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The second coronavirus infections described in the world are “anecdotal” but, at the same time, they are “underestimated”: in the first wave, not many PCRs were done
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Researchers focus on those who lose their antibodies within a few weeks of becoming infected and are most at risk of falling again
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Last August the first case of reinfection of covid-19 in the world. Today, seven months later, a total of 64 reinfections (which have involved the death of two people). They are very few if one takes into account that globally there have already been some 119 million infections. In addition, there are another 12,408 cases of reinfections suspicious, of which 35 people would have died, according to the rastreador ‘Covid-19 reinfection tracker’, It is updated daily and is used by researchers and the Ministry of Health. It happens that, at the beginning of the pandemic, in March 2020, many people did not undergo any diagnostic test and, therefore, do not have record someone from having passed the coronavirus or reinfection can be confirmed.
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But, nevertheless, they have gone through symptoms such as anosmia (loss of smell and taste), headache, the tos o la fever: unequivocal all of them from covid-19. “To confirm a covid-19 reinfection, you must have a sequence of the first virus and another of the second. But at the beginning of the pandemic this analysis was not done in a systematic way, “he explains. Roger Paredes, Head of Section of the Infectious Diseases Service of the Germans Trias i Pujol Hospital (Can Ruti, Badalona) and researcher at the AIDS Research Institute IrsiCaixa. Confirmed cases of reinfection are few (“anecdotal,” say some researchers), but also more than strictly documented.
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The ‘crux’ of reinfection
A person who passed SARS-CoV-2, the virus that causes covid-19, can keep giving positive for several weeks without already being ill or infectious, which is not the same than a reinfection. PCRs are so precise that they sometimes detect remains of a virus that is already inactive in the body. But a reinfection is something different: it is confirmed when two diagnostic tests, carried out in different periods, show that the genetic makeup Each virus is different to a degree that cannot be explained by ‘in vivo’ evolution. “Now people are being infected who had already been infected a year ago, when they were not doing PCR,” confirms Paredes.
The ignorance Around this new virus that is SARS-CoV-2 it is still big one year after its appearance. Therefore, to predict how it will act, researchers look at the behavior of other coronaviruses that preceded, such as SARS in 2002 or MERS in 2012. “In these coronaviruses, very similar to covid-19, there are cases of up to four reinfections described,” says this researcher from Can Ruti.
Most COVID-19 sufferers build immunity for “a minimum of 9 months,” but what happens afterward is unknown
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Most people who pass COVID-19 are known to generate antibodies that last “a minimum of nine months” and that “even [podrían durar] years”: “It looks like this will be the case, as with SARS and MERS,” he says. Nevertheless, between 15% and 20% of those infected lack these “durable antibodies” and are reinfected. They are patients of all ages and usually have a “mild covid”. Reinfections usually occur at an interval of two or three months between the first and second contagion.
Furthermore, according to the Head of the Microbiology Service of the Vall d’Hebron Hospital (Barcelona), Tomàs Pumarola, most reinfections are “asymptomatic”. “The infrequent thing is to have reinfections with apparent clinical pictures. Severe reinfection is extremely rare “, assures the microbiologist.
Can Ruti Hospital currently has some 250 suspected patients of being reinfected with covid-19. Most, Paredes warns, cannot be confirmed. “We only have one genomic confirmation and 10 highly probable cases,” he says. That confirmed case of reinfection is Ramon Valls, Palamós Hospital doctor who was infected in March 2020 and then in August. It is the only reinfection registered in Spain, at the moment, by the Ministry of Health. In Catalonia there is no specific registry of covid-19 reinfections.
“Covid-19 reinfections are underestimated. That is why we must extend the sequencing of viruses “, defends Paredes. According to the report ‘Coronavirus disease, covid-19’ from the Ministry of Health, last updated on January 15 and referring to a population study in the United Kingdom, the british variant (more contagious) does not cause more hospitalizations or reinfections than Wuhan.
Antibodies: Questions and Answers
The unknown around SARS-CoV-2 is, at the moment, immunity. How long do antibodies last after the virus has passed? And how much is generated by the vaccine? “We look at other coronaviruses and they remind us of what we see now: the more serious a covid-19 infection is, the higher the antibodies that a person generates and the longer it takes for them to fall again,” he says. Isabel Sola, Researcher at the Higher Council for Scientific Research (CSIC) at the National Center for Biotechnology.
“No coronavirus has returned 15, three or five years later. There is immunity And we know that it protects, at least, for about nine or 10 months. For how long they will protect is the unknown, “adds Sola, who qualifies as” anecdotal “the number of covid-19 reinfections in the last year.
The more seriously ill a person, the more immunity they generate and the more protected they are against reinfection
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But immunity does not depend only on antibodies, but also has another branch: the cellular response. If the antibodies are, as defined by Sola, “dissolved projectiles in the blood that recognize the virus and neutralize it “, the cellular response is given by those cells capable of identifying the other infected cells (” the virus factories “) and “destroy” them. “The sum of both branches [anticuerpos y respuesta celular] It ends up being very effective – emphasizes this researcher from the CSIC-. Antibodies are very easy to measure because they are all over the blood and a small prick is enough. But for the cellular response you need more blood and a more complex technology. “
All this serves to explain that protection against a virus or its reinfection is not only given by antibodies, but by the function of some cells, more difficult to measure but also offer a type of protection that is not always calibrated. “Even if the antibodies go down – they are very high a month and then progressively decrease -, that does not mean that you stop being protected: your immunity has memory. Everything points to immunity [frente al covid-19] it is durable “, he points out Alex Soriano, Head of the Infectious Diseases Service of the Hospital Clínic (Barcelona).
It may interest you
Therefore, it is “possible” that immunity against the coronavirus “does not last for life”, but it does that “something remains” in the body that makes the second infection “milder”. It happens with colds, for example. But with other viruses, such as dengue, reinfections are more malignant. “In coronavirus, something like this has never been described,” he says.
In any case, to know how long immunity to covid-19 will last, something is missing that researchers do not have for now: time. “Not enough time has passed since the first wave. And, precisely because we do not know for sure how long a person will be protected, we cannot abandon protection measures “, ditch this investigator.
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But, nevertheless, they have gone through symptoms such as anosmia (loss of smell and taste), headache, the tos o la fever: unequivocal all of them from covid-19. “To confirm a covid-19 reinfection, you must have a sequence of the first virus and another of the second. But at the beginning of the pandemic this analysis was not done in a systematic way, “he explains. Roger Paredes, Head of Section of the Infectious Diseases Service of the Germans Trias i Pujol Hospital (Can Ruti, Badalona) and researcher at the AIDS Research Institute IrsiCaixa. Confirmed cases of reinfection are few (“anecdotal,” say some researchers), but also more than strictly documented.
–
The ‘crux’ of reinfection
A person who passed SARS-CoV-2, the virus that causes covid-19, can keep giving positive for several weeks without already being ill or infectious, which is not the same than a reinfection. PCRs are so precise that they sometimes detect remains of a virus that is already inactive in the body. But a reinfection is something different: it is confirmed when two diagnostic tests, carried out in different periods, show that the genetic makeup Each virus is different to a degree that cannot be explained by ‘in vivo’ evolution. “Now people are being infected who had already been infected a year ago, when they were not doing PCR,” confirms Paredes.
The ignorance Around this new virus that is SARS-CoV-2 it is still big one year after its appearance. Therefore, to predict how it will act, researchers look at the behavior of other coronaviruses that preceded, such as SARS in 2002 or MERS in 2012. “In these coronaviruses, very similar to covid-19, there are cases of up to four reinfections described,” says this researcher from Can Ruti.
Most COVID-19 sufferers build immunity for “a minimum of 9 months,” but what happens afterward is unknown
—
Most people who pass COVID-19 are known to generate antibodies that last “a minimum of nine months” and that “even [podrían durar] years”: “It looks like this will be the case, as with SARS and MERS,” he says. Nevertheless, between 15% and 20% of those infected lack these “durable antibodies” and are reinfected. They are patients of all ages and usually have a “mild covid”. Reinfections usually occur at an interval of two or three months between the first and second contagion.
Furthermore, according to the Head of the Microbiology Service of the Vall d’Hebron Hospital (Barcelona), Tomàs Pumarola, most reinfections are “asymptomatic”. “The infrequent thing is to have reinfections with apparent clinical pictures. Severe reinfection is extremely rare “, assures the microbiologist.
Can Ruti Hospital currently has some 250 suspected patients of being reinfected with covid-19. Most, Paredes warns, cannot be confirmed. “We only have one genomic confirmation and 10 highly probable cases,” he says. That confirmed case of reinfection is Ramon Valls, Palamós Hospital doctor who was infected in March 2020 and then in August. It is the only reinfection registered in Spain, at the moment, by the Ministry of Health. In Catalonia there is no specific registry of covid-19 reinfections.
“Covid-19 reinfections are underestimated. That is why we must extend the sequencing of viruses “, defends Paredes. According to the report ‘Coronavirus disease, covid-19’ from the Ministry of Health, last updated on January 15 and referring to a population study in the United Kingdom, the british variant (more contagious) does not cause more hospitalizations or reinfections than Wuhan.
Antibodies: Questions and Answers
The unknown around SARS-CoV-2 is, at the moment, immunity. How long do antibodies last after the virus has passed? And how much is generated by the vaccine? “We look at other coronaviruses and they remind us of what we see now: the more serious a covid-19 infection is, the higher the antibodies that a person generates and the longer it takes for them to fall again,” he says. Isabel Sola, Researcher at the Higher Council for Scientific Research (CSIC) at the National Center for Biotechnology.
“No coronavirus has returned 15, three or five years later. There is immunity And we know that it protects, at least, for about nine or 10 months. For how long they will protect is the unknown, “adds Sola, who qualifies as” anecdotal “the number of covid-19 reinfections in the last year.
The more seriously ill a person, the more immunity they generate and the more protected they are against reinfection
—
But immunity does not depend only on antibodies, but also has another branch: the cellular response. If the antibodies are, as defined by Sola, “dissolved projectiles in the blood that recognize the virus and neutralize it “, the cellular response is given by those cells capable of identifying the other infected cells (” the virus factories “) and “destroy” them. “The sum of both branches [anticuerpos y respuesta celular] It ends up being very effective – emphasizes this researcher from the CSIC-. Antibodies are very easy to measure because they are all over the blood and a small prick is enough. But for the cellular response you need more blood and a more complex technology. “
All this serves to explain that protection against a virus or its reinfection is not only given by antibodies, but by the function of some cells, more difficult to measure but also offer a type of protection that is not always calibrated. “Even if the antibodies go down – they are very high a month and then progressively decrease -, that does not mean that you stop being protected: your immunity has memory. Everything points to immunity [frente al covid-19] it is durable “, he points out Alex Soriano, Head of the Infectious Diseases Service of the Hospital Clínic (Barcelona).
It may interest you
Therefore, it is “possible” that immunity against the coronavirus “does not last for life”, but it does that “something remains” in the body that makes the second infection “milder”. It happens with colds, for example. But with other viruses, such as dengue, reinfections are more malignant. “In coronavirus, something like this has never been described,” he says.
In any case, to know how long immunity to covid-19 will last, something is missing that researchers do not have for now: time. “Not enough time has passed since the first wave. And, precisely because we do not know for sure how long a person will be protected, we cannot abandon protection measures “, ditch this investigator.
– .
–
The ‘crux’ of reinfection
A person who passed SARS-CoV-2, the virus that causes covid-19, can keep giving positive for several weeks without already being ill or infectious, which is not the same than a reinfection. PCRs are so precise that they sometimes detect remains of a virus that is already inactive in the body. But a reinfection is something different: it is confirmed when two diagnostic tests, carried out in different periods, show that the genetic makeup Each virus is different to a degree that cannot be explained by ‘in vivo’ evolution. “Now people are being infected who had already been infected a year ago, when they were not doing PCR,” confirms Paredes.
The ignorance Around this new virus that is SARS-CoV-2 it is still big one year after its appearance. Therefore, to predict how it will act, researchers look at the behavior of other coronaviruses that preceded, such as SARS in 2002 or MERS in 2012. “In these coronaviruses, very similar to covid-19, there are cases of up to four reinfections described,” says this researcher from Can Ruti.
Most COVID-19 sufferers build immunity for “a minimum of 9 months,” but what happens afterward is unknown
—
Most people who pass COVID-19 are known to generate antibodies that last “a minimum of nine months” and that “even [podrían durar] years”: “It looks like this will be the case, as with SARS and MERS,” he says. Nevertheless, between 15% and 20% of those infected lack these “durable antibodies” and are reinfected. They are patients of all ages and usually have a “mild covid”. Reinfections usually occur at an interval of two or three months between the first and second contagion.
Furthermore, according to the Head of the Microbiology Service of the Vall d’Hebron Hospital (Barcelona), Tomàs Pumarola, most reinfections are “asymptomatic”. “The infrequent thing is to have reinfections with apparent clinical pictures. Severe reinfection is extremely rare “, assures the microbiologist.
Can Ruti Hospital currently has some 250 suspected patients of being reinfected with covid-19. Most, Paredes warns, cannot be confirmed. “We only have one genomic confirmation and 10 highly probable cases,” he says. That confirmed case of reinfection is Ramon Valls, Palamós Hospital doctor who was infected in March 2020 and then in August. It is the only reinfection registered in Spain, at the moment, by the Ministry of Health. In Catalonia there is no specific registry of covid-19 reinfections.
“Covid-19 reinfections are underestimated. That is why we must extend the sequencing of viruses “, defends Paredes. According to the report ‘Coronavirus disease, covid-19’ from the Ministry of Health, last updated on January 15 and referring to a population study in the United Kingdom, the british variant (more contagious) does not cause more hospitalizations or reinfections than Wuhan.
Antibodies: Questions and Answers
The unknown around SARS-CoV-2 is, at the moment, immunity. How long do antibodies last after the virus has passed? And how much is generated by the vaccine? “We look at other coronaviruses and they remind us of what we see now: the more serious a covid-19 infection is, the higher the antibodies that a person generates and the longer it takes for them to fall again,” he says. Isabel Sola, Researcher at the Higher Council for Scientific Research (CSIC) at the National Center for Biotechnology.
“No coronavirus has returned 15, three or five years later. There is immunity And we know that it protects, at least, for about nine or 10 months. For how long they will protect is the unknown, “adds Sola, who qualifies as” anecdotal “the number of covid-19 reinfections in the last year.
The more seriously ill a person, the more immunity they generate and the more protected they are against reinfection
—
But immunity does not depend only on antibodies, but also has another branch: the cellular response. If the antibodies are, as defined by Sola, “dissolved projectiles in the blood that recognize the virus and neutralize it “, the cellular response is given by those cells capable of identifying the other infected cells (” the virus factories “) and “destroy” them. “The sum of both branches [anticuerpos y respuesta celular] It ends up being very effective – emphasizes this researcher from the CSIC-. Antibodies are very easy to measure because they are all over the blood and a small prick is enough. But for the cellular response you need more blood and a more complex technology. “
All this serves to explain that protection against a virus or its reinfection is not only given by antibodies, but by the function of some cells, more difficult to measure but also offer a type of protection that is not always calibrated. “Even if the antibodies go down – they are very high a month and then progressively decrease -, that does not mean that you stop being protected: your immunity has memory. Everything points to immunity [frente al covid-19] it is durable “, he points out Alex Soriano, Head of the Infectious Diseases Service of the Hospital Clínic (Barcelona).
It may interest you
Therefore, it is “possible” that immunity against the coronavirus “does not last for life”, but it does that “something remains” in the body that makes the second infection “milder”. It happens with colds, for example. But with other viruses, such as dengue, reinfections are more malignant. “In coronavirus, something like this has never been described,” he says.
In any case, to know how long immunity to covid-19 will last, something is missing that researchers do not have for now: time. “Not enough time has passed since the first wave. And, precisely because we do not know for sure how long a person will be protected, we cannot abandon protection measures “, ditch this investigator.
– .
