Group B Strep bacteria which one in every 4 to 5 pregnant women carry, and which can cause death or serious complications in their babies, could be targeted in a cost-effective way by a future vaccine – even if it costs the NHS as much as £54 a dose.
Group B Strep (GBS) infection, caused by Group B Streptococcus, is the most common cause of life-threatening infection in newborn babies, and of meningitis in infants up to age 5. On average in the UK, two babies a day develop group B Strep infection, one baby a week dies from their GBS infection and another baby every week survives with long-term health issues.
The UK’s current group B Strep prevention strategy involves identifying pregnant women whose babies are at raised risk of developing GBS infection and giving them antibiotics during childbirth. However, GBS infection in babies, although not common, is increasing despite the prevention measures.
With several potential group B Strep vaccines for pregnant women now in development, health economists have been looking to see if a vaccine could be affordable for the NHS once one is licensed for use.
Dr Kyriaki Giorgakoudi, Lecturer in Health Economics at Brunel University London, said:
“Group B Streptococcus is part of the body’s natural flora, and most of us who have it don’t experience any adverse effects. But for young babies, GBS can be dangerous.
“GBS disease affects 1 in 1000 babies in the UK, which is nearly 750 babies every year, with more than 1 in 20 of these cases being fatal.”
Dr Giorgakoudi and her colleagues – from the Universities of Cambridge and Birmingham, St George’s, University of London, and Public Health England – designed a mathematical model and plugged in everything currently known about GBS disease in the UK, factoring in extensive data about health outcomes and economic costs.
In the study, funded by the Meningitis Research Foundation and published in the journal Vaccine, the researchers used their model to explore different scenarios and identify when maternal immunisation would represent value for money.
Taking a conservative view of the benefits of a GBS vaccine, and following the Joint Committee on Vaccination and Immunisation’s guidelines on cost-effectiveness studies, the model shows the maximum vaccine price for which maternal immunisation remains cost-effective at £54 per vaccine dose.
“Cost-effectiveness in healthcare is about understanding the best we can do with the currently available financial resources, and how we can allocate these resources to get the most health benefits,” Dr Giorgakoudi said.
“Our study estimates that introducing a GBS vaccine would prevent 369 cases of GBS in infants annually. Twenty-one infant deaths will be averted and 103 maternal disease cases will also be avoided. Considering these benefits in the base case scenario we explored, we have showed that a GBS vaccine would be cost-effective for the NHS up to a maximum price of £54 per dose.”
But with GBS disease also implicated in stillbirths, pre-term births and fatal maternal sepsis, adding these into the model, alongside the impact of GBS disease on the health of family members caring for survivors, resulted in an even higher cost-effective vaccine price of £107.
The prospect of a vaccine reducing group B Strep infection is encouraging news for key organisations for whom reducing these infections in babies is a priority, including Group B Strep Support.
Jane Plumb MBE, Chief Executive of Group B Strep Support, said
“Current prevention strategies can only prevent early-onset group B Strep infections (those developing in the first week of life). A vaccine has the potential to prevent not only early-onset GBS infections, but also late-onset (7-90 days), plus the much rarer but still very important late miscarriages, stillbirths, preterm births and maternal infections caused by GBS.
“Group B Strep infections are becoming more prevalent in the UK – a safe and effective vaccine will consign these infections in babies and mothers to the past, something we very much want to see.”
Dr Giorgakoudi added:
“We don’t know exactly how many years in the future a vaccine will be ready to roll out.
“But when it is, a maternal immunisation strategy in combination with the current antibiotic strategy is highly likely to be a cost-effective intervention against infant GBS disease for the NHS, assuming the vaccine is safe, effective, and can be purchased and administered at a reasonable price.”
The research study is published in the November 2018 issue of Vaccine – click here to read more.