A study published in PLOS Medicine in March 2023 suggests that the human and financial benefits of a Group B Streptococcus (GBS) vaccine would be significant but equitable access would depend on tiered pricing.  


Streptococcus agalactiae is commonly known as Group B Streptococcus (GBS), and is described by the study authors as an “important bacterial pathogen” that causes morbidity and mortality in both pregnant and nonpregnant adults.  

The disease is particularly threatening to neonates and young infants. The study states that in 2020, an “estimated 20 million pregnant women globally were colonised with GBS”. This resulted in 231,000 cases of early-onset GBS (EOGBS), which occurs in the first 6 days of life, and 162,000 late-onset GBS (LOGBS) cases.  

“Together, these were estimated to have caused 58,000 to 91,000 infant deaths depending on the assumptions made about mortality in cases without access to healthcare.”  

In addition to the tragic deaths that occur, survivors of iGBS are “at risk of long-term neurological sequelae”.  


Current prevention strategies are based on “intrapartum antibiotic prophylaxis (IAP)”. The authors note that many higher-income countries have reduced EOGBS incidence with IAP by identifying eligible patients through risk factor-based screening or routine testing. However, IAP has “several limitations”. It is not effective against LOGBS- or GBS-associated stillbirths. Furthermore, the need for “access to laboratory testing” and the “requirement to deliver antibiotics intravenously” creates a limit to the “prospect of attaining high IAP coverage in many low-resource settings”.  

In addition to access issues, there are “concerns that routine administration of antibiotics” can contribute to AMR and have “unintended impacts on the gut microbiota of newborns”. Thus, there is a need to develop alternative approaches.  

Maternal immunisation 

The authors identify maternal immunisation as a potential strategy that would afford protection to “mother, unborn foetus, and newborn infant”. They refer to other immunisation strategies, such as the tetanus vaccination, and influenza and pertussis vaccinations, which have been successfully used in many areas.  

The study 

Although there have been “previous economic evaluations” of maternal GBS vaccination for specific locations, the authors suggest that none has estimated the value “in all world regions”. Thus, they perceived a need to produce a global economic evaluation of GBS vaccination to “drive investment”. It would also encourage adequate financing and pricing mechanisms for the vaccine. The study conducts such an evaluation across 183 countries, drawing on “recently updated global disease burden estimates for GBS”.  

The study assumes the cost per dose as follows: 

  • $50 in high-income countries 
  • $15 in upper-middle-income countries 
  • $3.50 in low- and lower-middle-income countries 

The conclusions in the paper indicate that a “high-coverage” programme could avert “hundreds of thousands of GBS cases”. This would also prevent “tens of thousands of deaths, stillbirths, and cases of long-term disability”. The programme would have an estimated net cost of around $1.3 billion, with “most costs occurring in Europe and North America”. 

“Our results suggest high coverage of a competitively priced maternal GBS vaccine has the potential to save tens of thousands of lives globally and is likely to be a cost-effective investment, particularly if the vaccine can reduce GBS-associated prematurity.”  

Although the study is limited by lacking data, the authors believe that a 1-dose vaccination programme could save millions in healthcare costs. For more discussion on costs and benefits associated with vaccine development and deployment, join us at the World Vaccine Congress in Washington next month!