What happens after lockdowns diminish Covid-19? What next?
We're all sitting in lockdown in much of the world. Lockdown should reduce the famous R0 number for the virus to less than one -- which means that each patient who gets it infects less than one person. An R0 of more than 1 means a virus spreads. More than 2 means it spreads like wildfire. Less than one means it dies out. Much less than one means it dies out fast. That's what they did in Wuhan.
There's a problem not being spoken of as much, namely what happens then. Unless you wipe out the disease completely in a region, once you end the lockdown measures, it will come back, and you need to lockdown again. This cycle of waves has been called "The hammer and the dance" and it's better than the horror of unchecked growth, but it's a very long slog.
If you can wipe it out completely in a town, you can open up again, but not to the outside world. You need to build a border around your virus-free-zone and don't allow anybody in without highly accurate testing and isolation. If your region is an island or country, this may be doable. Even so, air travel becomes highly minimal until the vaccine.
Completely wiping it out is hard, though. Tests have false negatives (the test says you are clear when you're not.) People hide and cheat if there are economic consequences for testing positive.
One possible savior would be a treatment. If some treatment arises that cuts the rate of hospitalization and death way down, the virus can be tolerated like flu (which is pretty nasty) or other diseases with lower death rates. Lots of research is going on into antivirals of various sorts.
A working treatment could bring the total death rate (as percentage of the population, not just the infected) below that of flu or other diseases we tolerate.
Donald Trump's advisors did not just pull Chloroquine out of thin air for him to promote. It was being tested in China back in January and many other tests are underway. The doses used are risky, so that's why more testing is needed before wide deployment. There are also those attempting to find out why Chloroquine inhibits the virus. In one model, it acts in a fairly simple way by allowing zinc ions to enter cells and block RNA replication. If this is true, fortunately there are many, much safer, substances which do that.
Of course, the world will also drive like crazy for a vaccine. Many are searching for ways to reduce the vaccine timeline, including testing existing vaccines for similar substances, and considering manufacturing a promising vaccine before it is proven, at the risk that if it fails later tests this money is wasted, but if it passes, the value is immense.
Better, faster testing. Everybody. Every day or two.
Another saviour is better, cheaper, faster testing. Better means both fewer false negatives, and detection very quickly after infection, and in particular not long into (or before) the infectious asymptomatic period.
If the virus is at low levels, say 1 in 10,000, testing can be made cheap using Group Testing, a technique where you mix up swabs from a group of say, 256 people, and if you get a positive, breaking them up into 2 halves and repeating the test, and so on until you know who's positive and who's clear. To do this you need a test with a low false negative rate, though in some cases you can lower that rate by just repeating the test multiple times. That may mean taking lots of swabs (which is cheap) but the test still is done far less than once per person.
Due to false negatives, tests would be taken multiple times until the accuracy level was sufficient.
Tests would be available every day. Carts would roam the streets collecting test samples (multiple swabs from each person) and issuing/updating "clear" cards for people who passed earlier tests. Cards would be good for only a couple of days, and would be needed if you want to go places where you will be in proximity with other people, like work, or flights.
Some places, like international flights, might require multiple tests plus a short isolation period. Services would crop up to document your isolation period.
Due to false negatives and incubation periods, some people with infection would pass the test. Some virus would spread. But the spread would be much smaller, and with contact tracing, detected quickly and stamped out quickly.
You would get a wallet card with your photo and an electronic tag regularly updated with the date of your last test and to show it's authentic. This may not be needed if card fraud is not a problem. Card fraud (giving a clean test card to an untested or infected person) would have harsh punishments. The auth tags would not be remembered by any readers, under penalty of imprisonment.
Your name or other information would not be on the card, just your face and the auth tag.
Testing of the recovered/immune.
Tests for antibodies -- which reveal you had the virus but now are immune, can also play a central role. Those who pass such tests should (unless against all expectations that recovery does not give immunity) be able to fully travel, and participate in society, and keep things moving. You would get a permanent card.
Privacy-protecting contact tracing
Android and iOS would be updated to support an emergency contact tracing mode, which would stay on until June, and then be disabled unless renewed by emergency law. The protocol would be designed to be privacy protecting. Security experts are working on such protocols. An example of a possible protocol would be to have each phone transmit a different seemingly random token by broadcast Bluetooth every so often. Other phones would pick up and record these tokens. There would be no way to correlate them.
If you were found to be infected, you would publish your list of tokens to a database. Other phones could check this database from time to time to see if they have stored any of them, indicating they were close to the infected person. (Signal strength would be recorded with the token.) Having several tokens would indicate you were in proximity for more than a brief time. (You don't want to trigger if you just passed somebody on the sidewalk.) If so, you would isolate and make sure to do testing. If you had symptoms you would publish provisionally, then fully (or revoking) after getting results.
The OS update would be applied to as many old phones as possible. Those old phones (sitting in closets mostly) would be updated and given to those who don't carry a smartphone. Even if you never use the phone, you would carry it when going outside because it could save your life, by helping you know as fast as possible that somebody you had close contact with was infectious.
(It should be noted that GPS tracklogs, which most cell phone users already keep in things like Google location history, are not adequate. They only tell if you were in the same rough area which would cause way too many false positives and panic, and they have big privacy concerns. They also only sample at long intervals. You need to know whether you just walked in the same building as somebody or if you sat down for a chat.)
Isolation of only the at-risk
This proposal is disturbing, and not just because I'm at-risk. As it becomes clear that the fatality rate is low (but not zero) for people who are young and have none of the comorbidities (including, but not limited to diabetes, hypertension, heart disease, lung problems, etc.) it is not out of the question to end isolation for the healthy under-60s, but continue it for the at-risk. This would require that the non-isolated stay away from the at-risk. If they live together, they must live in isolation, or move out. Almost all children would be low-risk, but the parents of older children might not be, creating a problem.
This would restart the economy but cause effectively massive age discrimination in the world and workplace. Laws would need to be put in place to protect those who could not work because of isolation, assuring that they can't lose their jobs or be passed up for promotion without extremely well documented and extreme reasons. Of course, the isolated would continue to work from home, and also guide and supervise the more junior people via video and augmented reality "remote assist" functions.
The law would need to be extreme. It would be almost impossible to fire or lay off people who isolated for a period of time, to assure it never happens that somebody ends a career due to the virus. As we know, there are laws to protect people who go on family leave, and they aren't strong enough.
Research into immunity through small doses
It is currently being investigated how much the size of your dose affects the severity of the disease. It is speculated that it may be possible to receive a small dose, through the skin (ie, not in the lungs) and take low risk, but gain immunity. Volunteers could participate in trials to attempt to learn if it's true and what the small dose is. Volunteers would be young and healthy with no known health problems. If they get immunity, they would be rewarded with a card. If they get sick, they will be promised top grade medical care and ventilator priority, but if people get sick the trials would get stopped. Also tested would be the use of small doses and possible treatment candidates to see if they can make the risk of complications from the inoculation dose extremely small.
This sort of research is the sort the medical community will not want to do, under the "first, do no harm" doctrine. On the other hand, many healthy people (who already have a very low chance of complications) might well be quite willing to do it for the chance at immunity.
Economist Robin Hanson has been proposing deliberate infection to flatten the curve for some time, though it is unlikely anybody in the high risks groups would be willing to take that risk (even if the trade-off is "get it early" vs. "maybe get it or not later but when they are out of ICU beds." However, he has switched to promoting low dose "variolation" which was used a a precursor to vaccines.