Exploring the Continued Need for COVID-19 Vaccines and Boosters - Episode 7
Mitchel Rothholz, RPh, MBA, and Jeff Goad, PharmD, MPH, share thoughts on COVID-19 vaccines and boosters in anticipation of an uptick in cases in the coming months.
Mitchel Rothholz, RPh, MBA: The term that a lot of folks in public health are using is fall booster reset. Let’s talk more about why they’re calling it a reset and how the new recommendation for boosters has changed. Jeff, give us some insight. We’ve got folks who’ve had their primary dose and 1 or 2 boosters. Now we’ve got the bivalent. How has that landscape changed with the new bivalent booster?
Jeff Goad, PharmD, MPH: It makes it a bit confusing for pharmacies and providers to make sure they’re using the right vaccine. We’ve already seen an enormous number of tops—gray, purple—and there’s a rainbow of files that we have to deal with. From the administration side, it increases the level of scrutiny that pharmacists and other providers need to have when administering the vaccine.
In trying to figure out the appropriate regimen for patients going forward, this fall reset we’re talking about is an immune reset. For people who had their primary series last year, who had a booster dose at the end of 2021, and who might have had one more recently if they’re over 50 years old, we can restart the immune response to this virus. Even though there has been time in between [the doses], we have what’s called anamnestic responses, or memory responses, which we can stimulate to get the immune system back up and ready. That’s the same strategy we use for many diseases and vaccine strategies. These periodic boosters will be our strategy going forward, but what it will look like a year from now is anyone’s guess.
Mitchel Rothholz, RPh, MBA: The timing of the bivalent vaccine is something that ACIP [Advisory Committee on Immunization Practices] had a lot of discussion around. There was discussion whether 2 or 3 months since your last dose of a COVID-19 vaccine is a better time frame. Give a little insight in terms of the 2-month time frame, why it was landed on, and why the fall is the focus for bivalent COVID-19 vaccines.
Jeff Goad, PharmD, MPH: Some of it is science based, and some of it is the practicality of trying to get the right data in time to make good decisions. For example, when you start to do small studies to test out a new bivalent, and then the strains suddenly change on you—you’re looking at a BA.1, but now BA.4 and BA.5 are predominant—you have to adapt your strategies. Looking at when the immune titers and antibody levels begin to fall, as we learn more about Omicron vs Delta, we saw antibody titers falling a little more rapidly. Trying to combine what we know about the immune science and the practicalities of getting vaccinations into people, 2 months was the number that we arrived at. Before, it was 4 months, so your patients certainly have questions: “How come it went from 4 months down to 2?”
As we learn more about the immune response and the durability of the immune response, it helps us more accurately pick an interval that may protect people in the short run. There were a lot of data looking at this. We use modeling systems to help predict. If you waited until November, the models suggest that you’re losing lives. People are dying if you’re going to try to time the surge. It’s like people in the markets. Trying to time the market is a fool’s errand. The models suggest that if we have the technology and the data, then we need to prepare people in case there’s a fall surge, not trying to time a fall surge.
Mitchel Rothholz, RPh, MBA: One statistic that was brought up during the ACIP discussion was that more than 100,000 hospitalizations and deaths could be prevented by doing it earlier in the fall. That was a driver in that decision as well. A lot of providers were also focused on the flu vaccine and the importance of being able to coadminister the flu and COVID-19 vaccines, but it’s pretty clear from the discussions that this isn’t a problem. You can do concomitant administration of the necessary vaccines, whether it’s flu or other recommended vaccines.
We have an opportunity to protect patients. Let’s optimize that opportunity and do that. One thing that came up—questions that the public will ask providers and pharmacists and everybody they come in contact with—is the clinical data that the decision for the bivalent vaccine was based on. There’s a model, from the flu vaccine, that has been in place for a number of years. The FDA used this in its consideration for approval of the bivalent. Could you give a little insight in terms of a comparison of how we look at the flu vaccine every season compared with the approach that was used with the COVID-19 vaccine?
Jeff Goad, PharmD, MPH: With the flu vaccine, we have more of a global surveillance system in place to help us understand what strains are circulating. All those data are collected and evaluated in the laboratory to find which strains are more likely to cross-react with more of the circulating strains. It’s a very organized system that has been in place for many years, and it helps us design a Northern and Southern Hemisphere vaccine. Do we always get it right? No, we’ve been fooled many years. But there are lots of factors for why the system doesn’t always accurately predict which strain should be in the vaccines that we make each year during the summer in the Northern Hemisphere to protect us through the winter.
The lessons learned from flu for COVID-19 include getting a surveillance system in place that’s reliable, that has enough of an early warning system. If we’re going to start to design regional approaches—I’m not suggesting we do that because data aren’t there yet to design regional approaches—we need to have a surveillance system in place that allows us to say, “A BA.2.16 sublineage emerging is going to take hold. It’s already in X number of countries and in X percent of the population. It’s at a low level in the United States.”
Unlike most flu vaccines, which are grown in eggs, mRNA technology can be adapted very quickly—within hours—to create a template to make the new vaccines. We have technology at our fingertips that allow more customized design for vaccines. As you pointed out, those pesky clinical studies take time but give people confidence that this vaccine has been tested and works in a population. We can’t skip steps. Even though we have a process that’s robust and quick, we need to make sure it works and is safe.
Transcript edited for clarity.