Last updated March 18, 2020 at 4:32 pm
Will our healthcare system hold up under the weight of coronavirus? What’s the deal with herd immunity? Two Australian experts talk facts.
Why This Matters: You’ve got coronavirus questions, we’ve got answers (from experts).
The coronavirus situation is evolving by the hour. It’s important we listen to the experts to provide the facts and guide our decision-making.
Professor Allen Cheng from the School of Public Health and Preventative Medicine at Monash University and Professor Bruce Thompson, Dean of Health at Swinburne University, answer coronavirus questions about herd immunity, face masks and whether we’re heading the same way as Italy.
Read even more expert answers here.
What’s the deal with herd immunity?
It (Herd Immunity) is a risky strategy, but may very well be the ultimate outcome.
It’s hard to get enough situational awareness to know when things might need to be tightened up, we don’t know the duration of immunity after infection, the intensity of transmission in children isn’t clear, and it would be hard to prevent mixing between less susceptible and more susceptible groups.
Public health interventions are a very blunt tool – it’s hard to work out how effective they are, and can’t easily be turned on or off. – AC
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The Herd Immunity concept works on the principle that if I am vaccinated or already had the virus I am protected from it, but more importantly I cannot give it some else.
Furthermore if you have say have 100 people, 1 has the virus and the other 99 people have either been vaccinated or indeed had the virus, there is nowhere the virus can go – ie it can’t be transmitted so it eventually dies out.
So it comes down to statistics. If 1 person has the virus and the other 99 are not vaccinated or have it, the virus will spread easily. The more people that are vaccinated the better, as it makes it harder for the virus to spread.
So the UK saying let the virus spread and all will be fine, as it will eventually build up a herd immunity. That would be fine if there was no risk to having the virus. However we know that the mortality is ~1-3% which in a population of the size of the UK could mean hundreds of thousands of deaths and millions hospitalised. This is not correct approach to take. – BT
Could Herd Immunity be a factor influencing why kids are under-represented among more severe Covid-19 cases?
No that is not the case. The reason why children and younger people overall have not been as affected is that they are usual health and well with an immune system that is working as it should.
People with comorbidities such as asthma, emphysema, bronchitis, diabetes, heart disease are at higher risk irrespective of age. As we get older, as with everything else, our immune system gets tired as well. – BT
Is the 1.5 metres for social distancing accurate? Is there any scientific basis for it?
The 1.5m level clearly isn’t a sharp demarcation (you’re not safe at 1.51m and at risk at 1.49m!), and some more recent studies have suggested that most droplets do fall mostly within 1m, so the 1.5 recommendation allows for some uncertainty.
Here’s a paper that looks at droplet spread with coughing. – AC
Should healthy people wear a mask?
The advice from the Australian Department of Health and Chief Medical Officer is correct. As panic buying of masks is stopping supply to the hospitals which really do need them. – BT
But a study in The Lancet finds wearing masks is effective in a hospital setting during SARS.
Yes in a hospital setting where you know that the person has the virus. – BT
Should we be reconsidering the role of masks given that an “absence of evidence of effectiveness should not be equated to evidence of ineffectiveness”?
We know they are effective on an individual basis if the person in front you has the virus and yes I take the point that no evidence is indeed evidence however from my previous point we don’t have the supply chain for everyone to have them and the hospitals need them. – BT
What is flattening the curve and why is it important?
The flattening of the curve is in relation to the number of people who have the virus.
Basically we are trying to stop the increase, or rise, in the number of new cases so if you imagine the curve of number of cases versus time, if there are no new cases the curve flattens out. The reason why it is some important is that we are demonstrating that the control measures are working and the virus is not being spread and hopefully eventually dies out. – BT
What is the best ways for individuals and communities to do this?
The best thing to do is the simple things like hand washing and hand sanitising.
If you are sick then isolate – staying at home is perfectly fine. Keep a distance from each other. It is very similar to having a horrible cold. If you have a horrible cold you don’t want to give it to anyone and if you know someone with a horrible cold you normally don’t want to catch it, so you distance yourself. Don’t shake hands or kiss each other etc. – BT
What is the current situation like for the healthcare system and will it hold up?
At this stage all is OK, however if the virus spreads as it has done in other countries like China and Italy it will put huge pressure on the health care system. This the very thing that we are trying to avoid by placing the country into isolation.
It is also bigger than COVID-19 as taking up hospital beds with COVID-19 is displacing people with the usual things people go to hospital for. Plus we are about to enter influenza season which 300,000 people had in Australia and which killed ~800 people. –BT
Why Australia hasn’t moved to general school closures?
This is an interesting argument. Understandably we need to protect the most vulnerable which are the elderly and people with comorbidities. So increasing their exposure is not a great idea. So if the government does close schools, which on one level makes sense, then children need to be looked after by a low risk group. – BT
Is Australia heading for the same situation as Italy? What’s the modelling?
Hopefully not! And is the very reason the government is correctly following the advice of the CMO and putting into place the current measures. The sooner we do this, the quicker we can stop the spread of the virus.
We know from countries such as Singapore that have putting in isolation measures they have effectively stopped the increase in cases. Countries that didn’t do this such as Italy etc have struggled to contain the virus. –BT
What works to contain the spread? Any data/research on that would be very valuable.
The basic stuff. Hand washing, hand washing and hand washing! Social isolation. –BT
Why does it take a long time to build a vaccine?
A vaccine is like a medicine. First it needs to be developed. For any medicine to be sold it needs to go through the standard process of clinical trials including phase 1 – 3 trials. We need to ensure that the medicine is safe, will not do harm, and know how effective it is. – BT
How would a coronavirus vaccine work and how would it be deployed?
Same is an influenza vaccine. – BT
Are there examples of other coronavirus vaccines we can look to/studies showing SARS/MERS safety/efficacy?
Yes they do help point us in the right direction. – BT
For the latest updates from the Australian Government Department of Health, visit their website.