Expert Says It’s Possible to Reach COVID-19 Herd Immunity in US by June


Although challenges around COVID-19 vaccine production and delivery have been addressed and improved in recent months, problems have continued in the implementation of a national vaccination program.

Two main challenges around coronavirus disease 2019 (COVID-19) vaccination have been increasing vaccine production and delivery, but both of these areas have been addressed and improved in recent months, according to Mark McClellan, MD, PhD, at the Society for Advancing Business Editing and Writing Healthcare 2021 virtual symposium.

However, problems have continued regarding the implementation of a national vaccination program. McClellan explained that the struggles the country is facing in this area are not unusual in light of the country’s history implementing large-scale health care campaigns, such as the Affordable Care Act or Medicare Part D.

“I was in government for creating Medicare Part D, and we had big bumps initially in connecting data systems and reaching people and other public health responses, which again have never been at this scale, but similar issues did arise,” McClellan said.

McClellan noted that he hopes the country is learning how to make these national health care campaigns more efficient as the United States continues to face these problems during the COVID-19 pandemic.

“Hopefully we’re learning. I just want to make sure at this point that we’re not only thinking about how to get the vaccination capacity up and deal with that excess demand but anticipating these additional issues that are going to come if we’re successful in that first part,” McClellan said. “This needs to be complimented by really filling in the steps to address questions that that big swath of Americans who aren’t sure about vaccination need addressed so they can make a confident individual decision.”

However, McClellan explained that despite issues around vaccine hesitancy, it should be possible to vaccinate 30% to 40% of the population without too much additional work beyond addressing logistical issues regarding the total supply of vaccine available, especially in light of the fact that 10% of the population have already been vaccinated.

“Hopefully that can happen over the next couple of months,” McClellan said. “Then there’s another 30% that really does want to be confident about being able to contain spread throughout all of our communities [in] the United States and get the burden down on hospitals.”

Once the vaccination numbers are high enough, McClellan noted that the next big challenge will be to begin the process of reopening schools and other group environments, which will only be possible once there’s a higher level of widespread containment of the virus.

“This is going to be where we’ll need to focus in the coming weeks and be ready for that,” McClellan said.

Yet, it won’t be necessary to get to an 80% or 90% vaccination rate in the country before there is a real impact on containing the pandemic and all of its consequences, McClellan explained.

“Thirty percent of Americans have probably already been infected, and a lot of those are unfortunately in groups that are hesitant about or don’t want the vaccine, so a lot of people that are getting vaccinated are people who disproportionately haven’t been infected yet,” McClellan said.

If both of these groups are combined in estimations of the results of both immunity and vaccinations, a real decline in both spread and hospitalizations should be sustainable.

“But we have still some very important work to go,” McClellan said. “We could in theory have enough vaccines for all adult Americans who want them by early this summer, at the pace we’re on now. But that’s going to require a big gap to close between having the vaccines for everybody who wants them and having enough people who want them.”

McClellan also noted that the presence of the variants highlights the need to ramp up vaccinations to make sure the variants are not widely spread in the country.

“The very important thing now is: We need to get people vaccinated before those variants spread,” McClellan said. “Instead of aiming for getting to 70% herd immunity levels between vaccinations and immunity from people who have recovered by late summer, the numbers are there to potentially do it sooner by June.”

For this reason, the faster people are vaccinated, the fewer opportunities there will be for variant versions to spread and for more variants to emerge, McClellan explained. This will allow for life to begin to return to a greater level of normality soon.

“I think in a matter of months, Americans should be able to go back to doing a lot of the things that they did before. Maybe not the summer 100,000 person concerts, but more group activities, restaurants reopened, schools reopened, more businesses reopened, and more travel,” McClellan said.

This process is going to occur in steps as we reach higher levels of vaccinations throughout the country while simultaneously continuing to conduct COVID-19 testing, McClellan explained.

“If you have those things in place, the virus will still be out there and still be something to watch for mutation, but we won’t have anything like the consequences we’re having now. People won’t be going to the hospital, they won’t be losing loved ones, they won’t have to worry if they can go out and enjoy a dinner in a restaurant. So, it is going to take all of these steps to get there,” McClellan said.

However, McClellan noted that it remains important to recognize that the pandemic is a global issue, so it’s important to increase vaccination rates beyond just the United States in order to protect Americans in the long-term.

“As long as there are high rates of outbreaks in other parts of the world, there is going to be continued spread,” McClellan said. “So that’s a big job that is going to take more into next year, but I think we’re making progress, and hopefully we can keep accelerating that and have a much more normal life, not the same as pre-pandemic, but much more normal life not that far off.”


McClellan M, Cancryn A. Vaccine policy: What is the thinking behind who gets the vaccine and when? Presented at: Society for Advancing Business Editing and Writing Healthcare 2021; February 10, 2021. Accessed February 19, 2021.

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