{"id":28462,"date":"2020-09-01T06:27:55","date_gmt":"2020-09-01T02:27:55","guid":{"rendered":"http:\/\/www.mauritiustimes.com\/mt\/?p=28462"},"modified":"2020-09-01T06:27:55","modified_gmt":"2020-09-01T02:27:55","slug":"a-man-was-reinfected-with-coronavirus-after-recovery-what-does-this-mean-for-immunity","status":"publish","type":"post","link":"https:\/\/www.mauritiustimes.com\/mt\/a-man-was-reinfected-with-coronavirus-after-recovery-what-does-this-mean-for-immunity\/","title":{"rendered":"A man was reinfected with coronavirus after recovery \u2013 what does this mean for immunity?"},"content":{"rendered":"

\"\"<\/em><\/p>\n

 <\/p>\n

Reports describe a Hong Kong man who was reinfected with the coronavirus after returning from Europe. Does that mean he wasn’t immune after the first infection?<\/em><\/span>\"\"Is it possible to get COVID-19 twice?\u00a0May James\/AFP via Getty Image<\/a><\/span><\/span><\/h5>\n

A 33-year old man was found to have a second SARS-CoV-2 infection some four-and-a-half months after he was diagnosed with his first, from which he recovered. The man, who showed no symptoms, was diagnosed when he returned to Hong Kong after a trip to Spain.<\/span><\/p>\n

I am a virologist with expertise in coronaviruses and enteroviruses, and I\u2019ve been curious about reinfections since the beginning of the pandemic. Because people infected with SARS-CoV-2 can often test positive for the virus for weeks to months, likely due to the sensitivity of the test and leftover RNA fragments, the only way to really answer the question of reinfection is by sequencing the viral genome at the time of each infection and looking for differences in the genetic code.<\/span><\/p>\n

There is no published peer-review report on this man \u2013 only a press release from the University of Hong Kong \u2013 although reports say the work will be published in the journal Clinical Infectious Diseases. Here I address some questions raised by the current news reports.<\/span><\/p>\n

Why wasn\u2019t the man immune to reinfection?<\/span><\/strong><\/p>\n

Immunity to endemic coronaviruses \u2013 those that cause symptoms of the common cold \u2013 is relatively short-lived, with reinfections occurring even within the same season. So it isn\u2019t completely surprising that reinfection with SARS-CoV-2, the virus that causes COVID-19, might be possible.<\/span><\/p>\n

Immunity is complex and involves multiple mechanisms in the body. That includes the generation of antibodies \u2013 through what\u2019s known as the adaptive immune response \u2013 and through the actions of T-cells, which can help to educate the immune system and to specifically eliminate virus-infected cells. However, researchers around the world are still learning about immunity to this virus and so can\u2019t say for sure, based on this one case, whether reinfection will be a cause for broad concern.<\/span><\/p>\n

How different is the second strain that infected the Hong Kong man?<\/span><\/strong><\/p>\n

\u201cStrain\u201d has a particular definition when referring to viruses. Often a different \u201cstrain\u201d is a virus that behaves differently in some way. The coronavirus that infected this man in Europe is likely not a new strain.<\/span><\/p>\n

A STAT News article reports that the genetic make up of the sequenced virus from the patient\u2019s second infection had 24 nucleotides \u2013 building blocks of the virus\u2019s RNA genome \u2013 that differed from the SARS-CoV-2 isolate that infected him the first time.<\/span><\/p>\n

SARS-CoV-2 has a genome that is made up of about 30,000 nucleotides, so the virus from the man\u2019s second infection was roughly 0.08% different than the original in genome sequence. That shows that the virus that caused the second infection was new; not a recurrence of the first virus.<\/span><\/p>\n

The man was asymptomatic \u2013 what does that mean?<\/span><\/strong><\/p>\n

The man wasn\u2019t suffering any of the hallmark COVID-19 symptoms which might mean he had some degree of protective immunity to the second infection because he didn\u2019t seem sick. But this is difficult to prove.<\/span><\/p>\n

I see three possible explanations. The first is that the immunity he gained from the first infection protected him and allowed for a mild second infection. Another possibility is that the infection was mild because he was presymptomatic, and went on to develop symptoms in the coming days. Finally, sometimes infections with SARS-CoV-2 are asymptomatic \u2013 at the moment it is difficult to determine whether this was due to the differences in the virus or in the host.<\/span><\/p>\n

What can we say about reinfection based on this one case?<\/span><\/strong><\/p>\n

Only that it seems to be possible after enough time has elapsed. We do not know how likely or often it is to occur.<\/span><\/p>\n

Should people who have recovered from COVID-19 still wear a mask?<\/span><\/strong><\/p>\n

As we are still learning about how humans develop immunity to SARS-CoV-2 after infection, my recommendation is for continued masking, hand hygiene and distancing practices, even after recovery from COVID-19, to protect against the potential for reinfection.<\/span><\/p>\n

Megan Culler Freeman<\/strong><\/span>
\nPediatric Infectious Diseases Fellow, <\/span>
\nUniversity of Pittsburgh<\/span><\/p>\n

\n

* Published in print edition on 1 September 2020<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

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