PARIS | An American has caught COVID-19 twice within a month and a half of each other and the second infection was more severe than the first, according to a study released Tuesday which details this case of reinfection, one of five identified so far in the world.
• Read also: Trump declared negative for COVID-19
• Read also: All developments in the COVID-19 pandemic
“There are still many unknowns about SARS-CoV-2 infections and the immune system response, but our work shows that a previous infection might not necessarily protect against future infection,” said Pr Mark Pandori, lead author of the study published in the medical journal The Lancet Infectious Diseases.
This implies “that people who have tested positive for SARS-CoV-2 should continue to take precautions, including physical distancing, wearing a mask and washing their hands”, since reinfection is possible, continued the Pr Pandori, quoted in a press release from The Lancet Infectious Diseases.
According to this medical journal, five cases have been confirmed so far: in Hong Kong (this was the first, announced on August 24), Belgium, the Netherlands, Ecuador and the US state of Nevada ( it is he who is the subject of this new study).
“This does not mean that there are not more, especially because many cases of COVID-19 are asymptomatic” and therefore difficult to spot, however warned the Pr Pandori, University of Nevada expert.
These five cases were different: for those in Nevada and Ecuador, the second infection was more severe than the first, while the other three were the reverse.
The Nevada case concerns a 25-year-old man, in whom no immune disorder or other disease pre-existing to his COVID-19 infection has been detected.
On April 18, he was declared positive for the first time, with a few symptoms (sore throat and headache, cough, nausea, diarrhea). He was placed in solitary confinement and his condition improved. It is then declared negative twice.
But 48 days later, on June 5, he tested positive again, this time showing more severe symptoms, including breathing difficulties that required his admission to the emergency room and the administration of oxygen. This patient has since recovered.
A genetic analysis has shown that these two successive infections were caused by two different strains of the SARS-CoV-2 coronavirus, which is essential for us to be certain that it is indeed a reinfection.
“More research is needed to understand how long immunity to SARS-CoV-2 lasts and why some of these second infections, although rare, are more severe,” said Pr Pandori.