Eden’s team traced the RSV-A types back to early 2020, concluding that their origins were “a 50-50 call”: they either mutated in Australia or entered from overseas when Tens of thousands of people have returned home as Australia prepares to close its borders and becomes localized due to state border closures.
Although modellers predicted that RSV would return post-lockdown in greater numbers due to children not being immune to previous exposure, it was assumed that this would occur during the winter. The summer surge of infections, also seen in parts of Europe and Israel, came as a surprise.
“It was something we had never seen before,” Eden said, noting that there was no spike in cases last summer, likely due to high transmission of COVID-19. at the beginning of the year. “Viruses tend to suppress each other a bit; they bother each other.
Professor Peter Collignon, an infectious disease doctor and ANU microbiologist, said the past two years had revealed a lot about the behavior of respiratory viruses.
“RSV never went away, but the flu is interesting because it really seems like we import everything, and now it’s happening earlier and in greater numbers than it was a few years ago,” he said. said, adding that he had previously assumed the flu existed in an undetected community. levels during the summer.
Collignon said the winter surge in respiratory infections would likely have a greater impact on children than in previous seasons, with reduced immunity due to falling virus rates over the past two years.
Children and teenagers account for more than half of this year’s flu cases in New South Wales, which is experiencing an early flu season.
From Wednesday, flu shots will be free for all NSW residents, following state-funded shots for those not included in the federal scheme.
As pandemic restrictions in New South Wales have eased, data shows cases of RSV as well as other respiratory infections, including rhinovirus and parainfluenza, are all on the rise.
There were 1,140 cases of RSV confirmed by a PCR test in the week ending May 22, up from 766 the previous week and 508 the previous week, according to NSW Health respiratory surveillance reports.
Around 930 children under the age of five presented to hospital with bronchiolitis, a lung infection usually caused by RSV, in May, of whom around 40% were admitted.
Eden undertakes genomic analysis of the recent wave of RSV cases and expects increased social mixing and the reopening of international borders to be the source of the infections.
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