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Experts say COVID-19 herd immunity will be difficult to achieve unless more of the world gets vaccinated. Lana Stock/Getty Images
  • Experts say herd immunity is an increasingly elusive goal when it comes to COVID-19.
  • While the United States is making progress with vaccinations, there’s still a long way to go.
  • On a global scale, a small percentage of people have been vaccinated.
  • Until a majority of Americans are vaccinated, it’s still best to follow mask wearing and physical distancing guidelines.

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our coronavirus hub and follow our live updates page for the most recent information on the COVID-19 pandemic.

For a nation weary of the COVID-19 pandemic, the promise of vaccinations — and, eventually, herd immunity — has been the light at the end of the tunnel.

More than 40 percent of all people in the United States as well as more than half of adults have received at least one vaccine dose.

However, herd immunity, which would result in the coronavirus eventually fading away, remains a trickier proposition

And one that experts say seems increasingly unlikely.

“Herd immunity is the idea that once a certain percentage of the population is immune to an infection, the infection can no longer spread within the population,” explained Dr. James Wantuck, the chief medical officer of PlushCare, a provider of virtual primary care.

“The thinking is that even though not 100 percent of the population is immune, there aren’t enough people left to spread it for the infection to sustain itself, meaning it simply disappears from the population over time. This is how we have eradicated some infections, like smallpox, through a mass vaccination program,” Wantuck told Healthline.

So far, the vaccination program in the United States has been successful.

And while the prospect of the coronavirus dying out through a combination of vaccinations and herd immunity is appealing, the nation’s top doctor is urging caution.

Earlier this month, Dr. Anthony Fauci said in a White House briefing that, in the COVID-19 context, it’s difficult to define what exactly would constitute herd immunity.

“Rather than concentrating on an elusive number, let’s get as many people vaccinated as quickly as we possibly can,” Fauci said.

Analyzing the numbers through a U.S. lens shows signs of clear progress. But global numbers are a different story.

Dr. Tom Kenyon, the chief health officer at Project HOPE and a Centers for Disease and Control and Prevention (CDC) trained epidemiologist who spent more than 2 decades at the CDC, told Healthline that vaccinations have been working.

But he noted that we have a long way to go.

“We should not let ourselves be misled by this early domestic progress when the majority of Americans remain unvaccinated — and when only 3 percent of the global population has been fully vaccinated,” he said.

Kenyon noted that, at current vaccination rates, only 10 percent of people in the majority of developing countries will be vaccinated in the next year.

“The global vaccine inequity needs to be addressed because it is the right thing to do from a humanitarian standpoint but also to prevent the global proliferation of other variants that threaten the usefulness of current diagnostic tests, therapies, and vaccines,” he said.

Because of the slow rate of vaccinations in much of the world and the emergence of coronavirus variants, it seems increasingly unlikely that herd immunity will be able to stop the coronavirus in its tracks.

While it’s understandable that people want to get back to a sense of normalcy, experts say the best practice is to continue in pandemic mode for the time being.

Kenyon said that everyone who’s able to get vaccinated should do so as soon as possible while continuing to wear masks and physically distance around people who are not vaccinated.

“One thing is clear: This pandemic is far from over,” Kenyon said. “Crushing waves of new cases are on the horizon if we behave recklessly, such as the recent lifting of mandatory mask mandates by some governors and the large public gatherings we witnessed over spring break.”

“Recurrent spikes in cases have always followed the premature abandonment of public health precautions,” he added. “Hospital beds are again filling to capacity, which is why health experts are begging U.S. residents to wear masks and socially distance from others until most people are vaccinated.”

Kenyon concluded by stressing that the pandemic cannot be controlled locally if it goes unchecked globally.

“It’s dangerous for any country or community to behave as though it’s in the clear if the science, numbers, and facts say the opposite,” he said.

“It is not only our human imperative to make vaccines accessible to all countries faster and in sufficient quantities,” Kenyon said, “but also our only viable way out of this global health crisis.”