“Statement Card”: immunologists warn that there is no certainty that infected people will not be infected again

Recent data on the spread of the new coronavirus indicate that 2,006,513 confirmed cases are registered in the world and 128,886 people have already died. But there is also the number of patients who have recovered from the disease and who have already reached 495 540.

In Chile, the Ministry of Health (Minsal) indicates that to date, 2,937 people have recovered from Covid-19. Minsal said document will be issued to these patients “Registration card”after the rapid tests begin to detect new antibodies to coronavirus, which can last from one to two weeks.

This group will be the population is immune to the virus and cannot transmit itHealth Minister Jaime Manyalich explained: “These people with this registration card they will be exempted from all types of quarantine or restrictionsBecause it is they who can help the community tremendously, because they are not dangerous. ”

However, how immunity works after Covid-19 disease is an area in which science still has many uncertainties. How the human immune system responds to infection and what this means for the spread of the disease is unclear.

Researchers know that immunity after any infection can vary. from a lifetime to its complete absence. In case of coronavirus further research the outbreak of Sars in 2002 and 2003 and the outbreak of Merce, which began in 2012.

Sars-CoV-2, the coronavirus that causes Covid-19, is third epidemic of coronavirus people are still in this century.

“The immune response to Covid-19 has not yet been studied,” they explain from the US Centers for Disease Control and Prevention (CDC). And although studies show that patients with Mers-CoV infection are unlikely to get infected soon after recovery, “this is not yet known. whether a similar immune defense will be observed in patients with Covid-19“, Pointed out the body.

They need, they need More research to see if a person can be re-infected with a new coronavirus. The CDC encourages recovered patients to follow the general hygiene measures already described, such as staying away from sick people, washing their hands often, and covering their face every time they cough and sneeze.

The Chilean Association of Immunologists (Asochin) indicated in a letter issued yesterday and signed by all its members that “today scientific evidence is not enough ensure that all patients recovering from Covid-19 are immune to Sars-CoV-2 infection. “

Fabiola Osorio, president of Asochin, academician of the medical faculty of the University of Chile, He explains that it is not that the patients who have recovered do not generate immunity, but that they, as a scientific community, emphasize that it cannot be guaranteed that they are all protected. “There is a minimum period of three months or more, during which the immune system will protect them, but they don’t know how long it lasts, and we don’t know what the necessary elements of the immune system to create this immunityDetails

Current data indicate that the period from tocalving of Sars-CoV-2 antibodies is from 7 to 14 days“What is accompanied by a progressive, but not sharp decrease in viral load,” they explain in Asochin.

Above, they say, may indicate that there is The “window” of time at which patients produce antibodies without completely killing the virus“These data are compatible with studies that show that the genetic material of the virus can be detected by PCR up to 37 days (20 days on average) from the onset of the disease,” they explain.

Although the level of recovery is promising, this does not mean that recovered people are not at risk. The presence of the virus once does not mean that you will no longer get sick. The possibility of reinfection is a particular problem. For example, South Korean Centers for Disease Control and Prevention reported 91 patients infected with Sars-CoV-2 and then they tested negative for the virus, but then again they tested positive. It is not known whether any of these cases could be reinfection, but if they were, they would question the strength of the immune system that developed in patients.

It’s important to remember that the first reports of a disease in the world appeared less than four months ago, and therefore “not enough time has passed to allow make sure that the first infected people in the world are really immune to reinfection“, Emphasizes the letter Asochina.

In some cases, cases of re-infection have been reported, but this is not a generality, Osorio points out in this regard: “It is impossible to find out if this is a re-infection, that is, a person has recovered and has become infected again, or if, for example, reactivation of the same virus that Outgoing PCR was poorly detected in the background. To date, this evidence is not final, so you can’t talk about re-infection so categorically“

Although experience with other coronaviruses shows that infected people should have minimal protection for at least three months, it is important to have scientific evidence to support this hypothesis. “Rapid tests to detect specific antibodies (IgM / IgG) against Sars-CoV-2, which will be introduced in our country, allow us to detect the presence or absence of these antibodies, but they do not allow quantifying the quantity (names) or evaluating additional important parameters related to its function, such as neutralizing activity against the virus“They say from Asochin.

Important at this time scientific collaboration“Given that we are facing a difficult pandemic, it’s important to present the evidence we have,” Osorio says.

Scientific societies in many countries emphasize that the immune response against Covid-19 is not fully understood. “Many immunologists around the world make such statements to show that we know little about this virus because we studied this for a very short timeIt’s important to present this evidence so that it is considered in different aspects and that it is accessible to the public, ”Osorio explains.

Studies of more than 150 patients who recovered from Sars-CoV-2 infection show that the production of neutralizing antibodies varies greatly. “In Chile only 40 days have passed since the first cases appeared and it seems to us that the application of such a measure as an extract card requires a deeper analysis of the current discharge criteria, and this may include a preliminary pilot study that is being conducted in other countries, ”Asochin said in a letter.

Osorio emphasizes that they cannot be ignored, that there are parameters characteristic of this coronavirus. To begin with, he says that his infectiousness (the power of infection) is very high, she’s never seen, “therefore, immunologists try to interpret previous studies, because the truth is that this answer will not necessarily be the same as that observed in previous epidemics such as, for example, Sars or Merce. Each virus should be considered as a unique object.“.

The CDC asked for precautions and argued that his actions were in the same vein: “The idea is not to exclude evidence. Of course, antibody tests can be very useful for us, the point is to be more careful with the interpretations and position them in a pandemic in which we do not fully know the immune response against this virus. We do not intend to cancel the measures used, on the contrary, we think that they are favorable, and what we are doing is a warning signal that the conclusions these tests give us are not yet proven“.

This type of aspect can affect, for example, quarantine and times of social isolation, “those that need to be reassessed,” says Osorio. “In that sense, what Chile should do this is to look at countries that have tried to be more successful in solving the problem of coronavirus“.

The good news, says Osorio, is that today, scientists around the world are working to uncover what is not known about coronavirus: “Something encouraging is that a lot of research is going on.only that today we cannot make statements, but these studies are being carried out, and in a short period of time we hope to get answers. ”