COVID-19 travel restrictions and public health measures have lead to a change in the genetics of Respiratory Syncytial Virus (RSV), a common winter virus in Australia, a new study says.
The study, published in Nature Communications, is one of the first to document the impact of COVID-19 on already existing viruses in Australia.
The research found RSV vanished for the first time in recorded history during 2020, but made a quick resurgence in the summer of 2020 – 2021 after border restrictions and health measures were lifted.
Following outbreaks in Western Australia, New South Wales and the Australian Capital Territory, researchers genetically sequenced the “out-of-season” virus, and found distinct changes in its genetic code.
All but one of the previous strains of RSV has “gone extinct”, prompting lead researcher Dr John-Sebastian Eden from University of Sydney’s Institute for Infectious Diseases to issue a warning.
“For each outbreak only a single genetic lineage had survived all the lockdowns,” Eden said.
“We need to be vigilant – some viruses may have all but disappeared, but will likely rebound in the near future, possibly at unusual times and with stronger impact.
“We need to be prepared for large outbreaks of RSV outside of normal seasonal periods and our health systems to be prepared.”
There is currently no vaccine for RSV, which is highly contagious.
The virus infects the airways and lungs and while it generally causes mild, cold like symptoms, infection can be serious – particularly for infants and older adults.
The warning comes amid a spike in flu infections as a particularly virulent and nasty influenza strain tears through the country.
The number of known flu cases recorded in Victoria this year grew from 10,000 to 15,000 in the past week, while in NSW there were 1140 cases of respiratory illness last week – compared with 766 the previous week.
The study raises questions as to how rapid spread and evolution of RSV could inform the re-emergence of other viruses including influenza.
“The constellation of flu strains circulating pre and post-COVID-19 has also changed a lot, leading to challenges in how we choose the composition and timing of our annual vaccines,” Eden said.
“For example, the flu season in Australia has kicked off much earlier than in previous years.”