By Thomas J. Duszynski
The light at the end of this dark COVID-19 tunnel is quickly getting brighter – but you still won’t have a normal summer.
Even as efforts to distribute and administer the COVID vaccine accelerate, the U.S. is unlikely to achieve herd immunity until mid-September. That’s even with the one-dose Johnson & Johnson /zigman2/quotes/201724570/composite JNJ +0.28% vaccine that could be authorized for use by the end of February and will provide an alternative to the two-dose Pfizer /zigman2/quotes/202877789/composite PFE +0.93% and Moderna /zigman2/quotes/205619834/composite MRNA -5.21% vaccines already being administered.
And this is the best-case scenario. It assumes we have an adequate supply of vaccine, accessible vaccination sites, staff available to provide vaccines and enough people interested in being vaccinated. Any challenges with those, and it could take longer.
Here’s the math:
About 332.2 million people live in the U.S. Using the 70% threshold that many agree would provide herd immunity, more than 249.1 million persons must be vaccinated. But because not everyone who is vaccinated will develop antibodies, we need to exceed that number to have some assurance that at least 70% will develop antibodies.
After subtracting the 73 million people living in the U.S. who are under 18, there are approximately 241.8 million individuals, which is short of the herd immunity threshold of 70%. Children under 16 years currently are not eligible for the vaccine. This is simply because this group didn’t participate in any of the clinical trials needed for vaccine approval. This is standard, and there are trials currently being conducted for them. But we still need to count this group when assessing herd immunity.
More than 27 million Americans have already received at least one dose and more than 6 million are fully vaccinated. So we still need to vaccinate more than 226.5 million to achieve the herd immunity threshold.
That goal of 226.5 million currently requires 453 million doses of vaccine (this will change if the Johnson and Johnson vaccine gets approved for use by the FDA since it only requires one dose). The U.S.’s average vaccination rate over seven days is running at just under 1.6 million a day .
In my experience, it is taking an average of 4 minutes to administer a shot, about twice as long as it takes to administer a flu shot, excluding paperwork. Assuming 10,000 vaccination stations that operate at least 8 hours per day, including weekends, it would take until Jan. 19, 2022 to reach the 70% herd immunity threshold.
If the Johnson and Johnson vaccine is approved for emergency use, the threshold can be reached in late fall. The FDA has scheduled an advisory committee meeting on Feb. 26 to discuss the matter. If the committee backs the vaccine, the FDA could decide to grant the EUA within days after the meeting.
Much of the delay in getting vaccines in arms is simply because there aren’t enough doses to meet the demand. That’s why we repeatedly hear of people frustrated by their attempts to get an appointment, which is leading to people line-jumping by claiming to be a health-care worker or just hanging out at vaccination sites hoping there are unused doses at the end of the day that shouldn’t go to waste.
Pfizer has said that it expects to deliver 200 million doses for the U.S. by July 31 and Moderna aims to deliver 200 million doses by June 30 . Johnson & Johnson has said it expects to deliver 100 million one-shot doses for the U.S. in the first half of the year , assuming it gets the regulatory go-ahead.
While these numbers suggest that the U.S. could have enough vaccines to reach herd immunity by the end of June or early July, it’s not that simple. There are other variables: the number of vaccination sites, the number of people that can be vaccinated per hour at those sites, and the number of hours those sites operate per day and administrative factors.
People also have to be willing to get vaccinated. Vaccine hesitancy, in which people are skeptical of the vaccine for a variety of reasons, may keep us from reaching that threshold that quickly. It must be countered by actively engaging with those population and offering clear, consistent recommendations from trusted sources.