Australia may have highly undetected COVID-19 numbers

The largest COVID-19 wave to hit Australia may have been bigger than previously believed, according to a new study.

When the Omicron wave hit in December, the number of cases in the nation increased from less than 1,500 each day to over 100,000 in only one month. Epidemiologists now believe that there were at least twice as many cases as were actually reported.

The National Centre for Immunization Research and Surveillance (NCIRS) as well as Kirby Institute of Sydney examined 5,185 blood donor samples collected in late February and early March of this year to check for COVID-19 antibodies.

The researchers looked for two different types of specific antibodies, one of which is only present in the body following a COVID-19 infection and cannot be produced by vaccination.

At least 3.4 million Australian adults, or 17% of the population, were predicted to have contracted the virus by February end, 2022, with the great majority of infections occurring during the Omicron wave.

This implies that at least twice as many persons as was officially reported were afflicted. That idea could be shocking to some people, but NCIRS director Kristine Macartney said the data was not unexpected.

According to similar studies conducted in other regions of the world, there may be five to ten times as many illnesses as are officially recorded.

How did such a huge number of cases go by undetected?

According to the survey, the percentage of individuals having antibodies was greatest in Queensland and Victoria, at 26 and 23%, respectively. The lowest rate, 0.5%, was in Western Australia, which will remain locked for some time yet.

Not every person who contracts COVID-19 will exhibit symptoms or undergo testing, therefore their cases might not be counted in the official statistics.

In official counts, only instances discovered by PCR testing or self-reported positive fast antigen tests are counted.

According to Professor Macartney, up to 30 to 40% of infections can indeed be asymptomatic, meaning people don't experience any unpleasant symptoms or sensations that could suggest they're sick. "So they won't, rationally, go get a test in the majority of circumstances."

Other factors, such as limited availability to fast antigen tests and PCR testing, may prevent some COVID-19 carriers from getting tested.

Are cases still being underreported?

Possibly, although it's uncertain by how much if it is. When a second batch of blood samples is taken in the upcoming weeks, researchers hope to have a clearer understanding of this.

"It's possible it'll be double. Until we conduct the tests, we won't know "explained Professor Macartney.

Despite the relaxation of COVID-19 regulations and safety measures, many immune-compromised Australians remain extremely cautious about the virus.

Australians, according to Professor Dantas, should exercise caution but not worry. The next three to four months will be "trying times for us," she added, "now that we have eliminated the mask restrictions and we are heading into our flu season."

"It's just a question of being careful, taking personal responsibility, and also being aware that there are others among us who are vulnerable and we need to watch out for one other in the community," the speaker said.