New study: This is what we know about Corona virus immunity...

From some of what we learned from the Corona crisis in 2020, is that we are used to having more questions than answers regarding “Covid-19”, such as how long the virus survives on hard surfaces, or the specific symptoms when infected with it, or what is related to the immunity acquired from infection. Fall ill.

However, with each new study, a spirit of hope arises in us, so that we may quote some new information on this disease. One of those studies is the recent one in the journal “The Lancet – Infectious Diseases”, which dealt with the fifth documented case in the world of recurrent infection with COVID-19.

The useful summary is that after that study there are still pending questions regarding immunity, and more tests are still needed, according to the findings of the researchers participating in the study.

However, the study raises various hypotheses and calls on the rest of the researchers to find a solution to the immunity puzzle from the emerging corona virus.

A hit is stronger than the first

The patient under study is a twenty-five-year-old man from Washoe County, Nevada, USA, who tested positive for two different types of SARS-Cove 2 virus. This confirms that a new infection can occur only a short time after the initial infection, and that it is stronger than the previous infection. Between the first infection of the American young man in April of this year and the new infection, the results of two Corona virus tests on this young man were negative.

But in June, he was rushed to hospital after showing severe symptoms of COVID-19, including fever, headache, fatigue, coughing, nausea and diarrhea. At the hospital, he had a positive Covid-19 test. Currently, the young man has been discharged from the hospital after his condition has improved and he has recovered from the second infection.

The study authors wrote that infection with Covid-19 does not necessarily lead to the development of sufficient immunity against the virus to prevent it from becoming infected again. This means: maintaining a safe distance, wearing a mask, and washing hands periodically.

Just speculation

“There is still a lot we don’t know about SARS-Cove-2 and the immune system’s reaction to it,” says Mark Banduri, of the Nevada State Laboratory of Public Health at the University of Nevada, who is the lead author of the study. Necessarily from a new infection. “

Banduri adds: “It is important to note that this is only one case in which it does not allow for generalization of the entire phenomenon. Even with more research needed, any new infection with the virus will have major implications for our understanding of acquired immunity from Covid-19, especially in There remained a shortage of effective vaccines. “

Commonalities between cases?

After examining the DNA of the virus taken from the patient’s body in April and June, researchers found differences between them, which means that the patient was exposed to two different types of SARS-CoV-2, according to the study. Besides the young man from Nevada, four second cases of coronavirus were documented in Belgium, the Netherlands, Hong Kong and Ecuador. But only an Ecuadorian patient showed more severe symptoms when infected with the virus again.

Mark Banduri explains: “We need more research to know the duration of immunity obtained by those who contracted SARS-Cove 2, and why – despite the rare cases of infection with the virus again – the symptoms of the second infection are more severe than the first … So far we have only seen cases of infection. A second is counted on the fingers of one hand. But that does not mean that there is no more, especially since many cases of Covid-19 infection pass without any symptoms. Currently, we can only speculate on the causes of infection with the virus again.

Similar to the Ecuador patient, the American patient showed more severe symptoms when infected with the virus a second time. As for the cases in Belgium, the Netherlands and Hong Kong, there was no difference in the severity of symptoms between the first and second infections.

Various assumptions

For this, the study authors put forward several hypotheses to explain the severity of symptoms in the second cases, including that the patient may have been exposed to a greater density of the virus the second time, which caused more severe symptoms, or he may have been infected with a more widespread type of virus the second time.

Another hypothesis is that the principle of antibody-dependent reinforcement (ADE), by which viruses use the immune system to spread further in the body, may be the cause. This phenomenon has been observed in the SARS-Cove beta virus, in addition to other diseases, such as dengue fever. Through this mechanism, the infection-promoting antibodies bind to the surface of the virus, not in order to fight it, but to better receive it by the body’s cells, and thus these antibodies support the reproduction of the virus.

In addition, according to the authors of the study, there is a possibility – albeit minimal – of a continuous injury that carries within it the possibility of stopping and starting again. But proving the correctness of this hypothesis requires a certain rate of mutation for the SARS-Cove 2 virus. Although the Corona virus mutates, it does not mutate significantly like the virus that causes influenza, for example, according to what virologist Hendrik Strek says, in an interview with DW.

An alternative explanation for this is infection with two strains of the virus at the same time, except that this means that the second strain was not identified in April. Conversely, this also means that the first strain was assumed to have faded during the examination in June.

In this regard, the study authors admit that they are not able to assess the immune response during the first infection with SARS-Cove 2 or the effectiveness of that response during the second infection.

Undetected cases

One should also not forget that the American patient, like the other four documented cases, had shown symptoms of infection with Covid-19, which means that there is a possibility that there are people who were infected once and twice with the virus but did not suffer from any symptoms, and thus they were not discovered Through the inspection mechanisms prevalent around the world.

About that Mark Banduri writes in the study: “In general, there is a lack in the United States and around the world in the mechanisms for sequencing the genetic sequences of cases infected with Covid-19, in addition to the possibilities of examination and testing, which limits the possibilities of diagnosing, monitoring and genetically tracking the virus among researchers and workers in the institutions Health. “

For her part, a researcher in the immune system at Yale University of America, Akiko Iwasaki, who was not involved in preparing the study, wrote: “The more cases of the second infection documented, the greater the scientific community’s understanding of how to protect against SARS Cove 2 and the effect of infection with it on human immunity.”

The researcher adds in her comment that this information will be the primary key to identifying the vaccines most capable of developing individual immunity and the so-called “herd immunity”

Hannah Fox / Yasser Abu Muileq