Reopening Arizona Might Be A Long Road, Experts Warn
Arizona Gov. Doug Ducey has extended social distancing in the state to May 15 while allowing a limited expansion of retail operations next week and holding out hope for a May reopening.
But the state might have far to go before it is ready to reopen safely.
In his statement, Ducey lauded the value of social distancing and emphasized statewide progress in battling the coronavirus.
"The goal is that there will be no unpleasant surprises going forward, and we're going to follow the facts and CDC guidelines," he said.
But experts like Crystal Watson of the Johns Hopkins Center for Health Security say states have many hurdles yet to clear before they can safely reopen.
"First, we need a sustained reduction in daily case numbers. We need to be sure that infections are coming down to a manageable level," she said.
White House guidelines call for 14 days of downward trends in symptoms and cases before a state should consider a phased reopening.
Ducey said Arizona's symptom rates declined, though not its cases, and the state has seen other improvements.
"There are available beds, there are available ICU beds, there are available ventilators," he said.
That's progress. But without reliable treatments, with a vaccine still at least a year away, and with far too few cases for herd immunity, Arizona needs better information if it is to avoid, or absorb, a likely second wave.
That means more and better testing.
"We have not been testing people who are mildly or moderately ill. We're mostly testing people who present at a hospital and are sick enough to warrant at least having a look at them," said Watson.
Ducey hopes to address that with a three-Saturday "testing blitz," where people without symptoms who have been exposed can get tested.
That's good news, since experts like Dr. Nahid Bhadelia of the Special Pathogens Unit at Boston University School of Medicine believe 25-50% those infected might never develop symptoms.
"If that's the case, there might be a large group of people who've had it, may be immune to it, and we just don't know," she said.
And not knowing is the problem — a knowledge gap born of tests that often lack clinical validation.
"You've got to take it for a test drive in a real population to see how it plays out because the accuracy of the test is determined by many other points than just what you see in the laboratory," said Bhadelia.
Clinical trials, shortages and processing lags aside, experts have cast doubt both on nucleic acid tests, which look for genetic material from the virus, and antibody tests, which look for evidence of an immune response to it.
Nucleic acid tests like polymerase chain reaction depend on the body "shedding," or emitting virus, at or near the sampled site.
"Depending on what time and when you collect the sample, and how well the sample is collected, that might also affect the accuracy of whether or not the test is positive," said Bhadelia.
Antibody tests, meanwhile, can give either false positives or false negatives because immunity is complicated, changeable and imperfect. But Bhadelia says we also simply don't have enough data.
"We haven't even determined how high the levels of false positivity or false negativity are. We don't know what to tell people," she said.
Even with accurate tests, experts don't yet know if a recovered patient gains immunity to the virus or, if so, how high antibody levels must rise to confer it. Some kits don't even provide levels — just a "yes" or a "no," like a pregnancy test.
"Quantitative antibody tests give you an idea of what the levels are. And so they're a bit more useful to tell you one way or the other," said Bhadelia.
These limitations underscore the need for effective contact tracing — the ability to track, notify, screen and quarantine people who have interacted with someone who has the coronavirus.
"This capacity is really needed to break those chains of transmission, but more importantly, at a population level, it's to manage this epidemic on an ongoing low level," said Watson.
The current testing limitations and delays — and the symptomless way the coronavirus can spread — mean contact tracers cannot wait for test results before asking those affected to self-quarantine, as Watson explained.
"Those contacts, if they were infected, will go on to be infectious themselves and spread it to others, if we're waiting for a test result," she said.
The Maricopa County Department of Public Health has announced plans to increase contact tracing to 8-10 times its current capacity. As of April 24, the agency employed only 25 investigators.
"We need a massive workforce upgrade for public health. Public health knows how to do this. We just don't have enough people," said Watson.