Gold Coast scientists have moved a step closer to finding a vaccine for gonorrhoea, which has taken on superbug status in 2018.
A research team including experts from Griffith University and Public Health England have pinpointed the potential for a meningococcal B vaccine named Bexsero to generate protection against the sexually transmitted disease which affects more than 100 million people worldwide each year.
The breakthrough comes at the end of a year when the infection gained ‘super gonorrhoea’ status in Australia and the UK.
Challenging
“Some strains of the bacteria Neisseria gonorrhoeae are now resistant to all antibiotics typically used to treat gonorrhoea, and unfortunately vaccine development for gonorrhoea has been very challenging,” Associate Professor Kate Seib from Griffith’s Institute for Glycomics said.
“Gonorrhoea is a significant public health problem in Australia where the rates of infection have increased by 63% during the past five years. If left untreated, gonorrhoea can lead to complications including pelvic inflammatory disease, adverse pregnancy outcomes, neonatal complications, and infertility.
“We urgently need new ways to treat and prevent gonorrhoea, and this work provides a new opportunity to progress gonococcal vaccine development.”
Reduced rates of gonorrhoea were previously observed in New Zealand, following a vaccine campaign with the MeNZB meningococcal B vaccine, as reported in The Lancet in 2017.
Prevention
Dr Seib is now building on the independent findings of this earlier study to determine if the meningococcal B vaccine, Bexsero, could offer a feasible approach to the prevention of gonorrhoea. Bexsero was licensed in 2013 and contains the same outer membrane vesicle (OMV) antigen associated with the New Zealand MeNZB vaccine plus three additional recombinant antigens.
“We have shown that gonorrhoea has many proteins that match the OMV antigens in both the MeNZB vaccine used in the New Zealand campaign and the Bexsero meningococcal vaccine.”
Serum from Bexsero-vaccinated humans recognises the gonococcal counterparts of the antigens, which supports the finding that the MeNZB vaccine could have generated protection against gonorrhoea. The antigen NHBA, which is present in Bexsero but not MeNZB, is conserved in gonorrhoea strains and is strongly targeted by serum from Bexsero-vaccinated humans. This could provide additional cross-protection against gonorrhoea, above that predicted for MeNZB.
“It could potentially be better,” she said. “We have been working to identify the full set of gonorrhoea proteins targeted by Bexsero and determine exactly how this immune response could protect against gonorrhoea.”
Professor Mark von Itzstein, Director of Griffith University‘s Institute for Glycomics, said gonorrhoea is now recognised as a major issue by the World Health Organization.
“This is particularly due to the emergence of drug resistance. The research undertaken by Associate Professor Kate Seib presents exciting opportunities for new vaccine discovery to tackle this world problem.”
The research is published in Clinical Infectious Diseases (DOI: 10.1093/cid/ciy1061).