Virus cases are likely exploding
An official tally of confirmed COVID-19 cases around the world is near 2.5 million but in reality that number is likely much higher.
The rapid rate in which this virus has spread around the world and the varying ways in which it presents itself in patients means it is basically impossible for every case and death to be accurately reported.
Data from John Hopkins University reveals there has been more than 170,000 coronavirus related deaths. But just as the true number of cases is likely higher, the death toll is thought it be vastly different as well.
UNSW Sydney's Professor Mary-Louise McLaws, who is an adviser to the World Health Organisation, told news.com.au that a discrepancy in the reported cases and the actual number is not unusual during an outbreak like COVID-19.
"It is more than likely we will never know the true extent of cases and deaths from the outbreak," she said.
Prof McLaws said the gap between confirmed cases and actual numbers would differ from country to country depending on their testing and tracing capabilities.
"In Australia we have a very developed surveillance system and regulations around testing and contact tracing. Not every country has that in place," she said.
"They just don't have the resources or training for it. In some of our lower resourced countries in southeast Asia they may not have the ability to keep up with the spread of the virus. Because of this there may be a long period of time where they are still catching up on confirmed cases."
She said the extent of the outbreak may be even lesser known in some African countries due to their surveillance and case tracking resources.
This could result in some COVID-19 related deaths being missed because the patient either had mild symptoms or it was passed off as some other illness.
Prof McLaws said the majority of countries will likely have to revise their death tolls as they reassess past deaths and find links between known virus cases.
"We are not seeing that many deaths at the moment but there will be more," she said.
"There will be more found in nursing home and small areas where they are waiting for the authorities to come and make a final decision or for test results to be returned.
"There is always a lag time."
On Friday, China revised the death toll in the epicentre of Wuhan up 50 per cent than previously reported, highlighting seriously current numbers on infections and deaths around the globe may be understating the true toll of the pandemic.
Many people were shocked at the drastic increase, but Prof McLaws said large spikes in deaths and cases are actually very common during these situations.
"What China has done is very normal. It happened during SARS, it happens with every outbreak. It comes after re-examination of the unknown, suspected and probable cases," she said.
During outbreaks, particularly for respiratory viruses like COVID-19, countries will often have data catch up periods where they identify a bunch of cases that weren't previously classified as being a confirmed case, Prof McLaws explained.
When these cases are identified, they are often recorded as the date of diagnosis rather than the date the patient started to get sick, resulting in a large amount of cases being recorded in one day.
"Sometimes a data catch up happens because authorities haven't been able to keep up with surveillance. Often they can be caught off guard and label patients in the early phase of the outbreak as having pneumonia," Prof McLaws said.
"They may then go back when they have time to reanalyse their data to see whether or not it fulfils a known exposure to a case of COVID-19.
"Some of the test kits may give a false positive for a false negative. Often it is a false negative. So they may label the patients as suspicious and go back later and test for the antibody response and reclassify them as confirmed cases."
Many countries are yet to hit their peaks in the outbreak, with the number of daily cases continuing to rise.
Authorities and experts say both infections and virus deaths have been under-reported almost everywhere.
Thousands of people have died with COVID-19 symptoms without ever being tested.
Four months into the outbreak, nations are still struggling to lift their testing capacities - and many are still far from their announced goals.
Prof McLaws said in high medically resourced countries like Australia the numbers will likely become quite accurate at some point, but in other areas with less resources the true numbers will likely never be recorded.
"I understand the community's initial concern about the numbers changing and being revised but it is commonplace in a very large outbreak," she said.
"It is not unusual and it is nothing untoward. It is not dishonest. Particularly in a very busy outbreak like this."
Originally published as Virus cases are likely exploding