A 25-year-old college student from Washoe, Nevada, is the first documented case in the United States, and the fifth in the world, of reinfection with the new coronavirus.
The first infection occurred at the end of March, and the young man was already recovered by mid-April, after presenting negative results in tests for COVID on two occasions.
But in early June, almost two months after the first infection, the student tested positive again, after again presenting symptoms of COVID, which this time were much more serious.
He recovered, after needing hospitalization.
How did you develop COVID twice?
Usually, when a person becomes infected, they acquire immunity to that germ. That immunity can be permanent, and can occur either through exposure to the virus, or through immunization.
Or it may be temporary, like the one generated by the flu vaccine.
Little is known about the immunity it generates COVID. Some patients appear to develop powerful antibodies, and others few or none, as must have been the case in this patient.
The scientists note that what is more unusual is the severity of the second infection in the young. In general, second infections are usually milder because immunity would already be generated thanks to antibodies.
What is an antibody
Antibodies are molecules produced by the immune system to fight infection.
These are proteins that plasma cells (a type of white blood cell) “make” in response to an antigen (a substance that causes the body to produce a specific immune response). In this case the new coronavirus.
Each antibody can bind to only one specific antigen. The purpose of this union is to help destroy the external agent. Some antibodies destroy antigens directly. Others make it easier for white blood cells to destroy them.
In a let’s say traditional infection, the robust production of antibodies is like a kind of army that defends the organism from another potential infection. The antibodies “recognize” if a germ that has already infected that body reappears and simply prevents it from entering.
But with COVID it is not yet known how this defense mechanism works. In fact, the young man who was reinfected in Nevada is healthy and did not have any pre-existing conditions that would indicate that his immune system was weakened and he could not develop a robust immune response.
The study based on this case hypothesizes that it is more difficult to generate an immune response to COVID.
The other cases of reinfections were registered in Hong Kong, the Netherlands, Belgium and Ecuador.
Although concrete answers to this enigma are still lacking, the new coronavirus is considered to infect people in very different ways. And there would be a large number of asymptomatic carriers, spreading the virus without even knowing they have it.
Sources: The Lancet Infectious Diseases, CDC China, NPR.