As we continue to navigate the COVID-19 pandemic — entering what some experts are deeming a second wave and others a mere continuation of the first — the world’s eyes are focused on the likeliest path out of this crisis: a vaccine.
We recently received some good news to this end. Among the hundreds of vaccine candidates in various stages development for COVID-19, Pfizer and BioNTech’s mRNA-based vaccine has shown to be more than 90% effective in Phase 3 clinical trials. Days after Pfizer’s statement, Moderna announced its coronavirus vaccine demonstrated 94.5% efficacy in Phase 3 trials.
While a COVID-19 vaccine is on pace to hit the market at warp speed, a universal coronavirus vaccine — one that would protect against all variations of the virus — will likely be much longer in coming. Many of the same factors driving the need for universal vaccines against respiratory viruses like SARS-CoV-2 and influenza are what make it so difficult — and, as of yet, impossible — to develop one.
No “Outrunning” the Virus
As Medical News Today explains, RNA viruses — of which SARS-CoV-2 is one — have characteristically high mutation rates. The implications of mutation rates are highly complex and vary in severity, and there is mixed consensus as to how mutations will influence the course of the virus and vaccine development efforts. A possibility, as highlighted by Georgia State University Research Magazine, is that a COVID-19 vaccine may only be effective against one or more strains used in the initial vaccine trials. Additionally, novel viruses are constantly emerging, which makes the prospect of a universal vaccine particularly compelling — and all the more challenging.
This helps to explain the need for a new flu vaccine each year as well as why the flu vaccine varies in effectiveness from season to season. (The Centers for Disease Control and Prevention reported that the 2019/2020 seasonal influenza vaccine was just 45% effective in preventing the flu.) New strains of the flu virus are constantly emerging and evolving, requiring scientists to effectively outpace an ever-mutating pathogen.
How Close Are We to a Universal Vaccine?
In the urgent effort to contain the coronavirus, bringing a COVID-19 vaccine to market quickly and safely is paramount. However, experts agree that universal vaccines must also be a priority in mitigating future pandemics.
We could be close — or, at least, closer —to a universal flu vaccine; the American Society for Microbiology lists several universal influenza candidates in late-stage clinical trials. One of these candidates, Imutex’s FLU-v, induced higher immune responses than a placebo group in a March 2020 study published in the Annals of Internal Medicine and reported by LiveScience.
There are also programs underway for the development of a universal coronavirus vaccine. The French biotech Osivax recently secured €30 million in public funding to advance the development of both universal coronavirus and influenza vaccines. Meanwhile, a team of researchers out of the Washington University School of Medicine is working to develop a coronavirus vaccine, with the hope that their recent success in eliciting T-cell responses in animals can eventually apply to broader range of coronaviruses, according to LeapsMag.
Building a Line of Defense Against the Current & Future Pandemics
In addition to their complexity, a historical barrier to developing a universal coronavirus vaccine is that outbreaks as severe as the current coronavirus pandemic have been relatively few and far between. In 2016, a team of scientists in Texas had made progress in developing a coronavirus vaccine; but by then, more than 10 years removed from the SARS outbreak of 2003, they “just could not generate much interest,” Dr. Peter Hotez, one of the researchers, told NBC News.
Hotez’s sentiment is one that has been echoed by other members of the scientific community: that a “loss of interest” has impeded the development of a vaccine to protect against future coronavirus outbreaks. It is hopeful that the unprecedented collaboration and innovation we are currently seeing in the effort to develop a COVID-19 vaccine, along with advancements toward a universal flu vaccine, could change the trajectory — strengthening our defense against respiratory viruses that have long threatened global health.