COVID-19 Vaccine Boosters: Roadblocks, the Future, and Communicating the Benefits to Patients

Watch the Peer Exchange series, "COVID-19 Expectations on the Roll-out of Booster Shots," here.

Increasing uptake of the initial series of COVID-19 vaccines is important for potentially reaching the stage of chronic endemicity. However, communicating to the general public about the benefits of vaccination and the uncertainty inherent in the scientific research, along with the rapidly changing eligibility criteria for COVID-19 boosters, are ongoing challenges.

In a recent Contagion® Peer Exchange moderated by Peter L. Salgo, MD, panelists discussed strategies to communicate the benefits of COVID-19 vaccination (initial series and booster shots), barriers to increasing uptake of COVID-19 boosters, and needs for improving global access to COVID-19 vaccination.

COMMUNICATING THE BENEFIT OF COVID-19 BOOSTER SHOTS TO PATIENTS

Communicating to patients that COVID-19 boosters are recommended (although not mandatory) and are most appropriate for individuals with compromised immune systems (because of older age or a medical condition) who are more likely to have protection wane over time, according to Donald J. Alcendor, PhD. However, he added that the ability of the current vaccine to protect against most variants of concern (including the Omicron variant, to some extent) is promising. “In the long run, what we will have is a virus that will become endemic in our population,” Alcendor said. “The idea of thinking we can chase variants with boosters is a failed effort. We must realize that.”

Salgo added that recommendations are often based on population data and change frequently over time, which can be difficult for the general public to comprehend. “It’s not always A plus B equals C; A plus B usually equals C, and it’s pretty good within a statistical variability, but it’s not the same,” Salgo said. “It sounds to me as if some of what we’re hearing [regarding] the waffling on the messaging is not waffling at all. Rather simply, medicine is as good as it can be and never will be much better than that.”

Communicating uncertainty and basic concepts about infectious disease and immunity, including how vaccines work and how viruses are transmitted, replicated, and mutated, to the general public has been an ongoing challenge throughout the COVID-19 pandemic, Angela Rasmussen, PhD, explained. “When a broad public health recommendation is made, when you’re trying to make those recommendations on the fly in the face [of] a lot of uncertainty, and when there’s a whole giant peanut gallery criticizing the public health agencies’ every move, it becomes very challenging to get it right every time,” Rasmussen said.

Rasmussen added that the politicization and misinformation on public health practices related to the COVID-19 pandemic has added another roadblock to public engagement with complex topics. “Most people I’ve talked to just want to be safe and want this pandemic to be over,” she said. “It’s just a really challenging environment to be dealing with all these different moving parts and try to chart the correct path through all this.”

COVID-19 BOOSTER ROADBLOCKS

The frequent changes in eligibility criteria have made it difficult for everyone—from the general public to the individuals administering the vaccine—to keep track of who can obtain a booster, Alcendor said. He added that individuals may show up to vaccine events without knowing whether they are eligible for a booster, and some underserved populations may have difficulty finding boosters. The lack of interest in boosters (or initial series doses) is also a major problem, and administration of first and second vaccine doses to unvaccinated individuals should be prioritized, Alcendor said.

Jason C. Gallagher, PharmD, FCCP, FIDP, FIDSA, BCPS, added that COVID-19 vaccine boosters are in relative oversupply, with vaccination sites shifting from large sites to small clinics and pharmacy chains. He also said mandates for boosters are less important than those for the initial vaccine series, and the major goal is to deliver the initial series to as many individuals as possible to improve community protection.

Rasmussen said hospitalization rates are likely to be lower in immunized populations, and individuals will be exposed to the spike antigen from SARS-CoV-2 (whether through vaccination or infection), but immunity from infection can be highly variable and short-lived. “We also expect this virus to become endemic, which means we’re not going to be rid of it anytime soon,” Rasmussen said. “In the United States, we’ll eventually move from being in constant crisis mode to a more ‘normal’ [state]. In other parts of the world, that process is going to take different periods of time, [which] has to do with vaccination.”

Rasmussen also cautioned that SARS-CoV-2 is a zoonotic virus that can infect many species, including white-tailed deer, cats, and raccoons, and zooanthroponotic transmission (in which the virus is transmitted from humans to animals to humans) remains a key concern. Notably, the Omicron variant is evolutionarily different from other SARS-CoV-2 variants because it is thought to have emerged via transmission from a different animal species.

“It’s going to be very hard to predict the new variants we might be dealing with and how they might impact a vaccinated population,” Rasmussen said. “But the good news…is that the vaccines have proven to be very cross-protective against severe disease, hospitalization, and death for all the variants of concern we’ve looked at. That’s going to be the marker we’re always going to have to look to. In a year’s time, in the United States, Canada, and countries that have adequate access to vaccination—we’ll stop living in acute pandemic times and move into the chronic phase of endemicity.”

Rasmussen predicted that the United States is likely to achieve some level of herd immunity in the next 1 to 2 years from a combination of vaccine- and infection-acquired immunity. “If unvaccinated [individuals] are exposed, especially if they’re reinfected and exposed multiple times to the virus, they’ll eventually develop memory immune responses,” she said. “That may be somewhere on a protective spectrum.”

COVID-19 BOOSTERS AND THE FUTURE

Alcendor said vaccinating as many individuals as possible and addressing inequities in the distribution and manufacturing of vaccines in the developing world remain key priorities moving forward. In the same way that outbreaks can occur in highly unvaccinated communities, high rates of vaccination within a community can also prevent local outbreaks, Jeff Goad, PharmD, MPH, explained.

Gallagher added that the extensive media coverage of new variants has increased awareness of the global effects of COVID-19, which may help increase the focus on vaccinating individuals in parts of the world with low access to vaccines, and Rasmussen said global vaccine equity can have altruistic and selfish purposes for high-access areas. “If we don’t want to keep playing Whac-A-Mole with different variants— constantly responding to a crisis—it’s in our best interest to [ensure] unvaccinated [individuals], whether they live in a lower middle-income country or a wealthy country like the United States, have access to vaccines,” she said. “It’s crucial that we do everything we can to get them vaccinated. At the population level, that’s our best protection.”