Dozens of public health labs across the country now use a more generalized test for orthopoxvirus, a larger category that includes monkeypox, smallpox and other viruses. Two (2) biotechnology companies, Roche and Abbott, have announced plans to roll out monkeypox PCR tests, although right now, their test kits are for research use only (RUO).
The US Centers for Disease Control (CDC) and Prevention says it’s exploring ways to get monkeypox-specific testing out to states. There are already 74 labs across 46 states — part of a network known as the Laboratory Response Network — that are “using an FDA-cleared test for orthopoxviruses,” CDC Director Dr. Rochelle Walensky said.
Current capacity is around 7,000 of these tests weekly, with the potential to expand if needed.
Dr. Amesh Adalja, Senior Scholar at the Johns Hopkins Center for Health Security at the Bloomberg School of Public Health, said a lot of that capacity “was set up in response to the threat of biological weapons, and smallpox is the most worrisome orthopoxvirus.”
The testing that CDC does is more specific to the monkeypox virus, and the Agency can genetically sequence samples, as well. For example, it was by looking at the viral genetic code of the first US patient — a man in Massachusetts who had recently traveled to Canada — that researchers were able to see that his case of monkeypox closely matched that of a case in Portugal. However, Dr. Jennifer McQuiston, a Veterinarian and Deputy Director of the CDC’s Division of High Consequence Pathogens and Pathology, underscored that the testing that goes on at CDC is not really necessary for patient care. “The orthopox test that’s in place is an actionable test,” she said.
Experts say that action may include isolating patients, making treatments and vaccines available, and contact tracing to determine who else might have been exposed to the virus. Because other orthopoxviruses are not spreading in countries where they are not endemic like the US, one can assume that a positive orthopox test here is indeed monkeypox, according to Adalja.
Countries like Spain have shifted to include orthopox-positive cases as confirmed monkeypox cases in their counts. The CDC tracker of US cases lists “total confirmed monkeypox/orthopoxvirus cases.”
“I think that more diagnostic tests closer to patients is better. Commercial assays are even better,” Adalja said. “But the fact is, there are no other orthopoxviruses out there right now.” He does not believe that a lack of monkeypox-specific testing is hindering the public health response “because an orthopox-positive [case] is going to be monkeypox until proven otherwise in this scenario that we’re in right now.”
He added that this is a very different situation from the COVID-19 testing stumbles of 2020, when the world was dealing with a novel coronavirus without a major testing alternative, meaning it was often difficult to tell COVID-19 apart from other respiratory viruses like the flu. Monkeypox, on the other hand, we have known about for decades, and there is a plan in place. “It’s not the same as COVID,” Adalja said.
REFERENCE: CNN Health; 30 MAY 2022; Jacqueline Howard and Michael Nedelman