How did a person get infected with the coronavirus again?

It became known this week that one residentHong Kong re-infected with coronavirus after returning from Europe. A 33-year-old man was newly diagnosed with SARS-CoV-2 infection about four and a half months after he was first diagnosed and recovered. He returned from a trip to Spain (although many are recommended not to leave their countries yet), after which doctors diagnosed an asymptomatic course of the disease. But why has this man not worked out immunity to coronavirus? Are we expecting a second, third, or maybe even a fourth wave of the pandemic?

Hong Kong reports first coronavirus re-infection

Don't jump to conclusions. The fact is that people who have already had COVID-19 often test positive for the virus within weeks or even several months. According to virologists, this is due to the sensitivity of the test and the remaining RNA fragments. Therefore, the only way to really answer the question of re-infection is to sequenced the viral genome, that is, to determine the genetic code of the disease.

There is no published expert report yetabout this person - only a press release from the University of Hong Kong. Although the media write that the work will be published in the journal Clinical Infectious Diseases. Therefore, this story still raises more questions than answers.

Content

• 1 Why did a person get re-infected with coronavirus?
• 2 Is the new coronavirus different from the old one?
• 3 Why are there no symptoms of coronavirus?
• 4 What is known about re-infection with coronavirus?
• 5 How long is immunity to coronavirus?
• 6 Should people recovered from coronavirus wear a mask?

Why has a person re-infected with coronavirus?

Immunity to endemic coronaviruses - thosethat cause symptoms of the common cold are relatively short-lived, and recurrences occur even within a single season. Therefore, it is not surprising that reinfection is possible. SARS-CoV-2, a virus that causes COVID-19.

Human immunity is very complex and includesseveral mechanisms in the body. In particular, the production of antibodies - through the so-called adaptive immune response and through the action of cells, which can help train the immune system and destroy cells infected with a particular virus. However, researchers around the world are still studying the immunity to coronavirus, and therefore based on this one case can't say with certaintythat we must start to panic because of the second wave of the pandemic.

It's too early to talk about a new pandemic, but everyone should comply with protective measures

Is the new coronavirus different from the old one?

To answer this question, you need to studystrain of "new" coronavirus - in other words, to determine its type. Human immunity, as a rule, develops a protective reaction against one strain of the virus. And the virus found in Hong Kong has a different strain, scientists say.

The genetic makeup of the sequenced virus that caused re-infection is reported to contain 24 nucleotides - the building blocks of the viral RNA genome. This differs from the composition of the SARS-CoV-2 virus that infected a man for the first time. SARS-CoV-2 has a genome that consists of approximately 30,000 nucleotides, that is, the new virus was different from the original one.

The strain of the new coronavirus differs from the original

Why are there no symptoms of coronavirus?

The man who allegedly re-infected (so farthere is no evidence for this), did not suffer from any of the characteristic symptoms of COVID-19, which could mean that he had a certain degree of protective immunity to the second infection. Because he didn't look sick. But this is difficult to prove.

There are three possible explanations here. First, the immunity he received from the first infection protected him and allowed him to transfer the second infection in a mild form. Another possibility is that the infection itself was mild because the person did not feel unwell or other signs of illness.

Finally, sometimes SARS-CoV-2 infections are asymptomatic - at the moment it is difficult to determine if this was due to differences in the virus or in the human body.

What is known about re-infection with coronavirus?

Only that it seems to be possible after enough time. We don't know how likely or how often this will happen. Yet for several months it has not yet been revealed not a single official case re-infection with coronavirus. This is the first one.

If you are interested in science and technology news, subscribe to us on Yandex.Zen so as not to miss new materials!

How long is immunity to coronavirus?

Now no one knows. Research suggests that acquired immunity works differently depending on the type of infection. So, for example, the human body remembers the measles virus for life, so it is enough to be vaccinated in childhood so as not to get sick. But the flu can get sick several times in one season - by contracting different strains.

Since the SARS-CoV-2 coronavirus appeared quite recently, there are no long-term observations of the immunity of a person who has had the virus. Russian vaccine against coronavirus Sputnik V, as its creators say, provides an immune response for 2 years.

Should people recovered from coronavirus wear a mask?

Definitely yes. Since scientists are still studying how people develop immunity to SARS-CoV-2 after infection, it is recommended that you continue to wear a mask, practice hand hygiene, and distance yourself even after recovering from COVID-19 to protect yourself from the possibility re-infection... As we have seen, this is possible.