Vaccines versus superbugs
But vaccines also have a crucial role to play in protecting us against a far deadlier and far more predictable threat: drugresistant infections.
In contrast to unexpected, rapidly spreading outbreaks such as the Zika epidemic, antimicrobial resistance is like a slow-motion car crash that has already begun. Resistant pathogens cause about 700,000 deaths every year. If we fail to take the necessary precautions, they will be killing some ten million people a year by 2050.
Developing new antibiotics and putting in place methods to extend the lifespans of existing medications will help maintain a supply of effective treatments. But vaccines offer a unique opportunity. By reducing the number of infections, they limit the need for medication.
And because the use (or overuse) of antibiotics is what leads to drug resistance, the pressure on the pipeline of effective treatments will be alleviated.
Unfortunately, the value that vaccination can provide in this area has yet to be properly recognised. As a result, we are not moving fast enough to develop the types of vaccines that could be used to prevent antimicrobial resistance.
Vaccine development takes a long time, often more than ten years. It is a high-risk endeavour, with the vast majority of potential vaccines failing to reach the market. Consequently, many vaccines are not commercially viable, even if they would be useful for society.
Indeed, there is no vaccine available for any of the three resistance threats that the US Centers for Disease Control and Prevention considers “urgent”: Clostridium difficile, carbapenem-resistant enterobacteriaceae, and drug-resistant Neisseria gonorrhoeae. Nor are there enough candidate vaccines against these pathogens undergoing clinical trials.
There have also been problems developing vaccines to combat tuberculosis or – more worrying still – multidrug-resistant TB. The World Health Organisation has warned that the Sustainable Development Goal of eradicating TB by 2035 will not be achieved unless new drugs, better diagnostics, and improved vaccines are developed. And yet a new vaccine remains many years away, especially given that funding for TB vaccine research has declined in recent years.
Even vaccines that are already available are not being used widely enough to have a large impact on antibiotic use and resistance. Every year, infections caused by the Streptococcus pneumoniae bacteria kill more than 800,000 children under the age of five.
These deaths are completely preventable – by a jab that is already available in many parts of the world, the pneumococcal conjugate vaccine. Universal vaccination would save millions of lives and prevent 11.4 million days of antibiotic use per year in children younger than five. Similarly, the rotavirus vaccine could be used to prevent outbreaks of diarrheal diseases, a chief cause of child mortality in developing countries and a major driver of antibiotic use.
Vaccines also have an important role to play in protecting livestock and fish from infections, optimizing the application of antibiotics in agriculture – where their overuse is an important cause of growing resistance.
Maximising the potential of vaccines to fight antimicrobial resistance thus requires the wider application of existing vaccines in humans and animals. But it also entails developing new vaccines, which, in the short-term, could be kick-started by a $2 billion Global Innovation Fund for earlystage research in vaccines and other viable alternatives to antibiotics.
And in areas where research and development is not an attractive proposition, developers must be provided an opportunity to make a return from useful products. Depending on the characteristics of different products, possible interventions would include advance market commitments and market-entry rewards.
Vaccines hold the potential to have a huge impact on drug resistance, if they are included as part of a broad series of interventions to combat the problem. Fortunately, awareness of this challenge is starting to take root.
At the World Economic Forum’s annual gathering in Davos last month, 85 companies, including vaccine developers, large pharmaceutical companies, diagnostic developers, and biotech firms, committed to further action to reduce drug resistance. And later this year, the World Health Assembly, the G-7 and G-20 summits, and the UN General Assembly will all address the topic. The momentum now gathering in the public and private sectors is creating an opportunity that must not be missed.