Can someone be infected with COVID-19 more than once?
Can someone be infected with COVID-19 more than once?
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We are still learning a lot about what kind of immunity a person has after being infected with COVID-19, and how long that immunity lasts. A a small number of people have reportedly become reinfected with virus following an initial infection and research is ongoing. According to the US Centers fo Disease Control and Prevention (CDC), "reinfection means a person was infected (got sick) once, recovered, and then later became infected again. Based on what we know from similar viruses, some reinfections are expected. We are still learning more about COVID-19." In a press conference on December 4th, 2020, the World Health Organization acknowledged emerging evidence that suggests that COVID-19 immunity is unlikely to be lifelong, which suggests reinfection may be possible. The most reliable way to measure immunity to COVID-19 is unclear, and, whether from infection or vaccination, scientists still do not know how long immunity to COVID-19 may last. Though reinfection has been documented, there are many ongoing questions about whether or not reinfection poses an ongoing risk, how common it is, and what kind of immunity to the virus people might obtain once they have been infected. Currently researchers believe that most people will be protected from reinfection for up to six months following infection, but research is ongoing. There are multiple pre-print studies with large participant groups that suggest immunity does last for up to six months but decreases over time. Antibodies decrease more quickly in young adults who have had an asymptomatic infection. Pre-print studies have also suggested that reinfection is possible. It is important to note that there is a shortage of peer-reviewed papers (so other scientific experts are not yet able to rigorously study the data or full results). It is also important to note that antibody levels may not be a strong indicator of immunity against the virus and likelihood of reinfection. To prevent infection, reinfection, and spread of COVID-19, experts recommend frequent hand washing, social distancing (6 feet/2 meters apart), avoidance of crowded areas (especially indoors), wearing a face mask (though the U.S. CDC now suggests wearing a cloth mask over a surgical mask or a high grade respirator), and staying home when you are sick or know that you have been exposed to COVID-19.
We are still learning a lot about what kind of immunity a person has after being infected with COVID-19, and how long that immunity lasts. A a small number of people have reportedly become reinfected with virus following an initial infection and research is ongoing. According to the US Centers fo Disease Control and Prevention (CDC), "reinfection means a person was infected (got sick) once, recovered, and then later became infected again. Based on what we know from similar viruses, some reinfections are expected. We are still learning more about COVID-19." In a press conference on December 4th, 2020, the World Health Organization acknowledged emerging evidence that suggests that COVID-19 immunity is unlikely to be lifelong, which suggests reinfection may be possible. The most reliable way to measure immunity to COVID-19 is unclear, and, whether from infection or vaccination, scientists still do not know how long immunity to COVID-19 may last. Though reinfection has been documented, there are many ongoing questions about whether or not reinfection poses an ongoing risk, how common it is, and what kind of immunity to the virus people might obtain once they have been infected. Currently researchers believe that most people will be protected from reinfection for up to six months following infection, but research is ongoing. There are multiple pre-print studies with large participant groups that suggest immunity does last for up to six months but decreases over time. Antibodies decrease more quickly in young adults who have had an asymptomatic infection. Pre-print studies have also suggested that reinfection is possible. It is important to note that there is a shortage of peer-reviewed papers (so other scientific experts are not yet able to rigorously study the data or full results). It is also important to note that antibody levels may not be a strong indicator of immunity against the virus and likelihood of reinfection. To prevent infection, reinfection, and spread of COVID-19, experts recommend frequent hand washing, social distancing (6 feet/2 meters apart), avoidance of crowded areas (especially indoors), wearing a face mask (though the U.S. CDC now suggests wearing a cloth mask over a surgical mask or a high grade respirator), and staying home when you are sick or know that you have been exposed to COVID-19.
Publication
What our experts say
We are still learning a lot about what kind of immunity a person has after being infected with COVID-19, and how long that immunity lasts. A small number of people have reportedly become reinfected with the virus following an initial infection and research is ongoing. According to the US Centers for Disease Control and Prevention (CDC), "reinfection means a person was infected (got sick) once, recovered, and then later became infected again.” Re-infection has always been thought possible, based on what we know from similar viruses. Cases of re-infection have now been reported and confirmed, however, they remain rare.
In a press conference on December 4th, 2020, the World Health Organization acknowledged emerging evidence that suggests that COVID-19 immunity is unlikely to be lifelong, which suggests reinfection may be possible. We now know that both natural immunity from infection, and acquired immunity from vaccines both decline with time. Natural immunity from infection can vary depending on the individual and the severity of the infection, and does not provide similar protection in all individuals who get sick with the virus.
There are multiple pre-print studies with large participant groups that suggest immunity does last for up to six months but decreases over time. Antibodies decrease more quickly in young adults who have had an asymptomatic infection.
Pre-print studies have also suggested that reinfection is possible. It is important to note that there is a shortage of peer-reviewed papers (so other scientific experts are not yet able to rigorously study the data or full results). It is also important to note that antibody levels may not be a strong indicator of immunity against the virus and likelihood of reinfection.
The most reliable way to measure immunity to COVID-19 is unclear, and, whether from infection or vaccination, scientists still do not know how long immunity to COVID-19 may last. This is particularly hard to measure because long lasting immunity depends on the immune system remembering the defense mechanism against a specific infection, and at the moment, we do not have enough information on how the body reacts to COVID-19 to be able to examine this mechanism more closely.
Though reinfection has been documented, there are many ongoing questions about whether or not reinfection poses an ongoing risk, how common it is, and what kind of immunity to the virus people might obtain once they have been infected. Currently researchers believe that most people will be protected from reinfection for up to eight months following infection, but research is ongoing. There is also the question of how infection from one variant can protect against other variants of COVID-19. A study published in August 2021 reported a case of a severe reinfection with the Delta variant, in Delhi, India, despite this person having had complete vaccination, and a breakthrough infection with the Alpha variant three weeks after her second dose of the vaccine.
To prevent infection, reinfection, and spread of COVID-19, experts recommend frequent hand washing, social distancing (6 feet/2 meters apart), avoidance of crowded areas (especially indoors), wearing a face mask (though the U.S. CDC now suggests wearing a cloth mask over a surgical mask or a high grade respirator), and staying home when you are sick or know that you have been exposed to COVID-19. Vaccination is recommended for all eligible individuals, as well as booster doses for those who have completed initial vaccination.
We are still learning a lot about what kind of immunity a person has after being infected with COVID-19, and how long that immunity lasts. A small number of people have reportedly become reinfected with the virus following an initial infection and research is ongoing. According to the US Centers for Disease Control and Prevention (CDC), "reinfection means a person was infected (got sick) once, recovered, and then later became infected again.” Re-infection has always been thought possible, based on what we know from similar viruses. Cases of re-infection have now been reported and confirmed, however, they remain rare.
In a press conference on December 4th, 2020, the World Health Organization acknowledged emerging evidence that suggests that COVID-19 immunity is unlikely to be lifelong, which suggests reinfection may be possible. We now know that both natural immunity from infection, and acquired immunity from vaccines both decline with time. Natural immunity from infection can vary depending on the individual and the severity of the infection, and does not provide similar protection in all individuals who get sick with the virus.
There are multiple pre-print studies with large participant groups that suggest immunity does last for up to six months but decreases over time. Antibodies decrease more quickly in young adults who have had an asymptomatic infection.
Pre-print studies have also suggested that reinfection is possible. It is important to note that there is a shortage of peer-reviewed papers (so other scientific experts are not yet able to rigorously study the data or full results). It is also important to note that antibody levels may not be a strong indicator of immunity against the virus and likelihood of reinfection.
The most reliable way to measure immunity to COVID-19 is unclear, and, whether from infection or vaccination, scientists still do not know how long immunity to COVID-19 may last. This is particularly hard to measure because long lasting immunity depends on the immune system remembering the defense mechanism against a specific infection, and at the moment, we do not have enough information on how the body reacts to COVID-19 to be able to examine this mechanism more closely.
Though reinfection has been documented, there are many ongoing questions about whether or not reinfection poses an ongoing risk, how common it is, and what kind of immunity to the virus people might obtain once they have been infected. Currently researchers believe that most people will be protected from reinfection for up to eight months following infection, but research is ongoing. There is also the question of how infection from one variant can protect against other variants of COVID-19. A study published in August 2021 reported a case of a severe reinfection with the Delta variant, in Delhi, India, despite this person having had complete vaccination, and a breakthrough infection with the Alpha variant three weeks after her second dose of the vaccine.
To prevent infection, reinfection, and spread of COVID-19, experts recommend frequent hand washing, social distancing (6 feet/2 meters apart), avoidance of crowded areas (especially indoors), wearing a face mask (though the U.S. CDC now suggests wearing a cloth mask over a surgical mask or a high grade respirator), and staying home when you are sick or know that you have been exposed to COVID-19. Vaccination is recommended for all eligible individuals, as well as booster doses for those who have completed initial vaccination.
Context and background
As scientists, public health professionals, and doctors monitor the COVID-19 pandemic, they continue to learn about how the virus spreads, its symptoms, and other factors important to diagnosis, testing, monitoring, and long-term public health planning. The possibility of reinfection continues to be a major concern with reports that some patients who had fully recovered from the virus later redeveloped symptoms. Some case reports detail how both symptom monitoring and testing have been performed, and, in some instances, patients have documented recovery of COVID-19 with negative virus test results only to become ill and test positive weeks or months later.
While there are still many aspects of the virus and the pandemic that are unknown, recent research suggests that reinfection is indeed possible. It is important to note that, unlike other viruses, the number of antibodies needed to prevent reinfection with COVID-19 is unknown as is the level of antibodies needed to suggest that someone is “immune” to the virus. Studies to further understand immunity as well as the possibility for reinfection are ongoing.
As scientists, public health professionals, and doctors monitor the COVID-19 pandemic, they continue to learn about how the virus spreads, its symptoms, and other factors important to diagnosis, testing, monitoring, and long-term public health planning. The possibility of reinfection continues to be a major concern with reports that some patients who had fully recovered from the virus later redeveloped symptoms. Some case reports detail how both symptom monitoring and testing have been performed, and, in some instances, patients have documented recovery of COVID-19 with negative virus test results only to become ill and test positive weeks or months later.
While there are still many aspects of the virus and the pandemic that are unknown, recent research suggests that reinfection is indeed possible. It is important to note that, unlike other viruses, the number of antibodies needed to prevent reinfection with COVID-19 is unknown as is the level of antibodies needed to suggest that someone is “immune” to the virus. Studies to further understand immunity as well as the possibility for reinfection are ongoing.
Resources
- Longitudinal evaluation and decline of antibody responses in SARS-CoV-2 infection (MedRxiv)
- Direct observation of repeated infections with endemic coronaviruses (J of Inf Disease)
- Prevalence of SARS-CoV-2 in Spain (ENE-COVID): a nationwide, population-based seroepidemiological study (Lancet)
- Study in Primates Finds Acquired Immunity Prevents COVID-19 Reinfections (NIH Director's Blog)
- Interview with Virologist Dr. Rasmussen (Gizmodo)
- What Is COVID-19? (JAMA)
- Scientists say Hong Kong man got coronavirus a second time (AP)
- First Documented Coronavirus Reinfection Reported in Hong Kong (NYT)
- Genomic Evidence for a Case of Reinfection with SARS-CoV-2 (The Lancet Preprint)
- Coronavirus disease (COVID-19) pandemic, WHO press conferences (WHO)
- Reinfection with COVID-19 (US CDC)
- Antibodies to SARS-CoV-2 are associated with protection against reinfection (medRxiv)
- Declining prevalence of antibody positivity to SARS-CoV-2: a community study of 365,000 adults (medRxiv)
- The duration, dynamics and determinants of SARS-CoV-2 antibody responses in individual healthcare workers (medRxiv)
- Robust neutralizing antibodies to SARS-CoV-2 infection persist for months (Science)
- Antibody prevalence for SARS-CoV-2 in England following first peak of the pandemic: REACT2 study in 100,000 adults (medRxiv)
- What reinfections mean for COVID-19 (Lancet)
- Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021 (U.S. CDC)
- Longitudinal evaluation and decline of antibody responses in SARS-CoV-2 infection (MedRxiv)
- Direct observation of repeated infections with endemic coronaviruses (J of Inf Disease)
- Prevalence of SARS-CoV-2 in Spain (ENE-COVID): a nationwide, population-based seroepidemiological study (Lancet)
- Study in Primates Finds Acquired Immunity Prevents COVID-19 Reinfections (NIH Director's Blog)
- Interview with Virologist Dr. Rasmussen (Gizmodo)
- What Is COVID-19? (JAMA)
- Scientists say Hong Kong man got coronavirus a second time (AP)
- First Documented Coronavirus Reinfection Reported in Hong Kong (NYT)
- Genomic Evidence for a Case of Reinfection with SARS-CoV-2 (The Lancet Preprint)
- Coronavirus disease (COVID-19) pandemic, WHO press conferences (WHO)
- Reinfection with COVID-19 (US CDC)
- Antibodies to SARS-CoV-2 are associated with protection against reinfection (medRxiv)
- Declining prevalence of antibody positivity to SARS-CoV-2: a community study of 365,000 adults (medRxiv)
- The duration, dynamics and determinants of SARS-CoV-2 antibody responses in individual healthcare workers (medRxiv)
- Robust neutralizing antibodies to SARS-CoV-2 infection persist for months (Science)
- Antibody prevalence for SARS-CoV-2 in England following first peak of the pandemic: REACT2 study in 100,000 adults (medRxiv)
- What reinfections mean for COVID-19 (Lancet)
- Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021 (U.S. CDC)
