Covid-19 cluster confusion: what you need to know

By Susan Strongman, RNZ

To date, there are 177 Covid-19 cases associated with the Auckland August Cluster. The current number of active cases within the cluster is 55.

But somewhat confusingly, the Ministry of Health has divided sections of the Auckland August Big Group into five of what it calls “subgroups.” This occurs despite some experts arguing that these classifications are not helpful and that the cases should be referred to as several separate groups or an outbreak.

Subgroups include cases associated with Mt Roskill Evangelical Fellowship Church (33 cases), ‘bereavement events’ (15 cases), North Shore Hospital emergency department (3 cases), cases in the eastern suburb of Botany Auckland (6), and cases related to the well-known general practitioner Joe Williams (5).

None of these subgroups has been epidemiologically related to the August Auckland cluster. This means that contact trackers have not been able to determine when or where a person from the August group infected with Covid-19 came into contact with and infected another person from any of the subgroups.

However, two of the subgroups are epidemiologically linked to each other; the Mt Roskill Evangelical Fellowship subgroup and the grieving subgroup. The virus was transmitted when a church member visited a grieving family, while awaiting the results of a Covid-19 test, inadvertently infecting members of the grieving group with the virus. Among those infected were a St Dominic’s Catholic College student and a bus driver, both classified as members of the grieving subgroup.

Genomic tests, which look at the genetic sequence of the virus, allow scientists to link Covid-19 cases to each other, but not to identify how the case was transmitted from person to person. Through genomic testing, we know that all subgroups are linked to the Auckland August group, but we do not know how the virus was transmitted from one person in the Auckland August group to the first infected person within each sub-cluster.

Auckland August Cluster:

• 177 cases in total, of which 55 are active. A death.
• The origins of this group remain under investigation.

On August 11, a person in his 50s, who worked at the Americold refrigerator in Mt Wellington, tested positive for Covid-19. More cases of the virus were detected in the workers’ colleagues and relatives.

On September 4, Americold staff member Alan Te Hiko, who was 50, was the youngest person to die in New Zealand from the coronavirus. The origins of this group continue to be investigated.

Subgroup of the Mt Roskill Evangelical Scholarship:

• 33 cases. 17 assets.
• Genomically linked to Auckland August Cluster.

The subgroup was originally larger, but split in two, when the cases associated with the bereavement events were classified as a subgroup by the Ministry of Health. The epidemiological link to the August Auckland group is unknown.

Grief Event Subgroup:

• 15 cases. All active.
• Genomically linked to Auckland August Cluster.
• Epidemiologically linked to the Mt Roskill Evangelical Fellowship subgroup.

The virus was transmitted when a member of the Mt Roskill Evangelical Fellowship visited a grieving family, while awaiting the results of a Covid-19 test, inadvertently infecting members of the grieving group with the virus. Among those infected were a St Dominic’s Catholic College student and a bus driver, both classified as members of the grieving subgroup.

Botany Subgroup:

• Six cases. An active one.
• Genomically linked to Auckland August Cluster.

The first case in this subgroup was reported on August 28 and the most recent case was reported yesterday (September 14). According to the Herald, the group consists of two households. The epidemiological link to the August Auckland group is unknown.

North Shore ER Subgroup:

• Three cases. None active.
• Genomically linked to Auckland August Cluster.
On August 21, a man in his 30s arrived at the North Shore hospital with symptoms of the virus. It is not clear how this man became infected with Covid-19.

GP subgroup:

• Five cases. Four recovered. A death.
• Genomically linked to Auckland August Cluster.

It is unknown how 82-year-old former Prime Minister of the Cook Islands and prominent physician Joe Williams contracted the Covid-19 infection that led to his death on September 4. Five other cases of the virus are associated with this subgroup, and the virus is genomically linked to the Auckland August group. The epidemiological link with the group is unknown.

Outliers:

There are two other community cases of Covid-19 in New Zealand, which are not linked to the Auckland August cluster either genomically or epidemiologically. These cases, both now recovered, were identified in a worker at the isolation and quarantine center run by the Rydges Hotel in Auckland, and in the brother of a person who visited the Hobbiton film set.