President Donald Trump recently tweeted that he was immune to COVID-19. Twitter wasn’t too happy and slapped a warning label on the message, saying that it “spread misleading and potentially harmful information.” Later, one of America’s leading experts, Dr. Anthony Fauci, partially defended Trump’s statement. So now we must ask: What is the truth when it comes to coronavirus immunity?
In an interview, Fauci said that Trump is “temporarily immune,” but he is not sure how long the immunity will last.
Humans develop immunity to viruses after having contracted them. One typical example is chickenpox. Once someone gets ill and recovers, they remain immune for several decades, possibly for a lifetime. Some people are naturally immune to an illness from birth or early age. Scientists have uncovered a strong relationship with the birth year. For instance, people born after 1968 are less likely to die or become acutely ill from the H5N1 virus.
The likely explanation is that people born after this year have natural exposure to the related H1N1 or H2N2 viruses from childhood. Scientists call this learning from early exposure “imprinting.” Those who have natural immunity never need to develop new antibodies to a novel disease. Most people, however, create new antibodies when they catch a new virus.
Yellow fever is an example of a disease for which a suitable vaccine lasts a lifetime. The reason is that the virus is stable and doesn’t change much over time. Scientists have had far less success in developing a vaccine for the seasonal flu because it mutates. For that reason, people can catch the flu many times during a lifetime. The antibodies only give a temporary immunity until the virus changes so much that the immune system fails to recognize it anymore.
Humans are exposed to many coronaviruses, and, therefore, a large portion of the population is likely naturally immune to COVID-19. The infection is not well-understood. It is still uncertain whether the virus is mutating rapidly. Therefore, scientists do not know how long immunity will last. If it behaves like the seasonal flu, the effect will only last a couple of years. The pandemic will then follow a similar path to other viruses, such as the 1968 Hong Kong flu.
There have also been recorded several cases of people who have contracted COVID-19 twice. Some have used this as evidence that one cannot become immune. A more likely explanation is that a part of the population never becomes entirely immune to some viruses.
Trump has been measured to have an immune response to the illness. Therefore, he is probably correct in saying that he is currently resistant to the disease and cannot spread it to other people. The only uncertainty is for how long the effect will last. Will he be immune for the rest of his life, or maybe only a few months? We don’t know yet.