We need simple, transparent metrics to pursue monkeypox containment
What gets measured gets managed
We are two months into the monkeypox outbreak in the United States and the window for extinguishing transmission is closing. Monkeypox is, in theory, a containable disease. The virus produces distinctive symptoms and is spread through close and intimate contact, unlike SARS-CoV-2 which transmits easily through the air. However, if we do not move swiftly to interrupt transmission, monkeypox could be the second emerging infectious disease to become endemic this decade. This challenge is daunting, and it comes at a time when our nation’s public health professionals are weary. More resources for public health will likely be needed to get a handle on this new threat, and political leaders should support them to get this crucial work done.
There are recent signs of progress. After weeks of tight supply, nearly 800,000 doses of vaccine are expected to become available in the next weeks. This will be welcome news to residents in New York City and Washington DC, where vaccine appointments for people at highest risk filled up within minutes. Availability of diagnostic testing is also expanding as commercial laboratories come online. Testing was previously limited to public health laboratories, where it was (and may still be) underutilized.
Despite these positive developments, public health officials must adopt a goal-oriented approach to stopping the epidemic. To start, our nation’s leaders should establish and continuously communicate the strategic objectives of the outbreak response. The public needs to hear a clear articulation that eliminating domestic transmission is the goal. The choices that officials make now about how aggressively to manage the virus will impact population health for years to come. If containment is no longer the objective, the public deserves to hear that policy position and its justification.
The Centers for Disease Control and Prevention can help by developing metrics and targets with which to measure progress towards containment. Current data on the outbreak is limited to a snapshot of cumulative case counts—even data on previous days’ counts is not readily available. Much more information is needed to monitor and accelerate progress toward the goal of containment.
I propose three core indicators, inspired by those used during the successful effort to contain the 2014 Ebola outbreak in West Africa. If local response teams were off target, they adapted their practices to achieve better results. A similar approach to monkeypox would ensure that the public health response is effectively identifying cases and breaking chains of transmission.
The first metric is number of individuals tested. Not all jurisdictions require test providers to report both positives and negatives results. In this case, they should. Test volume is crucial for understanding whether test availability is broad enough to turn up most cases. Basic demographic information on who is tested can also clarify whether the outbreak is expanding into new subpopulations like women and children—or whether the lack of reported cases in those groups is simply because they are not tested.
The second metric I recommend is the proportion of cases arising from known contacts. Ideally, all new cases would develop in people who are already in quarantine because of a recognized exposure, suggesting that epidemiologists have the outbreak surrounded. The current measure of this metric is likely low. It can be improved over time by using forward and backward contact tracing to uncover and follow chains of transmission to the edges of the outbreak.
Until we reach the point where most new cases develop in people already in quarantine, a third metric of days from symptom onset to isolation can serve as a stopgap. This metric captures components of surveillance effectiveness, test administration and turnaround time. Cases should be identified, diagnosed, and isolated as quickly as possible to prevent onward transmission.
These three simple indicators would ensure our response efforts are effective and advancing the goal of containment. They should not be limited to official use. It is in the public’s interest to assess progress towards control. State and local public health departments should publish weekly updates on the local status of these indicators. Many people mistakenly believe that the CDC collects and owns public health data. It does not. It is state and local public health departments we must look to for this transparency. CDC can help by aggregating a national picture and by providing guidance and support to jurisdictions in their efforts to regain control of the virus.
We must not back down from this fight. Future generations will either benefit or bear the consequences of the trajectory of this outbreak. Goal oriented, transparent metrics can help us to prevail.
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