This is the end of the season. The Vox science team usually has a little fun and puts together a list of bad ideas in health and science at the end of the year along with the end of the year. In the past, we have targeted homeopathic medicine, declaring it was time to end the relevance of the fatal Stanford prison experiment and dispel myths about climate change. This year, however, we have only one target for intellectual demolition.
At the end of 2020, let us leave behind the idea of using herd immunity acquired through natural infections as a way to combat the Covid-19 pandemic. It is a lot of words to describe a simple, terrible idea: that we can end the pandemic sooner if more people – especially young people with less risk – become infected with the coronavirus and develop immunity as a result.
In response to a pandemic, the idea is unprecedented. “Herd immunity has never been used in the history of public health as a strategy to respond to an outbreak, let alone another pandemic,” said Tedros Adhanom Ghebreyesus, director general of the World Health Organization. said in October. “It’s scientifically and ethically problematic.”
And yet it prevailed – especially in the White House.
Former White House adviser Scott Atlas (who is a neuroradiologist, not an epidemiologist) especially said he needed to do more infections. “When younger, healthier people get infected, it’s a good thing,” Atlas told the San Diego news station in an interview with KUSI-TV in San Diego in July. ‘The aim is not to eliminate all cases. It is not rational, it is not necessary if we only protect the people who are going to have serious complications. ”
Let it be clear, this is not a ‘good thing’ when young people get sick. Some of these young people may die, more may become seriously ill, and some that are not yet understood may have long-term consequences. The more people are infected, the greater the chance that rare, horrible things can happen, such as a 4-month brain arousal that tested positive for Covid-19. For this reason, it is a foolish game to try to keep infections only in young people or at low risk.
It is a bad idea to build up herd immunity through natural infections
There is an almost understandable issue as to why some people would strive for a herd immunity strategy. We are isolated from those we care about, businesses hurt, education suffered, and so did our mental health. What if we could just go back to some parts of normal life and take the risks for those who are least likely to get hurt?
This thinking proved reckless. Sweden, a country that has pursued a more permissible strategy when it comes to social distance, has the highest Covid-19 mortality rate in Europe.
And look what happened in Manaus, Brazil: the city of about 2 million people experienced one of the most serious, uncontrolled Covid-19 outbreaks in the world. Researchers now estimate that between 44 and 66 percent of the city’s population was infected with the virus, meaning that the possibility of herd immunity was reached there (another estimate linked the infection rate to 76 percent). But during the epidemic period, there were four times as many deaths as normal in Manaus for that stage of the year.
More typically, the term “herd immunity” is referred to in the context of vaccination campaigns against infectious viruses such as measles. The concept helps public health officials think through math how many people in a population need to be vaccinated to prevent outbreaks. It is not intended to be applied to control a pandemic by natural infection. Here are five reasons why:
- Although we can limit exposure to the people least likely to die from Covid-19, this group can still have devastating consequences from the infection – such as hospitalization, long-term symptoms, organ damage, missed work, high medical bills and yes, dead.
- Herd immunity is a very high standard for natural infections. There is no single perfect estimate of the percentage of the American population already infected by the virus. But by all accounts, this is nowhere near the figure needed for herd immunity to get started. The CDC now estimates that there were 91 million SARS-CoV-2 infections in the US – about 27 percent of the population (although it can be an overestimation). It will take about 60 percent of the population to achieve herd immunity. It’s a rough guess; it can be higher. So we are about halfway there. Who wants to double the destruction already caused by this virus? In the US, more than 330,000 people died. (In addition, herd immunity does not work nationwide, but community-by-community basis. In other words, some communities are still much more vulnerable than others.)
- Scientists do not know how long naturally the immunity against the virus is acquired or how often re-infections can occur. If immunity decreases and the rate of re-infection is high, it will be all the more difficult to build up herd immunity.
- By causing the pandemic to rage, we are risking the herd immunity threshold. Having reached the herd immunity threshold does not mean that the pandemic is over. “All it means is that, on average, each infection causes less than one persistent infection,” Harvard epidemiologist Bill Hanage told me. “It’s of limited use if you’ve infected a million people already.” If each infection causes an average of 0.8 new infections, the epidemic will slow down. But 0.8 is not zero. If a million people are infected at the moment herd immunity is reached, the already infected people could, according to Hanage’s example, infect another 800,000 people.
- A herd immunity strategy is likely to do more harm to some groups than others. There are several reasons why someone may experience a severe case of Covid-19. It’s not just age – conditions such as diabetes and hypertension also exacerbate the risk. So do social factors, including poverty, working conditions and incarceration.
In the U.S., severe Covid-19 deaths have affected minorities and disadvantaged populations excessively. Promoting herd immunity through coronavirus infections can further isolate these already marginalized communities from society, as they may not feel safe in a more relaxed environment. Or, worse, we risk sacrificing their health to achieve a population immunity sufficient to control the virus.
The herd immunity will soon be a good thing – due to vaccinations
Fortunately, we now have a way to build up herd immunity without the risks of infections: vaccines. Unlike the immunity conferred by an actual viral infection, immunity obtained by vaccine does not carry the cost of illness and death. Vaccinations are safe. And while they will not reverse the pandemic overnight, they will help end it.
We still have to wait hard. Vaccination of vaccines will be slow. Throughout 2020, ‘herd immunity’ was used as a shorthand for ‘let the pandemic spread’. There was also persistent and erroneous wishful thinking by some who said that herd immunity has already been achieved, or can be achieved sooner than scientists say, or can be achieved without incurring terrible losses. Yes, the economic constraints of the pandemic were and still are painful. But also true: the government could have done more to help.
Soon, herd immunity will become a good news phrase when we collectively – and safely – build on it through vaccines. As the vaccines are distributed, herd immunity will develop in a controlled, ethical manner. The pandemic will subside.
Let us not forget: the calls to build up herd immunity through infections were a terrible, terrible idea. Let us not repeat this in the future.