3rd May 2020
Despite a late start in our response to the pandemic, Australia’s covid-19 graph of new cases looks like it is definitely flattening. Most days over the last few weeks, the number of new cases is about 20-30 nationally at the most. Even in the most popular state, new cases are often in single digit numbers. Does that mean that we have finally “eliminated” the virus? Is the pandemic finally over now?
As of 3rd May 2020, we have a total of 6799 cases of Covid-19. If we were to dissect the numbers, we find that 64% of cases were acquired overseas (including cruise ship travellers). When we closed our borders and (finally) got control of the arrival of cruise ships, overseas acquired cases fell dramatically. Of the 36% of locally acquired cases, only 10% came from unknown sources. This amounts to about 680 nationally (as of March 27) which is really a small manageable number.
85% of the cases have recovered leaving 926 cases still active. Thus, we have small numbers of cases whose origin is still unknown but the numbers are small enough that we are able to track and manage the pandemic efficiently. Is that the reason why our curve is flattening and in due course, we will be on track in eliminating the virus from the community?
One thing that is not discussed much out there is the issue of the asymptomatic carrier. We all know that some patients have more severe symptoms than others. Similarly, some patients only get fairly mild symptoms, nothing more than just a sniffle or perhaps just a scratchy throat.
It’s only naturally, some will have symptoms so mild that they are asymptomatic. What proportion of patients with Covid-19 are asymptomatic? Unfortunately, we don’t know. The pandemic have unfolded so rapidly that there just isn’t enough time to conduct any scientific studies to ascertain the proportion of asymptomatic carriers. Preliminary case reports (not quite formal scientific studies) estimated the proportion to range between 5-60% (read more here). That’s a pretty large range to be confident about the accuracy of the figures. So, it could be any number. We also don’t know how long the asymptomatic carrier are contagious for. The symptomatic Covid-19 patient is generally contagious for about 2 weeks but the carriers could be contagious for longer.
So far, in Australia, we have only been testing those with symptoms. Our case numbers is only reflective of who we test. The more we test, the more we may find but we won’t know the proportion of those who are asymptomatic if we do not test them. The state and federal governments are now encouraging testing anyone with or without symptoms. Perhaps, only then would we have the answer to that question.
So, is our curve flattening because we are close to eliminating the virus from the general community? Since we only have 20-30 new cases a day in Australia, this is very encouraging, isn’t it? What if the reason why we are flattening the curve because we have kept the asymptomatic carriers at home with social distancing restrictions. If you are asymptomatic but you are mainly at home, you may not have the opportunity to spread the virus.
How will we know which is the reason for the flattening of the curve? Well, when we relax the social distancing restrictions but opening up the economy, we may find out, perhaps, the hard way. That’s why it’s crucial that the government relaxes the restriction a bit at a time to know, which bit is the cause of a spike if there is one.
It is probably also a good idea to install the CovidSafe app on your phone just in case, we are not on the trajectory to eliminating the virus yet. I mean, how can you tell if someone next to you is not one of those asymptomatic carrier?