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Biomedical subjects

Edward H Kaplan

Publications and source records attributed to Edward H Kaplan.

9 recordsLinked to original sources
PubMed2003

Emergency response to an anthrax attack.

We developed a mathematical model to compare various emergency responses in the event of an airborne anthrax attack. The system consists of an atmospheric dispersion model, an age-dependent dose-response model, a disease progression model, and a set of spatially distributed two-stage queueing systems consisting of antibiotic distribution and hospital care. Our results underscore the need for the extremely aggressive and timely use of oral antibiotics by all asymptomatics in the exposure region, distributed either preattack or by nonprofessionals postattack, and the creation of surge capacity for supportive hospital care via expanded training of nonemergency care workers at the local level and the use of federal and military resources and nationwide medical volunteers. The use of prioritization (based on disease stage andor age) at both queues, and the development and deployment of modestly rapid and sensitive biosensors, while helpful, produce only second-order improvements.

Anthrax↗
PubMed2003

Analyzing bioterror response logistics: the case of smallpox.

To evaluate existing and alternative proposals for emergency response to a deliberate smallpox attack, we embed the key operational features of such interventions into a smallpox disease transmission model. We use probabilistic reasoning within an otherwise deterministic epidemic framework to model the 'race to trace', i.e., attempting to trace (via the infector) and vaccinate an infected person while (s)he is still vaccine-sensitive. Our model explicitly incorporates a tracing/vaccination queue, and hence can be used as a capacity planning tool. An approximate analysis of this large (16 ODE) system yields closed-form estimates for the total number of deaths and the maximum queue length. The former estimate delineates the efficacy (i.e., accuracy) and efficiency (i.e., speed) of contact tracing, while the latter estimate reveals how congestion makes the race to trace more difficult to win, thereby causing more deaths. A probabilistic analysis is also used to find an approximate closed-form expression for the total number of deaths under mass vaccination, in terms of both the basic reproductive ratio and the vaccination capacity. We also derive approximate thresholds for initially controlling the epidemic for more general interventions that include imperfect vaccination and quarantine.

Bioterrorism↗
PubMed2003

Optimizing admissions to an intensive care unit.

This paper presents a model for optimizing admissions to an intensive care unit (ICU) where the objective is to maximize the expected incremental number of lives saved from operating the ICU. The probability distribution of the number of occupied ICU beds is modeled using queueing theory. Three different admissions policies are considered: first come first served (FCFS), first come firstserved for all referrals whose expected incremental survival benefits gained from ICU admission exceed some hurdle (FCFS-H), and first come first served for all referrals whose expected incremental survival benefits exceed a bed specific hurdle (BSH) that depends upon the number of occupied beds (FCFS-BSH). The model is applied to data describing patients referred to the ICU at Jerusalem's Hebrew University-Hadassah Hospital. After statistically estimating the distribution of expected incremental survival benefits among those referred to the ICU, we show that if only those referrals where ICU admission would improve the probability of survival by at least 19.4 percentage points were admitted, an additional 18 statistical lives would be saved annually compared to the FCFS policy, a relative life saving improvement of 17.9%. Implementing the more complex optimal bed specific hurdle policy would save an additional 1.4 statistical lives annually beyond what can be achieved with FCFS-H, a marginal improvement of only 1.2%.

Decision Support Techniques↗
PubMed2003

Detecting bioterror attacks by screening blood donors: a best-case analysis.

To assess whether screening blood donors could provide early warning of a bioterror attack, we combined stochastic models of blood donation and the workings of blood tests with an epidemic model to derive the probability distribution of the time to detect an attack under assumptions favorable to blood donor screening. Comparing the attack detection delay to the incubation times of the most feared bioterror agents shows that even under such optimistic conditions, victims of a bioterror attack would likely exhibit symptoms before the attack was detected through blood donor screening. For example, an attack infecting 100 persons with a noncontagious agent such as Bacillus anthracis would only have a 26% chance of being detected within 25 days; yet, at an assumed additional charge of $10 per test, donor screening would cost $139 million per year. Furthermore, even if screening tests were 99.99% specific, 1,390 false-positive results would occur each year. Therefore, screening blood donors for bioterror agents should not be used to detect a bioterror attack.

Anthrax↗
PubMed2002

Emergency response to a smallpox attack: the case for mass vaccination.

In the event of a smallpox bioterrorist attack in a large U.S. city, the interim response policy is to isolate symptomatic cases, trace and vaccinate their contacts, quarantine febrile contacts, but vaccinate more broadly if the outbreak cannot be contained by these measures. We embed this traced vaccination policy in a smallpox disease transmission model to estimate the number of cases and deaths that would result from an attack in a large urban area. Comparing the results to mass vaccination from the moment an attack is recognized, we find that mass vaccination results in both far fewer deaths and much faster epidemic eradication over a wide range of disease and intervention policy parameters, including those believed most likely, and that mass vaccination similarly outperforms the existing policy of starting with traced vaccination and switching to mass vaccination only if required.

Centers for Disease Control and Prevention, U.S.↗
PubMed2002

A model-based evaluation of a cultural mediator outreach program for HIV+ Ethiopian immigrants in Israel.

This article presents a model-based evaluation of a program designed to reduce HIV transmission from HIV-infected Ethiopian immigrants in Israel. Rather than rely on self-reported variables such as condom use, this study's approach focuses on pregnancy rate reduction, estimated from administrative periodic reporting data, as a measure of unprotected sexual exposure. The models show that among both HIV+ women and the female sex partners of HIV+ men, the ongoing pregnancy rates estimated during the intervention were significantly lower than the estimated baseline pregnancy rates, suggesting reductions in unprotected sexual exposures among those participating in the program.

Community-Institutional Relations↗
PubMed2002

Allocating HIV-prevention resources: balancing efficiency and equity.

The primary goal of HIV prevention is to prevent as many infections as possible. This requires allocating HIV-prevention resources according to cost effectiveness principles: those activities that prevent more infections per dollar are favored over those that prevent fewer. This is not current practice in the United States, where prevention resources from the federal government to the states flow in proportion to reported AIDS cases. Although such allocations might be considered equitable, more infections could be prevented for the same expenditures were cost-effectiveness principles invoked. The downside of pure cost-effective allocations is that they violate common norms of equity. In this article, we argue for a middle ground that promotes both equity and efficiency in allocating federal HIV-prevention resources.

Acquired Immunodeficiency Syndrome↗