Brazilian cases shed more light on the risk of COVID-19 reinfection

After analyzing people who have been infected twice with COVID-19, researchers believe that reinfection with SARS-CoV-2 may be more common than previously thought.

The findings were obtained from an analysis of 33 cases of recurrent COVID-19 in Brazil, which was primarily a female health care worker. Recurrences were often more severe than the initial infection with the SARS-CoV-2 virus, killing one person.

Analysis led by the University of Sergipe in Brazil and Imperial College London in London shows that spontaneous immunity to SARS-CoV-2 does not necessarily guarantee protection against reinfection with COVID-19.

According to researchers, their case series-Recently published Published in the Journal of Infection, it is considered to be the largest study to date. Reinfection is more common than previous estimates, indicating that it can be as high as 7% in some groups.

The authors note complacency regarding the assumed level of protection from naturally acquired immunity and emphasize the need for continuous immune monitoring of the population, especially among the population most likely to come into contact with the virus. I will.

Professor Danny Altmann of the Faculty of Immunology and Inflammation at Imperial College London said: “From this case series, a significant proportion of healthcare professionals showed PCR-confirmed COVID-19 infection on two separate occasions. Recurrence of the infection tends to be more severe, with one person Died.

“This is the largest case series to date and provides some evidence that people with a weak antibody response to SARS-CoV-2 are more likely to be infected with the virus again in the future. ..

“Our findings can be important when considering herd immunity thresholds and the level of naturally acquired defenses against viruses, as well as risks such as front-line healthcare professionals. It also suggests the need for continuous sampling and immune monitoring between groups. “

In case of reinfection

Monitoring cases reported through the Health Center of the Federal University of Sergipe in Brazil, the authors reported 33 cases of SARS-CoV-2 infection confirmed by a second PCR after a disease-free period after the first infection. Has been identified. The majority of patients with recurrent infections were health care workers (30) and women (27), with an average duration of 51 days between the first and second infections.

There was also some underlying biological evidence, with 42% (14) of recurrent cases having A + blood group. In addition, when SARS-CoV-2 antibody was analyzed in more than half (17) of 33 cases, the antibody response after the initial infection was lower than that in the control group (31 of 62 cases). The severity of the second COVID-19 episode was associated with existing health conditions such as obesity, hypertension, diabetes and asthma.

The researchers emphasize some limitations in the analysis that the PCR test between the first and second infections, which is only available in 2 of 33 cases, is negative. The genomic sequence from the swab was obtained from only one case, but showed different viral sequences between the first and second infections.

“Recurrent” infection

Professor Altman has been careful to call these cases “recurrence” rather than “reinfection” because the persistence of the virus cannot be completely ruled out. However, these people know that COVID-19 infection was first confirmed and recovered. He returned to work for some time before the second COVID-19 infection was confirmed, during which time the PCR results were negative in at least two cases.

“In the COVID-19 pandemic, see how logically it is difficult to obtain diagnoses such as PCR tests and genomic sequencing during peak demand for outbreaks, and to archive cotton swabs for future analysis. I’ve been. It’s absolutely impossible to be sure. None of these were healthcare workers who recovered, returned to work, and then suffered some form of severe recurrence, but certainly. It’s not too disturbing.

“But I’m convinced that this case series highlights an important finding that reinfection may not be as rare as previously thought. This is a naturally acquired SARS-. It should be taken into account when assuming population-level protection against CoV-2. infection.. ”