When Alyssa Kremer's three-year-old son Harrison got sick earlier this year, she thought it was just his asthma.
"He actually fell asleep on the couch, which was quite abnormal for him to do in the middle of the day, and I tried to wake him up, and he suddenly stopped breathing."
When Harrison didn't respond to his ventolin, he was rushed to hospital in Brisbane where doctors found he had respiratory syncytial virus (RSV).
Harrison was one of the thousands of children who tested positive to the virus during a surge between February and March.
RSV is a common and highly infectious virus that most children will catch before they turn two and it can cause severe illness in children under three.
Vaccine development
Researchers from the Mater Mothers' Hospital in Brisbane hope a vaccine being developed and tested at the moment could "relegate RSV to the history books".
Glenn Gardiner, director of the hospital's maternal fetal medicine service, is leading the trial and said the vaccine was entering a major phase of testing, after five years of research.
"This trial is really a much larger trial about the efficacy of the vaccine, having previously been very satisfied that the vaccine is safe."
Dr Gardiner said the vaccine worked by stimulating a pregnant women's immune response to the virus.
"It's simply a protein of the virus that stimulates the immune response so that the mother's antibodies are increased across the placenta and give the baby enough antibody protection to last in the first few months of life."
Dr Gardiner said the spike in RSV rates earlier this year had seen an increase in interest from parents wanting to take part in the trial.
He said researchers were still looking for participants.
Testing immune response
And while RSV case numbers are now low in Queensland, with just over 350 confirmed cases being recorded since July 1, Dr Gardiner said there were other methods they could use to test the effectiveness of the vaccine.
"For example, you can measure antibody levels in both the mother and the baby and in the umbilical-cord blood at birth, to see the immune response to the vaccine."
Alyssa Kremer, who's taking part in the trial, said she hoped the vaccine would provide her next child with protection from the disease.
"And then Harrison actually having RSV just made it that much more real for me and solidified in my mind straight away that this was definitely something that I needed to do."
Researchers hope after another year of trials, they'll be able to assess the data and if the results are positive, then work towards developing a commercial vaccine.
