investigation
World war COVID: Why reinfection is the new risk and how Omicron is actually protecting us

So what’s really going on with COVID-19? Outward signs suggest the pandemic is in society’s rear-view mirror. It’s way down the pecking order in the evening news, injection mandates are gone and people no longer have to whip out their phones to show their vaccination status in order to buy a coffee or a glass of wine. Venues are packed and maskless, live music and international acts are back, and people are packing their suitcases to go on overseas holidays. Even China is relaxing its restrictions on movement within the country and easing quarantine requirements for international visitors. Many of the go-to experts during the pandemic claim what we’re witnessing now is simply people “living with COVID”. But they also claim there is worrying complacency and large dollop of wishful thinking by a large number Australians who think the health crisis is essentially “over”. They’ve moved on, even if the disease hasn’t. Global hotspot but low mortality rates At this moment, Australia is a global hotspot. Only France, New Zealand and Taiwan are experiencing more per capita cases. Infections are trending up nationally, due to the Omicron sub-variants BA.4 and BA.5. But COVID is not headline news because hospitals are coping and only a tiny number of those who catch the virus end up in the morgue. Australia has a case-fatality ratio of 0.1 per cent. It was 3 per cent in 2020. A combination of a milder strain of the disease, a successful vaccination program and effective anti-viral therapies means that for every thousand Australians who are infected today, only one will die. Professor Nigel McMillan, Program Director for Infectious Diseases and Immunology, at Griffith University, Queensland, posed a different perspective. “We’re getting 50 deaths a day at the moment. I mean, the average road toll on Australia every day is 20. This is more than twice the road toll. And we’re not even blinking an eyelid at it,” he said. “Sometime this month Australia will pass 10 000 deaths from COVID-19. Ultimately, we’re on track to have 14,000 deaths from COVID this year. Now that puts COVID as the number two killer in the nation behind coronary heart disease.” Only four other nations have had a bigger leap (405 per cent) in fatalities so far this year, he added. Many readers would still be thinking the odds are favourable. After all, haven’t we been reminded these past three years that no activity is risk-free. Sharks haven’t stopped surfers paddling out and we still love our cars, regardless of road fatalities. The trouble with this virus, though, is that it can turn on a dime. And there’s still so much scientists don’t yet understand about its long-term health implications. Fast-mutating virus “I am concerned that the pace of mutation means the world is continuing to play catch up,” said World Health Organisation Director-General Tedros Adhanom Ghebreyesus on Thursday. Associate Professor Allison Imrie, who specialises in virology and anti-viral immunity at the University of WA School of Biomedical Sciences, said scientists don’t know what direction the virus will take in “the short, medium or long term future.” “That’s something that we just have to wait and see, unfortunately, because we know the virus evolves really quickly,” she said. “We know that there are many places in the world where vaccination rates are very low, but there’s a lot of transmission, and it’s that combination that classically can drive escape variants.” Escape variants are strains with the ability to evade the immunity that people acquire through vaccines and previous infections. According to WHO, the average rate of vaccination in “low-income countries” is 13 per cent. Only 58 countries on the planet have reached the organisation’s 70 percent target. Scientists warn that from these poorer unprotected nations that escape variants would most likely emerge and then spread to the rest of the world. BA.5: the “sticky” sub-strain Omicron remains the dominant variant circulating globally, accounting for 94 per cent of genomic sequences reported in the past 30 days. Between June 6 to June 19, the sub-variant BA.5 increased from 28-to-43 per cent. BA.4 and BA.5 had caused global cases to increase by 20 per cent last month. Professor Catherine Bennett, chair in epidemiology at Deakin University in Melbourne, said BA.5 might put more people in hospital. “What we’re seeing with BA.5 is perhaps a greater potential to cause more infections of the lung,” she said. “People who are vulnerable might end up in hospital when they might not have with early variants of Omicron.” Prof. Bennett said Omicron had by chance “developed a relationship with the human host, that actually helps edge out other variants.” “So Omicron has this weird thing where it boosts your immunity against Delta and the other variants. So you’re even less likely, if they’re still hanging around, to get infected by them. But Omicron doesn’t protect you from another Omicron infection. It’s pretty smart. If you wanted to develop a mechanism that would keep you as the dominant strain, that’s what you do.” It explains why people are getting re-infected with Omicron. Prof. Bennett said people have a false sense of security based on the fact that they’ve had an infection and their symptoms were mild. “It doesn’t mean the same will happen next time, you might get a bigger infecting dose. You can’t take your experience with one infection as an indication of what will happen if you get infected again. “Then there’s other people who had an infection and it was terrible, even though it didn’t put them in hospital, and they’re now quite cautious about it. They need to understand that doesn’t protect them from an infection in another four weeks.” Prof. Bennett said there was a possibility future Omicron sub-variants could be more virulent. “We might see a little bit of that with BA.5. It might not be a big leap where suddenly everyone ends up in hospital, it might be incremental, like we’ve seen with BA.5 in that it might be sticky and can get into the lungs more efficiently … that’s the sort of thing you might see.” Long-term complications There’s another reason to avoid re-infection. “Re-infections are now being linked to a greater risk of Long COVID,” said Prof. Bennett. “That’s not saying ‘be scared, wear a mask, don’t go anywhere’. It’s saying, with the information we have, it’s really wise to avoid re-infection.” Prof. Imrie said people should be mindful about long-term complications. “When I talk to my colleagues, who work with this illness, with associated diseases, some people really emphasize this prospect of long term complications from a virus that we don’t really understand fully,” she said. “We just don’t understand exactly what this virus is doing, what it’s capable of. “It’s not an acute infection that disappears completely like say, for example, the common cold viruses, right? “We know it’s a systemic infection. So it can actually have effects on your other organ systems. That’s the concern. “And there’s a study that’s coming out of Sydney, for instance, from St. Vincent’s Hospital and University of NSW, that’s starting to define these complications that are a direct result of the infection. For instance, it’s impacting neuro-cognitive function in some people who fit the clinical definition of Long COVID, about 20 per cent of that group. “There are these complications that we still don’t fully understand. It will take time to become more familiar with them. So it’s not right to dismiss this infection as a fairly trivial one.” Aside from what future sub-variants of Omicron might look like, there remain concerns about entire new strains emerging. “An RNA virus, by definition, will just keep evolving,” said Prof. Imrie said. “But there are other new sources of evolution that may not be related to Omicron. There might be some other completely different variant of concern that can then emerge and then be amplified as people travel more. There’s no reason why that can’t happen.” Bill Gates, the billionaire Microsoft co-founder and public health advocate, made the same warning in May. “I don’t want to be a voice of doom and gloom, but it’s way above a five per cent risk that this pandemic, we haven’t even seen the worst of it,” he said. Zoonosis The biggest fear was the risk of further crossover from the animal kingdom. “We don’t exactly know where Omicron came from,” said Prof. Bennett. “Is it related to the other variants? Or is that another crossover from an animal virus? “An animal virus could get in, recombine with the human virus, and suddenly you get a big difference, a big shift yet again, because you’ve actually got this new kind of virus and it can take off in a different direction. “You can’t say that’s not going to happen, chances are pretty low, but we’ve got so much infection in the world population, the mutations are happening, recombination can happen. That’s the fear. “That’s why it’s so important to try and keep infection rates down, even if they’re not putting a lot of people in hospital. “It’s still about trying to slow down the mutation clock, slow down the risk for these crossovers with animal strains. And that’s what will keep us safe, longer term.” Prof. Imrie echoed the sentiment. “I think people are complacent because we’re living in a time now where you’re seeing very low rates of severe disease. So most people think it’s fine. The assumption is it will always be like that from now on, but we just don’t know that. “We have to just be optimistic, but also be mindful that virulent variants can emerge …we have to be able to respond quickly, if that happens.” New vaccines WHO this week said it second generation vaccines that targeted the current virus variants was critical. “Building on existing vaccines that limit severity and prevent death, developing second generation vaccines that stop – or at least lower infection – would be a major step forward,” Dr Tedros said. “And the ideal solution would be the development of a pan-coronavirus vaccine that covers all the variants so far and potentially future ones. This is feasible.” Prof McMillan said it would be desirable if the next boosters rolled out in Australia. were these second generation vaccines. “A lot of us have had three doses, (the last one) coming along to more than six months old. We’re all probably needing a boost,” he said. On June 25, Pfizer and BioNTech announced results of trials on two Omicron-adapted vaccines. “They elicited a substantially higher immune response against Omicron BA.1 as compared to the companies’ current COVID-19 vaccine,” the companies said. “We look forward to discussing these data with the scientific community and health authorities so we may rapidly introduce an Omicron-adapted booster as soon as possible if authorized by regulators,” said Albert Bourla, chairman and CEO of Pfizer. Prof Imrie said the quick development of effective antivirals had been a “game changer” and she was impressed with how protective (against severe disease) the existing vaccine had been, given it was based on the original Wuhan strain. Infant shots On Thursday, Australia’s Therapeutic Goods Administration announced it had granted conditional approval for vaccinations for children aged six months to five years. “It’s important to appreciate that this is only the first step in the process for this vaccine to be approved for use in this age group in Australia,” said Hassan Vally, an Associate Professor in Epidemiology at Deakin University. “What it means is that Pfizer have been given the go ahead to apply for provisional registration for the use of this vaccine in young children. When they do this, the TGA will go through all of the available information with a fine tooth comb before making a decision whether to approve the vaccine for this age group.” University of Sydney vaccine expert Professor Robert Booy said “the issue of COVID in young children is especially focused on that small minority who has a major medical problem including immunosuppression.” “Should the new Pfizer vaccine be recommended in Australia it would best be focused on children at high risk of severe COVID,” he said. Poor countries left behind Dr Tedros said it wealthy nations had their priorities skewed. “If rich countries are vaccinating children from as young as six months old and planning to do further rounds of vaccination, it is incomprehensible to suggest that lower-income countries should not vaccinate and boost their most at risk and then work to strengthen their own walls of immunity,” he said on Wednesday. “Tests and new treatments like antivirals should also be available in every country … If we don’t share the fruits of science equitably, then we undercut the philosophy that all lives have equal worth.” Scientists say only global immunity will slow down the mutation clock and minimise the threat of new and more dangerous variants emerging.

investigationWorld war COVID: Why reinfection is the new risk and how Omicron is actually protecting us

investigation
World war COVID: Why reinfection is the new risk and how Omicron is actually protecting us