If there’s one bright side to the worldwide health crisis that crashed into our lives last year, it must surely be the effect it had on science – and vaccine science most of all. Think about it: to date, there are more than 20 different vaccines for a disease we didn’t even know existed two years ago. That’s amazing! Can you imagine if the same kind of breakthroughs were available during the time of the Black Death?
What’s that? We’re actually still living through the time of the Black Death?
It’s true: while thankfully much, much rarer today than it was 700 years ago, the disease responsible for wiping out up to 60 percent of Europe is still out there, and it still kills people. That’s why now, the team behind one of the first successful coronavirus vaccines has launched a Phase 1 trial for an even bigger fish: a vaccine for the plague.
“The coronavirus pandemic has shown the importance of vaccines to defend populations from the threat caused by bacteria and viruses,” said Andrew Pollard, Director of the Oxford Vaccine Group. “Plague threatened the world in several horrific waves over past millennia, and, even today, outbreaks continue to disrupt communities. A new vaccine to prevent plague is important for them and for our health security.”
What we know as “the plague” is actually three different diseases: there’s the bubonic plague of Black Death fame, but there’s also pneumonic plague and septicemic plague. If you’re ever forced to choose between them, perhaps in some kind of supervillain hostage situation, take the bubonic form – without treatment, you’ll have a 40 percent chance of not dying. That's not great, but the other two will almost certainly kill you.
The reason we don’t all live in constant day-to-day fear of the world’s OG pandemic is that, while it is undoubtedly fatal, the plague is also quite easy to prevent and treat. The disease is caused by infection by the Yersinia pestis bacteria, which is usually found in small mammals and their fleas. Consequently, it can usually be thwarted with a simple antibiotic regimen, assuming such medicines are readily available, and standard hygiene practices.
The few thousand cases that do still occur today are overwhelmingly found in Africa, where local ecosystems in countries like the Democratic Republic of the Congo and Madagascar provide a welcome home for the bacteria. Unfortunately, that can be a problem for treatment.
“Although antibiotics can be used to treat plague, many areas experiencing outbreaks are very remote locations,” explained Christine Rollier, Associate Professor of Vaccinology at the Oxford Vaccine Group. “In such areas, an effective vaccine could offer a successful prevention strategy to combat the disease.”
The potential plague vaccine uses the same technique used by the team in their creation of their coronavirus vaccine: an adenovirus viral vector platform. In basic terms, this refers to a genetically engineered cold virus – the adenoviral vector – which has been designed to imitate the pathogen the vaccine guards against. The body is tricked into thinking there’s an infection and learns to fight off this lookalike invader. Then, if and when the real virus actually does get into the body, the immune system will have had “practice” and so can hopefully stand a better chance at fighting the disease off. Think of it as a tiny biological punching bag: not particularly dangerous in itself, but good for training yourself up before you get in the boxing ring.
The Oxford team is still recruiting volunteers for the study, which will run for twelve months before the researchers evaluate the findings. If it’s as successful as the team’s coronavirus vaccine, we might soon see the end of humanity’s millennia-long battle against the plague.
