In January of 2020, Australia had 6,962 cases of the flu, back when the coronavirus was still in its early stages. Come April, the number of cases of the flu was only 229, when you might have expected that number to be much higher. The previous year at the same time, there were 18,705 cases. By this time Covid-19 was spreading across the globe infecting millions. Come August, Australia’s flu season was officially it’s mildest ever with a fewer than a 10th of the infections seen last year. This same pattern also happened in other places in the world, notably New Zealand, which we have covered in this blog before.
In September the WHO reported that the lower levels of the flu infections are a global phenomenon. Sarah Cobey, an epidemiologist at the University of Chicago said, “What we’re seeing in Australia, New Zealand, South America, Hong Kong, are really, really attenuated seasons of not just the flu, but also respiratory syncytial virus (RSV). There are many theories as to why this is the case, but a popular one is the effect social distancing is having on the flu.
Peter Palese, a microbiologist and expert in RNA viruses at Icahn School of Medicine at Mount Sinai, New York says, “We don’t really understand it, but it may have to and may have to do with a little bit of changes in terms of how we interact with each other. There is a possibility this might also continue in the future.” He continues, “The big problem with influenza is that it changes. We have to really think here worldwide.” Because of this we have to assume that it is unlikely that social distancing will eradicate the flu. Palese says, “And even if all of the UK, the US and China wear masks, that doesn’t mean that the rest of the world does it. And from what we have seen on television, not everyone in the US wears a mask.”
While there is a record low in terms of cases this year, it’s important to remember that the flu will still be spreading in some parts of the world. Even if we eliminated it entirely from the developed world, it could still come back just from a singular case. Cobey explains, “Humans are distributed in such a way that flu viruses can do that – they just keep hopping around different populations without going extinct”
This might not always be the case however, as scientists are now pushing harder for a universal flu vaccine – one that can protect you year after year. The idea for this vaccine is more about pushing our immune systems in the right direction. The problem is that there are multiple strains of the flu virus. Four main strains circulate each year, two in the influenza A group, two in the influenza B group. Palese says that a universal vaccine would only eradicate group B, “So in terms of influenza A, we would have to constantly vaccinate the entire population, which is basically impossible. And if we don’t do that, then animal strains, as I said, those in reindeer, those in chickens, those in pigs, those in horses, they can jump into humans.”
This is something to think about in the future, in the meantime we should focus on the now and how the flu is evolving now. Because of Covid-19, the flu strains may be evolving more slowly than normal. Cobey said, “What’s hard about influenza is that it’s always evolving into something new that we’ve never ever seen before. And so, it’s actually very hard to say, ‘if things were a little bit different, it would evolve like this’, because it’s kind of so unpredictable to begin with. But this could be really good – it’s exciting.”
What we don’t know for sure is whether or not social distancing has directly led to the lower flu numbers, it is just a theory at this point based on numbers of cases reported. Cobey believes it is important to focus on improving our efforts of prevention, “So that maybe when we have that vaccine, we don’t have to go back to exactly how things were before.”
Be sure to check back regularly with the ABN Blog for updates.