A CLUSTER of Catholic schools have anomalously shared in an isolated case of chickenpox, contrary to a decline in Canberra’s viral numbers.

Three primary schools, located several kilometres apart, have detected pupils over recent days carrying the highly-contagious infection that causes rashes on itchy skin.

Holy Spirit Catholic Primary School has been identified of carrying nearly all ACT cases.

The Nicholls school was found to have close to 30 of its children in kindergarten and years 3, 5 and 6, and a separate case in its early learning centre alone, infected with chickenpox.

A Catholic Schools Australia representative reported that the cases are regarded very mild, and that each of the three schools are imposing “high hygiene standards”.

The schools are required to enforce an exclusion period for infectious children away from classmates that has protected the Canberra community.

ACT Health, who has been monitoring the spread, said the number of notifications for the varicella disease to its protection service has not only been comparable – but likely reduced – to previous years.

The number of ACT recorded cases in 2021 are half the number of the first annual quarter of each of the previous two years, data has revealed.

It has made the low number of cases in the territory days out from the end of March even more remarkable that they have remained isolated to the three schools.

“However, not all cases of chickenpox are reported to ACT Health, and so the number of cases year-to-date may be an underestimate of the true incidence,” a spokesperson for ACT Health said.

The concern that ACT Health has is that about 90 per cent of known chicken pox incidences around Canberra are in residents that have had just a single dose of vaccine.

The public healthcare service recommends a second dose of the varicella vaccine, which is not funded under the national immunisation program, for children under 14.

“While there’s been a substantial decline in incidence of chickenpox cases, hospitalisations and severe outcomes since 2005 when the single dose varicella vaccine was added to the national immunisation program, it is still possible to catch chickenpox – albeit in a milder form – after receiving the single dose vaccine,” the spokesperson said.

The territory’s preventative varicella vaccination rate for two-year-olds looks considerably strong at 93 per cent, which stands above the national average.