The pandemic will be over when the U.S. reaches herd immunity. Herd immunity is the level of individual immunity where the spread of the disease from person to person becomes unlikely, and results in the whole community becoming protected, even those who are not immune.
Herd immunity is a function of the rate at which the virus spreads from person to person. For COVID-19, credible estimates are that each infected person infects another 2.3 people, which if true means that herd immunity is reached when 56.5% of the population is immune. We will reach that in the U.S. when the number of people who have the virus (whether they know it or not), plus the number of people who are naturally immune, plus the number who have been vaccinated equals 185 million.
Those basic facts, combined with some new data and analysis supplied to me by Anne Marie Knott, the Robert and Barbara Frick Professor of Business at Washington University in St. Louis, as part of the university’s source article on the stimulus package, give us better guidance for policy.
The No. 1 source of COVID-19 (73.8%) according to a contract tracing study of 46,000 cases, released by Gov. Andrew Cuomo of New York, was household/social gatherings. Restaurants and bars only accounted for (1.4%) of cases; but, by shutting down restaurants and bars and forcing people to get together in homes, the good governor may have put people at a 50 times greater risk. Most restaurants have put in mitigation measures, including table distancing, etc., rarely found in homes.
People engaged in outdoor work or activities have almost no chance (all well under 1%) of acquiring COVID-19 from the activity. This would also apply to outdoor dining when people are placed several feet from each other. Going to church and other religious activities account for very few cases – and, if some social distancing is practiced, the risk is almost nil – much less than being in most government office buildings (as a Los Angeles study showed).
As of Nov. 28, “CDC weekly death data indicates there have been 338,277 more U.S. deaths in 2020 than in 2019. While 245,075 are due to COVID, another 93,202 come from other causes … it appears COVID policies caused people to defer health care and those deferrals caused a 3.3% increase in non-COVID deaths relative to last year.” (Note, none of the death data should be viewed as being precise because of the different definitions and standards from jurisdiction to jurisdiction — but they do give us a good indication of the overall trends and problems.)
School closures have been very harmful. One sound study “finds substantially lower math performance in standardization test scores in Fall 2020 versus Fall 2019, particularly at lower grades.” The risk of death from COVID-19 for children 5-14 is almost “non-existent” with only 48 out of 41.2 million children of that age dying from COVID-19 — i.e., 0.0001%, while four times as many died from homicide.
Shutdowns appear to flatten the curve, but do not reduce total COVID-19 deaths. Ms. Knott notes that Sweden and Los Angeles County have about the same population, but Sweden did relatively little in intervention, and “L.A. County has had draconian interventions.” “COVID deaths in Sweden were almost double those of L.A. in May, L.A. deaths now exceed those in Sweden … L.A.’s restrictions have flattened the curve but they didn’t reduce total deaths.”
Florida and California provide another example where the growth in COVID-19 deaths is similar, even though Florida has a much higher percentage of the population over 65 (22% compared to 14.9%). Florida has had far fewer restrictions than California, including Disney World in Florida, which is open, while Disneyland in California is closed. “Not surprising, both Sweden and Florida have had milder contractions in GDP than California,” and far less economic hardship.
Death rates should rapidly decrease over the next three months as most of the most vulnerable (i.e., elderly with underlying conditions) are vaccinated.
There are estimates that perhaps 1% of the population (3 million or so) are currently infectious. Even so, most of them will not infect others with only short duration, casual contact. Meeting with a handful of people or so at a reasonable distance, including dining, does not put a person in undue risk. But until you know that you are immune, it is best to stay away from large groups in in-door settings, and make sure you have adequate levels of vitamin D and zinc.
People achieve immunity by having had COVID-19 or having asymptomatic immunity. Many people have innate immunity coming from things such as vaccines for related diseases or other past diseases. The combination of all of those who are immune for various reasons may be actually closer to the herd immunity level than is commonly believed.
It would be wise to greatly expand testing for antibodies so as not to waste limited supplies of vaccines. Those with the antibodies should be encouraged to go back to normal life in terms of work, travel and recreation, both for their own and the country’s economic well-being, and their mental health.