Super Spreaders vs. Response

Super-spreaders serve as critical infectious resources in multiple infectious diseases. Super-spreaders may appear asymptomatic or present mild symptoms and transmit pathogens to susceptible populations, leading to severe symptoms, and even death. Early identification of this population is extremely important to inhibit the spread of infectious diseases. Right now, the whole world suffers from a devastating infectious disease caused by severe acute respiratory syndrome coronavirus 2 (“SARS-CoV-2”). 


In the early hypothesis related to the interactions between host and pathogens, scientists believe that infected people may have an equal chance to transmit pathogens to secondary cases. At the beginning of a COVID-19 infection, there is a period known as the exposed or latency period before an infected person can transmit the infection to another person. 


Epidemiologists, Those That Study And Analyze The Distribution (Who, When, And Where), Patterns And Determinants Of Health And Disease Conditions Usually Observe A “20/80 Rule” Or The “1:4 Ratio” In The Way That Infectious Diseases Are Transmitted Within A Population. For Clarity, 1 Infected Person Will Infect 4 Healthy Persons. This “1:4 Ratio” Applies In Many Transmissions Of Infectious Pathogens Among Different Species. A COVID-19 Epidemic Model With Latency Period Follows The Same 1:4 Ratio, But New Variants Have Also Created An Asymptomatic Carrier, Which Can Spread The Virus, But Themselves Show Little To No Sign Of Infection. This Dramatically Changes The Current Covid-19 Epidemic Modeling Of A Typical 1:4 Ratio To That Of A “Super-Spreader”. Super-Spreaders Can Transmit Pathogens Disproportionately To More Than An Average Number Of Secondary Cases And Are Likely To Promote The Speed And Scale Of Outbreaks.  Usually, Super-Spreaders Transmit At Least Ten Individuals, Sometimes Even Up To 100 Secondary Cases, And Exponentially Increase Infections By A Factor Of 10+ Every 24-48 Hours, Without Testing Or Quarantine In Effect.   Thus, Asymptomatic Super-Spreaders Of COVID-19 Can Be Extremely Dangerous And Must Be Handled Time-Efficiently. 


In December Of 2020, The CDC Amended Its Coronavirus Testing Guidelines To Exclude People Who Do Not Have Symptoms Of COVID-19—Even If They Have Been Recently Exposed To The Virus. The Revisions Not Only Prompted Confusion And Alarm From Experts, But Also Cut Federal Funding, Which Prompted Several Insurance Carriers Not To Cover Testing Unless Symptoms Were Present,Thus Setting A “Potentially Dangerous” Precedent.  In January 2021, The CDC Amended The Agency’s Guidance, Further Announcing  That People Who Have Been In Close Contact With An Infected Individual—Typically Defined As Being Within Six Feet Of A Person With The Coronavirus And For At Least 15 Minutes—“Do Not Necessarily Need A Test” If They Do Not Have Symptoms.


Unfortunately, Directly Conflicting With CDC Guidance, Several Recently Published Research Reports, Most Notable A January 2021 Study By The Journal Of The American Medical Association (“JAMA”),  Have Determined That Most COVID-19 Cases Come From People Without Symptoms.  According To The JAMA Publication, Approximately 59% Of All Transmission Is Caused By Presymptomatic Individuals Without Developed Symptoms And Asymptomatic People Who Never Developed Symptoms. It Is Important To Note That The Corresponding Author Of This Research Was Jay C. Butler, MD, Office Of The Deputy Director For Infectious Diseases, U.S. Centers For Disease Control And Prevention. Moreover, The Research Funding And Support Were Performed As Part Of The U.S. Centers For Disease Control And Prevention’s Coronavirus Disease 2019 Response. 


The Findings Presented In The January 2021 Study By The JAMA Complement An Earlier Assessment And Reinforce The Importance Of Asymptomatic Transmission. Across A Range Of Plausible Scenarios, At Least 50% Of Transmission Was Estimated To Have Occurred From Persons Without Symptoms.  This Overall Proportion Of Transmission From Presymptomatic And Never Symptomatic Individuals Is Key To Identifying Mitigation Measures That May Control SARS-CoV-2.


Key Takeaways:

  • 59% Of COVID-19 Case Transmission May Occur From Persons Without Symptoms.
  • Traditionally, Super-Spreaders Transmit Infectious Diseases In Prior Pandemics At A 10-100 Factor, Meaning 1 Infected Person In Turn Infected From 10-100 Healthy People.
  • COVID-19, Asymptomatic Carriers (No Symptoms), Or Those Presenting Mild Symptoms, Can Transmit Pathogens To Susceptible Populations MUCH FASTER Than Traditional Super-Spreaders, Leading To Severe Symptoms, And Even Death.
  • Testing Barriers And Latency Time In Receiving Lab Results Lead To Non-Adoption For Frequent Use.
  • Asymptomatic Super-Spreaders Of COVID-19 Can Be Extremely Dangerous And Must Be Handled Time-Efficiently.


* In race between vaccines and variants, Massachusetts may be seeing an ‘uncoupling’ of COVID-19 cases and deaths, by Nik DeCosta-Klipa, (4-13-2021).

* Pfizer/BioNTech Covid-19 Vaccine Is Less Effective Against the South African And UK Variants, Forbes, (04-14-2021).

* Mutations could render current Covid vaccines ineffective in a year or less, epidemiologists warn, by Holly Ellyatt, CNBC (updated 03-30-21).

* Higher Reinfection Risk? Vaccine Resistant? NYC Drops New Report on COVID Variants, NBC, CH4 NYC, by Jennifer Millman (04-13-21).

Gao MERS, SARS, and ebola: the role of super-spreaders in infectious disease Cell Host Microbe, G. Wong, W. Liu, Y. Liu, B. Zhou, Y. Bi, G.F. 18 (4) (2015), pp. 398-401.

* Transmission dynamics of the etiological agent of SARS in Hong Kong: impact of public health interventions, S. Riley, C. Fraser, C.A. Donnelly, et al. Science, 300 (5627) (2003), pp. 1961-1966.

* Unclear but present danger: An asymptomatic SARS-CoV-2 carrier, Xuejing Yu, Genes Dis. 2020 Dec; 7(4): 558-566.