Four-week reporting period (23 October - 19 November 2023) Case definitions for confirmed and probable cases are in accordance with the coronavirus disease 2019 (COVID-19) CDNA National Guidelines for Public Health Units. Trends - Nationally, case notifications have slowly increased from late August to early September 2023, and have stabilised in recent weeks. In the four-week period 23 October - 19 November 2023, there were 26,871 confirmed and 11,612 probable cases, a total of 38,483 COVID-19 cases reported in Australia to the National Notifiable Diseases Surveillance System (NNDSS). In the most recent reporting fortnight, a total of 20,598 confirmed and probable cases were notified (an average of 1,471 cases per day), compared to 17,885 in the previous fortnight (an average of 1,278 cases per day), representing a 15% increase. Age group - Overall, notification rates among most age groups have stabilised following the end of the fifth Omicron wave in mid-August 2023. In the current reporting period, 23 October - 19 November 2023, the highest notification rate was observed among adults aged 90 years and over, whilst the lowest rates were among young people aged 10-19 years. Aboriginal and Torres Strait Islander people - In the reporting period 23 October - 19 November 2023, there were 1,014 new cases notified in Aboriginal and Torres Strait Islander people, accounting for 2.6% of all cases (1,014/38,483) during this time. In the Omicron wave to date (15 December 2021 - 19 November 2023), there have been 433,658 cases notified among Aboriginal and Torres Strait Islander people, representing 3.8% of all cases (433,658/11,443,294) during this period. Severity - Since the emergence of the Omicron variant, there has been a consistent decrease in the incidence of severe illness, with a smaller peak observed with each subsequent Omicron wave. This may be due to the lessening societal impact of the pandemic due to high COVID-19 vaccination coverage, hybrid immunity and access to oral antiviral treatments. Compared with previous Omicron waves, the number of cases with severe illness remained low and stable between mid to late August 2023, followed by a gradual increase from early September, signalling the start of the sixth Omicron wave. The overall crude case fatality rate from the start of the Omicron wave to date is 0.19%, which is lower than the crude rate during the Delta wave (0.71%). Virology - For samples collected in the four-week period 23 October - 19 November 2023, all sequences uploaded to AusTrakka were assigned against Omicron or recombinants consisting of Omicron lineages. This represents a 35% increase in the number of sequences compared to the previous reporting period. In this reporting period, of the 1,109 sequences uploaded to AusTrakka during 23 October - 19 November 2023, most (90.8%) were recombinant or recombinant sub-lineages; and 9.2% were BA.2 sub-sub lineages. Acute respiratory illness - Based on self-reported FluTracking data, there has been an overall decrease in the incidence of respiratory illness, 'fever and cough' and 'runny nose and sore throat' symptoms since the peak in early June 2023. Over the current period, the weekly average proportion of 'fever and cough' (1.4%) and 'runny nose and sore throat' (1.3%) were similar to proportions observed during the same period in 2022. International situation - According to the World Health Organization (WHO), as of 22 October 2023, over 772 million COVID-19 cases and over six million deaths have been reported globally since the start of the pandemic, with a global case fatality rate (CFR) of approximately 0.90%.
