Americans calling for herd immunity should look at Sweden's coronavirus experiment to see why it wouldn't work

• Some Americans are pushing herd immunity as a way to reopen the economy in the United States.
• The concept of herd immunity is to stop the transmission of a virus through mass infection — the more people who have antibodies, the quicker mass immunity to the virus will be reached.
• But the long-term immunity of COVID-19 remains unknown, and reaching herd immunity could lead to more deaths.
• Health officials have called herd immunity dangerous, and something that could take years to reach without a vaccine.
• Sweden's approach to the novel coronavirus seems to rely on herd immunity, and as a result it has kept businesses open throughout the pandemic.
• Visit Business Insider's homepage for more stories.

As Americans agitate to reopen the economy in the middle of the coronavirus pandemic, some of them are looking at one strategy to make it feasible: herd immunity.

You don't need to look further than Sweden's anti-lockdown experiment to see why that wouldn't work.

Sweden has taken a controversially relaxed approach to COVID-19. It has not initiated a nationwide lockdown to flatten the curve. Instead, Sweden seems to be pinning its hopes on herd immunity to stop the transmission of the virus through mass infection.

The idea is, if more people are infected and obtain antibodies, people will eventually gain immunity to the virus. The country has kept restaurants, schools, and gyms open, while urging its residents to social distance and wash their hands.

In the United States, the Trump administration has refused to set nationwide distancing rules, leading to scattershot lockdown and reopening efforts.

States across the US issued stay-at-home orders back in March, and several governors are starting to reopen businesses — which, if done too early, could put residents at risk of COVID-19 surges. Some people calling for economic reopenings, as well as anti-vaccine advocates, have pushed for herd immunity as a way out.

But scientists have called it dangerous rhetoric, saying that in the years people would have to wait for herd immunity to be achieved, hundreds of thousands more people could die from COVID-19. And beyond that, it remains unknown if antibodies from COVID-19 even result in longterm immunity.

No country in the world has reached herd immunity to COVID-19

Data suggests that no place on Earth has reached herd immunity to the coronavirus — less than 10% of the world has been exposed to the virus, according to estimates.

Experts say herd immunity requires 50 to 70% of the population to be exposed to the virus. Business Insider's Hilary Brueck reported that without a vaccine it could take four to five years to reach that point.

In those four or five years, hundreds of thousands of more people could die from COVID-19. And scientists are still uncertain if a COVID-19 infection even leads to immunity.

As of Friday morning, Sweden, which has a population of 10.23 million, had 29,207 confirmed cases of COVID-19, and 3,646 deaths from the virus — a death rate of 35.64 deaths per 100,000 people.

The US, meanwhile, has had 1.45 million confirmed COVID-19 cases and 86,607 deaths from the virus. With a population of 328.2 million, it has a death rate of 26.3 deaths per 100,000 people.

Health officials have called the concept of herd immunity 'dangerous'

Epidemiologists at Johns Hopkins University has called the concept herd immunity a "dangerous misconception," and said the US remains vulnerable to the virus. The World Health Organization, too, criticized the idea of herd immunity on Monday.

"This idea that, 'well, maybe countries who had lax measures and haven't done anything will all of a sudden magically reach some herd immunity, and so what if we lose a few old people along the way?' This is a really dangerous, dangerous calculation," WHO's Executive Director of Health Emergencies Mike Ryan said.

Ryan told reporters that humans "are not herds," and such plans around building immunity would only lead to more death.

"I think we need to be really careful when we use terms in this way around natural infections in humans, because it can lead to a very brutal arithmetic which does not put people, and life, and suffering at the center of that equation," he said.

The creator of Sweden's coronavirus plan even said even he isn't convinced it's working

The architect behind Sweden's coronavirus plan even said he's not sure if the relaxed approach is working.

"I'm not convinced at all," Anders Tegnell, Sweden's state epidemiologist, told the Swedish newspaper Aftonbladet on May 1.

On Tuesday, Sweden even changed one aspect of its COVID-19 strategy, after seeing a high death rate in Swedish nursing homes. Prime Minister Stefan Lofven's office announced that it would spend about $220 million (2.2 billion kronor) to help protect elderly people in nursing homes from the novel coronavirus.

Sweden and the US are both among the top 10 countries with the highest number of deaths per capita from COVID-19, according to data from Satista. Based on the data, Canada has nearly half the death rate of the US, at 15.1 deaths per 100,000 people.

And while Sweden is more densely populated than other Nordic countries, its neighbors' death rates per capita are much lower — Norway has a rate of 4.32 deaths per 100,000 people, and Finland has a rate of 5.2.

Other nations, including Spain and Italy, have higher death rates per capita than the US and Sweden. Both countries have older populations, which affects the death rate, along with other factors such as testing availability.

Emily Toth Martin, an associate professor of epidemiology at the University of Michigan School of Public Health told Business Insider reporter Anna Medaris Miller that the only way to gain herd immunity from the virus is through a vaccine.

"This is not just about getting through the current crisis," she added. "If this virus stays around, we need a vaccine to prevent resurgences in future generations."