What would herd immunity mean without a vaccine?

A dangerous concept has been misunderstood and circulated on social media: let everyone be exposed to COVID-19 and establish herd immunity quickly without a vaccine. Using the CDC Case Surveillance Data Report is the best way to compare outcomes in the United States to Malheur County. The report “describes demographic characteristics, underlying health conditions, symptoms, and outcomes among 1,320,488 laboratory-confirmed COVID-19 cases individually reported to CDC during January 22–May 30, 2020.”

If the public fail to protect each other from COVID-19 and enough people were infected to establish herd immunity without a vaccine, what would that mean in numbers for our population?

  • Some estimates require 70-90% of the population develop sufficient antibodies for herd immunity. (We still don’t even know that a positive COVID-19 test means that you have enough antibodies to not be reinfected.) Let’s settle on 80% of our population for herd immunity as an average.
  • 80% of our approximate population of 30,000 is 24,000. Hypothetically, 24,000 people would need to have COVID-19 in Malheur County to establish herd immunity before a vaccine.
  • The CDC data shows that 14% of cases required hospitalization and 5% of cases died.
  • Of the hypothetical 24,000 people in Malheur County who would be infected, that means that 3,360 people would require hospitalization.
  • Of the hypothetical 24,000 people in Malheur County who would be infected, that means that 1,200 people would die. (Even if only .5% of people died, that would be 120 lives lost that could have been saved.)

The CDC report shows that “among COVID-19 cases, the most common underlying health conditions were cardiovascular disease (32%), diabetes (30%), and chronic lung disease (18%). Hospitalizations were six times higher and deaths 12 times higher among those with reported underlying conditions compared with those with none reported.”

The Oregon Health Authority reports that 53.7% of adults in Malheur County have one or more chronic underlying health conditions. This means our population is at high risk of severe cases of COVID-19.

Help us dispel the myth that herd immunity without vaccine is an option. We must flatten the curve of new COVID-19 cases (we’re at 287 cases today with a 12.4% positive rate) to buy us more time. We all need to act to prevent the spread so our hospital system is not overwhelmed and lives are not lost.

5 thoughts on “What would herd immunity mean without a vaccine?

  1. Thank you for providing information that helps to show the seriousness of the virus. What’s happening with the number of positive cases in Malheur County indicates that it could be a good thing for local residents to be more careful and take the virus more seriously.

    (a 72 year old who is trying to be careful – for myself and for others)

  2. I agree fully with Steve. The devastating numbers of positive tests for Malheur County released on Sunday by the Oregon Health Authority can mostly be attributed to a failure by the population and especially by many businesses in a community where few sources of mass spread are identified by the authorities. When the number of daily new cases in Malheur County exceeds those in urban populated Multnomah County, local media are remiss in making the information provided in these brief statements on the health department’s web page their lead story on successive days to be sure our population is receiving accurate information.

    {a 66 year old who has altered behavior even more in recent weeks)

  3. The numbers you use in your hypothetical are misleading. You should use the Infection Fatality Rate (IFR) instead of the Case Fatality Rate (CFR). The CFR doesn’t account for the large number of undiagnosed mild/asymptomatic cases of COVID-19. The CDC recently came out with a best estimate IFR of .0065. Here is the link:


    Multiplying 24,000 potential infections by .0065 gives 156 deaths, in the hypothetical case of letting the disease run rampant in search of herd immunity. This is still a lot of deaths for a county with a population as small as Malheur County, and I think most people would consider this too big a number, but it certainly does change the discussion when you compare it to the inflated 1,200 deaths that you arrived at using a 5% CFR.

    There is already enough fear generated by the misuse of statistics by the media (mostly cable news). I don’t think the disease is a hoax, and I don’t think herd immunity through natural infection is a good option. I am optimistic that there will be a vaccine sooner than later. But using the CFR to inflate the potential number of deaths I feel does a disservice to the people of Malheur County.

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