What the latest COVID testing of sewage has revealed
No fragments of the COVID-19 virus have been detected in the latest sample of sewage to be tested from the Byron Shire, according to a NSW Health spokesman.
"The NSW Health sewage surveillance program most recently carried out sewage testing for the catchment that includes Byron Bay on Wednesday, 30 December and did not detect fragments of the virus that causes COVID-19," the spokesman said.
The comforting result comes after the Byron Shire went one month without sewage monitoring results.
This was in part because samples in mid-December were inadvertently frozen, but the council has said this accounts for just one missing week.
"NSW Health regularly carries out sewage testing in catchment areas across NSW," the NSW spokesman said.
"If fragments are detected in a catchment area the public is immediately made aware."
A Northern NSW Local Health District spokesman has meanwhile explained why frozen sewage samples aren't ideal, although the virus "can be detected from frozen samples".
"Detections from refrigerated samples are likely to be more representative of what may be present in the catchment," he said.
"For routine monitoring, the laboratory sets temperature parameters based on the best available information that sewage samples are better off kept refrigerated rather than freezing and thawing.
"Freeze thawing may reduce sensitivity, which can be crucial for samples with a very low number of virus fragments, such as regional locations with no known cases of COVID-19.
"The aim is to maximise detection of SARS-CoV-2 markers from samples.
"The analysis method used by our partners in the Sydney Water Laboratory differs slightly from the CSIRO method, but is generally the same process."