The World Health Organization has stressed the need to ramp up trials for vaccines designed to fight antimicrobial-resistant (AMR) bacterial pathogens and maximise the use of existing ones to stave off a 'silent pandemic'.
The agency has already declared AMR as one of the top 10 global public health threats and it released the first-ever report on the pipeline of vaccines currently in development on Tuesday.
Antimicrobials, including antibiotics, antivirals, antifungals and antiparasitics, are medicines used to prevent and treat infections in humans, animals and plants, says a report on bdnews24.com.
AMR occurs when bacteria, viruses, fungi and parasites change over time and no longer respond to medicines, making infections harder to treat and increasing the risk of disease spread, severe illness and death, according to the WHO.
As a result of drug resistance, antibiotics and other antimicrobial medicines become ineffective and infections become increasingly difficult or impossible to treat.
Resistant bacterial infections alone are associated with nearly 4.95 million deaths per year, with 1.27 million deaths directly attributed to AMR, the agency said.
Immunisation is a powerful tool to prevent and limit the spread of AMR infections. And, the new report aims to guide investments and research into feasible vaccines to mitigate AMR.
The WHO identified 61 vaccine candidates in various stages of clinical development, including several in late stages of development, to address diseases listed on the bacterial priority pathogens list.
While late-stage vaccine candidates are described as having high development feasibility, the report cautions that most will not be available anytime soon.
“Preventing infections using vaccination reduces the use of antibiotics, which is one of the main drivers of AMR. Yet of the top six bacterial pathogens responsible for deaths due to AMR, only one, Pneumococcal disease, has a vaccine,” said Dr Hanan Balkhy, WHO assistant director-general for antimicrobial resistance.
“Affordable and equitable access to life-saving vaccines such as those against pneumococcus, are urgently needed to save lives, and mitigate the rise of AMR,” she added.
The report calls for equitable and global access to already existing vaccines, especially among populations that need them most in limited-resource settings.
There are already vaccines available against four priority bacterial pathogens: pneumococcal disease, Hib, tuberculosis and typhoid fever.
Current Bacillus Calmette-Guérin (BCG) vaccines against tuberculosis do not adequately protect against the disease and the development of more effective vaccines should be accelerated, according to the WHO.
But the risk of the bacteria noted in the priority pathogens list is magnified by their resistance to antibiotics. The development of new antibacterial treatments is inadequate to address the mounting threat of antibiotic resistance, the WHO said in a 2021 report.
However, vaccines against these pathogens are unlikely to be available in the short term and the agency emphasised the urgent need to develop alternative interventions.
“Disruptive approaches are needed to enrich the pipeline and accelerate vaccine development. The lessons from Covid-19 vaccine development and mRNA vaccines offer unique opportunities to explore for developing vaccines against bacteria,’’ said Dr Haileyesus Getahun, director of WHO's AMR Global Coordination Department.
The report also examines some of the challenges facing vaccine innovation and development, including for pathogens associated with hospital-acquired infections (HAI).
These include the difficulty in defining target populations among all admitted hospital patients, the cost and complexity of vaccine efficacy trials and the lack of regulatory and policy precedent for vaccines against HAIs.
“Vaccine development is expensive, and scientifically challenging, often with high failure rates, and for successful candidates complex regulatory and manufacturing requirements require further time. We have to leverage the lessons of Covid vaccine development and speed up our search for vaccines to address AMR,” said Dr Kate O’Brien, director of the Immunisation, Vaccines and Biologicals Department at the WHO.