Pandemic Perspective #33 November 7, 2020
There has been a flurry of worrisome articles suggesting that infection with the virus of COVID-19 produces antibodies but that they decline rapidly, possibly to unprotective levels. The implication is that a vaccine will either be ineffective or that it will protect recipients for only a short time. Although these conclusions are possible they are at the moment unknowable, and in my opinion, unlikely. Not only will we have to await the analysis of a large number of re-exposed individuals, current testing methods will have to be refined, meaning that they will become more accurate and reliable.
Antibodies that the body makes in response to an infection or to a vaccine always decline eventually, sometimes to levels that are below the threshold of the laboratory tests that identify them. The immune system is remarkably complex, having evolved over millions of years to have many different mechanisms that provide redundancy that any engineer would be proud of. If you become a victim of the coronavirus your antibody response will depend on your genetic profile, your nutritional intake, your body fat percentage (obese persons respond significantly less well to vaccines than do persons of normal weight and possibly to natural infection as well), your level of physical activity and your past exposure to similar viruses. Then there’s the matter of the particular strain of coronavirus that you encountered and which mutations it has undergone.
I have observed that pessimistic journalists’ reports do not mention another – and possibly more important — arm of the immune system, cellular immunity. Some cells of the immune system store information that can be retrieved when the same or similar virus tries to attack. Knowledge of how these cells work is limited by the fact that they are harder to investigate than the antibody system and there is as yet no test available to clinicians that would help them to evaluate the cellular immune status of their patients.
There are silver linings behind the COVID-19 cloud. One of these is that in the next couple of years we will have detailed knowledge of how the body responds to infections in general and this novel coronavirus in particular. In the meantime, keep in mind that antibodies are only one element in a vast and incompletely understood response to infections.