Is Immunity to the COVID-19 Virus the New Passport?

Let me be clear from the beginning that this is a piece of speculative fiction designed to help people think about what might happen. It is not a prediction. It is also trying to use a possible future story to help people understand some of the technical details.

It has been driven in part by what I believe is some fundamental misunderstanding of things by the general public, so I have included some technical information at the end if people want to dig deeper.

I have also checked my views and assumptions with two medical specialists in two different countries, one of whom is currently in isolation after being in contact with a positive case. Their help has been valuable, any misstatements are mine and mine only.

For those that do not know, I am a futurist with a Masters Degree in Strategic Foresight, but I also am a veterinarian who has a research degree in diagnostic serology, and experience in both exotic disease preparedness and actual outbreaks of disease in large animal populations. So, I have a scientific background that helps me in addition to my futurist experience and skills, but I am not a human virologist, doctor or epidemiologist.

Lots of details are still uncertain. This will get better as we do more research, but I have done my best to state levels of confidence.

The story is driven by a few fundamental assumptions and actual events that I want to summarise before I start. Please read them even if you do not read the technical details at the end. I am trying to be very careful about what I publish:

Actual Event: Australia will force returning Australian travellers into Quarantine Hotels from midnight March 28th 2020 (

Assumption: We will have a blood test that will prove previous infection and current immunity in the near future (see the end of the article for some details).

Assumption: Immunity will be relatively long-lived (> 12 months – see the end of the article for details).

Assumption: Australia (and some other countries) will not be able to eliminate the virus and will live with a very low to low level of cases with varying restrictions on the general population. I will write a longer piece on this soon and link it to this article (see the end of the article for a summary and example).

Another detail: Lots of stuff is floating around about tests for the virus. Briefly, there are two basic types of test. The first is looking for virus or parts of a virus. The PCR test is the standard for this. There is some variation on when it will be positive. It will be positive in the vast majority of cases when people have symptoms. It will not be positive straight after people have been infected. The other type is an antibody test which tests for part of the body’s response to infection. An example is the “Point of Care” finger prick test which is about to be rolled out in Australia. It will be positive later than the virus tests. How much later is still an open question and variable between individuals (see the end of the article for details)

Another detail: Public health responses and individual responses are different things. Public health responses are statistical responses. They are designed to reduce transmission across large populations and make assumptions about human behaviour. This is why the Australian governments have tightened restrictions as they have seen examples of people flouting the rules because the actual behaviour did not meet their expectations of what the measures would achieve. Individual responses are different. My parents are both 81 with pre-existing conditions. I have given them very strict guidelines they should follow which are very much tighter than those to the general population. I may have also sworn at them for resisting my advice. I  make no apologies.

The Story


It is August 1st, 2020, in Australia. The level of daily confirmed COVID-19 cases in Australia has been between 50 and 200 every day since the middle of June. Initial controls reduced cases in April 2020, but relaxation of controls caused cases to rise again in May, and tighter controls (less severe than in March and April) were re-introduced. The situation seems stable. The business community is clamouring for reduced restrictions for international travellers because the tourism industry has suffered significant economic damage. Also as businesses start to gear up again under the less restrictive domestic rules, there are significant skills shortages in key industries due to the loss of skilled visa holders who returned home and no replacements being able to enter the country in the last 4 months. This is despite general unemployment still being very high. Business is arguing that allowing specific skilled workers in will allow them to function better and hire some of the Australians that are currently employed.

The Narrative

The government response is to relax requirements for international visitors with the following rules:

People can enter the country if they can do one of the following:

Option 1

Supply a certificate from their current country of residence that they have been tested for immunity by a registered medical practitioner using a test from an approved list. AND they agree to be tested at the border again in Australia.  If the second test does not demonstrate immunity, they have to return home /, OR they then agree to Option 2.

In this option, Australia will also only allow this to occur from a list of approved countries. Approval will be dependent on the state of the Pandemic in that country and as assessment of the medical system in that country.

Option 2

People agree that they will go into a designated quarantine hotel at their own expense for 14 days and be tested for the virus at the end of that stay. They agree that a positive test will mean a longer stay in quarantine and release will be based on requirements for release from isolation at the time (see for the rules revised on March 20th)

Key Points if this Story Comes True

Let me be clear that this is a methodology to reduce the chances of people who are infected entering the country. It will not stop that happening. There is significant variation between people’s responses to infection. The point at which 50% of people show symptoms after being infected is 5.1 days. At 14 days post infection this is 99% of people (medical advice, Emergency Disease Specialist at the frontline). There is no reliable data on whether a person who has been infected but is not showing signs will be picked up on a viral test on a particular day. What I am saying here is that 1 in 100 infected people will not show symptoms at 14 days. Some unknown percentage of those people will test negative at that point, and some unknown percentage of those people will be infectious after release. This means that some people who are quarantined for 14 days and test negative will go on to infect people in the community. It will be a very small number, but if 10,000 people a day enter the country (about 20% of normal traffic) it is just a numbers game. Again, there are still community transmission cases occurring anyway, so this is a public health response. We are not trying to stop 100% of infected people entering the country. The only way to guarantee that is to block all entry.

There are liability issues to be considered here. If a person goes through the quarantine/testing and ends up infecting people in a business who is liable? I would argue it should be the government on behalf of the community. If people are too scared to bring in vital workers because they might be liable that will stop the policy working. If the country as a whole wants this to happen to benefit the whole community then the community should bear the risk consequences.

There will be people who test as recovered and immune in their own country and then test as not immune here. That is just the nature of large-scale testing programs. Those individuals will scream blue murder at being turned away or having to spend at least two weeks more in isolation at their own cost. That will have to be clearly communicated to the visitors before they commit to travel. It should be a low number. By the time we get to August we will have a better handle on this.

A system as I have described will increased both time costs and dollar costs of entering Australia. This means that it will still severely restrict international tourists and business people coming to Australia except for those that are confident in their immunity. It will, however, facilitate longer-term visitors, especially skilled visa holders.


I think there will also be a market in the early stages for people who have a certificate in Australia that clearly shows they are immune.

Those people will be confident about getting out and about and will want to.

Those people will be able to access things like cheap tickets for flights. There may be even specific immunity certificate flights. The same applies to tourism destinations, pubs, cafes, etc hosting dinners or events where everyone is immune.

That is on the customer side. On the supply side, there will also be increased demand for services supplied by people who are immune. Imagine immune certificated plumbers, lawyers, cleaners, etc.

Of course, as in any field of human endeavour, this will create a market for people trying to get around the rules and fake certificates. There must be heavy penalties to dissuade this aligned to the fact that the individuals may be recklessly endangering other people’s lives.

Addendum 2

In a paper published in Nature the authors have stated:

“Seroconversion occurred after 7 days in 50% of patients (14 days in all), but was not followed by a rapid decline in viral load”

Seroconversion means the presence of detectable antibodies in the blood.Much more information will be needed but this indicates that a test showing antibodies will not indicate absence of infection or lack of ability to transmit virus.

Two positive antibody tests at least 14 days apart may do that but we do not have enough evidence for that at this stage. Again we need to differentiate between public health response and an individual response. If an antibody test say lets 1 in 200 people through that are infected that may work as a public health response. However if maintaining your workforce free of infection is critical to your ongoing operations that is a different decision.


As I said at the beginning, this is a piece of speculation. Even if such a system come in to being there will be differences due to greater knowledge in intervening months and the policy desires of the government as well as the attitude of the community.

Technical Details and References

General Immunity

At a very simple level, there are two kinds of immune responses. One is the cellular response which is where specific cells in our bodies do things like ingest viruses or destroy infected cells. The other is an antibody response. Antibodies are proteins that are produced in response to infection. They have complex shapes that can attach to specific parts of a virus and stop it attaching to cells or can clump viruses together to make them easier targets for our defence cells. This excellent summary from the British Immunology Society gives great descriptions and details some of the arms wars between our bodies and viruses:

Antibodies take 5-7(10) days to be created in response to an infection and numbers build up over a longer period than that. If we have been infected before or have been vaccinated, then our body is “primed” and can produce antibodies more rapidly. This is why generally vaccines are of no value after we have been infected, although there are exceptions.

A Blood Test for Immunity?

Once our response to an infection has kicked in, and antibody levels rise, we can use tests to detect those antibodies. The higher the levels of antibodies in our blood then the greater the chance we have of detecting them. This is a function of the individual response, the virus in question, and how long since we have been infected. Here is an interview with Professor Michael Kid describing the blood test that is about to be rolled out in Australia:

As we are dealing with newly developed tests, we need to be careful about saying what they can do. There will be false positives (test says positive when you are actually not infected) and false negatives (test says negative when you have the virus). This is a function of the test itself and its calibration, the time from infection to test, the virus in question, and the individual response. Given we are rapidly developing and deploying tests, there is less certainty about their accuracy. That certainty will build up over time.

The New Scientist has a useful general summary on tests:


There are two questions here. The first is whether we develop immunity after being infected. This appears to be true. The second is how long that immunity lasts. The answer to that is that we do not know because we do not have anybody who has been infected long enough to know. We can speculate from other types of coronavirus, but there possibly is a lot of variation there. This article in the New York Times discussed possible significant differences in immunity length between the SARS (eight to 10 years and the MERS virus infections, again with limited information:

Long-lasting immunity also discounts the possibility of significant mutation. Flu viruses mutate a lot which why we need a new vaccine every year. At this stage, it seems likely the COVID-19 virus will change much less. Again, we are working on limited information and extrapolating from basic science at this point (that the COVID-19 virus has a proof-reading system that corrects errors if mutations occur).

A non-peer reviewed paper (and therefore caution advised) seems to indicate the Macaques cannot be infected after becoming immune. It was only tested on 4 monkeys:

Harvard Medical School is doing research:

Assumption that we will not eliminate the Virus

As I have written in the scenarios we have produced (download at: I think it is unlikely that a country or region will eliminate the virus. China reduced new case numbers to zero, but then others emerged as restrictions were relaxed. Across tens or hundreds of millions of people eliminating a virus from a population once it as infected a significant but small part of the population is very difficult. As an example, South Korea has done a very good job in controlling infections in their country, but here is what is happening:


They have done a very good job in controlling infections but are still confirming about 100 cases a day on average since March 12th. In my view some variation on these numbers is the long-term picture in a well-controlled outbreak with fluctuations of different magnitudes at different times. I will write a longer piece on this soon and link it here.

Paul Higgins

March 28th, 2020