Loss of immunity due to lockdowns behind spike in NSW gastro cases, diseases expert suggests

<span>Photograph: DCPhoto/Alamy</span>
Photograph: DCPhoto/Alamy

The “incredibly unusual” spike in gastro cases in New South Wales recently is likely due to children not being exposed to germs as often during the Covid-19 pandemic, an epidemiologist has said.

On Wednesday, NSW Health issued a public health alert warning people in the state to be aware of symptoms of gastroenteritis.

The rate of reported rotavirus, a common cause of gastro, is five times the usual rate for this time of year. In the first two weeks of January, 197 cases were identified, compared with the usual average of 40 cases for the same period.

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“It’s incredibly unusual to have a surge in the new year, normally it’s between March and October,” said Robert Booy, an infectious diseases paediatrician at the University of Sydney.

“Over the past two to three years, children have somewhat lost their immunity and now people are coming together in crowds, at parties, and holiday events, and are spreading infection.

“Particularly between preschool children who have less hygiene, and then those children are infecting older children.”

Michael Wright, the deputy chair of the NSW Royal Australian College of General Practitioners, said there has been a spike in people attending emergency departments and presenting to general practices with gastro.

He said part of the increase in identified cases may also be to do with doctors conducting more testing to determine viruses as a result of the Covid-19 pandemic.

“Because we’re testing a lot of people for Covid, we’ve become more accustomed to try and work out the viral cause of a condition and so we’re getting more data on viruses as well.”

The director of NSW Health’s One Health branch, Keira Glasgow, said it was important to reduce the spread of gastro before schools return from summer break.

“Last week, there were more than 2,250 presentations to NSW emergency departments with symptoms of gastroenteritis. Presentations were particularly high in children under five years old, and in children aged five to 16 years old,” Glasgow said.

“The message to the community is clear – simple measures can help stop the spread of gastro. Maintaining good hand hygiene and keeping children at home when they are unwell will give us a good chance to slow the spread before February, when children will all be back together at school.”

Unlike NSW, the Queensland and Victorian health departments say they are not experiencing an uptick in gastro that warrants public health concern.

Booy said it’s hard to say yet when cases of gastro are likely to dip in NSW, but they will probably dissipate as more people become immune through infection.

People who catch viral gastro can experience symptoms including nausea, vomiting, diarrhoea, fever, abdominal pain, headache and muscle aches. It usually lasts one to two days, and NSW Health advises those who catch the bug to drink plenty of fluids and rest.

Immunisation against rotavirus infection is recommended for children as part of their immunisation schedule.