The Unsung Vaccine Ingredient That Could Help Protect More People Against Covid-19
Experts say so-called adjuvants in Covid-19 vaccines could enhance the immune response and produce longer-lasting immunity
It may seem like overkill that there are currently at least 29 Covid-19 vaccines in clinical trials, all of them designed to train the immune system to fight the coronavirus by recognizing a single protein, called spike (S), on its surface. But what sets all these candidates apart from one another is the various ways they deliver S protein, and whether they contain so-called adjuvants — special molecules that rev up the immune response against the coronavirus.
Many of the vaccine candidates that were the first to enter clinical trials actually don’t contain adjuvants because they already have some built-in immune-boosting activity. For example, the Pfizer vaccine, which appears to be 90% effective according to recent preliminary analysis, contains genetic material (mRNA), which has some inherent immune-stimulating power, and cranks out S protein once inside the body of the vaccinated person to coax the same kind of immune response (or better) as a natural infection would cause. The big benefit of this technology was speed of development and production, and adding anything extra to the formula, such as an adjuvant, could have cost valuable time in preparing the vaccine for testing.
But now that dozens of other vaccine candidates are in clinical trials and hundreds more are in lab studies, researchers are increasingly asking if adjuvants can do for Covid-19 what they have been doing for other vaccines for decades: enhance and guide the immune response, produce longer-lasting immunity, and lower the cost.
“What we probably will find out is that many of these adjuvants create a better vaccine, and they are all better a little differently, but they are all useful.”
“We will see waves of different vaccines coming out that have different adjuvants,” says Richard B. Kennedy, PhD, professor of medicine at Mayo Clinic in Rochester and co-director of its Vaccine Research Group. “What we…