Harnessing herd immunity

The introduction of immunisation programs over the past few decades has seen dramatic results for global health, with vaccines eliminating numerous diseases that once caused widespread disability and death.

Now, the University of Adelaide is taking vaccination knowledge to the next level with world-leading studies addressing herd immunity impact.

"B Part of It’s aim is not only to protect our adolescents against meningococcal B disease, but also to see whether there are additional benefits in protecting other people they come in contact with."Professor Marshall

The University of Adelaide’s B Part of It study into herd immunity is the largest of its kind in the world. In 2017, B Part of It provided free meningococcal B vaccines to 35,000 adolescents in South Australia. Having protected some of the state’s most vulnerable members from the disease, researchers are now evaluating the level of protection provided to unvaccinated members of the community. 

According to the project’s principal investigator, Professor Helen Marshall, this information is also vital for immunisation policy, in determining the benefits of a program in Australia for inclusion in the National Immunisation Program. Similar requirements also exist in many other countries so the results are of international importance. 

“B Part of It’s aim is not only to protect our adolescents against meningococcal B disease, but also to see whether there are additional benefits in protecting other people they come in contact with,” says Professor Marshall, who is the Medical Director of the Vaccinology and Immunology Research Trials Unit at the Women’s and Children’s Hospital and Deputy Director of Clinical and Translational Research at the University’s Robinson Research Institute. 

“We have the vaccines available, and we’ve put a lot of work into making sure they’re safe and effective for individuals, but we need to make sure we’re taking full advantage of any herd immunity too.” 

Helen Marshall

If enough individuals are immunised, a vaccine’s herd immunity impact has the potential to stop the spread of a disease altogether. In meningococcal B’s case this is critical, with five to 10 per cent of infections still fatal.  

Professor Marshall is also designing and evaluating interventions to increase vaccination uptake of recommended influenza and whooping cough vaccine among women during pregnancy. “We’ve found the best way to do that is to actually make immunisation a part of pregnancy care.” By creating systems that normalise immunisations—like other important procedures during antenatal care—Professor Marshall is optimistic maternal immunisations will rise to 100 per cent, significantly reducing health risks for newborns and mothers alike.  

“We’re very fortunate in Australia to be able to offer these vaccines and prevent diseases from re-emerging. But there’s still work to do on how best we use vaccines, to continually improve our immunisation programs. 

“We’re committed to the best outcomes for children and the community.” 

Learn more about Professor Marshall