Six people among 40 million cases: the mystery of those reinfected by the coronavirus

US President Donald Trump returned to the electoral campaign on Monday after overcoming the covid.

“I have passed it.

They say I'm immune.

I feel so powerful! ”Trump proclaimed to thousands at a rally in Sanford, Florida.

“I will kiss you all.

I will kiss the boys and the pretty women, ”he added.

The doctor Ramon Valls listened to his words with amazement.

"Do not sing victory", sentence.

Valls, a 62-year-old rheumatologist from the Hospital de Palamós (Girona), suffered the covid in March, with mild symptoms: tiredness, fever, loss of smell and little else.

He returned to work and, in late August, was reinfected, with a different strain of the virus.

This time he "plummeted".

Valls, a sportsman who has also been a doctor at the Palamós Football Club for more than 30 years, spent September in hospital with bilateral pneumonia and on the verge of death.

"Let no one lower their guard, because this can happen," he warns.

Reinfections with the new coronavirus are so exceptional that Valls's case has been analyzed in detail by the team of doctor Roger Paredes, from the Germans Trias Hospital, in Badalona.

"It is a reinfection, with 100% security," says Paredes, who has not yet published his results in a scientific journal.

If his data is confirmed, Ramon Valls would be the first healthy person registered to suffer a very serious reinfection in the world.

Spanish Ramon Valls is the first person in the world to suffer a very serious reinfection, according to his doctors

One of the essential questions to predict the immediate future of humanity is whether the new coronavirus will be able to reinfect and make people sick who have already overcome the covid.

If reinfections are common as the months go by, the fight against the pandemic will get complicated.

The good news is that, after almost 40 million confirmed infections, only five reinfections have been published to date, to which should be added that of Ramon Valls.

The bad news is that more disturbing cases are beginning to emerge.

Scientists from the University of Nevada confirmed this Tuesday the first known reinfection in the United States: a 25-year-old man, living in Reno, suffered the covid at the end of March and, just a couple of months later, in late May, he was infected again .

The worrying thing is that the second infection also caused more severe symptoms than the first.

In March he had a cough, nausea, diarrhea and a headache.

In the second contagion he had to be hospitalized to receive oxygen.

The young man did not suffer from other diseases and genetic analyzes of his viruses point to two different infections, not a relapse.

"All people, whether they have passed the covid or not, should take the same precautions to avoid becoming infected with the SARS-CoV-2 virus," underline the Nevada scientists, led by virologist Mark Pandori.

His research has been published in the specialized journal

.

The first known case of reinfection was detected in Hong Kong in August.

A 33-year-old man suffered a first mild infection in April and a second completely asymptomatic four months later, identified after a trip to Spain in a routine check at the Hong Kong airport.

On September 5, scientists from Leuven (Belgium) announced a second case: a 51-year-old woman who, after a mild COVID in March, was reinfected three months later with even milder symptoms.

Based on the experience with other coronaviruses that cause the common cold, this would be expected: that the second infections are milder than the first, thanks to the defenses already generated.

"Vaccines could induce a stronger immunity than that of the natural virus", reassures virologist Isabel Sola

On September 8, however, a third story was known very different from the previous ones.

A team of researchers from the San Francisco de Quito University (Ecuador) published the case of a 46-year-old man who, after a first mild infection in May, suffered a second more serious one in July, although he did not require hospitalization.

The fourth case, known this Monday, is absolutely unique: an 89-year-old Dutch woman with Waldenström's macroglobulinemia, a rare cancer that affects the body's defenses.

The patient died after a presumed reinfection, two months after having overcome the covid, reports

.

It is the first death recorded in the world of a reinfected person, although their situation is difficult to extrapolate.

Mark Pandori's team launches hypotheses that could explain these exceptional cases observed in Spain, Ecuador and the USA, with second infections more serious than the first.

One of the possibilities is that the reinfection occurred with a virus load so high that it was able to defeat the specific defenses generated in the first contagion.

Another option, the researchers point out, is for more aggressive strains of the virus, at least for affected patients.

A third theory, more worrisome and also more unlikely, is the dreaded “antibody-dependent potentiation”, a mechanism observed only in the laboratory in the coronavirus that causes severe acute respiratory syndrome (SARS): the antibodies generated in the first infection help the virus in the second contagion, instead of fighting it.

People who overcome COVID usually generate a complete immune response, with neutralizing antibodies - proteins that bind to viruses to block infection - and T lymphocytes, a type of white blood cell that destroy cells already infected by the coronavirus.

“From what we know so far, natural infection triggers an immune response that may not last forever.

It has been seen that the levels of neutralizing antibodies decrease in 2-3 months, although the T-cell response could be longer lasting ", explains virologist Isabel Sola, who together with her colleague Luis Enjuanes leads the development of an experimental vaccine against covid, at the National Center for Biotechnology, in Madrid.

“This suboptimal immunity may be due to the virus expressing proteins that inhibit the immune response.

Therefore, vaccines could induce a stronger immunity than the wild type virus.

Ideally, they could induce sterilizing immunity, as has been seen in animal models [in mice] with some intranasal vaccine candidates, ”Sola adds.

Doctor Roger Paredes believes that it is too early to draw conclusions.

“We do not know if reinfections are going to be exceptions or something general.

Most people were exposed to the virus in March and now, about six months later, we are starting to see reinfections.

This, at the very least, is a warning sign for us to be very vigilant, ”Paredes warns.

It's as frustrating as it is simple: there's only one way to know if your immunity to the coronavirus will last for a year.

You have to wait a year.

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