Covid-19 reinfection casts doubt on virus immunity: research

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COVID-19 sufferers could expertise extra extreme signs the second time they’re contaminated, based on analysis launched Tuesday confirming it’s potential to catch the doubtless lethal illness greater than as soon as.

A research revealed in The Lancet Infectious Ailments journal charts the primary confirmed case of COVID-19 in the US—the nation worst hit by the pandemic—and signifies that publicity to the virus could not assure future immunity.

The affected person, a 25-year-old Nevada man, was contaminated with two distinct variants of SARS-CoV-2, the virus that causes COVID-19, inside a 48-day time-frame.

The second an infection was extra extreme than the primary, ensuing within the affected person being hospitalised with oxygen assist.

The paper famous 4 different instances of reinfection confirmed globally, with one affected person every in Belgium, the Netherlands, Hong Kong and Ecuador.

Specialists mentioned the prospect of reinfection may have a profound impression on how the world battles via the pandemic.

Specifically, it may affect the hunt for a vaccine—the at the moment Holy Grail of pharmaceutical analysis.

“The potential for reinfections may have vital implications for our understanding of COVID-19 immunity, particularly within the absence of an efficient vaccine,” mentioned Mark Pandori, for the Nevada State Public Well being Laboratory and lead research creator.

“We want extra analysis to grasp how lengthy immunity could final for individuals uncovered to SARS-CoV-2 and why a few of these second infections, whereas uncommon, are presenting as extra extreme.”

Waning immunity?

Vaccines work by triggering the physique’s pure immune response to a sure pathogen, arming it with antibodies it to struggle off future waves of an infection.

However it’s not in any respect clear how lengthy COVID-19 antibodies final.

For some illnesses, similar to measles, an infection confers lifelong immunity. For different pathogens, immunity could also be fleeting at greatest.

The authors mentioned the US affected person may have been uncovered to a really excessive dose of the virus the second time round, triggering a extra acute response.

Alternatively, it could have been a extra virulent pressure of the virus.

One other speculation is a mechanism generally known as antibody dependent enhancement—that’s, when antibodies really make subsequent infections worse, similar to with .

The researchers identified that reinfection of any type stays uncommon, with solely a handful of confirmed instances out of tens of hundreds of thousands of COVID-19 infections globally.

Nonetheless, since many instances are asymptomatic and due to this fact unlikely to have examined optimistic initially, it could be inconceivable to know if a given COVID-19 case is the primary or second .

In a linked remark to The Lancet paper, Akiko Iwasaka, a professor of Immunobiology and Molecular, Mobile and Developmental Biology at Yale College, mentioned the findings may impression public well being measures.

“As extra instances of reinfection floor, the scientific group could have the chance to grasp higher the correlates of safety and the way continuously pure infections with SARS-CoV-2 induce that degree of immunity,” she mentioned.

“This info is essential to understanding which vaccines are able to crossing that threshold to confer particular person and herd immunity,” added Iwasaka, who was not concerned within the research.


Clinical study aims to better understand COVID-19 immunity


© 2020 AFP

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