"Herd immunity" before an immunization would kill many and not help the economy

Today’s Managing Health Care Costs Number is 4772

There's been a lot in the news about "herd immunity" lately - and clients might ask  you. So - a brief explanation, and some thoughts about the public policy debate.

Viruses stop spreading when each person who gets the infection doesn't transmit it - which means they don't come in contact with anyone who is susceptible while contagious.  Not everyone needs to have immunity - just  enough people need immunity  so that each new infection is a 'dead end' and the virus will die out.  That's herd immunity. Estimates are that we would reach herd immunity if about 60-70% of the population were no longer susceptible to SARS CoV2, the virus that causes COVID-19.

The hope is to reach herd immunity with an effective vaccine.  That will require patience.  We need to have a safe effective vaccine, manufacture it at a massive scale, and convince hundreds of millions in the US (and billions globally) to get vaccinated. Most people think this will take much of 2021.   In the meantime, the economic losses from the pandemic worsen. It's not surprising to hear some asking "Can we just let nature take its course?"   

If we reach herd immunity by continuing to have widespread infections, we could have over 1.2 million deaths in the US alone. (320 million people * 60% infection rate * 0.65% case fatality rate).   It could be worse, too, as mortality rates appear to be much higher when the medical system is overwhelmed.  

Some look at Sweden, which alone in Europe enforced no shutdowns or distancing this winter. Sweden's initial COVID infection rate didn't look especially bad. But by summer it was clear that this approach led to 4772 more deaths than if Sweden had the mortality rate of Denmark.  Sweden is small (10.2m population).  An excess mortality rate this size would mean 150,000 excess deaths in a country the size of the United States.

Source: Time Magazine

But Sweden didn't suffer less economic damage than other Nordic countries because it initially rejected public health measures. Its GDP loss in Q2 was the worst in Scandinavia.

Source: OECD

The Infectious Disease Society of America has weighed in on this debate.

“Community immunity,” or “herd immunity,” a goal of vaccination campaigns, should never come at the cost of planned exposure to infection of millions of additional people as well as the severe illness and preventable deaths of hundreds of thousands of people.

The Lancet recently published an editorial signed by many academics:

Any pandemic management strategy relying upon immunity from natural infections for COVID-19 is flawed. Uncontrolled transmission in younger people risks significant morbidity and mortality across the whole population. In addition to the human cost, this would impact the workforce as a whole and overwhelm the ability of health-care systems to provide acute and routine care. 

There are researcherswho support achieving herd immunity through allowing infections through the "low risk" population.  Unfortunately, even those who are not older and don't have underlying illness can die of COVID-19, and it's almost impossible to keep the young and healthy who get infected away from the old and the vulnerable who they have many interactions with. 

I remain enormously hopeful that we'll have a safe effective vaccine in early 2021. Wearing masks and physical distancing can save hundreds of thousands of lives in the meantime. There's even evidence that those who wear masks who do get COVID-19 have a lower risk of serious illness.  We don't need to have 1.2 million deaths to reach the end of the pandemic.