A former World Health Organisation scientist says the new BA.2 Omicron subvariant sweeping the world is one of the most infectious diseases the Earth has seen – and almost everyone will be exposed to the virus.
While the now-dominant strain is not as deadly as previous ones, including Delta, it is up to six times more transmissible than the original strain of Covid-19, Professor Adrian Esterman told Daily Mail Australia.
Predictions of a big surge in cases became a reality in New South Wales on Wednesday with 30,402 positive tests returned in the previous 24 hours, almost triple the number reported on Tuesday.
The BA.2 variant is also up to 30 per cent more infectious than the initial BA.1 version of Omicron which forced the reinstitution of lockdowns at Christmas.
‘We think [the first] Omicron is very similar to Delta and that BA.2 is then another 25-30 per cent more contagious,’ James Wood, a public health mathematician at the University of NSW told Daily Mail Australia.
The higher risk of contagiousness comes from the variant’s superior ability to ‘evade’ immunity – meaning even triple-vaccinated people are susceptible to catching the new strain.
A former World Health Organisation scientist says the new BA.2 Omicron subvariant that is sweeping the world is equal to one of the most infectious diseases on Earth and that young people are playing Russian roulette by thinking they are ok to catch it (pictured, Revellers dancing at Universal Nightclub in Sydney)
Professor Esterman, an epidemiologist and biostatistican, said it was very likely all Australians would be at risk of catching BA.2 this year – especially since the end of restrictions such as social distancing and indoor mask mandates
While BA.2 is not as deadly as previous ones, including Delta, and not comparable to measles for severity, it is up to six times as infectious as the original strain of Covid-19
Can you catch the new Covid-19 variant if you are vaccinated?
The BA.2 version of Omicron has an ability to ‘evade’ immunity, which includes vaccination.
While vaccination provides a high level of protection from severe disease, it is less effective against preventing someone from catching Omicron at all.
That even applies to boosters.
Generally vaccines were more effective at preventing symptomatic infection from Delta than Omicron.
For example, someone who had two shots in 2021 and a booster at the start of January would now have a 50 per cent chance of catching BA.2 if exposed.
Professor Adrian Esterman, an epidemiologist and biostatistician, said it was very likely all Australians would be at risk of catching BA.2 this year – especially given the return of people to schools, offices and public transport.
‘(At the moment) you are much more likely to get it; we’re already seeing that with the case numbers going up,’ he said.
Overall, case numbers Australia-wide are trending upwards.
NSW cases surged from 10,689 on Tuesday to 30,402 on Wednesday, though NSW Health attributed some of that increase to an additional 10,000 rapid tests in the system on Monday.
Of the 30,402 positive results, 22,748 were rapid antigen tests (RATs) and 7,654 were PCR lab tests.
But it is almost impossible to get an accurate picture of BA.2’s spread because so many rapid tests are believed to be unreported.
The only objective, verifiable figures are the numbers of people in hospital with Covid.
On Tuesday, that figure was 1,801 Australia-wide; a total that has been relatively steady throughout March.
On January 25, there were 5,390.
While not everyone exposed to a virus is infected by it, BA.2’s high ‘basic reproduction number’ or ‘R0’ of 12 – compared to 2.5 for the original Wuhan virus – could mean almost all Australians will come into contact with it in 2022.
The R0 is the average number of secondary infections produced by a typical case; an R0 of 12 means up to 12 people could be infected by each case.
‘Everyone’s been exposed to Covid-19, full-stop, and unless you’re very careful you will be exposed again this year,’ Professor Esterman said.
‘With face mask mandates being dropped, social distancing being removed, the chances are even higher.
‘Those things are put in place to dampen down transmissibility, that’s the whole point. When you remove them it’s just increasing transmission.
‘If you remove all of those protections, then your transmissibility almost gets back to the basic reduction number because we have very little immunity.’
While Omicron is generally less severe than the Delta strain, it is serious enough for some people that Professor Esterman likened wanting to catch Covid to gambling with your health.
‘If you say “I don’t mind getting infected” it’s a bit like Russian roulette because you do have that chance of getting seriously ill or having long-term health problems.’
Mr Esterman, who is 73, admitted his own son argues ‘it’s no worse than the flu’.
‘To a certain extent, he’s right: the death rates not worse than seasonal flu,’ he said.
One tragic case of a healthy young person dying from Covid was double-vaccinated power lifter James Kondilios, 23, who died at Sydney’s St Vincent’s hospital in January despite having no underlying health conditions
Professor Esterman believes a fourth jab should be introduced for vulnerable people in Australia
‘The trouble is it causes more severe disease in vulnerable people than influenza, and it has the capacity to cause real damage to younger people too.
‘There have been several cases of young, healthy and fit people dying from Covid. I cannot remember that ever happening with influenza.’
One was double-vaccinated power lifter James Kondilios, 23, who died with Covid at Sydney’s St Vincent’s Hospital in January despite having no underlying health conditions.
Professor Esterman said while death rates have dropped to now be comparable to the flu, Covid is far more infectious and the spectrum of long-term health impacts is much wider.
‘Covid-19 can attack every part of the body, from clotting to the heart and brain. There have even been cases of young children with multi-system inflammatory condition.’
Professor Esterman said it was ‘very likely’ people suffering from chronic fatigue syndrome got it as an immune system response to a previous viral infection.
‘These are the balance of risks individuals have to bear in mind.’
Professor Esterman said while death rates have dropped to now be comparable to the flu, Covid is far more infectious and the spectrum of long-term health impacts is much wider
Professor Esterman also issued a warning that the pandemic is ‘not over’ and it’s been ‘sheer luck’ that we are not in the middle of a wave that is both more infectious and deadlier
He pointed out that with six million reported deaths worldwide and 5,590 in Australia attributed to Covid-19, it was one of the deadliest pandemics in history.
Professor Esterman also issued a warning that the pandemic is ‘not over’ and it’s been ‘sheer luck’ that we are not in the middle of a wave that is both more infectious and deadlier.
‘It is true that pandemics become less infectious over time, but that happens over 100 years, not one year,’ he said.
He described it as ‘the toss of a coin’ as to whether the next variant causes more severe illness.
‘While it’s true to say it’s the beginning of the end, it’s not the end yet,’ he said.
Professor Esterman is an advocate of introducing a fourth dose for people at risk, who could include people with HIV/AIDs, kidney problems, diabetes, obesity and different cancers.
Despite warnings that even the triple vaccinated will be at greater risk of catching the new variant, the Australian Technical Advisory Group on Immunisation (ATAGI) is currently considering whether fourth doses should be rolled out and mandated, Health Minister Greg Hunt recently confirmed.