Reviewing the 1968 Influenza Pandemic

The Final Influenza Pandemic of the 20th Century 

With the exception of the U.S., most countries experienced mild epidemics during the first year of the 1968 pandemic. The estimated number of deaths was 1 million worldwide and about 100,000 in the U.S. Most excess deaths occurred in people 65 years of age and older.

After the pandemic, CDC and public health officials around the world reflected on the effectiveness of the response to the pandemic and developed strategies to increase global cooperation for greater influenza surveillance.

Influenza vials at WHO Collaborating Center, 1968

Courtesy of the World Health Organization

Adding Additional Influenza Surveillance

Walter Dowdle, then-director of the CDC Laboratory Program at the WHO Influenza Collaborating Center at CDC, stated that all lessons from 1957 had been applied to the 1968 pandemic. Yet there were still much that could be improved that the 1968 pandemic exposed. The value of additional influenza surveillance was one of the lessons of the 1968 pandemic. WHO added eight new influenza centers between 1968-1969. In 1969, there were 85 influenza centers in 55 countries. WHO was dedicated to improving communications throughout the influenza surveillance network.  

Serfling Curve

Serfling Curve Equation

Modeling the Severity of an Epidemic: The Serfling Curve

CDC’s Alexander Langmuir proposed using data to more accurately compare epidemic effects between countries. To demonstrate that influenza epidemics could be measured with data, he compared the number of deaths in the U.S. with those that occurred in England and Wales, using the expectancy curve calculated by CDC statistician Robert S. Serfling in 1963. Serfling constructed standard curves of expected seasonal mortality to create an early quantitative measure of influenza severity and localization. Using this formula, Serfling was able to create charts and graphs that reflected what one community could expect for influenza seasonal mortality. 

After the 1968 pandemic, Langmuir proposed that each country use similar methods, to enhance global influenza surveillance.

Influenza Influenza Conference at CDC, 1970

Page from CDC staff publication, The Word, describing the 1970 international influenza conference that reviewed evidence from the 1968 influenza pandemic

Reviewing the Evidence

In October 1969, CDC held a conference in Atlanta investigating the properties of the virus, discussing influenza A(H3N2) virus vaccines and their effect on various parts of the population, and discussing the national experiences of a few select countries. While at the conference, top public health scientists from around the world discussed what could be done to improve public health infrastructure, so that the world would be prepared for the next influenza pandemic.

The 1968 Influenza Pandemic
Reviewing the 1968 Influenza Pandemic