The list of new subvariants appearing within New Zealand is lengthy and growing. Many of these new subvariants are identified by their mutations, many of which are shared across several subvariants, but it can take weeks or months to determine whether these mutations will allow a subvariant to out-compete others circulating in the community. At the early stage of a new variant being identified in New Zealand, it is difficult to predict whether and when it will become established in the community.
So far, most Omicron variants have not demonstrated a change in severity of the disease. Early evidence overseas suggests the BQ.1.1 has a growth advantage relative to BA.5, the dominant variant currently circulating in New Zealand. In recent weeks in the Northern Hemisphere the colder weather, waning immunity, timing of last vaccinations and other behavioural factors, are likely to have contributed to an increase in BQ.1.1 cases. Evidence is still evolving as to how BQ.1.1 would compete against BA.5 in a New Zealand context and whether this could affect the level of COVID-19 circulating in the community in the coming months.
Relative to many other parts of the world, New Zealand currently has a high level of immunity based on high vaccine uptake and widespread relatively recent infection predominantly with BA.2 and BA.4/5 variants.
Vaccines are still expected to provide robust protection against severe disease, particularly in those who have received boosters. We encourage people to get their vaccine and booster doses when they fall due.
The recent increase in cases nationally falls within our expected modelling of a slow rise in cases from now to the end of the year, although this may still change.
We would expect regions to experience increases and decreases in COVID-19 cases at different times depending on a range of conditions. Local factors that could impact case numbers include levels of immunity in the community related to immunisation, previous infections, large events and indoor gatherings.
At this stage, there is no evidence that BQ.1.1 is driving an increase in cases but Manatū Hauora - the Ministry of Health, and Te Whatu Ora – Health New Zealand, alongside ESR, are closely monitoring the development of COVID-19 subvariants overseas and in New Zealand, including BQ.1.1.
The Ministry of Health carries out regular COVID-19 public health assessments and updates its advice to Government on appropriate public health measures based on the latest evidence.
The next update on cases, hospitalisations, deaths and trends analysis will be published by Te Whatu Ora on Monday 17 October.