Otago and Southland can expect more than 18,000 cases of Covid-19 this year, 70% of which are likely to occur in March and April, new modelling suggests.
The projections, to be considered by the Southern District Health Board tomorrow, suggest many more people will fall ill to the disease than previously expected due to the probable arrival in the region of the more transmissible Omicron variant.
Many more cases were predicted to lead to many more hospital admissions, 660, but the number of patients predicted to need intensive care was much lower, just 13.
Many more seriously ill people had been anticipated in earlier modelling but that was based on an outbreak of the Delta variant, also highly transmissible but much more virulent than Omicron.
The research, from the Northern Region Health Co-ordination Centre, based its findings on a reproduction rate of 10 infections for every Omicron case in the region.
Assuming an outbreak of 10 cases in Otago and/or Southland, after two weeks that was likely to have increased to 1000 cases, and to 5000 cases after 19 days.
"With the volume of cases, current testing strategies will not be fit for purpose," SDHB chief executive Chris Fleming warned.
"The number of presentations to the health system, either hospital or primary care for conditions unrelated to Covid, but where the patient is Covid positive, will also be significant."
Yesterday, the Ministry of Health announced 91 new community cases of Covid-19, all in the North Island.
Omicron has already become the dominant strain of Covid-19 found in the community and the ministry said it planned to stop reporting the variety of the disease in its case numbers.
Although the new case numbers modelling was not as steep as some earlier Omicron work provided to the SDHB, which had predicted a worst-case scenario of more than 20,000 cases this year, the new projections would still lead to extreme pressure on primary and community services.
With that many Covid-19 cases the vast majority would have to either be caring for themselves at home, or be managed by primary health in the community, Mr Fleming said.
Between 20% and 30% of the entire workforce was expected to be off work at the height of an outbreak, affecting supply lines for medical equipment and also treatment itself, assuming clinicians and hospital staff were affected to the same degree.
"We are having to identify what core services are in order to be able to prioritise the maintenance of these services in the height of the outbreak," he said.
"Planned and non-essential services will be disrupted, and this will create further backlogs in the health system post the resolution of the outbreak."
Should staff shortages become severe, hospitals might only be able to provide life-preserving services.
SDHB acting quality and clinical governance solutions director Dr Hywel Lloyd warned aged residential care and home support services would also be compromised by the predicted scale of the Omicron outbreak.
While care would be maintained wherever possible, there would be a limited availability of additional workers, and the ability to admit patients would be reduced or non-existent.