{"id":87936,"date":"2020-10-13T10:15:59","date_gmt":"2020-10-13T07:15:59","guid":{"rendered":"https:\/\/en.buradabiliyorum.com\/covid-19-reinfection-casts-doubt-on-virus-immunity-study\/"},"modified":"2020-10-13T10:15:59","modified_gmt":"2020-10-13T07:15:59","slug":"covid-19-reinfection-casts-doubt-on-virus-immunity-study","status":"publish","type":"post","link":"https:\/\/buradabiliyorum.com\/en\/covid-19-reinfection-casts-doubt-on-virus-immunity-study\/","title":{"rendered":"#Covid-19 reinfection casts doubt on virus immunity: study"},"content":{"rendered":"

“#Covid-19 reinfection casts doubt on virus immunity: study<\/strong>”<\/p>\n

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COVID-19 patients may experience more severe symptoms the second time they are infected, according to research released Tuesday confirming it is possible to catch the potentially deadly disease more than once.\n <\/p>\n

A study published in The Lancet Infectious Diseases<\/i> journal charts the first confirmed case of COVID-19 reinfection in the United States\u2014the country worst hit by the pandemic\u2014and indicates that exposure to the virus may not guarantee future immunity.<\/p>\n

The patient, a 25-year-old Nevada man, was infected with two distinct variants of SARS-CoV-2, the virus that causes COVID-19, within a 48-day time frame. <\/p>\n

The second infection was more severe than the first, resulting in the patient being hospitalised with oxygen support.<\/p>\n

The paper noted four other cases of reinfection confirmed globally, with one patient each in Belgium, the Netherlands, Hong Kong and Ecuador. <\/p>\n

Experts said the prospect of reinfection could have a profound impact on how the world battles through the pandemic.<\/p>\n

In particular, it could influence the hunt for a vaccine\u2014the currently Holy Grail of pharmaceutical research. <\/p>\n

“The possibility of reinfections could have significant implications for our understanding of COVID-19 immunity, especially in the absence of an effective vaccine,” said Mark Pandori, for the Nevada State Public Health Laboratory and lead study author. <\/p>\n

“We need more research to understand how long immunity may last for people exposed to SARS-CoV-2 and why some of these second infections, while rare, are presenting as more severe.”<\/p>\n

Waning immunity?<\/b><\/p>\n

Vaccines work by triggering the body’s natural immune response to a certain pathogen, arming it with antibodies it to fight off future waves of infection.<\/p>\n

But it is not at all clear how long COVID-19 antibodies last. <\/p>\n

For some diseases, such as measles, infection confers lifelong immunity. For other pathogens, immunity may be fleeting at best. <\/p>\n

The authors said the US patient could have been exposed to a very high dose of the virus the second time around, triggering a more acute reaction. <\/p>\n

Alternatively, it may have been a more virulent strain of the virus. <\/p>\n

Another hypothesis is a mechanism known as antibody dependent enhancement\u2014that is, when antibodies actually make subsequent infections worse, such as with dengue fever.<\/p>\n

The researchers pointed out that reinfection of any kind remains rare, with only a handful of confirmed cases out of tens of millions of COVID-19 infections globally.<\/p>\n

However, since many cases are asymptomatic and therefore unlikely to have tested positive initially, it may be impossible to know if a given COVID-19 case is the first or second infection.<\/p>\n

In a linked comment to The Lancet paper, Akiko Iwasaka, a professor of Immunobiology and Molecular, Cellular and Developmental Biology at Yale University, said the findings could impact public health measures.<\/p>\n

“As more cases of reinfection surface, the scientific community will have the opportunity to understand better the correlates of protection and how frequently natural infections with SARS-CoV-2 induce that level of immunity,” she said.<\/p>\n

“This information is key to understanding which vaccines are capable of crossing that threshold to confer individual and herd immunity,” added Iwasaka, who was not involved in the study.\n <\/p>\n\n

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Clinical study aims to better understand COVID-19 immunity\n <\/p><\/div>\n

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\n \u00a9 2020 AFP<\/p>\n

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Citation<\/strong>:
\n Covid-19 reinfection casts doubt on virus immunity: study (2020, October 13)
\n retrieved 13 October 2020
\n from https:\/\/medicalxpress.com\/news<\/a>\/2020-10-covid-reinfection-virus-immunity.html<\/p>\n

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