Analytics

Healthcare worker infections dashboard
By Dr Katherine MacKinnon, Medical Registrar, VIC

Below is a compilation of Victorian data of healthcare worker (HCW) and non-healthcare worker COVID-19 infections. This series started from the 16th July 2020, the date of first consistent reporting of healthcare worker infections in Victoria. Data from other states may be collated as it is released to the public domain.

 The Victorian DHHS definition of a HCW changed with launch of their dashboard to, “a healthcare worker is someone who works in health and aged care settings providing direct care to patients. This includes registered health practitioners, other health practitioners, diagnostic and ancillary staff. Support staff in these settings (such as those in administration or cleaning) are not considered healthcare workers.”  

Note from the Editor

This is a restrictive and somewhat arbitrary definition that may underestimate risk to HCWs. An investigation into an outbreak at a major Melbourne Hospital revealed that 19% (49/262) of HCWs were from supporting roles (e.g, security, administration, cleaners, laboratory staff). Our preference is to have all the de-identified data released for independent analysis.-Michelle Ananda-Rajah

Definitions

For occupations registered with the Australian Health Practitioner Regulation Agency (AHPRA), the most recent number of registered practitioners from the 2018/2019 annual report was used. These figures were inflated to estimate growth to 2020 by applying the same percentage growth rate in the preceding 12 month period. For paramedics, where no preceding growth was recorded, the total sector growth of 5.9% was applied.

Table 1. Estimated numbers of APHRA registered healthcare workers in Victoria
Registered 2018/2019 Growth over preceding 12 months Estimated 2020
Medical practitioner 29,322 3.4% 30,311
Nurse 101,498 3.6% 105,113
Midwife 1,495 9.9% 1,644
Nurse and midwife 7,591 -2.0% 7,438
Aboriginal and Torres Strait Islander Health Practitioner 21 7.6% 23
Chinese medicine practitioner 1,311 0.2% 1,314
Chiropractor 1,457 2.4% 1,492
Dental practitioner 5,536 2.8% 5,689
Medical radiation practitioner 4,061 2.6% 4,167
Occupational therapist 5,715 6.9% 6,109
Optometrist 1,521 4.5% 1,589
Osteopath 1,489 6.6% 1,587
Paramedic 5,108 5,411
Pharmacist 8,117 2.7% 8,336
Physiotherapist 8,317 5.6% 8,783
Podiatrist 1,719 4.0% 1,788
Psychologist 10,415 3.9% 10,818
Total 194,693 5.9% 201,611
Table 2. Estimated numbers of other healthcare workers in Victoria

Data for other occupations meeting the definition of healthcare worker was obtained from the Australian Jobs Report 2019 Edition supplementary occupation matrix, which outlines the number of persons employed by occupation, as well as growth predictions within the Health and Social Services Industry.

Employed Nationally 2018 % National HSS Industry 2018 Est. Employed VIC 2018 Projected Growth over 5yrs Projected Annual Growth Est. Employed VIC 2020
Aged and Disabled Carers 175,859 10.44% 46,023 39.34% 3,621 53,265
Dental Assistants 25,293 1.50% 6,619 6.59% 87 6,794
Dental Hygienists, Technicians and Therapists 6,604 0.39% 1,728 2.67% 9 1,747
Medical Imaging Professionals 23,018 1.37% 6,024 11.30% 136 6,296
Medical Technicians 35,318 2.10% 9,243 0.62% 11 9,266
Nursing Support and Personal Care Workers 98,944 5.87% 25,894 11.62% 602 27,098
Nutrition Professionals 7,037 0.42% 1,842 17.59% 65 1,971
Occupational & Environmental Health Professionals 30,226 1.79% 7,910 9.19% 145 8,201
Social Workers 37,691 2.24% 9,864 7.97% 157 10,178
Speech Pathologists and Audiologists 11,181 0.66% 2,926 38.31% 224 3,374
Total 451,169 118,074 128,191

Each occupation category for the 451,169 workers employed nationally was divided by the national Health and Social Services Industry in 2018 (1,685,100) to give a percentage of the industry workforce. This same percentage was then applied to the Victorian Health and Social Services Industry for each occupation to estimate the number of workers by occupation in 2018.

 To account for growth in the workforce between 2018 and 2020, the projected growth estimates from the report were applied to each occupation to estimate the number of workers in 2020. Collectively, these additional occupations make up a further 128,191 healthcare workers in 2020.

Adding these two data sources together (201,611 + 128,191) provides an estimated population size of 329,802 healthcare workers.

 The latest population of Victoria from the Australian Bureau of Statistics demographic data is 6,651,100. Hence the population sizes used are 329,802 Healthcare workers, and 6,321,298 Non-Healthcare workers.

Figure 1: Daily Incidence of COVID-19 cases among healthcare workers and non-healthcare persons.
16.10.20 - Figure 1

* Note there may be some delays in publicly identifying a case as a healthcare worker. These numbers reflect the time of reporting, not diagnosis, and may not always represent cases diagnosed on the same day. On 28 August and 29 September there were catch-ups in cases reassigned as healthcare workers which exceeded the daily case numbers, leading to a negative incidence in the non-healthcare worker population on those days. Similarly on 3 October the total number of healthcare workers reported was reduced by 9 cases (likely due to re-classifying cases as non-healthcare workers), leading to a negative incidence on that day. Numbers above the bars are daily counts. Y axis is number of COVID-19 infections.

Figure 2: The number of active cases of total COVID-19 infections among healthcare workers in Victoria.
16.10.20 - Figure 2

On the 16th July, the first date of consistent reporting on healthcare worker infections,  there were 388 total infections in healthcare workers since the beginning of the pandemic, 150 of which were active at that time.

Figure 3: Healthcare worker COVID-19 infections infections among Victorian cases.
16.10.20 - Figure 3

The graph shows the proportion of healthcare worker infections as a percentage of new cases and of all cases since the 16th of July 2020. A 7-day incidence is used rather than the daily incidence to account for fluctuations in the daily numbers. Total cases since the 16th of July (the first date of consistent reporting on healthcare worker infections) is used to more closely examine the risk to healthcare workers in Victoria’s second wave.
The dashed line represents the estimated prevalence of healthcare workers in the Victorian population. Healthcare worker infections are disproportionately increased relative to their estimated prevalence in the Victorian population, and this over-representation has increased with time during Victoria’s second wave.
In the month of September healthcare workers have consistently made up greater than 30% of new cases, with a maximum of 66% of new cases at the start of the month. Since the 16th July, greater than 20% (or 1 in 5) cases in Victoria was diagnosed in a healthcare worker.

Figure 4: Incidence of healthcare worker and non-healthcare worker infections, adjusted for population specific to HCW and non-HCW.
16.10.20 - Figure 4

This graph shows the incidence of COVID-19 infections reported in healthcare workers and non-healthcare workers adjusted for their respective populations. Both are expressed as a rolling 7-day average in order to minimise the daily fluctuations in case numbers. Incidence is adjusted for the population of HCWs in blue and non-HCWs in gold using the following estimates: 329,802 HCWs, and 6,321,298 Non-HCWs.

Figure 5: Odds ratio comparing the odds of healthcare worker vs non-healthcare worker infection using different population case numbers.
16.10.20 - Figure 5

This graph expresses the odds ratio of the odds of a healthcare worker becoming infected compared to the odds of a non-healthcare worker becoming infected with COVID-19. The Odds ratio is calculated daily to show change over time, and all healthcare worker occupations meeting the DHHS case definition are pooled in this estimate.

An odds ratio less than 1 indicates reduced likelihood of infection, an odds ratio equal to 1 indicates no difference in the likelihood of infection, and an odds ratio greater than 1 indicates increased likelihood of infection. The larger the odds ratio, the greater the odds of healthcare worker infection compared to a non-healthcare worker.

Table 3. Role specific odds ratios for HCWs
Table 3
Table 3 - 29.09.20
Table 3 - 22.09.20
Table - Occupation ORs
Table 2 - 10.09.20

Data on the occupation-specific infection rates obtained from the DHHS Healthcare Worker data dashboard, which is updated weekly on Tuesdays: https://www.dhhs.vic.gov.au/victorian-healthcare-worker-covid-19-data. Data on the dashboard lags the daily reported data by approximately 1 week, and the most recent download from the dashboard (13 October 2020) includes healthcare workers diagnosed up to 7 October 2020.

Support staff e.g. cleaners, admin, security staff are not represented in the Victorian DHHS definition for HCW.

The odds ratio compares the odds of a HCW becoming infected compared to the odds of a non-HCW becoming infected. An odds ratio less than 1 indicates reduced likelihood of infection, an odds ratio equal to 1 indicates no difference in the likelihood of infection, and an odds ratio greater than 1 indicates increased likelihood of infection. The larger the odds ratio, the greater the odds of HCW infection compared to a non-HCW.

References

  1. Victorian Department of Health and Human Services; Victorian healthcare worker coronavirus (COVID-19) data. Accessed 8 Sept 2020 from https://www.dhhs.vic.gov.au/victorian-healthcare-worker-covid-19-data
  2. Australian Government Department of Education, Skills and Employment. Australian Jobs Report – Supplementary Occupation Matrix. Downloaded 9 Sept 2020 from: https://docs.employment.gov.au/collections/australian-jobs
  3. AHPRA 2018/2019 Annual Report – Supplementary Table R3
  4. Australian Government Department of Education, Skills and Employment. Australian Jobs Report 2019 Edition. https://australianjobs.employment.gov.au/
  5. Australian Demographic Statistics. Australian Bureau of Statistics.