An expert warns the recent flooding in NSW may worsen transmission rates of rotavirus and more.
Rotavirus case numbers reached an all-time high in 2023, according to a report released in May this year from the Australian Centre of Disease Control.
The Australian Rotavirus Surveillance Program confirmed almost 1800 national cases during the period of 1 January to 31 December 2023, which is the highest number in more than 20 years of program operation.
More than 87% of cases were wildtype. New South Wales, South Australia and Queensland had the highest number of wildtype samples, each accounting for 20-23% of the national total.
New South Wales had a low level of notifications to the National Notifiable Disease Surveillance Service per 100,000 population throughout the year. However, a public health alert released in January stated that in the first week of the year there had been 114 notifications, compared to 80 for the whole of January the previous year.
Per 100,000, South Australia and Northern Territory had the highest number of rotavirus notifications. Northern Territory had an increase from June with the peak observed between August and September. This coincided with a health alert put out by the Northern Territory Centre for Disease Control in early August which warned of a spike in rotavirus cases, particularly in children, many of whom were unvaccinated.
Nearly half of the wildtype samples were collected from children under five years of age, with the majority in children aged between one and two (31%).
Around 13% of rotavirus cases were identified as the Rotarix vaccine-like strain, and more than 97% of these vaccine-like samples were in babies aged six months or younger.
Professor Gary Grohmann, virologist and board member of the Immunisation Coalition, told ARR that the large proportion of Rotarix-like strains in infants was likely due to shedding of the live vaccine.
“The problem there is simply poor hygiene, to be blunt,” he said. “[Infants] literally infect themselves, because hands go into eyes, nose and mouth constantly.”
Professor Grohmann said the increase in cases may have been due to increased testing and post-covid community movement, with a return to activities which promote virus transmission such as daycare centres and family get togethers.
“There is increased testing, but more importantly, there’s more sensitive testing,” said Professor Grohmann, former director of immunobiology and WHO ERL at the TGA.
“In terms of danger to the community, I think it’s very small. I don’t think there’s any great risk to the community from either vaccination or rotavirus going around Australia.”
“It’s generally the same message all the time: good hygiene and get vaccinated.”
Professor Grohmann said a wide variety of diseases had the potential to become a problem due to the recent flooding in NSW.
“Sewage systems can be destroyed, and treatment plants will overflow. There will certainly be viruses; norovirus, rotavirus [and] adenovirus,” he warned. “There’s also the danger of hepatitis A virus in those high flood situations.”
Professor Grohmann also highlighted human metapneumovirus, which was gaining traction around the world and may become part of a combination vaccine in the next few years for children under five and older adults.
