Hereford conference Covid cluster put out to pasture
One of New Zealand’s highestprofile coronavirus clusters has been put out to pasture.
The cluster known simply as the ‘‘world hereford conference’’ was officially closed late last week by the Ministry of Health, meaning it had recorded no new cases for two incubation periods.
That cluster – linked to delegates travelling to the Queenstown cattle conference – involved 39 cases.
It was one of two clusters in the Southern District Health Board catchment area. The other, the Bluff wedding cluster, remains open and is the country’s largest cluster at 98 cases.
Closing a cluster such as the hereford conference was ‘‘always great when we reach another milestone of closure of a cluster’’, the SDHB’s medical officer of health, Dr Susan Jack, told Stuff.
‘‘A huge amount of work goes into investigating and tracking contacts, and monitoring cases that are linked. So knowing the transmission chain has stopped and then having those two incubation periods to be confident there is not . . . any ongoing transmission is great.’’
Clusters showed how quickly Covid-19 could spread, she said.
‘‘You only need one person to be infectious, and then rapidly that can escalate to many others.’’
The clusters became apparent during daily team meetings, and that would then cause the investigation to ‘‘snowball’’.
Jack said one of the issues identified was the incubation period of the disease, which ‘‘was only just being established’’ at the time that cases and clusters were identified.
The cases also highlighted the importance of documenting all the information ‘‘to get the right story, and the picture of transmission’’.
About 400 people from 18 countries were at the conference. Several stayed on for a five-day South Island tour, and some are known to have visited Wa¯naka and gone to the town’s A&P show.
It wasn’t until March 18 that Herefords NZ confirmed that a conference attendee from overseas had tested positive for Covid-19.
That risk to the 400 conference attendees was initially downplayed as the infected person did not stay at the official hotels or attend tours.
But that would soon change as more and more cases linked to the conference emerged, and a cluster was declared by health officials.
Those early cases included an Australian, a Uruguayan farmer, a West Otago woman and a Dunedin woman in her 30s.
A positive test for a 58-year-old Te Aroha-based coach driver showed how quickly the virus could spread to other communities.
Heavily redacted emails released from the SDHB show conference organisers were also under pressure from suppliers over a possible outbreak. ‘‘They are frankly annoyed they were not told earlier,’’ one email said.
All conference participants were contacted and advised to self-isolate by late March.