500,000 to 700,000, according to the Harvard estimates, which is a daily minimum of about 152 tests per 100,000 people.

That level of testing is necessary to identify the majority of people who are infected and isolate them from people who are healthy, according to the researchers. About 20 percent of those tested so far were positive for the virus, a rate that the researchers say is too high.

“If you have a very high positive rate, it means that there are probably a good number of people out there who have the disease who you haven’t tested,” said Ashish Jha, the director of the Harvard Global Health Institute. “You want to drive the positive rate down, because the fundamental element of keeping our economy open is making sure you’re identifying as many infected people as possible and isolating them.”

The researchers said that expanded testing could reduce the rate to 10 percent, which is the maximum rate recommended by the World Health Organization. In Germany, that number is 7 percent, and in South Korea, it is closer to 3 percent. [The New York Times, 4/17/20]

One of the keys to reopening the economy is having enough tests to diagnose coronavirus infections, with the goal being to quickly identify new cases, isolate them, and track down others who may have been exposed.

“We’ve done such a good job of social distancing that we expect the rate of immunity to be quite low, which means we would expect there to be, over the course of the next several months, periodic outbreaks of the disease,” said Dr. Christopher Woods, a professor of medicine and infectious diseases at Duke University. “But now we hope to have the diagnostic tools and the public health tools to contain those outbreaks as they occur.”

Coronavirus testing in the United States has been slow from the start and we’re still only testing roughly a million people a week. Though President Donald Trump said Thursday that we’re doing a “great job” on testing, public health experts have said the number of people tested should be far higher before social distancing eases up — anywhere from 3 million to 30 million a week, to 20 million or more a day. [NBC News, 4/26/20]

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and member of the White House Coronavirus Task Force, says “we are not in a situation where we can say we are exactly where we want to be with regard to testing” capacity for COVID-19 in the U.S.

Fauci, in a discussion for TIME 100 Talks: Finding Hope on Thursday, says that the U.S. needs to not only increase the number of tests, which is happening as commercial testing companies increase production and the Food and Drug Administration continues to clear tests using different types of samples (including ones from the nose and saliva, as well as blood). But, he says, we also need to make sure tests can actually be run the way they should.

“We need to significantly ramp up not only the number of tests, but the capacity to perform them, so that you don’t have a situation where you have a test but it can’t be done because there isn’t a swab, or because there isn’t extraction media, or not the right vial,” says Fauci. “I am not overly confident right now at all that we have what it takes to do that. We are doing better, and I think we are going to get there, but we are not there yet.” [Time, 4/23/20]

Health experts also say the country needs a related and equally robust program to trace the people who have had contact with infected people, to avoid seeing those contacts themselves spread the coronavirus to others.

There are only about 120,000 samples or so being tested each day for the coronavirus in the United States, according to the federal Centers for Disease Control and Prevention.

Experts say that millions of people will have to be tested each day, even as many as 20 million to 30 million people, before the nation can return to a semblance of economic normality.

That is much more than the number of tests even projected to be produced by some major manufacturers by June.

“To avoid a second wave of viral spread you have to do what South Korea and other countries, including Germany, have done. You have to have testing in place, and aggressive testing,” said Dr. Tom Moore, an infectious disease specialist in Wichita, Kansas.

“We don’t have to test everybody, but we definitely need to test a significant portion of the community,” said Moore, a former board member of the Infectious Diseases Society of America.

“This is a Herculean task,” he said. “I don’t know how it’s going to be solved in the immediate future, but it needs to be.”

Moore and other experts say that a second or third wave of Covid-19 infections could end up killing more people than the first wave, lead to another series of shutdowns of businesses, and ultimately end up doing greater economic damage than has been seen to date from the pandemic. [CNBC, 4/16/20]

But how much testing is enough?

There's no exact number to aim for, but here's a guiding principle: You want a low percentage of your tests to come back positive, around 10% or even lower, says William Hanage, an epidemiologist at Harvard.

That 10% benchmark is based on recommendations from the World Health Organization. Why should positives be low? If a high percentage of tests come back positive, it's clear there's not enough testing to capture all of the infected people in the community. "The lower the percentage of tests you're doing that come back positive, the better," Hanage says.

Some countries that have done extensive testing have positive rates near this 10% benchmark, or lower. South Korea is "testing so many people that only 3% of them are positive," said Rochelle Walensky, an infectious disease specialist at Massachusetts General Hospital, during a livestream hosted by the medical journal JAMA.

But, so far the U.S. appears to fall short of this benchmark. Nationally, according to CDC data, about 18% of tests have been positive to date, and 21% were positive in the week ending April 11.

The U.S. has one of the highest percentages of confirmed cases versus tests conducted globally, according to Our World In Data, an online platform published by Oxford University. [NPR, 4/22/20]

Few scientists ever imagined that these tests would become an instrument of public policy — and many are uncomfortable with the idea. Antibody tests, which show who has been infected, are often inaccurate, recent research suggests, and it is not clear whether a positive result actually signals immunity to the coronavirus.

On Friday, the World Health Organization warned against relying on these tests for policy decisions. While countries such as Italy have even floated the idea of “immunity passports” for people who test positive, W.H.O. officials noted that it is not known to what extent people carrying antibodies are immune to the virus.

(The W.H.O. on Saturday backed off an earlier assertion that people with antibodies may not be immune at all.) [The New York Times, 4/26/20]

The shortcomings of antibody testing were on vivid display in two other recent surveys, one in Santa Clara County and the other in Los Angeles County.

Both drew sharp criticism from scientists, who said the tests had a rate of false positives too high to be used in places the virus has left largely untouched and therefore may have few true positives. 

...

“We’re kind of heavily leaning on these tests when they’re not perfect,” said Saskia Popescu, an epidemiologist at George Mason University in Fairfax, Va.

“And we still have a lot of people susceptible, so it’s a dangerous thing to heavily rely on them right now.”

[Dr. Michael Osterholm, an infectious diseases expert at the University of Minnesota] said an antibody survey, because it provides “historical data” on who was infected, is like a smoke alarm that gives out a report once a month.

“It doesn’t work very well if you have a fire right now,” he said.

Diagnostic tests for the virus offer a better snapshot of the current picture, he added, and states should focus on acquiring accurate diagnostic tests that can provide timely data on the rise or fall in the number of infections.

“That should be the data we use to judge opening or not opening” the economy, Dr. Osterholm said. [The New York Times, 4/26/20]

The Food and Drug Administration is dealing with a flood of inaccurate coronavirus antibody tests after it allowed more than 120 manufacturers and labs to bring the tests to market without an agency review.

The tests, which look for antibodies that indicate whether a person has been exposed to the virus, have been eyed as a tool to help reopen the country by identifying people who may have immunity. Antibody data could also help determine the true extent of the U.S. outbreak by finding cases that were never formally diagnosed.

Normally, the FDA does its own quality check before allowing tests on the market. Agency leaders have said they tried to create more flexibility for makers of antibody tests to help inform discussions about when people can safely return to work and school, and to identify survivors whose antibody-rich blood could help treat the sick.

But many of the tests available now aren’t accurate enough for such purposes. Some are giving too many false positive results, which could mislead people into thinking they have already been infected.

The problem has gotten so bad that the New York City Health Department warned health providers last week against using the tests to determine whether someone is infected with the coronavirus or has developed immunity through exposure.

Public health experts say the FDA shouldn’t have waived its reviews of antibody tests and are calling on it to crack down. To date, the FDA has granted a formal emergency use authorization, in which it reviews data from manufacturers, to just seven of the tests.

“We're facing a public health epidemic," David Kessler, who led the FDA under Presidents George H.W. Bush and Bill Clinton and is now advising former Vice President Joe Biden on the coronavirus, told POLITICO. “If FDA is not looking at validation studies, then FDA is not doing its job."

…

Scott Becker, the CEO of the Association of Public Health Laboratories, has criticized the FDA for allowing “crappy” antibody tests onto the market without adequate review. "Ideally they would scrap the current policy and start over, but I don't think that's practical given this crisis,” he said. “The best we can hope for is a rigorous and expansive evaluation." [Politico, 4/27/20]

“There’s even more concern there. They’ve had even less regulatory control," said Dr. Greg Poland, director of the Mayo Clinic's Vaccine Research Group. “How are manufacturers testing these? Are they rushing these out prematurely? That economic motive is what requires regulatory oversight."

…

“Nobody’s done what I would call a thorough head-to-head comparison with a validated gold standard," Poland said. “I’m actually surprised that some of these kits can be used clinically."

Poland said he's concerned about the tests giving false positives.

“One of the things I’m afraid of is that people are going to go to drive-thru testing who have not had (the) disease and are going to be told that they’re protected" because the test shows they have antibodies. “And they’re going to act and react according to that misinformation. That’s a problem." [USA Today, 4/24/20]

Amid the haste to develop antibody testing, we may be setting ourselves up for disaster.

“Testing is not a panacea. Testing is a tool and no test is perfect. What people are looking for does not exist," said Dr. Alan Wells, executive vice chairman of the section of Laboratory Medicine at University of Pittsburgh Medicine.

…

Some scientists, however, say that beyond companies knowingly scamming consumers, even the antibody tests manufactured by larger companies with fairly reputable histories overpromise and underdeliver.

“There is just so much variety in these assays out there, and we too have seen some tests to have a very high level of false positive results using samples that were collected prior to the outbreak," said Eliza Theel, Ph.D., director of Mayo Clinic Infectious Diseases Serology laboratory testing.

Another major issue experts cite is the lack of standardized validation protocols. "You can cherry pick what your controls are," said Wells.

Validating tests with the right samples is essential in order to minimize the potential of false positives and negatives.

“False positive means that the antibody reaction detected an antibody, but from some other coronavirus or some other related infection," according to Dave Koch, Ph.D., director of clinical chemistry, toxicology and point-of-care testing at Grady Memorial Hospital in Atlanta. “There is also possibility of a false negative: I actually have the virus but the antibody hasn't shown up yet or hasn't gotten to the detection limits in the bloodstream yet." [ABC News, 4/26/20]

Q: If I have antibodies to the virus that causes Covid-19, does that mean I’m protected from getting it again? If so, for how long?

A: We don’t know. “Just because people have an antibody response to this virus does not mean that they are protected against being reinfected,” says [Dr. David Walt, professor of pathology at Harvard Medical School].

Marc Jenkins, director of the Center for Immunology at the University of Minnesota Medical School, says the assumption is that the presence of antibodies provides some level of protection and could last a few years. The question is, how many antibodies do you need? Different people make different amounts of antibodies based on their genetics and other factors, including how intense their viral infection was. It is possible that people with milder infections—or who are asymptomatic—may not develop as many antibodies and may have less protection from the next infection, he says.

“Most likely, people who have recovered from Covid-19 with antibodies in their bloodstream will be immune for months or one to two years,” says David Reich, president of Mount Sinai Hospital in New York. “But this is unknown currently, and we have to study that over time.”

Meanwhile, some experts say it’s possible that people with antibodies may not be immune. Gregory Storch, a professor of pediatrics at Washington University in St. Louis, says for most viruses, the presence of antibodies corresponds to immunity, but there are exceptions, such as HIV and hepatitis C. “People may have antibodies in their blood at the same time they are actively infected with those viruses,” he says. With respiratory syncytial virus (RSV), a common respiratory virus in babies, children can have an antibody response but still become infected a second time, he says. [The Wall Street Journal, 4/23/20]

The emergence of dozens of tests never reviewed by the FDA — many of which are being aggressively marketed — could confuse doctors, hospitals, employers and consumers clamoring for the products, according to critics who say the agency’s oversight of the tests has been lax. The questions are taking on special importance as federal and state officials debate strategies, including using serological testing, to help determine when they can end state and local lockdowns.

“A test is only as good as its results,” said Kelly Wroblewski, director of infectious disease programs at the Association of Public Health Laboratories, which has been urging the FDA to take a closer look at the unapproved tests. “Having many inaccurate tests is worse than having no tests at all.” [The Washington Post, 4/19/20]

The results in New York State offer an early glimpse of the promise and pitfalls of widespread antibody testing.

Public health officials tested 3,000 residents at grocery stores and big-box retailers throughout the state. In New York City, about 21 percent of participants were found to carry coronavirus antibodies.

The rate was about 17 percent on Long Island, nearly 12 percent in Westchester County and Rockland County, and less than 4 percent in the rest of the state.

New York’s survey was reasonably well designed and the results largely credible, experts said. But unlike Mr. Cuomo, few saw happy news in the numbers.

“I just don’t see any way to put a silver lining on any of these results,” said Carl Bergstrom, an infectious diseases expert at the University of Washington in Seattle. “I think that the efforts to spin it that way are irresponsible.”

If one in five residents in hard-hit New York City has been exposed to the virus, he and others said, then four in five are still vulnerable — and that underscores how far we are from the pandemic’s end.

New York’s results suggested a death rate of between 0.5 and 1 percent, figures some conservative commentators have argued are too low to justify statewide lockdowns.

Public health experts like Dr. Bergstrom took the opposite view. “If the mortality rate is 1 percent, we’re looking at 2 million deaths, which is unprecedented in our nation’s history and unimaginable,” he said.

“Anyone talking about the death rate as ‘only 1 percent and so we should not worry about it’ has an extraordinarily callous view.”

The New York survey confirms what experts have long believed: that because of the lack of tests, the state has undercounted the true number of infections by about a factor of 10.

Reopening society with such a huge vulnerable population, and without careful consideration, could be disastrous, allowing the virus to sweep through the country, Dr. Bergstrom and others said. [The New York Times, 4/26/20]