Can someone who recovered from Covid-19 be treated again? This is a fundamental question in the fight against the global epidemic, the answer of which has not yet been decided conclusively, although scientists hope that infected people acquire immunity to the virus for a few months.

"The acquisition of immunity means that a person has developed an immune response against a virus that will allow him to eliminate it," explains Professor of Immunology at the General Authority of Marseille Hospitals, Eric Vivier. Since the immune response has a memory, this allows him not to become infected with the same virus again at a later time.

In general, when infected with viruses with RNA such as the SARS-Cove-2 virus, known as the emerging corona virus, it takes “about three weeks to obtain a sufficient amount of protective antibodies,” and this protection lasts several months.

But this remains purely theoretical, as the new virus, which is currently spreading, still carries a lot of mystery, which does not allow confirmation of anything.

"We don't know that ... We can only generalize from previous Coronaviruses, and even for these viruses, the available data are limited," said Mike Ryan, WHO Director of Emergency Programs. Professor Francois Malo of the University College London said that for the SARS virus (severe acute respiratory syndrome) that caused about 800 deaths in the world in 2002-2003, the patients who recovered had protection against the disease "for an average of two to three years", and thus "could Sure, it is again infected with the virus, but the question arises after how much time? This is what we will only know when it happens. ” A recent Chinese study not reviewed by other scientists demonstrated that monkeys infected with and recovered from the virus did not catch the infection again. But "this does not mean anything" in the long run, according to the opinion of the researcher at the Institut Pasteur Friedrich Tangi, because the study was conducted over a relatively short period of time that does not exceed a month. In this context, information received from Asia, especially from South Korea, according to several people who showed tests for their infection after recovering from the virus, raises many questions.

Experts believe that this could theoretically point to a second infection, and they consider this unlikely, and they currently favor other hypotheses.

Professor Baloo said it is possible for some patients that the virus will not be eliminated and cause a "chronic" infection similar to the one that causes the herpes virus, which can remain latent without causing symptoms in the person who is pregnant with it. It is also possible, in his view, that the patient is not essentially cured, and that the results of the tests that showed his recovery are wrong, as the tests to detect the new Corona virus are not completely reliable. He said: "This may suggest that people remain able to transmit infection for a long time, for a few weeks, and this is not a matter of reassurance."

Protective antibody

A study of 175 patients who recovered in Shanghai, and published its results in early April without a scientific review, showed that most patients secreted antibodies 10 to 15 days after the disease began, with varying degrees of intensity.

But Maria van Kirkhav, who is responsible for dealing with the epidemic at the World Health Organization, noted that "knowing whether antibody means immunity is a completely different matter."

Warning

It is possible that the patient has not recovered at all, or that the results of the tests that showed his recovery are wrong.

Francois Malo:

“It certainly can, but the question is after how much time? This is what we will only know when it happens. ” 

A Chinese study: «Monkeys infected, recovered, and did not catch infection again, but this does not mean anything.