Researchers from Nagoya University in Japan have highlighted the necessity of personalized isolation strategies for managing mpox. Their findings confirm the efficiency of the existing standard methods for concluding isolation, while also proposing that incorporating more testing-oriented approaches could help minimize unnecessary isolation after the infectious stage. These conclusions could enhance response strategies.
Mpox, a disease linked to the monkeypox virus, experienced a notable surge in cases from mid-2022. The variant responsible for the 2022 outbreak, known as clade IIb, spread worldwide, primarily targeting men who have sex with men. This situation has prompted an increasing demand for effective isolation strategies that safeguard public health while respecting individual freedoms.
Utilizing individual patient data from clade IIb mpox cases—which was the predominant strain during the 2022 outbreak in Europe and America—researchers from Nagoya University have introduced a sophisticated modeling framework aimed at refining isolation protocols for mpox patients.
Their study indicates that current standard isolation practices are effective, but implementing protocols based on testing could further limit unnecessary isolation following the infectious period. Their research, featured in Nature Communications, may enhance our response methods and shorten isolation durations.
“Our methodology underscores the vital importance of recognizing individual differences in viral shedding patterns to reduce both the risks of prematurely ending isolation and the chances of unnecessarily prolonged isolation,” remarked Shingo Iwami. “Based on our findings, utilizing PCR testing may alleviate the isolation burden on mpox patients while mitigating further transmission, particularly in times of rising mpox cases.”
The main tactic for controlling mpox spread has been the isolation of those infected. Current guidelines for isolating mpox patients focus on visible symptoms. Typically, symptoms last around three weeks.
Nevertheless, the duration of mpox infection can vary significantly among patients. Some health officials worry that strategies based solely on symptoms or set timeframes might overlook this variability. As a result, individuals reentering the community might still be contagious.
Iwami and their team aimed to enhance isolation strategies by creating a modeling framework to determine when infected individuals are no longer contagious, thereby fine-tuning isolation procedures. They developed these models using data on viral load in lesion samples from previous mpox studies.
The findings revealed a wide range in the duration of viral shedding, which lasted from 23 to 50 days for different individuals. The researchers also noted greater variability in viral shedding durations among the mpox cases that emerged in Europe and the US in 2022.
Employing these insights, the team evaluated three isolation strategies: a symptom-based rule where isolation ends with symptom resolution; a fixed-duration rule where isolation concludes after a set timeframe—usually three weeks; and a testing-based rule relying on negative test results at varying intervals and frequencies.
Their observations indicated that the fixed-duration approach struck a balance between risk and unnecessary isolation but lacked flexibility. In contrast, the testing-based strategy could significantly shorten this isolation period, depending on test frequency and timing. They deduced that, although the fixed-duration rule was effective, the testing-based model presented a more customized solution that could align better with individuals’ contagious periods.
“The testing-based strategy has shown effectiveness in reducing the chances of prematurely ending isolation and curtailing unnecessary isolation time,” Iwami stated. “Our analysis suggests that 63% of individuals within the studied population could experience shorter isolation periods with the testing-based strategy compared to symptom-based or fixed-duration rules.”
“To keep the risk of early isolation termination below 5%, PCR testing optimized through our simulations could cut down isolation durations by an average of more than a week, compared to the general isolation guideline that relies on symptom disappearance,” he noted. “Our simulations indicated that if patients are tested at intervals of 2 to 5 days and yield three to four consecutive negative results, we can safely terminate their isolation,” he added. “This highlights the inadequacies of blanket isolation policies.”
Adopting a testing-based rule will necessitate thorough planning and resources, but it could prove more effective in managing isolation lengths and easing burdens for those in isolation. Public health policies could integrate these findings when crafting more flexible and responsive isolation frameworks. By leveraging detailed viral load data and advanced modeling techniques, public health agencies can establish more efficient isolation protocols that minimize the risks associated with both premature and unnecessary prolonged isolation.
Iwami expressed, “Though our research relied on clade IIb data, if comparable information becomes available for clade Ib, the variant currently spreading in Africa, we believe the methods from this study could serve as a valuable tool for determining the optimal duration of infection prevention and control.”
