News·4 min read

COVID-19 Vaccine Hesitancy and Reaching Herd Immunity

People wear face masks while walking in New York City.
Getty Images
August 23, 2021

For months, Americans 12 years and older have been eligible to get a COVID-19 vaccine. CDC data shows that as of Aug 22, about 60% of that group is fully vaccinated. And the US is inching closer to pre-pandemic life as vaccination rates increase following the introduction of the delta variant in the US.

Here’s why vaccination rates are rising… 

One more time for the people in the back: the delta variant. It’s a highly transmissible COVID-19 variant that is currently the dominant strain in the US. It has spread to at least 132 countries around the world. And caused a renewed spike in cases around the US, with hospitalization rates reaching similar levels to summer 2020. Many people who have gotten severely sick have not received a vaccine – people who haven’t rolled up their sleeves accounted for over 99% of COVID-19 related deaths in June.  

While the delta variant is widespread throughout the US, it's particularly been an issue for states with lower vaccination rates (think: Alabama, Louisiana, Mississippi) that have created dangerous pockets for the variant to spread. But data shows that the severity of the current outbreak is encouraging people to get vaccinated – with vaccination rates spiking in August (think: more than 1 million doses administered a day in mid-August, versus 800,000 a day earlier that month).

Before the rise though, the US’s vaccination campaign seemed to drastically slow down. Officials have turned their efforts to groups that are less likely to be vaccinated, including younger and minority Americans, as well as people living in rural areas. And two obstacles they have faced are…

  • Vaccine hesitancy. Regardless of demographics like age, sex, race, or political affiliation, many Americans are dealing with vaccine hesitancy. Some were waiting for one of the vaccines authorized for emergency use to get full FDA approval. And on Aug 23, it happened. The FDA gave Pfizer its full seal of approval – making it the US’s first vaccine to reach that step. Experts believe the move could encourage some Americans to get the shot and businesses and governments to impose vaccine mandates. Others are hesitant after consuming misinformation, or not enough info, about the vaccines. (Btw, an expert from Johns Hopkins breaks down the facts here). Minority communities may also be hesitant to get a shot, rooted in mistrust in a health care system where systemic racism exists. Experts say convincing Americans who fall in these buckets to get a shot could be a challenge.

  • Accessibility. In April, President Biden said that 90% of Americans are within five miles of a vaccination site. But some people haven’t been able to get a shot because of things like scheduling conflicts (think: taking time off work), transportation limitations, or they don’t have internet access to book an appointment. In an effort to make things easier, many places have walk-in sites where people don’t need to make an appointment for their vaccine. In July, Biden also announced changes to the federal vaccination campaign that put more of an emphasis on communities, including door-to-door outreach and setting up vaccine sites at workplaces. PS: You can find vaccine sites in your area here.

Efforts are already underway to try to solve these problems. And businesses, cities, and states are offering incentives ranging from free beer and donuts to $100 and savings bonds for anyone who gets vaccinated. But this likely won’t be enough to get every single eligible American to get a shot – which officials see as a barrier to achieving herd immunity.

Here’s what you should know about herd immunity…

Herd immunity happens when a large part of a community becomes immune to a disease, making community spread less likely. While it hasn't been clear when the US could reach herd immunity when it comes to COVID-19, experts have predicted that anywhere between 70-90% of the population would need to be immune to hit that point.

The not-so-good news: experts now say it’s not clear when – or even if – the US will reach herd immunity. A report from The New York Times says the virus will instead continue to be a threat, but at a lesser level. All of this depends on how much of the country (as well as the world) becomes vaccinated, and how variants continue to spread. Another potential twist in all this: we don’t know exactly how long vaccine immunity lasts (though US health officials have said people who got Pfizer or Moderna vaccines should get a booster eight months after their second shot). But the CDC is leading a number of studies on vaccine effectiveness, to make sure that COVID-19 vaccines are working as they should. Even if the US doesn’t reach herd immunity, experts say vaccinations and keeping infection rates low will still play an important role in getting closer to normalcy.


Every day, the US continues to make more progress in the fight against COVID-19. But the delta variant is causing a bump in the road. While it’s too soon to know if vaccination rates will continue to stay on the up and up, experts hope the FDA approval of Pfizer’s vaccine will encourage more people to roll up their sleeves. The more we can mitigate the spread of the virus, the faster we can potentially return to pre-pandemic life.

Updated on Aug 23 – Updated to include the FDA's full approval of the Pfizer vaccine.

Updated on Aug 10 – Updated to include the latest information on vaccination rates, vaccine hesitancy, and herd immunity.

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