• A new study by the World Health Organisation (WHO) has named 17 bacteria, viruses and parasites that regularly cause disease as top priorities for new vaccine development.

• The study is the first global effort to systematically prioritise endemic pathogens based on criteria that included regional disease burden, antimicrobial resistance risk and socioeconomic impact.

• The study reconfirms longstanding priorities for vaccine research and development (R&D), including for HIV, malaria, and tuberculosis — three diseases that collectively take nearly 2.5 million lives each year.

• Attention is also given to pathogens such as Group A streptococcus, which causes severe infections and contributes to 280,000 deaths from rheumatic heart disease, mainly in lower-income countries.

• Another new priority is Klebsiella pneumoniae — a bacteria that was associated with 790,000 deaths in 2019 and is responsible for 40 per cent of neonatal deaths due to blood infection (sepsis) in low-income countries. 

WHO Priority endemic pathogens list

Pathogens where vaccine research is needed:

• Group A streptococcus

• Hepatitis C virus

• HIV-1

• Klebsiella pneumoniae

Pathogens where vaccines need to be further developed:

• Cytomegalovirus

• Influenza virus (broadly protective vaccine)

• Leishmania species

• Non-typhoidal Salmonella

• Norovirus

• Plasmodium falciparum (malaria)

• Shigella species

• Staphylococcus aureus

Pathogens where vaccines are approaching regulatory approval, policy recommendation or introduction:

• Dengue virus

• Group B streptococcus

• Extra-intestinal pathogenic E. coli

• Mycobacterium tuberculosis

• Respiratory syncytial virus (RSV).

Significance of the new study

• WHO asked international and regional experts to identify factors that are most important to them when deciding which vaccines to introduce and use. The analysis of those preferences, combined with regional data for each pathogen, resulted in top 10 priority pathogens for each WHO region. 

• The regional lists were then consolidated to form the global list, resulting in 17 priority endemic pathogens for which new vaccines need to be researched, developed and used.

• Global decisions on new vaccines have often been solely driven by return on investment, rather than by the number of lives that could be saved in the most vulnerable communities. This study uses broad regional expertise and data to assess vaccines that would not only significantly reduce diseases that greatly impact communities today but also reduce the medical costs that families and health systems face.

• This new WHO global priority list of endemic pathogens for vaccine R&D supports the Immunization Agenda 2030’s goal of ensuring that everyone, in all regions, can benefit from vaccines that protect them from serious diseases. 

• The new study supports the goal of ensuring that everyone, everywhere, can benefit from vaccines that provide protection against serious diseases.

• This global prioritisation exercise for endemic pathogens, complements the WHO R&D blueprint for epidemics, which identified priority pathogens that could cause future epidemics or pandemics, such as COVID-19 or severe acute respiratory syndrome (SARS).

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