Epidemic Basics for Health and Human Services Administration

Last Friday the 28th of February, the CDC’s website (1), suggested that while the virus has been identified, there is more to learn about the new disease, COVID-19. It was additionally indicated that this disease spreads easily and at a sustained rate. The infection spreads primarily person-to-person wherein an infected person coughs or sneezes and then respiratory droplets land on mouths and nostrils or are inhaled by another person within six feet away. Secondarily, the virus is also spread when a person touches a surface or an object with COVID-19 on it and subsequently touches their own eyes, mouth, and nose.

While managers of public service agencies usually have access to assistance and guidance of public health officers, an administrator equipped with the understanding of the dynamics of epidemics can affirmatively and timely meet the threat to the community served and to the agency’s workers.

The dynamic system (2) illustrated above describes how the flu, a viral disease spreads through a closed population over time. The similarity of a virus as a causative agent of COVID-19 makes this an appropriate model (3) to study the current epidemic threat. Its computer model form can allow rapid testing of response action plans with a variety of what-if experiments.

The Infection Cycle. The infection cycle can be seen in the illustration above by tracing through the loop described by red arrows. For any given infectious disease, there are persons in the population who belong to the “susceptibles”. When an infectious person joins this population and makes an “infectious contact” with another, the infected person may not be immediately symptomatic. Some asymptomatic individuals do not show symptoms but are carriers nevertheless. After the contact, there are now two persons who make up the “infectious population”. In the next iterations, there will be four infectious persons, then eight and so on exponentially, unless interrupted, and until all of those susceptibles are infected.

Recovery. Most infected persons after the disease's incubation period become “symptomatic” and eventually progress to the “recovered” part of the population. The eventual status of some symptomatic person may turn “terminal”.

Responding to dynamic epidemic threats requires deliberate development and rapid execution of response plans. The illustration above suggests that infectious contacts decline with the reduction of the infectious population. This is when test kits for COVID-19 are so valuable so those infected can be detected and placed into the symptomatic group. These kits and procedures must be readily available and in an amount required by the population subject to the threat. Placing symptomatic persons in quarantines is another approach in reducing infectious contacts. The effectiveness of this measure, however, depends on whether the acquisition of quarantine spaces can keep pace with the rate of infection. Vaccination of all persons in the population can minimize the number of susceptibles. Of course, the point is moot if once the vaccine is developed, all of those susceptible have succumbed to the disease. Even when readily available, can the inoculation rate overtake the infection rate?

By Noel Jagolino, management consultant, 2020

Content contributor, Mgmtlaboratory.com

References:

1. www.cdc.gov/coronavirus/

2. Systems Dynamic Model by George P. Richardson. Visiting Professor in Science Technology and Public Policy, Humphrey Institute of Public Affairs, University of Minnesota 2009.

3. Systems dynamic model developed using Vensim, a software by Ventana Systems, Inc.