As Ebola fears again spread beyond Africa, the world faces a familiar question: How best to react to the threat? What lessons from past threats, including Covid-19, can we apply?
These days, of course, mechanisms aimed at thwarting contagious diseases are controversial, from quarantines to personal protective equipment to vaccines.
And yet the potential danger of Ebola is not controversial, it is actual. According to the Centers for Disease Control and Prevention, the virus has broken out two dozen times in the last half-century, across broad swathes of Africa. The World Health Organization finds that the worst of these outbreaks, in 2014-16, caused more than 11,000 deaths. Notably, that outbreak reached the United States.
Speaking of the latest outbreak, one aid worker told The New York Times, “The virus is far ahead of us, and it’s spreading fast.” The new Bundibiguo strain has, in fact, killed more than 200, reaching beyond the Democratic Republic of Congo. This much dispersion is ominous, as it comes on the eve of the FIFA World Cup; its games to be held next month in 11 U.S. cities, and five more cities in North America. The State Department expects, from around the world, as many as 10 million visitors.
Anticipating this danger, the U.S. is taking stern public-health measures that will hopefully keep the threat at bay, and yet a hard-learned lesson of public health is to build in redundancy, echelons of safeguarding.
One such layer of defense is vaccination. These days, vaccines are a touchy subject. But of course, in these days of polarization, everything is a touchy subject.
Yet because so much is at stake, with Ebola and whatever else might emerge from nature’s cauldrons, this is a good time to consider some recent developments on the vaccine front.
Vaccines have been around since the 18th century, and they are rightly credited with the eradication, or near eradication, of such dread maladies as smallpox and polio.
In 2020 came a new kind of vaccine, mRNA, which was central to the first Trump administration’s triumphant Operation Warp Speed, combating Covid. Without a doubt, mRNA is a powerful technology with much to offer, although in some quarters, it has raised powerful concerns. These issues have been, and will be, debated vigorously in the courts of both scientific and public opinion.
Yet even the strongest and most optimistic proponents of mRNA vaccines concede that they are expensive to manufacture, dependent on sophisticated cold-chain refrigeration logistics, and operationally difficult to distribute. It’s a painful fact that the public-health infrastructure in Central Africa, where Ebola and other hemorrhagic fever outbreaks have emerged, lags behind what’s needed.
So it’s encouraging that other vaccines, including for Ebola, work on a different scientific basis, relying on the adenovirus, the bug behind mere common cold, as the vector.
Indeed, a growing number of scientists are now exploring next-generation adenoviral vaccines, capable of mucosal delivery through intranasal administration. That is, not a shot, a nose spray.
The prospect is that these next-gen vaccines, easier to administer, and less infrastructure-intensive, are also potentially better at stopping viral spread.
This mucosal approach can be fairly described as a paradigm shift. Rather than relying solely on injected systemic immunity, these newer vaccines aim to create immune protection directly at the site where many viruses first enter the body: the respiratory mucosa. So, the scientific principle of parsimony is pleased, by putting the vaccine right on the target, the mucous membrane through which we breathe, without implicating other parts of the human body.
An effective mucosal vaccine may not only protect individuals from severe disease, but could also reduce transmission dynamics. In outbreak settings, that could mean fewer infections, fewer chains of spread, and greater ability to contain emerging pathogens before they become global emergencies.
Equally important, such vaccines may prove easier to deploy quickly and at scale. No needles. Less reliance on specialized distribution systems. Potentially lower manufacturing costs, and greater acceptance among populations wary of injections.
A lesson from Covid is that the science of medical prevention and treatment is never settled. In the last few years, we have been reminded, yet again, that society benefits when multiple scientific approaches compete, evolve, and improve simultaneously.
America’s biodefense strategy should therefore encourage a diversified portfolio of vaccine technologies, including cutting-edge adenoviral systems. And there’s evidence, in fact, that the mucosal approach also works on some kinds of influenza
In the meantime, we already know adenovirus-based Ebola vaccines can work. The next question is whether modernized versions can work even better.
The story of medical progress is one of new thinking and life-saving. More of that, please.
James P. Pinkerton worked in the White House domestic policy offices of Presidents Reagan and George H.W. Bush.
