DECRYPTION – At this stage, this “immune passport” is likely to be not only ineffective, but even dangerous.
The idea of testing the whole population with inexpensive serological tests to determine who are the people who have already had the disease and could resume a normal life without confinement is attractive. However, at this stage, this “immune passport” risks not only being ineffective, but even dangerous. Even if the serological test was very effective, with 95% reliability, both to say who developed antibodies in response to the virus, and to find out who did not.
For France, at the current stage of the epidemic, the problem does not come from the test as precise as it is, but from the still too large proportion of the population who have not been in contact with the virus. A statistical effect well known to epidemiologists, and fairly easily calculated on a corner of the table.
Suppose that all people infected with the coronavirus are then immunized, therefore protected from a second infection (which is far from being
