Modelling mass asymptomatic testing strategies for early containment of infectious disease outbreaks in prisons

ObjectiveInvestigate a strategy of mass asymptomatic testing and isolation ("pulse testing") aimed at early containment of outbreaks in prisons in comparison to or combination with a symptom-based isolation strategy. MethodsSimulations using an individual-based time-since-infection model were run under different pathogen and intervention strategy scenarios. Measured outcomes were the proportion of outbreaks contained and number of individuals isolated. ResultsFor R0 = 2, 25% probability of being asymptomatic (pa = 0.25), a COVID-19-like infection dynamics and perfect adherence, one pulse test contained approximately 20% of outbreaks, and three tests up to 50%. With no asymptomatic cases, three tests performed similarly to isolating cases one day after symptoms ({approx} 55% outbreaks contained), but symptom-based isolation degraded significantly faster than pulse testing with increasing pa. With perfect adherence, combining both interventions contained between {approx} 25% (R0 = 3, pa = 0.5) and > 90% (R0 = 1.5, pa = 0) of outbreaks. Across all scenarios, pulse testing isolated substantially fewer individuals than symptom-based isolation, e.g. {approx} 5% versus {approx} 30% for R0 = 2 and pa = 0.25. ConclusionIf implemented promptly upon outbreak declaration and with high adherence, pulse testing may stop outbreaks early, substantially reducing the number of isolations and mitigating the impact on prison regime and resident/staff wellbeing. However, for large R0 or delayed implementation, effectiveness drops rapidly.