But even though there was already a monkeypox test, lab workers had to do each step by hand, Morice says. Federal guidelines state that testing should only be done by swabbing the lesions of a person suspected of having the virus. These lesions look like pimples or blisters and can appear on the face, hands, feet, around the genitals or anus, or in the mouth or rectum. Then the wiped samples are subjected to a PCR or polymerase chain reaction test, which extracts and amplifies genetic material to look for monkeypox virus DNA. When performed manually, this involves multiple steps of adding liquid, mixing reagents, and isolating the DNA.
This makes testing slow. Commercial labs like the Mayo Clinic have worked to automate the process. Until recently, the clinic could only process 20 to 30 tests a day using the manual protocol, but soon it will be able to run several hundred tests a day, Morice says.
This type of test also raises some other problems. “The current tests force you to swab a lesion. For people with internal lesions, this may not be possible or it may be very painful,” says Makofane.
A monkeypox test can’t be done until a person has visible symptoms — and it can take several days for a rash to appear. Some people may have very subtle or very few lesions. While it’s not clear whether the disease can spread before the blisters form, Rivers says it would be better to catch an infection sooner so people can have access to treatment and vaccines as soon as possible. To best prevent onset of the disease, the CDC says the vaccine should be administered within four days of the exposure date.
Like Covid-19 testing in the early days of the pandemic, monkeypox testing must be ordered by a doctor. Morice says that because it’s such a new disease in the United States, many doctors may not know how to test for monkeypox, or may not consider referring patients who they don’t think belong to at-risk populations . While most cases have occurred in men who have sex with men, not all have. For example, Indiana health officials have reported that around 20 percent of cases in the state involve women, and two infections in the United States have been identified in children.
Financial constraints, stigma, and lack of insurance or transportation to testing sites can also be barriers that prevent some people with symptoms from getting tested.
The US Food and Drug Administration says monkeypox should only be diagnosed by swabbing lesions, but a study published in June by researchers in Spain points to other possible methods of testing for the virus. They detected monkeypox viral DNA in both saliva and semen samples from 12 patients with confirmed infection.
The idea is already being pursued by Flow Health, a Californian company that offers Covid-19 testing. The company is working on a monkeypox test that requires a person to spit into a plastic tube. Then laboratory workers perform a PCR test, extracting and amplifying viral DNA from the sample.
CEO Alex Meshkin Says Saliva-Based Test Could Have Benefits; For example, it could enable the screening of pre-symptomatic cases, which has been crucial for Covid-19 testing. It could also be done at a pharmacy, at a mass testing site, or even at home to avoid the potential embarrassment of seeing a medical provider. “Relying on a painful and invasive lesion swab that can only really be performed in a clinic will inherently have relatively low demand due to the inherent barriers of traditional healthcare,” says Meshkin.
However, in a July 15 safety advisory, the FDA warned that testing specimens not obtained from a lesion could produce false results. The agency noted that it was not aware of any clinical data to support the use of other sample types, such as blood or saliva.
According to Rivers, a research priority should be to develop other modalities so that the tests can reach as many people as possible: “It is important to determine whether, for example, testing oral fluids is as accurate as swabbing lesions.”