Public health response following an iGAS outbreak in a residential aged care facility in Queensland

During an 18-day period, beginning in April 2020, three residents with invasive group A streptococcal infections (iGAS) were reported at a single residential aged care facility (RACF) in Brisbane's northern geographical region. All three cases were hospitalised with severe illness; two of the cases died as a result of the illness. The Metro North Public Health Unit (PHU) led the public health investigation and response, targeting infection control measures and offering chemoprophylaxis to all 142 staff and 119 residents at the facility. The outbreak was declared over in June, after 30 days of no new cases. Isolates from all three cases were shown to have identical strain typing, emm89. The benefits and challenges of implementing mass chemoprophylaxis in this setting are discussed.