News

Herd immunity 'is a dangerous suggestion,' health director says

By Steve Smith, Henderson County Health Director, Published: October 31, 2020

It’s discouraging for all of us to see the current trends with increasing cases in the world, our country, state and county. Despite valid efforts by many to socially distance and wear masks along with public health efforts for testing, case investigations and contact tracing, cases are continuing to climb because we’re simply dropping our guard.

Herd immunity is a topic frequently mentioned by callers as we look forward to the availability of Covid-19 vaccine in 2021. Herd immunity for any particular disease can be calculated from a disease’s reproduction rate or the number of cases generated by one case of illness. If the reproduction rate is less than 1, the spread of disease will eventually die out. If it is greater than 1, cases can spread exponentially.

Many estimates for coronavirus today place its reproduction rate in an unprotected population somewhere between 2 and 6. In contrast, measles which is more infectious has a reproduction rate above 14. Protective measures like wearing face masks are the only way to reduce the reproduction rate. This different calculation would then be the effective reproduction rate which considers control measures and immunity that might be generated through vaccinations. This is why the 3 W's are so important….it’s really our primary tool right now for reducing the spread of Covid-19: Wear a face mask. Wait 6 feet apart. Wash hands or use hand sanitizer.

Given the reproduction rate for coronavirus, the estimates for achieving herd immunity range from around 55 percent to 80 percent of the population and no jurisdiction in the country is close to that percentage.  We are emphasizing these statistics because some have suggested that we should just let Covid-19 spread in an uncontrolled fashion in order to achieve herd immunity. That is not a reasonable strategy and is a dangerous suggestion since it would generate hundreds of unnecessary deaths in our county. 

Dr. Tom Friedman, a former CDC Director now linked to an effort called Resolve to Save Lives, estimated that a wholesale abandonment of current strategies for the purpose of letting the disease spread would likely create 500,000 unnecessary deaths in the country.  Let’s not waste any time speculating about this option and resolve to save lives right here in Henderson County.

If you’re interested in a more in-depth discussion about coronavirus transmission and herd immunity, we like this article in The Atlantic, This Overlooked Variable is the Key to the Pandemic. Stay strong and let’s all continue to do our part to protect each other and the entire community including our most vulnerable. Every life matters.  More about our local preparations for Covid-19 vaccinations in the next post.