In February, as the world suffered from the beginning of the COVID-19 pandemic and little was known about the new coronavirus, Colombian cyclist Fernando Gaviria was one of the first world-famous athletes to become infected.
What at that time was a practically unknown infection, kept him hospitalized for two weeks in a hospital in Abu Dhabi, where he was participating in a race in the United Arab Emirates.
That first infection was difficult to overcome, according to Gaviria. But, as with most viruses, doctors predicted a long immunity after being exposed to the coronavirus and having developed COVID-19.
However, that immunity lasted only seven months because in October he received the second diagnosis of COVID-19.
Gaviria said he was completely surprised because this time he had no symptoms.
The Gaviria case represents a double mystery.
First. Gaviria, 26, a native of La Ceja, a town in the Antioquia region, belongs to that elite of high-performance athletes who are supposed to be in excellent health. A protective shield against any disease.
The second. The possibility of being reinfected with the coronavirus that causes COVID-19 seems remote, but it does happen. In fact, the world record reveals only 25 cases, with another 500 suspects.
First case of reinfection recorded in the United States
Interestingly, the first documented case of COVID-19 reinfection in the United States was also a young, healthy person.
A 25-year-old college student from Washoe, Nevada, was the first documented case in the United States, and the fifth in the world, of reinfection with the new coronavirus.
His case, analyzed in a paper published in The Lancet Infectious Diseases, raises many questions about the virus and the disease it develops, COVID-19.
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.
Compared with the case of Gaviria, immunity was much shorter, and in the case of the young university student, the second infection was the most serious.
How can you develop COVID twice?
Usually, when a person becomes infected, they acquire immunity to that germ. That immunity can be:
- Permanent. And it can develop either from exposure to the virus, or from a vaccine.
- Temporary. Like the one generated by the flu vaccine. The flu virus mutates (changes) each season, which is why a new formulation of the vaccine is needed each winter.
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 the Nevada patient. And Gaviria himself.
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 the antibodies. Gaviria is an example, his second infection did not even show symptoms.
Even this second reinfection of Gaviria has been controversial for the scientific community. Some doctors believe that he tested positive because there were traces of genetic material from the virus in his body.
However, an article published in The Lancet Infectious Diseases that analyzed the case of the young man from Nevada considers that there was reinfection since the patient tested positive the first time, and then tested positive again after several negative tests.
This sequence of tests occurred both in the young man from Nevada and in the case of Gaviria.
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 traditional infection, robust antibody production is like a sort of army defending the body 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 was healthy and did not have any pre-existing conditions that would indicate that his immune system was weakened and that he could not develop a robust immune response.
The study based on this case hypothesizes that it may be 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, who spread the virus without even knowing they have it.
Reinfections and vaccines
With several COVID-19 vaccines just around the corner, the possibility of reinfection leaves the door open for research to answer this question: will the COVID-19 vaccine be a seasonal vaccine?
So far, several vaccines, including those from Pfizer, Moderna and AztraZéneca laboratories, have submitted requests for emergency approvals in the United States, and the one from Pfizer has obtained approval in the United Kingdom.
In Latin America, Argentina, Mexico and Brazil are the main players in this race for a vaccine.
But this critical question cannot yet be answered. And, if it is confirmed that the risk of reinfection is not an exception to the statistic but is a broad risk, the need for vaccine stock will be much greater.
Vaccines against COVID-19 in advanced clinical trials require two doses, received about a month apart, to be about 95% effective in preventing infection.
The flu vaccine requires a single dose and immunizes for one season.
The immunization time for COVID vaccines is not yet known. The cases of the young man from Nevada and the cyclist Fernando Gaviria show that, at least, this immunity can be erratic and different in each person.
If the vaccine turns out to be seasonal, requiring two doses, the amount of production and the complexity of distribution will be two of the main challenges. In a public health strategy that will literally involve all of humanity.
Sources: The Lancet Infectious Diseases, CDC China, University of Nevada, CDC.