Seventy per cent of those attending came from the Auckland-Hamilton area.
Covid-19 wastewater testing was done at Paihia on Thursday, and samples sent to Institute of Environmental Science and Research (ESR) with analysis due to be carried out yesterday.
"I was absolutely horrified," festival organiser Shirley May said of hearing the news on Tuesday of a community Covid-19 case in Auckland.
May is among about 30 people from the Bay of Islands Jazz and Blues Festival who have already been to get tested at the Kawakawa Covid-19 testing station.
"All I could think of was about how many people at our festival might have been in contact with that person," she said.
Her concern grew as the case was confirmed as the more infectious Delta strain. It was added to as the number of Auckland cases and places of interest increased.
The first Ministry of Health official contact tracing location of interest was in Hillsborough, Auckland on August 1. The North Shore has strongly featured with these. More than 100 locations are now listed, from across a swathe of Auckland, and Coromandel.
"There were definitely people here at the jazz festival from the North Shore for example," May said.
The festival took place across three venues in Paihia, one at Haruru Falls and two in Russell. It is one of Northland's biggest annual events. Most of this year's 43 acts were from Auckland.
Glenn Rainham, Far North District Council (FNDC) manager infrastructure operations, said Paihia wastewater testing had been carried out because it was the Far North's key tourist town.
He said the testing had also been done at the Kerikeri and Kaitaia wastewater treatment plants – FNDC's two biggest of 15 across the district.
May said she had been closely monitoring her health since the festival to see if Covid-19 symptoms developed.
Her message to festival-goers was to do the same and continue to check the Ministry of Health's locations of interest listing.
This year's festival attendance was more than 30 per cent up on its previous year. About 900 people attended in 2019.
The 2021 attendees came from "all over the country", May said.
She said it was entirely possible people at the event had been at some of the locations of interest.
Many attendees stayed for a week, arriving on Thursday.
"Quite a lot of people stayed on until Tuesday," she said.
Meanwhile, Kaipara District Council (KDC) has not had official requests for Covid-19 wastewater testing – in spite of being Auckland's next door northern neighbour, with Mangawhai a popular holiday spot for those from the city.
Whangārei District Council (WDC) was unable to respond to Northern Advocate Local Democracy Reporting about local Covid-19 wastewater testing by edition time.
Covid-19 wastewater data is used as an additional tool to understand how the virus is spreading in the community. The virus that causes Covid-19 is shed in human waste, often before a person knows they are infected.
High levels of Covid-19 virus in wastewater sampling can be followed by a rise in clinically diagnosed cases.
Wastewater data captures symptomatic and asymptomatic cases.
The wastewater tested comes from toilets, showers, baths, basins, sinks and laundries and is then passed through the sewerage system.
The Bay of Islands Jazz and Blues Festival began in 1985 and was cancelled for the first time last year because of Covid-19.
