Johns Hopkins Med School Prof: Herd Immunity by April

"Some medical experts privately agreed with my prediction that there may be very little Covid-19 by April but suggested that I not to talk publicly about herd immunity because people might become complacent and fail to take precautions or might decline the vaccine. But scientists shouldn’t try to manipulate the public by hiding the truth. As we encourage everyone to get a vaccine, we also need to reopen schools and society to limit the damage of closures and prolonged isolation. Contingency planning for an open economy by April can deliver hope to those in despair and to those who have made large personal sacrifices."

Dr. Makary is a professor at the Johns Hopkins School of Medicine and Bloomberg School of Public Health, chief medical adviser to Sesame Care, and author of “The Price We Pay.”

 

The Wall Street Journal carries a piece today that explains how we will have herd immunity from Covid by April. I hope you can access it.  

Here are some excerpts:

Amid the dire Covid warnings, one crucial fact has been largely ignored: Cases are down 77% over the past six weeks. If a medication slashed cases by 77%, we’d call it a miracle pill. Why is the number of cases plummeting much faster than experts predicted?

In large part because natural immunity from prior infection is far more common than can be measured by testing. Testing has been capturing only from 10% to 25% of infections, depending on when during the pandemic someone got the virus. Applying a time-weighted case capture average of 1 in 6.5 to the cumulative 28 million confirmed cases would mean about 55% of Americans have natural immunity.

Antibody studies almost certainly underestimate natural immunity. Antibody testing doesn’t capture antigen-specific T-cells, which develop “memory” once they are activated by the virus. Survivors of the 1918 Spanish flu were found in 2008—90 years later—to have memory cells still able to produce neutralizing antibodies.

Researchers at Sweden’s Karolinska Institute found that the percentage of people mounting a T-cell response after mild or asymptomatic Covid-19 infection consistently exceeded the percentage with detectable antibodies. T-cell immunity was even present in people who were exposed to infected family members but never developed symptoms. A group of U.K. scientists in September pointed out that the medical community may be under-appreciating the prevalence of immunity from activated T-cells.

Covid-19 deaths in the U.S. would also suggest much broader immunity than recognized. About 1 in 600 Americans has died of Covid-19, which translates to a population fatality rate of about 0.15%. The Covid-19 infection fatality rate is about 0.23%. These numbers indicate that roughly two-thirds of the U.S. population has had the infection.

In my own conversations with medical experts, I have noticed that they too often dismiss natural immunity, arguing that we don’t have data. The data certainly doesn’t fit the classic randomized-controlled-trial model of the old-guard medical establishment. There’s no control group. But the observational data is compelling.