Italy starts antibody tests for virus immunity in Lombardy

Experts are cautious about the results amid doubts how long the immunity could last

Italy started on Thursday antibody tests in hard-hit region of Lombardy seeking information about coronavirus immunity to help prosperous industrial region return to work faster, news wires reported.

Nearly 13,000 people have already died of the virus in this densely populated region, whose capital is Milan, or more than half of Italy’s total dead.

Although Germany has already started nation-wide antibody tests and countries such as Finland and Britain have announced plans to roll them out, many questions remain about how reliable data derived from the tests will be.

Italian health authorities have said 20,000 tests would be performed every day in Lombardy. First to be tested are those in the worst-hit provinces: health workers, those under quarantine showing coronavirus symptoms and those they have been in contact with, as well as others with mild symptoms. Authorities hope to roll out the tests to the wider region after 29April.

The head of Italy’s National Health Council, Franco Locatelli believes the antibody tests would help authorities determine the spread of the coronavirus.Data would also provide “very relevant information on herd immunity” which would useful in developing strategies to help restart the country, he said, such as who could be allowed to go back to work.

The kits, made by Italian biotech firm DiaSorin, look for the presence of antibodies in the blood. Such antibodies indicate that the person has been exposed to the virus, pointing to some level of immunity. They differ from the more common swab tests, which test molecules from nasal secretions to determine whether a person currently has the virus.Lombardy's swab testing has revealed that 24% of those tested have the virus.

Some experts believe at least 60 to 70% of a population must be immune to the virus in order to gradually wipe it out. But recent studies, such as one conducted in March and April by France's Institut Pasteur, have found that so-called "herd immunity" was harder to attain than believed, AFP reported. At a high school in the Oise department, site of one of the country's first outbreaks, researchers found only 26 percent of students, teachers and their families carried antibodies.

Moreover, it is not known for how long immunity to coronavirus lasts, meaning there is a risk those deemed "immune" may be re-infected and pass along the virus to others.

In the 2002-2003 Sars epidemic, those who had contracted the virus but recovered were immune for two to three years on average, according to Francois Balloux, director of the Genetics Institute at London's University College. "One can certainly get reinfected but the question is, after how much time? We won't know until retroactively," Balloux told AFP.

Even more risky, a person who has developed antibodies can still carry traces of the virus, and thus be contagious. Therefore, experts such as Italy's Locatelli say antibody tests should be accompanied by swab testing.


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