Clinical and health systems research |Clinical Trials

What is Group A Strep?

Group A Strep is a bacteria (a type of germ) that can cause a range of infections. These infections can cause mild to severe disease.

Group A Strep commonly causes infection of the skin (“school sores”) and the throat (“Strep throat”).

What is invasive Group A Strep disease?

Sometimes, Group A Strep can infect parts of the body that don’t normally have bacteria them, such as:

• the lungs (causing pneumonia)
• the brain (causing meningitis), and
• the blood (causing bacteraemia).

This is known as invasive Group A Strep disease, or iGAS for short. iGAS is a serious infection that causes people to become very unwell. Most people with iGAS need to be treated in hospital, often for an extended period. In some cases, iGAS can lead to life-threatening complications, and sadly people may not recover and pass away.

What is the ISAAC trial?

People who share a house (a contact) with someone with iGAS (a case) are much more likely to develop iGAS themselves soon after the iGAS case becomes sick. This is called secondary iGAS.

For a similar severe bacterial infection – meningococcal disease – all close contacts are given antibiotics to prevent them from getting sick.

This approach however isn’t standardised for iGAS. More research is needed to determine which contacts should be given antibiotics and which antibiotics should be used. The ISAAC trial will answer these questions about how to prevent secondary iGAS so that in the future, doctors can ensure everyone who needs antibiotics receive them.

In the ISAAC trial, household contacts of iGAS cases will be invited to participate in the study. People who want to take part, will be randomised to receive either:

(1) no antibiotics,

(2) a beta-lactam antibiotic, or

(3) azithromycin (a different antibiotic).

Participants will also be asked to take throat swabs (at baseline and day 14) to see if they have the Group A Strep germ in their throat after participation. This is a marker of risk for secondary iGAS.

Participants will also complete surveys at baseline, day 14 and day 30.

Information for participants

If participation in the ISAAC trial has brought you distress, help is available:

• Beyond Blue is available 24/7 on 1300 22 4636
• Lifeline is available 24/7 on 13 11 14
• For young people aged 5 to 25, Kids Helpline is available 24/7 on 1800 55 1800
• For Aboriginal and Torres Strait Islander people, 13YARN is available 24/7 on 13 92 76

Research team

Trial steering committee

Trial lead

Associate Professor Katherine Gibney

Associate Professor Katherine Gibney is an infectious diseases physician, public health physician and medical epidemiologist. Associate Professor Gibney works at both the Royal Melbourne Hospital and at the Doherty Institute, where she researches Group A Strep.

Professor Asha Bowen

Professor Asha Bowen is a clinician-researcher, focusing on skin health. Professor Bowen is a paediatric infectious diseases physician at Perth Children’s Hospital, and a researcher at The Kids Research Institute Australia. 

Professor Steven Tong

Professor Steven Tong is an infectious diseases physician and clinical trial specialist. Professor Tong works at both the Royal Melbourne Hospital and at the Doherty Institute, where his research interests include skin pathogens.

Professor Andrew Steer

Professor Andrew Steer is a paediatric infectious diseases physician at the Royal Children’s Hospital and the Director of Infection, Immunity and Global Health, and Group Leader of the Tropical Diseases Research Group, at the Murdoch Children’s Research Institute. Professor Steer’s research focuses on tropical diseases.

Mr Mark Mayo

Mr Mark Mayo is the Deputy Director First Nations Leadership, the Co-lead for The Ramaciotti Regional and Remote Health Sciences Training Centre and a Senior Researcher at Menzies School of Health Research. Mr Mayo’s research focuses on global and tropical health.

Dr Mark Davies

Dr Mark Davies is a Laboratory Head the Doherty Institute, where his research interests include genomic sequencing approaches to understand the emergence and evolution of bacterial pathogens, including Group A Strep.

Professor Nigel Crawford

Professor Nigel Crawford is a consultant paediatrician at the Royal Children’s Hospital and a vaccinologist at Murdoch Children’s Research Institute. Professor Crawford’s research areas are infection, immunity and global health.

Professor Benjamin Howden

Professor Benjamin Howden is a public health microbiologist, infectious diseases physician and molecular biologist. He is Director of the Microbiological Diagnostic Unit Public Health Laboratory at the Doherty Institute.

Ms Kimberley McMahon

Ms Kimberley McMahon is a Nurse Management Consultant at the Centre of Disease Control within Northern Territory Health. Ms McMahon has extensive experience in managing the public health follow-up of iGAS cases and outbreaks.

Associate Professor David Price

Associate Professor David Price is a biostatistician and mathematical modeller at the Doherty Institute. Associate Professor Price’s research focuses on the optimal design of experiments, with a strong focus on those regarding infectious diseases.

Contact

For more information, please contact the ISAAC study team:

• Associate Professor Katherine Gibney (Trial Lead): katherine.gibney@unimelb.edu.au
• Ms Giulia Quattrocchi (Trial Manager): giulia.quattrocchi@unimelb.edu.au

If you have any complaints about how the ISAAC trial is being run, please contact:

• Royal Melbourne Hospital Human Research Ethics Committee
  • P: (03) 9342 8530           
  • E: research@mh.org.au (ATTN: Manager Ethics Office)
• Director, Office for Research
  • P: (03) 9342 8530           
  • E: research@mh.org.au (ATTN: Complaints Manager)

Funding

The ISAAC trial is funded under the NHMRC Clinical Trials and Cohort Studies Grants 2023 (GNT2032163).

The ISAAC trial is sponsored by the University of Melbourne, Victoria, Australia.