New National Notifiable Diseases Surveillance System (NNDSS) data shows pneumococcal disease is increasing.

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October 31, 2023 2:30 pm Australia/Sydney

The latest annual data published by the National Notifiable Diseases Surveillance System (NNDSS) have shown a rebound of invasive pneumococcal disease (IPD) to close to pre-pandemic levels.1

In the yearly update released on 5 September 2023, IPD cases for 2022, which had fallen during 2020 and 2021, have returned to similar pre-pandemic levels with the highest cases seen in children under the age of 2 years, adults aged 60 to <70 years and children aged 2 to <5 years.1

Cases in adults >70 years (70-74, 75-79, 80-84, 85+), considered at-risk age groups, have also risen but not to the levels seen in infants.1

The 2022 data release shows serotypes covered by vaccines currently listed on the National Immunisation Program (NIP) as well as serotypes not covered by currently funded pneumococcal vaccines are contributing to case numbers.1

Professor Robert Booy, Infectious Diseases Paediatrician, University of Sydney, says the return of disease incidence to pre-pandemic levels is not a surprise, but it is concerning that Streptococcus pneumoniae serotype 3, has once again become the most dominant IPD-causing serotype.1

“Throughout the first two years of the pandemic, IPD cases fell largely due to COVID non- pharmaceutical intervention (COVID-NPI) and the current resurgence of IPD cases was expected. Serotype 3 has been the most dominant serotype since 2014.1 In 2022 it remained the most dominant serotype in children <5 years including the most vulnerable cohort of 0 to <2 years. We’ve also seen a rise in serotype 33F to become the second most prevalent serotype in 2022 among infants <2 years followed by serotypes 19F, 15B and 22F together with 38,”1 Prof Booy said.

The NNDSS 2022 data show that serotype 3 followed by serotype 19F were also the two most dominant serotypes in adults aged > 70 years, however, in contrast to paediatric cohorts, serotypes 23A together with 6C, followed by 22F and 33F rounded off the top six IPD-causing serotypes.1

Professor Paul Van Buynder, Public Health and Infectious Diseases Epidemiologist, Griffith University, Queensland, says “While it is not known whether these trends are transient or permanent, given the ongoing dominance of serotype 3, a review of the pneumococcal landscape and how to best meet the challenges is required. We have an excellent pneumococcal program in place that to date has served the Australian population well, but we should now look at how we can best optimise the program in response to the evolving landscape.”

“As IPD cases return to pre-pandemic levels it’s advisable young children, Indigenous Australians and older adults keep up with the pneumococcal NIP schedule, that an optimal schedule is implemented,” he added.

The pneumococcal vaccination program for Australia is currently under review with the Government assessing pneumococcal vaccines funded under the National Immunisation Program (NIP) for eligible individuals.3

According to fortnightly data updates on the NNDSS Surveillance Dashboard, overall, 911 cases of IPD were reported nationally in the first two quarters of 2023 compared to 698 cases in the first two quarters of 2022.4 In children aged 0 to <5 years, 134 cases of IPD were reported in quarters 1 and 2, 2023 compared to 116 cases in quarters 1 and 2, 2022 while IPD cases in adults aged >70 years has increased from 178 in quarters 1 and 2, 2022 to 243 in quarters 1 and 2, 2023.4 Reported cases of IPD in 2023 thus far indicated that total cases for 2023 will surpass 2022 totals.4


  1. Australian Government Department of Health and Aged Care. National Notifiable Diseases Surveillance System (NNDSS) Public Dataset. Invasive Pneumococcal Disease Notifications in Australia 2009-2022 (NNDSS data as at 09/09/23). Available at system-nndss-public-dataset-pneumococcal-disease-invasive?language=en. Accessed 9 September 2023.
  2. Luck JN et al. Frontiers Cellular & Infection Microbiology. 23 December 2020;10:Article 613287.
  3. Australian Government Department of Health and Aged Care. Pneumococcal Disease. Accessed 25 September 2023.
  4. Australian Government Department of Health and Aged Care. National Notifiable Diseases Surveillance System (NNDSS) National Communicable Diseases Surveillance Dashboard. Datasets Quarters 1 and 2, 2022 and Quarters 1 and 2, 2023, Invasive Pneumococcal Disease. Available at Data as at 28 August 2023. Accessed 28 August 2023.