Oral vaccine could prevent rheumatic heart disease in NZ

Published: 28 September 2025

Dr Catherine Tsai is developing an oral or nasal vaccine that could help eradicate rheumatic fever which leads to one of the country’s most persistent and preventable heart conditions, rheumatic heart disease.

Dr Catherine Tsai from the University of Auckland has received project funding from the Heart Foundation to develop an oral/nasal vaccine to protect people from Group A Streptococcus (Strep A), the bacterium that causes rheumatic fever and, in some cases, develops into rheumatic heart disease. 

Catherine is one of several researchers and doctors tackling the “holy grail” of eliminating rheumatic fever. 

Despite being largely eradicated in other developed nations, New Zealand has one of the highest rheumatic heart disease rates in the world. On average, about 140 New Zealanders die from rheumatic heart disease every year. 

Nearly all cases of rheumatic fever in New Zealand occur among Māori and Pacific children and teenagers, a reflection of long-standing systemic challenges such as inadequate housing, limited access to healthcare, and institutional inequities. 

Rheumatic fever starts with a sore throat and can lead to damage to heart valves (rheumatic heart disease), despite being completely preventable if antibiotics are prescribed for a sore throat. 

Following an episode of rheumatic fever, patients currently require monthly intramuscular antibiotic injections for several years to reduce the risk of recurrence. This is a significant burden on individuals and health system.

How an oral/nasal vaccine would work

If successful, the new vaccine will be like taking regular medicine through the mouth or as a nasal spray. It will use a safe, food-friendly probiotic (the kind of bacteria found in things like yogurt) to carry pieces of the Strep A bacteria into the body to stimulate a protective immune response. 

“I like this approach because it avoids needles. It acts as a vaccine but it’s more like taking a probiotic supplement,” Catherine says. 

Because Strep A bacteria usually enter the body through the throat or nose, delivering the vaccine to those same areas could train our immune system how to stop the bacteria from entering and spreading in our body.  

Catherine says oral or nasal vaccine delivery would be cheaper, more accessible, child-friendly, and may reduce people’s hesitancy. 

“Right now, we rely on frequent throat swabs to check for the bacteria and then quickly give a range of antibiotics, but that takes a lot of time and resources. An oral or nose spray vaccine would be a much more effective solution. 

“It doesn’t need trained medical staff to administer it. That makes it more practical and affordable, especially in communities with fewer resources.” 

The fight against rheumatic fever and rheumatic heart disease 

The urgency to combat rheumatic fever and rheumatic heart disease prompted the Government to support efforts to develop a suitable vaccine.    

New Zealand is now one of only three developed countries, alongside Australia and Canada, where rheumatic fever remains prevalent, driving collaboration between researchers on both sides of the Tasman.    

Although researchers in New Zealand and Australia are leading efforts to tackle rheumatic fever, there are still no licensed vaccines for the disease.  

Catherine’s work is part of wider University of Auckland research into rheumatic fever vaccine development, which will complement existing work underway in Australia.  

The Heart Foundation has also funded other research in the quest to find a vaccine for rheumatic fever. 

Heart Foundation Medical Director Dr Gerry Devlin says Catherine’s research could be a groundbreaking moment in the fight against rheumatic heart disease. 

“A vaccine is the holy grail in eliminating this serious disease.” 

"It is a disease that affects New Zealand’s most vulnerable communities, and we need to eradicate it,” he says.