We’re Testing for Monkeypox the Wrong Way
Suspicious that he might have the viral illness, Kohn immediately isolated. Two days later, a painful, itchy rash appeared in an intimate location. He knew then that he was in for a ride. Kohn found an urgent-care center where a doctor was able to swab his skin lesions and send them off to a lab, where technicians searched for signs of the virus’s genetic material. Then he waited, alone, in his home.
More than 15,000 monkeypox cases have been confirmed around the world since the outbreak began in May, but the condition, which spreads through close contact with the rash or body fluids of an infected individual, has been difficult to diagnose because of a lack of available testing. New York City was at one point able to test only 10 patients a day. When Kohn got sick, the system was still running at significant delays. While an analogous COVID test can be turned around by the next day in many cases, Kohn’s positive result for monkeypox took four days to arrive—all while a blistering rash spread out across his body. (Six days after that, Kohn received a phone call from a contact tracer working for the local department of health. He may have been exposed to monkeypox, the person warned.)
In terms of sheer numbers, the nation’s monkeypox-testing capacity has increased dramatically since Kohn’s run-in with the system. On Monday, the Centers for Disease Control and Prevention announced that the U.S. is now capable of evaluating 80,000 cases a week, up from 6,000 initially. But another, more important bottleneck remains stubbornly in place: The CDC’s official guidance recommends that labs test for monkeypox using only samples of a patient’s skin, taken at the site of a visible rash. As a result, people like Kohn, whose fever and swollen lymph nodes come on a few days before their lesions, must let the illness grow before it can be diagnosed. Others may develop hidden sores in their mouth or anus, and not realize that they can be tested. And many more without symptoms will be left to wait and wonder, after an exposure, whether they might have been infected.
As the outbreak spreads—with more than 2,000 cases in the U.S., by the latest count—public-health authorities have doubled down on this restriction: Testing for the virus must make use of swabs taken from a lesion, according to a “Safety Communication” issued by the Food and Drug Administration last Friday. “The FDA is not aware of clinical data supporting the use of other sample types, such as blood or saliva, for monkeypox virus testing,” the communication said, and testing of these other types “may lead to false test results.” This alarming messaging, delivered at a crucial moment in the virus’s spread, will have a profound effect on how quickly new monkeypox infections can be identified, isolated, and treated.
With this disease, like many others, early detection is invaluable as a means of promoting early treatment. Vaccination shortly after exposure can prevent monkeypox from occurring in many cases, and inoculation during the early phase of illness may reduce the severity of symptoms or curtail the contagious period. Although no medications have been approved specifically for monkeypox, several antivirals originally meant for smallpox are thought to help. As we have seen with the COVID antivirals Paxlovid and remdesivir, these types of therapies tend to work best when given as early as possible.
It may be just as important to identify those infected asymptomatically. An intriguing study out of Belgium, posted earlier this month but not yet peer-reviewed, examined swabs taken from the mouth and anus of 224 men in May. Samples had originally been collected to look for gonorrhea and chlamydia, but the scientists found monkeypox DNA in three of them. None of those men reported any symptoms of disease before or after testing, nor did any of their close contacts. Nevertheless, the study’s authors believe that these and other potential asymptomatic carriers could well be contagious. (Guidance from the CDC, last updated at the end of June, says that spreading can happen only after symptoms start.) In the meantime, other studies, conducted in Europe and Africa, have shown that monkeypox DNA is in many cases detectable in saliva, blood, urine, and rectal samples, even before a rash appears.
Matt Ford, a 30-year-old actor and video producer who lives in Los Angeles and New York, told me that he suspects he passed the virus on during the very early phase of his infection. He caught monkeypox last month, and was subsequently placed under public-health isolation. But in the week between his exposure and when he first noticed skin spots, he said, he spent an evening with a guy he was seeing. That guy would later come down with the disease himself. In retrospect, Ford had been a little tired during that time, but he had not felt unwell enough to pay it any mind. If people really are passing on the virus with few to no symptoms—and we don’t know for sure—then an early-detection test collected by mouth, vein, or rectal swab might prevent this onward spread.
Yet last week’s warning from the FDA was very specific: Unless you have an active rash, don’t bother to get tested. When I asked the agency what specific data it was relying on for its safety communication, an FDA spokesperson repeated only that the organization is “not aware of clinical data supporting asymptomatic testing or testing samples other than those taken directly from a suspect lesion.” CDC Director Rochelle Walensky also confirmed to reporters last week that a skin lesion is required for testing from her organization’s perspective, though she said that the CDC is exploring the possibility of saliva, throat, and blood tests.
This “absence of evidence” maneuver by authorities should be quite familiar at this point. In December 2019 and January 2020, the Chinese government publicly stated that there was no clear evidence of human-to-human transmission of the new coronavirus, and the World Health Organization repeated the claim. Three months later, in April, officials from the WHO cited “no evidence” that wearing masks prevented COVID transmission in a wider community setting. In the case of monkeypox testing, such conservatism is particularly self-defeating. When public-health authorities warn of a lack of clinical data for the effectiveness of blood and saliva tests, they are not only ignoring a small but growing list of published studies; they are also making it that much harder for researchers to collect more clinical data. The FDA and the CDC should be encouraging labs to run and evaluate new tests, Jay Varma, a public-health physician and professor at Cornell, told me. Instead the agencies are telling labs to stay away from them.
The FDA is correct that any new test for monkeypox would almost certainly produce some false results. (Even the gold-standard skin tests for monkeypox can misclassify cases.) But the advantages of having an early diagnostic for monkeypox are beyond dispute: Most people would take precautions to reduce their chance of exposing others if they knew they were infected, and contact tracers could hunt down additional cases far more quickly.
Ideally, one could imagine integrating monkeypox testing into the sexual-health infrastructure that is already in place. Many members of the gay community are used to receiving regular screening for HIV and other sexually transmitted diseases, according to Joseph Osmundson, a clinical assistant professor of biology at NYU. “There is a real desire in the community for scale testing” for monkeypox, too, he told me. Throat and rectal swabs collected for gonorrhea and chlamydia, for example, could also be tested for the virus. Varma suggests checking participants at any event where casual sex is expected to occur.
As things stand, physicians, patients, and laboratories would have to defy the explicit advice of U.S. public-health authorities in order to make this happen. Labs are legally permitted to create their own monkeypox diagnostics, even in the face of the FDA’s official warnings. Indeed, some organizations have already begun doing so. (If the U.S. government were to formally declare monkeypox a public-health emergency—as some politicians are calling for—then, ironically, this regulatory flexibility could be revoked.) Benjamin Pinsky, the medical director of the clinical-virology lab at Stanford, has overseen the testing of more than 70 patients for monkeypox, using samples from the nose, mouth, rectum, and bladder, as well as traditional skin scrapings. The newer methods have already picked up a few cases, he told me, but developing those tests without the cooperation of the government has been difficult. Pinsky said that public-health labs initially refused to provide him with real patient samples to confirm the validity of his approach. Many less-experienced lab directors will be dissuaded entirely from setting up their own protocols, because designing a diagnostic from scratch is far more complicated than using an off-the-shelf tool provided by the government. Also, no lab director would be eager to explain to hospital administrators why he or she is openly flouting an official safety warning.
One need only look back at the COVID testing snafus of 2020 to get a sense of what can happen when the government works against, rather than with, the medical community. At the start of the pandemic, the FDA prohibited labs from developing their own COVID-detection methods without first completing an arduous authorization process. Hospitals were encouraged to rely on the CDC’s official test, just as they are now for monkeypox. The government COVID test turned out to have a serious manufacturing defect, which thankfully hasn’t been repeated during the monkeypox outbreak. But excess caution remains a problem, and has once again left the country dangerously short of diagnostic capacity. U.S. hesitation also puts the country out of step with the international community. The WHO, parts of Canada, and the United Kingdom, for instance, all recommend analyzing a throat swab in some circumstances.
It’s not that the FDA’s concerns are unfounded. A monkeypox-testing bonanza, in which anyone and everyone can start to market their own services with limited oversight, could have undesirable consequences. Once the rules were loosened for COVID tests, small and inexperienced laboratory outfits served up diagnostic errors on occasion, or engaged in exploitative practices. But most labs follow proper quality-control procedures, and the Centers for Medicare and Medicaid Services still provides routine supervision. Any risk of false results in such an environment must be weighed against the more serious consequence of missing cases entirely. Less testing for monkeypox this summer will inevitably lead to more people suffering from ulcerating rashes, drenching night sweats, malodorous rectal discharge, and expansive onward spread.
Members of the gay community want easier and earlier testing for monkeypox. Public-health experts want the same thing. Aggressive case-finding may be the only way to get the current outbreak under control, and most large labs have the ability to detect the presence of monkeypox DNA in a variety of body fluids. We don’t yet know the real-world performance of a monkeypox-screening program based on all these fluids, but doctors could and should be coordinating with one another and with public-health agencies to find out. “We want the best diagnostics, the best vaccines, the best treatment protocols, and the best science in the world,” Osmundson told me. “But we are also in an emergency, and people are getting sick, and they are not able to access the care they need.”