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covid19_victoria

Covid-19 in Victoria

Introduction

  • population 6.4 million
    • 4.5 million live in Greater Melbourne
      • Western Health with Werribee Mercy services:
        • 255,000 in City of Wyndham
        • 209,000 in City of Brimbank
        • 157,000 in City of Melton
        • 97,000 in City of Hobsons Bay
        • 91,000 in City of Maribyrnong
        • plus NW regions such as Sunbury, Gisborne
        • by comparison, the population of the whole of Tasmania is 522,000
    • 188,000 live in Geelong
    • 104,000 live in Ballarat
    • 94,000 live in Bendigo
  • pre-Covid19 healthcare capacity
    • Victoria has very limited ICU capacity with only 476 ICU beds, much fewer per capita than NSW, Italy and far fewer than Japan and South Korea, but the Victorian govt is planning to at least double capacity and hopes to secure 2000 ventilators from overseas and may consider converting the Melbourne Convention and Exhibition Centre into a makeshift intensive care hospital and morgue 1)
    • Doubling the number of ICU beds means finding another 10,000 intensive care nurses if one wishes to maintain a 1:1 patient to nurse ratio. In reality, when it comes to this the system will operate in crisis mode and nurse ratios may need to be changed and standard of care reduced.
    • the Vic. Premier announced it will create and additional 4000 ICU beds to bring the capacity to 4500. The Victorian government will spend $1.2 billion on buying machines and personal protective equipment for healthcare professionals. A further $65 million will be spent on capital works and upskilling the health workforce.2) Unfortunately, it is hard to see how the number of ventilators, accessories and critical care enabled staffing could practically be uplifted to support anywhere near this level given global demands.

Covid-19 timeline

  • 1st March: 9th case in Victoria; DHHS starts to drive hospitals to increase capacity, use telehealth3) and consider introduction of fever clinics when testing demand ramps up.
  • 11th March 2020: WHO declares it a pandemic
  • 14th March: 1st Victorian case to have been acquired in Australia without a known local contact with an overseas traveler
  • 19th March: mass gatherings of more than 100 people indoors and 500 outdoors banned in Australia, resulting in sports being played without crowds, tourist destinations such as The Twelve Apostles Visitor Centre, the 1000 steps, Werribee mansion and Buchan Caves closed.
  • 20th March: Australia bans entry of all non-residents and residents arriving will have to self-isolate for 14 days
  • 21st March: Stage 1 restrictions introduced
  • 24th March: WA, SA and NT close borders to eastern states
  • 24th March: Vic and NSW Stage 2 lock down - only essential services open, while schools and non-essential retail, gyms, etc to close
  • 28th March 2020: 1st Covid-19 patient to die at Western Health, 2 others intubated in ICU
  • 29th March: all residents arriving in Australia enforced quarantine in hotels on arrival for 14 days
  • 30th March: Stage 3 social distancing restrictions put in place - no more than 2 people together outside; beaches, outside gyms and playgrounds closed;
  • 31st March: 917 confirmed cases of which only 37 have been acquired in Australia without a known local contact with an overseas traveler (536 from OS travel and 281 local contacts of these travelers, and most cases are those in their 20's and live in CBD, inner eastern suburbs and Mornington Peninsula); 4 deaths; over 45,000 tested;
  • 1st April: massive funding boost for ICU beds as the number of confirmed coronavirus cases rose by 51 overnight, bringing the state's total to 968. The Health Department believes 39 people acquired the disease through community transmission. 32 people in hospital, including six in intensive care, and 343 people have recovered.
  • 22nd April: minimal community transmission evident; Reff estimated to be 0.5 due to the strict social distancing laws4); re-introduction of some elective surgery, particularly cat 1 priority cases;
  • 24th April: notification of a small outbreak with 16 positive cases at Albert Road Clinic, a private mental health facility in Melbourne
  • 30th April: four residents and one worker tested positive in Hawthorn Grange aged care facility
  • 1st May: voluntary screening of asymptomatic HCWs begins and plans to screen 100,000 people in next 2 weeks to ascertain degree of community spread
  • 2nd May: notification of 8 employees at a meat processing plant testing positive after one had presented to hospital with initially asymptomatic disease. Facility was closed for further cleaning and contact tracing.
  • 7th May: 62 cases now connected with the Cedar meat processing plant 5) as HCW's at two aged care facilities test positive - Bacchus Marsh and Footscray. Victoria's known active cases rise to 114.
  • 9th May: 76 cases now connected with the Cedar meat processing plant outbreak;
  • 11th May: Premier announces easing of restrictions starting 13th May - 5 family/friend visitors indoors and 10 outdoors; Can now go hiking, golf, fishing but no overnight stays including camping, hotels or AirBnB; Cafes still restricted to take aways only; Communal outdoor gyms and playgrounds remain closed; 6)
  • 14th May: new outbreak amongst workers at MacDonald's Restaurant in Fawkner
  • 17th May: Premier announced further easing of restrictions as of 1st June with cafes and restaurants allowed to re-open with max. 20 patrons per enclosed space which will increase to 50 by June 22 and 100 from mid-July but public bars will remain closed only the bistros can open, and restaurants will be required to keep contact details of all patrons and comply with a range of rules. Cedar Meats outbreak now at 100.

Predictive modelling

  • epidemic calculators:
    • day 0 is mid-Feb 2020, day 150 is thus mid-July
    • the timing of the peak is very sensitive to the duration a patient is likely to be infectious or the incubation period, and less sensitive to reductions in R0
    • some things to note with this calculator:
      • it is really designed to examine community spread and not cases brought in from outside the region
      • it would appear that given it displays calculated numbers of infected persons rather than tested confirmed cases, one should probably use the true fatality rate of around 0.7% rather than case fatality rates, and thus the hospitality rates should also be reduced to have the unconfirmed community cases added to the denominator and thus hospitalization rates should perhaps be reduced from 20% down to around 3-5%
      • unless you untick the display fatalities option, the chart of those in hospital is actually in ADDITION to fatalities to date so you need to look at the value on the left legend to determine how many are in hospital, not the Y axis value.
    • for a suburban region of population 750,000, incubation period 5 days, infectious period 6 days, CFR 0.7%, time to hospitalization 5 days, hospitalization rate 4%, hosp. LOS 15 days, time to death 18 days, initial R0 of 2.2:
      • if no social distancing measures and R0 remains at 2.2:
        • peak hospitalizations will occur at day 130 with around 6,400 in hospital although there are only around 1000 actual beds and deaths at this time would be around 2,100 with 70 deaths per day at CFR of 0.7% but given the health services would be overwhelmed, CFR may well be 5 times this much as is the Italian scenario. Hospitalized cases would continue for about 250 days as herd immunity exceeds 80% and total fatalities would reach over 4,000 if hospital capacity was able to meet demand but the realities are that fatalities would probably be 5 times this much.
      • if social distancing reduces R0 to 1.6:
        • peak hospitalizations will occur at day 180 with around 3,200 in hospital although there are only around 1000 actual beds and deaths at this time would be around 1,800 with 33 deaths per day at CFR of 0.7% but given the health services would be overwhelmed, CFR may well be 3-5 times this much as is the Italian scenario. Hospitalized cases would continue for about 1 year and presumably social distancing will need to be almost as long. Total fatalities would reach over 3,000 but may be 3-5x this much if system is over-whelmed.
      • if social distancing reduces R0 to 1.2:
        • peak hospitalizations will occur at day 270 with around 700 in hospital which is now manageable while deaths at this time would be around 840 with 7 deaths per day. Hospitalized cases would continue for almost 2 years and presumably social distancing will need to be almost as long. Total fatalities would reach over 1,600.
      • if extreme social distancing reduces R0 to 0.8:
        • peak hospitalizations will occur at day 25 after the reduction to R0 of 0.8 with around 45 in hospital and deaths at this time would be around 14, HOWEVER, borders would need to remain closed until a vaccine is available otherwise it will start all over again. Hospitalized cases would continue for about 1 year and presumably extreme social distancing will need to be almost as long. Total fatalities would be around 50.
covid19_victoria.txt · Last modified: 2020/05/17 18:07 by gary1