Tips From Harvard

We Need a Radically Different Approach

This excellent article is an interview with two Harvard Professors published in Jacobin Magazine, who describe themselves as “a leading voice of the American left“. I make this distinction because of the accusations of political ideology which often frame perceptions of challenging opinions. Francois Balloux tweeted this today, which highlights the phenomenon:

I consider myself as a mainstream scientist believing in the values of the ‘enlightenment’. Politically, I’m slightly left of centre. It’s been an interesting experience to be widely framed at best as a contrarian, and at worst as a far-right libertarian crackpot during #COVID19.

I’ve copy-pasted a short portion of the article below, which is of particular interest to me after a dinner debate last night with people who are very convinced that lockdown is an evidence-based response; that a vaccine is the only way out of lockdown; that the term “herd immunity” is akin to a form of genocide; and that for herd immunity to even occur, 95% of people will need antibodies. Yet evidence on Covid-19 immunity is far more complex than this, as Covid-19: Do many people have pre-existing immunity?, published in the British Medical Journal, outlines.

Beyond what I have shared below, the article discusses other aspects of the pandemic worth learning about. Especially why and how to implement an age-targeted public health approach which can protect those at risk of Covid disease whilst simultaneously protecting those at risk of the impacts of lockdown. This is surely the way forward.

Katherine Yih is a biologist and epidemiologist at Harvard Medical School where she specializes in infectious disease epidemiology, immunization, and post-licensure vaccine safety surveillance. Yih is also a founding member of the New World Agriculture and Ecology Group, a former and current member of Science for the People, and a long-time activist in farm labor and anti-imperialist struggles.

Martin Kulldorff is a professor of medicine at Harvard Medical School. Kulldorff has developed methods for the detection and monitoring of infectious disease outbreaks which are used by public health departments around the world. Since April, he has been an active participant in the COVID-19 strategy debate in the United States, his native Sweden, and elsewhere. This interview has been lightly edited for clarity.

The uncertainty surrounding the coronavirus has convinced many policymakers, at least in the United States, that the best course of action is to stay at least partially locked down until a vaccine is developed. What are your thoughts? Is it wise to wait for the vaccine?

Katherine Yih:

I don’t think it’s wise or warranted to keep society locked down until vaccines become available. There are nine vaccines in large-scale efficacy trials as of mid-September 2020, and my guess is that at least one will be approved for use in the United States by some time in 2021. But this is not certain to happen. Furthermore, neither the effectiveness nor the duration of immunity from any of these vaccines is known as yet.

There are additional uncertainties about how many vaccines can be manufactured, distributed, kept at the requisite temperatures, and administered in a short amount of time after authorization or licensure, and whether a sizeable portion of the population will refuse vaccination. So we can hope but we certainly can’t count on a vaccine saving us either as individuals or as a population in the short term.

Regarding policy, early in the US epidemic, based in part on the experiences of Italy and Spain, the urgency of “flattening the [epidemiologic] curve” was emphasized. It was indeed crucial to take steps to ensure that hospitals and health care resources not be overwhelmed, as they very nearly were in parts of New York City, for instance.

But I have been struck by how this emphasis on keeping the numbers down at all costs has not evolved with time. There is a kind of simplistic goal of keeping people from getting infected, period. Now this may seem like a worthy goal, but with a highly contagious respiratory virus to which most of the world’s population is probably still not immune, people are going to get infected. The virus will spread, quickly or less so, until herd immunity is reached.

Instead of a medically oriented approach that focuses on the individual patient and seeks (unrealistically) to prevent new infections across the board, we need a public health–oriented approach that focuses on the population and seeks to use patterns, or epidemiologic features, of the disease to minimize the number of cases of severe disease and death over the long run, as herd immunity builds up.

Martin Kulldorff:

We will have a vaccine sometime between three months from now and never, and we must do our utmost to protect older high-risk individuals until then. The US Food and Drug Administration (FDA) criteria for a successful vaccine is 95 percent confidence that it is effective in at least 30 percent of the recipients. Hence, if and when a safe vaccine is approved, it may not be able to protect us on its own, without the help of some immunity from natural infections.

Children and young adults have minimal risk, and there is no scientific or public health rationale to close day care centers, schools, or colleges. In-person education is critically important for both the intellectual and social development for all kids, but school closures are especially harmful for working-class children whose parents cannot afford tutors, pod schools, or private schools.

The vaccine and “herd immunity” are often presented in opposition to each other in strategic discussions, with the latter evoking viscerally negative reactions. . .

Martin Kulldorff:

Somehow, herd immunity has become a toxic phrase, which is strange, since it is a scientifically proven phenomenon just like gravity. Except for the occasional skier, people do not argue for or against gravity. Whatever strategy we use for COVID-19, we will eventually reach herd immunity, either with a vaccine, through natural infections, or a combination of the two.

So, the question is not whether we get to herd immunity or not. The issue is how to get there with the minimum number of casualties. We do not know what percent immunity to the coronavirus is needed to achieve herd immunity, but we do know that if there are many older people in the group that is infected, there will be many deaths. On the other hand, if mostly young people are infected, there will be very few deaths.

Katherine Yih

I think the visceral reaction is against the notion that societies should do nothing and just let the virus spread unchecked throughout the whole population, thereby achieving herd immunity quickly, and killing a lot of older and vulnerable people along the way. The mere mention of “herd immunity” seems to conjure up this reckless, let-her-rip approach in people’s imaginations.

But herd immunity is something that simply happens with infectious diseases — when enough people have been infected (or vaccinated) and become immune, the pathogen is sufficiently blocked by the immune people that it can no longer spread in the population (although it doesn’t necessarily go extinct, due to newly susceptible people entering the population and importations of the pathogen from other human populations).

Herd immunity can be achieved by natural infection, effective vaccination, or a combination of the two. And the process of getting to herd immunity can be managed in such a way that the more vulnerable people are protected from infection while others help the population reach herd immunity, thereby minimizing the number of deaths.

Further, if many of us incorporate fairly sustainable measures like frequent handwashing into our daily lives, the proportion infected needed for herd immunity will be less than otherwise. Laissez-faire is certainly not the only way and certainly not the responsible way to get there.

One thought on “Tips From Harvard

  1. I have seen it suggested that herd immunity for Covid could be as low as 20 percent. The level at which herd immunity is achieved is surely an important consideration for deciding policy. Yet the idea of herd immunity is constantly kicked into the long grass as if irrelevant. Not looking is a great way of not finding the answer. Seems the political class don’t want facts to get in the way of their agenda – whatever that is.


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