Saturday, November 14, 2020

Beyond COVID Previous Influenza Outbreaks throughout History

The Historical Precedence of Influenza Identification, Spread and Eventual Adaptation into the Population   

What is Influenza 

Influenza, also referred to as the flu, is a respiratory infectious disease that is caused by a negative-sense RNA virus (Orthomyxoviridae). The most common types of influenza viruses that impact the human population include Type A, Type B, and Type C. The virus strain spreads around the world in yearly outbreaks. An influenza pandemic occurs when a strain of the virus is transmitted to the human body (usually from another species) and spreads massively. This may also result in the identification of a new strain of the virus. 


Examples of Influenza Pandemics (not comprehensive)


1918-1919 

H1N1 Influenza A virus 


1930's

Influenza B virus 


1940's 

Inactivated Flu vaccine 

For inactivated Influenza A virus 


1940's

Influenza B viruses discovered 

Arrival of Mechanical ventilators 


1942

Two dose Flu vaccine 

Protection against Influenza A & Influenza B virus


1947

Flu epidemic 

Changes in antigenic composition of influenza viruses 

Rendered existing vaccines ineffective

Required to renew annually  

Monitor international circulating viral strains 


1957

Flu pandemic

H2N2 novel flu virus emerges 


1960

1st Recommendation for annual Influenza vaccination 

Over 65/very weak/immunocompromised


1960's

South Africa outbreak 

Reservoir for influenza A virus (wild birds)

H3N2 new influenza virus emerges 

pandemic 


1970's 

H1N1 swine flu 

25% of US pop vaccinated 

twice the level needed to block pandemic 


1996

H5N1 virus avian influenza 

Hong Kong


2003 

SARS I epidemic 

China 


2007

H5N1

US Vaccine 


2009 

H1N1 pandemic

new influenza A virus 

Mexico


2020 

SARS-COV-2

COVID pandemic 

China 


There are many viral strains currently circulating worldwide and this does not interfere with daily living


Management of previous epidemics 

Resulting consequences


Current management of COVID/SARS-COV-2 

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