The battle against drug-resistant superbugs has neglected a key weapon, scientists say: using vaccines to quell the spread of resistance.
As drug-resistant infections sweep across the globe, public-health organizations have focused mainly on developing new antimicrobial treatments and cutting the overuse of existing ones, to prevent resistant strains emerging.
While the search for new antibiotics continues, several studies have highlighted that vaccines also have benefits against AMR. By reducing cases of diseases, they slow the rise of drug-resistant pathogens, because the microbes have fewer opportunities to multiply and evolve.
Researchers cite, for example, the introduction of vaccines against the most prevalent strains of pneumococcus bacteria (Streptococcus pneumoniae) in the 2000s — which studies in the United States have shown cut instances of pneumonia while simultaneously slashing the number of infections resistant to front-line antibiotics such as penicillin (L. M. Hampton et al. J. Infect. Dis.205, 401–411; 2012). The same benefit was seen in South Africa when the country introduced a pneumococcal vaccine in 2009, says James Wassil, vice-president for vaccines at New York City-based drug company Pfizer.
Even vaccines against viral diseases, such as influenza, can help to prevent overuse of antibiotics. Many antibiotics are prescribed to treat opportunistic bacterial infections that occur in people weakened by flu — and a flu vaccine can lessen the chances of these infections occurring. While the search for new antibiotics continues, several studies have highlighted that vaccines also have benefits against AMR. By reducing cases of disease, they slow the rise of drug-resistant pathogens, because the microbes have fewer opportunities to multiply and evolve.
As well as advocating the wider roll-out of existing vaccines against flu and pneumonia, scientists are keen to develop new vaccines against other infections. Vaccines have an advantage over antimicrobials in that they rarely generate resistance, says David Livermore, a microbiologist at the University of East Anglia in Norwich, UK. That’s because antibiotics are administered after an infection has started, when there is already a dense population of microbes from which new resistant strains can evolve. Vaccines, by contrast, prevent infections from arising in the first place.
Still, researchers say, more evidence of vaccines’ action against AMR is needed if authorities are to be persuaded to roll them out more widely for that purpose. One way to start may be to check whether existing vaccines have unexpected benefits against resistant infections.