COVID-19 Herd Immunity Unlikely This Year

One of the most important concepts in infectious diseases is herd immunity. This term refers to a situation in which enough people in a group — locally or in an entire country, or even the world — are immune to a particular infection, either because they’ve had it and developed natural immunity, or because they’ve gotten a vaccine.

Early in the COVID-19 pandemic[1], there was some discussion by certain health experts about potentially stopping the spread of the virus through natural herd immunity. This would require identifying people likely to develop severe illness if they got COVID-19, isolating them from the rest of the population, and then encouraging the spread of the virus in the remaining population. This strategy was quickly dismissed by most experts, since even under the best scenarios, it was projected to result in many more deaths than have already taken place due to COVID-19.

To get cutting-edge diabetes news, strategies for blood glucose management, nutrition tips, healthy recipes, and more delivered straight to your inbox, sign up for our free newsletter[2]!

But herd immunity through vaccination is the goal of most vaccination programs, and has always been the goal of vaccine distribution for COVID-19. This means that if enough people get vaccinated, the virus stops spreading in the community — and even people who haven’t been vaccinated are protected from the disease as a result.

Unfortunately, based on current projections, experts say it’s unlikely the vaccine rollout in the United States will happen fast enough to achieve herd immunity by the end of 2021.


Vaccination off to a slow start

While the United States has already vaccinated a greater share of its population than most countries, it still faces the daunting challenge of vaccinating a large population through many different health systems, as noted in a Reuters[3] article on an expert panel discussion at the Reuters Next conference earlier this month.

As of January 14, an estimated 3.37% of the U.S. population has received a COVID-19 vaccine. This is a far cry from what would be needed to achieve herd immunity — a number that experts disagree on, but which is widely believed to be in the ballpark of 90%. Four countries are ahead of the United States in percent of people vaccinated: Israel at 24.96%, United Arab Emirates at 15.45%, Bahrain at 6.44%, and Britain at 4.94%.

Even at the currently estimated “best case” pace of vaccination, the United States and the world won’t get back to normal anytime soon, according to Dale Fisher, chairman of the World Health Organization’s Outbreak Alert and Response Network. He told the conference that for the pandemic to be brought to an end, “We know we need to get to herd immunity, and we need that in a majority of countries. So we are not going to see that in 2021.” If some countries somehow do manage to achieve herd immunity this year, “even then that will not create ‘normal’ especially in terms of border controls,” he notes.

Another potential problem, Fisher added, is that as the virus responsible for COVID-19 continues to mutate, current vaccines could become less effective or ineffective. This situation might require developing and distributing new vaccines, a massive challenge that would involve further testing and trials as well as production and distribution.

Another expert at the conference, Pandu Riono, an epidemiologist at the University of Indonesia, stated his view that many governments are too reliant on vaccines in their plans to get the pandemic under control. Instead of simply waiting for enough people to be vaccinated as the pandemic rages on, governments could be putting more resources into expanding testing and contact tracing — as well as putting stricter restrictions on behavior in place when needed. Using these existing tools to maximum effect could reduce illness and death while allowing for a faster return to normal.

Travel restrictions lack consistency

One reason why herd immunity will need to be achieved in most countries is that current restrictions on international travel aren’t consistent from country to country, or even from airline to airline. While some countries require a negative test result for COVID-19 in incoming travelers, other countries don’t — and even this restriction will inevitably fail to prevent some people with the virus from entering.

While some airlines have proposed requiring a COVID-19 vaccine to travel at some point — including Australia’s Qantas Airways — other airlines have no such plans. And Gloria Guevara, chief executive of the World Travel and Tourism Council, told the conference that such restrictions amounted to discrimination, given the lack of universal access to a vaccine. “We should never require the vaccination to get a job or to travel,” she stated, adding that the travel sector accounts for as much as 10% of global employment.

The key to making global travel safe, she added, is putting global testing protocols for COVID-19 in place, and doing so as quickly as possible. This view was supported by statements from Tony Fernandes, CEO of AirAsia Group, at the conference.

So far, the Reuters article notes, over 90 million people worldwide have developed COVID-19, and about 1.9 million people have died from the viral infection.

Want to learn more about coronavirus and diabetes? Read “Coronavirus and Diabetes: A COVID-19 Update,”[4] “Healthy Eating During Hard Times”[5] and “COVID-19: Staying Safe at Work.”[6]

  1. COVID-19 pandemic:
  2. sign up for our free newsletter:
  3. Reuters:
  4. “Coronavirus and Diabetes: A COVID-19 Update,”:
  5. “Healthy Eating During Hard Times”:
  6. “COVID-19: Staying Safe at Work.”:

Source URL:

Disclaimer Statements: Statements and opinions expressed on this Web site are those of the authors and not necessarily those of the publishers or advertisers. The information provided on this Web site should not be construed as medical instruction. Consult appropriate health-care professionals before taking action based on this information.