As an eighth wave of COVID-19 sweeps across Australia there has been a sharp rise in the number of people contracting the virus in the Northern Territory.

Whilst reporting of the COVID-19 through Rapid Antigen Tests (RATs) is no longer mandatory, the NT Centre for Disease Control has been notified of more than 500 cases over the most recent four-week period, mostly in Darwin, East Arnhem and Katherine regions.

The figure is an increase from the 160 confirmed cases in the two weeks between 21 October and 3 November, which itself was double the number from the previous two weeks.

Due to the lack of reporting, health officials are concerned the number could be higher.

This is of particular concern in the NT, where vaccine booster numbers remain low. Only an estimated 43 per cent of NT residents 75 years and over have received a COVID-19 vaccination in 2023.

The Central Australian Aboriginal Congress (CAAC), the territory's largest Aboriginal community-controlled health organisation, told National Indigenous Times that the rise of cases - especially amongst older and more vulnerable patients - was concerning.

"The big issue for us is that the dominant public message is that COVID-19 is the same as Influenza. This is leading fewer people to be up to date with boosters," CAAC said.

"COVID is not the flu. It mutates naturally and more frequently, so boosters are vital. It is also a much more deadly disease, and a virus that affects the vascular system.

"This brings with it an increased risk of subsequent cardiac events and strokes; a big concern in our population where there are already too many people at high cardiovascular risk."

The National Indigenous Times reported earlier this month on the high prevalence of rheumatic heart disease (RHD) in Indigenous people. Nearly a third of the NT identify as Aboriginal or Torres Strait Islander.

The CAAC said the population demographics could exacerbate the fatalities and serious impact of the disease.

"The threat of severe illness continues to be greater for older patients and for those with chronic disease or other frailties. Unfortunately, Aboriginal people are over-represented in this category," they said.

"Congress is concerned that we might be seeing excess deaths because of the longer-term effects of COVID, and we are working with the Menzies School of Health research to seek funding for a longitudinal study that could tell us whether this is true or not.

"In the meantime, we need people to adopt the precautionary principle when it comes to COVID as we still do not know the long-term implications of repeat infections."

Federal data indicates more than 6000 COVID-19 cases in the NT this year, and the Territory has the fastest growing rate of seniors aged 65 years and over in country.

The ABC reported earlier this month an Alice Springs aged-care facility had been hit by an outbreak which impacted over a third of the residents.

The CAAC said the messaging around COVID-19 hadn't changed.

"Stopping transmission is the way to protect yourself and your loved ones. Wash your hands and cough/sneeze safely. Wear a mask if you are in crowded indoor settings. Stay home if you feel sick and be sure to self-test using a RAT," they said.

"If you do test positive, talk to your GP or health service about whether you need treatment, especially if you are over 30 or have other health issues."

The NT Centre for Disease Control said GPs were encouraged to consider anti-viral treatment for all eligible COVID-19 patients.

"Vaccination remains key to protecting our community. Ensure that your patients are up to date to prevent severe COVID-19 disease and further deaths," they said in statement to all NT practitioners.