An
estimated 3,905,966 Australian residents contracted
SARS-CoV-2/COVID-19 (probably the Omicron or Omicron sub-variants) between the beginning of December 2021 and end of
February 2022.
That
is 3.9 million people infected in a three month period.
According to NCIRS - Australian COVID-19 Serosurveillance Network:
"Prevalence
of anti-nucleocapsid antibodies was 17.0% (16.0–18.0) overall.
Seroprevalence was highest in Queensland (25.8%; 23.3–28.5),
followed by Victoria (22.6%; 20.1–25.2) and NSW (21.4%; 19.1–23.9).
Seroprevalence was lowest, at 0.5% (0.2–1.2) in WA (Figure 4A). No
differences in seroprevalence across jurisdictions were observed
following age adjustment compared with unadjusted seroprevalence..." [my yellow highlighting]
On
the last day of February 2022 there were still 204,973 confirmed
active COVID-19 cases across Australia and the daily number of
confirmed active cases steadily grew during
March before
peaking at 483,680 cases as
the month ended.
On
3 April
national
confirmed active Covid-19 daily cases reached 502,377 before
slowly falling to remain stubbornly well above 400,000 until
mid-April when cases number began to fall again.
On
1 May 2022 Australia had 326,554 confirmed active COVID-19 cases, by
16 May 385,923 & by 31 May 278,717.
As of 4pm on Monday, 20 June 2022, Australia-wide there were est. 211,622 active cases of COVID-19 recorded by the Australian Government Dept. Of Health.
All these March to June 2022 figures are considered to also be a significant under reporting of actual infection numbers in the general population.
~~~~~~~~~~~~~~~~~~~~~~~~~
Media
release, 20 June 2022:
National
antibody study confirms COVID-19 cases higher than reported
At
least 17% of Australian adults are estimated to have recently had
COVID-19 at the end of February 2022.
Adults
aged 18–29 years had the highest proportion of antibodies to
SARS-CoV-2, the virus that causes COVID-19.
Queensland
had the highest antibody positivity rate, while Western Australia
had the lowest.
The
next blood donor survey and a paediatric serosurvey have commenced
and will provide an updated snapshot to mid-June 2022.
It
is estimated that at the end of February 2022 at least 17% of the
Australian adult population had recently been infected with
SARS-CoV-2, the virus that causes COVID-19, according to results
released today from Australia’s most recent serosurvey of
antibodies to the virus in blood donors. The vast majority of these
infections are believed to have occurred during the Omicron wave that
began in December 2021. Based on survey results, the proportion of
people infected was at least twice as high as indicated by cases
reported to authorities at the end of February 2022. [my yellow highlighting]
The
serosurvey was conducted by the National Centre for Immunisation
Research and Surveillance (NCIRS) and the Kirby Institute at UNSW
Sydney, in collaboration with Australian Red Cross Lifeblood, Royal
Melbourne Hospital’s Victorian Infectious Diseases Reference
Laboratory at the Doherty Institute and other research partners.
The
highest proportion of adults with antibodies to SARS-CoV-2 was in
Queensland (26%), followed by Victoria (23%) and New South Wales
(21%), while Western Australia had the lowest (0.5%).
The
serosurvey method detects higher proportions of infection than
routine surveillance based on cases diagnosed and reported at the
time of infection, which misses people who didn’t present for a
test or whose positive test result was not reported to authorities.
The
national antibody survey was conducted in late February to early
March 2022, approximately 6 weeks after the peak of the Omicron wave
in New South Wales, the Australian Capital Territory, Queensland and
Victoria and prior to substantial transmission in Western Australia.
“The
general pattern of antibody positivity in blood donors was consistent
with the pattern in reported cases to the end of February 2022: New
South Wales, Victoria and Queensland having had big outbreaks, and
Western Australia having very limited community transmission,” says
Dr Dorothy Machalek, lead investigator on the project from the Kirby
Institute. “Similarly, young blood donors had the highest rate of
infection, matching higher reported case numbers in this age group.”
Researchers
examined 5,185 de-identified samples from Australian blood donors
aged 18–89 years for evidence of COVID-19–related antibodies. Two
types of antibody to SAR-CoV-2 were tested: antibody to the
nucleocapsid protein, which provides an indication of past infection,
and antibody to the spike protein, which can indicate past infection
and/or vaccination.
Evidence
of past infection was highest among donors aged 18–29 years at
27.2%, declining with increasing age to 6.4% in donors aged 70–89
years across Victoria, New South Wales and Queensland. In Western
Australia, evidence of recent infection was extremely low across all
age groups. Nationally, the proportion of the population with
antibodies to the spike protein was far higher, at around 98%.
“As
expected a very high proportion of the blood donors had antibodies to
the spike protein of the COVID-19 virus, with little variation by age
group and sex. This was likely due to high vaccination rates among
blood donors, as well as in the wider population,” says Professor
Kristine Macartney, Director of NCIRS and Professor at The University
of Sydney.
“Future
rounds of the blood donor serosurvey will allow us to understand how
many infections occur throughout 2022,” Professor Macartney said.
“We are also conducting a second national paediatric serosurvey
that started collection in June and this will give us better insights
into transmission in children and teenagers.”
The
ongoing blood donor survey, co-led by the Kirby Institute and NCIRS
in collaboration with Australian Red Cross Lifeblood, also involves
investigators at the Royal Melbourne Hospital’s Victorian
Infectious Diseases Reference Laboratory at the Doherty Institute,
NSW Health Pathology ICPMR, The University of Sydney and Murdoch
Children’s Research Institute.
The
residual blood donation samples used in the survey were obtained from
Lifeblood’s processing centres across the country and delinked from
any identifying information apart from age, sex and post code.
Individual results can therefore not be provided back to blood
donors.
“Australian
Red Cross Lifeblood encourages anyone wanting to contribute to this
type of research to become a regular donor. There are many benefits
to donating, including finding out your blood type,” says Professor
David Irving, Director of Research and Development at Australian Red
Cross Lifeblood.
The
next round of the Lifeblood donor survey has commenced from mid-June.
This time point will estimate SARS-CoV-2 antibody prevalence
following the spread of the Omicron BA.2 and other subvariants. Data
are provided to all states, territories and the Commonwealth
Government under the Australian National Disease Surveillance Plan
for COVID-19.
Read
the full report here
~~~~~~~~~~~~~~~~~~~~~~~~~
Seroprevalence
of SARS-CoV-2-specific antibodies among Australian blood
donors, February–March 2022, The
Australian COVID-19 Serosurveillance Network, Final
report, 3 June 2022, p. 7. Click on image to enlarge
SOURCES
A
collection of infographics providing a quick view of the coronavirus
(COVID-19) situation in Australia since 5 April 2020.
