Early warning that Covid might lurk in Hawke’s Bay can be provided by wastewater sampling now underway in the region.
Wastewater is used water from toilets, showers, baths, basins, sinks and laundries that passes through the sewerage system. ESR (a Crown Research Institute) is testing wastewater because it can indicate the presence of viral fragments showing that SARS-CoV-2 – the virus that causes COVID-19 – is present.
Such sampling can detect the virus with great sensitivity, faster and more cheaply than testing of individuals. The testing is sensitive enough to discover approximately 10 cases in an area of 100,000 people. According to this University of Otago Public Health Expert article, SARS-CoV-2 signals in wastewater can “appear 4-5 days earlier in comparison to clinical testing”. And, “It gives more valuable results (eg, at least 93% assurance of detecting a small number of cases vs 54% for community testing) at only around 1% of the cost.
This testing now covers 75% of the total NZ population and over 90% of the population connected to wastewater systems. You can get more info on the process here.
BayBuzz has been informed by ESR that wastewater sampling is occurring weekly (“at a minimum”) for Waipawa, Waipukurau and Hastings, and twice weekly for Napier. No positive returns to date.