So now that many provinces and states are relaxing the social distancing restrictions, which in the U.S. they like to call “opening up the economy”, there seem to be many different plans. It is not at all clear how this is being done. That’s because it is trial and error, with very little science.
Here’s the science. The Imperial College London published a study in which they measured the effect on the transmission rate of different social distancing policies (interventions). They measured the following interventions:
– Self isolation
– Social distancing
– School closing
– Public events
– Lockdown
When all interventions are applied, the transmission rate is 0.8. A transmission rate less than 1 decreases the rate of the virus spreading, so this is why Lockdown has been successful in controlling outbreaks. But without Lockdown, the transmission rate of all the other interventions combined is 1.6, which will result in the virus spreading.
https://www.imperial.ac.uk/mrc-global-infectious-disease-analysis/covid-19/report-13-europe-npi-impact/
As Lockdown is removed, it is critical to have contact tracing and testing to isolate new cases quickly before they can infect others. The model of how this has been done successfully is South Korea. Here is the best report I’ve seen on how South Korea did this.
https://www.cbc.ca/player/play/1729976899648
Neither the U.S. nor Canada currently have enough trained people working as contact tracers or enough testing capacity to achieve the success of South Korea. If new cases cannot be isolated, the virus will start to spread. It will be necessary to re-introduce Lockdown to prevent the rapid epidemic spread of the virus. This pattern results in the multi-wave model where there are alternating periods of relaxed restrictions and Lockdown, repeating every 2 to 3 months. Here is a more detailed article based on a report published by a team of epidemiologists
https://www.statnews.com/2020/05/01/three-potential-futures-for-covid-19/
Health authorities are hoping that if they do not relax too many restrictions they can keep the transmission rate low enough to avoid re-introducing Lockdown. It is pie in the sky to think that any state or province will be able to find a magic combination of interventions that will allow most major parts of the economy to resume without resulting in a transmission rate that is a lot more than 1 and closer to the Imperial College threshold of 1.6.
The prediction based on our model (and others) is that there will be a second wave in October and restrictions approaching Lockdown that will need to be reimposed. This may exclude school closing for grade schools but not high schools and universities, as has been done in other countries. Lockdown will be lifted in early December, just in time for Christmas shopping.
After that the next wave requiring Lockdown will start in March. However the government and health authorities won’t say anything about this until well into the new year.
Many states are proceeding to open their economies even though they do not have control of the current virus outbreak and cases are increasing. This means their cases and death rates will get even worse. I don’t think we should be surprised that many states are ignoring recommendations of health experts and authorities. The U.S. society is a much less caring society than the rest of the western countries. There are millions of Americans who do not have coverage for basic health care let alone any kind of medical emergency. The U.S. is the only western country that has such poor health care for its citizens. So it should be no surprise that so many states are ready to tolerate very high death rates from this pandemic. While the Government of Canada has a target to limit the total number of deaths from Covid-19 to be less than 5% of the population over the next 2 years, the U.S. has no such guidelines or targets. There are many states that will have a lot more deaths than this with their current policies.
