Coronavirus Antibodies Found in Almost 60 Percent of People Tested in Italian Province Hit Hard by COVID-19

Almost 60 percent of the residents of a northern Italian province tested for coronavirus antibodies had positive results, according to health officials.

Of 9,965 people in Bergamo who had their blood samples collected between April 23 and June 3, 56.9 percent had antibodies against the virus, according to a news release the province's health department sent to Newsweek.

Antibodies were meanwhile discovered in a little over 30 percent of 10,404 health operators, Reuters reported citing health authorities in the province located in the hard-hit Lombardy region. Newsweek has contacted Bergamo's public relations office for confirmation.

The bloods came from a "random" sample of the population, thought to be broad enough to reflect the number of people infected with the coronavirus in the province, health officials said, according to Reuters. The Bergamo health agency later said that the samples came from people in the hardest hit areas of the province, and many had been put under quarantine.

After the first outbreak of the the novel coronavirus in China late last year, Italy quickly became one of the worst affected countries. It has the fourth highest death toll from COVID-19, the disease caused by the virus, at almost 34,000, including over 16,000 in Lombardy. As the graph by Statista below shows, the U.S. is the country with the most known COVID-19 cases.

Countries with most COVID-19 cases
Spread of COVID-19 cases in the U.S.
U.S. states with highest COVID-19 cases.

In a separate example of what is known as a serosurvey, around 60 percent of about 400 sailors aboard the U.S. Navy's Theodore Roosevelt aircraft carrier had antibodies for the coronavirus, Reuters reported on Monday, citing unnamed U.S. officials.

An official told the news agency: "The outbreak investigation did not encompass the entire crew, and the results of this study cannot be generalized to the entire crew." A formal announcement is expected on Tuesday, according to Reuters. Newsweek has contacted the U.S. Navy.

By identifying antibodies to the coronavirus after the point at which a person can be diagnosed with a regular test, it is hoped that such screenings could help to paint a more accurate picture of how many people the virus has infected. Some have argued they could be used to create so-called immunity passports for individuals who have fought off the disease.

However, there are fears surrounding their accuracy and whether they risk giving a false sense of security amid the pandemic. Last month, the American Medical Association (AMA) highlighted three limitations of antibody tests, including that they may give false positive results and could mistakenly pick up antibodies from other viruses. The immunity of those who have caught the coronavirus is also little understood, it said.

Dr. Patrice A. Harris, president of the AMA, said in a statement at the time: "Given that we do not yet have scientific evidence showing if, when and for how long individuals might become immune to COVID-19, physicians and the general public should not use antibody testing to consider anyone immune to the disease—doing so may lead individuals to falsely assume they can stop physical distancing and further the spread of illness.

She also urged physicians to only use tests authorized by the U.S. Food and Drug Administration "and only for the purposes of population-level studies, evaluating recovered individuals for convalescent plasma donations, or along with other clinical information as part of a well-defined testing plan for groups or individuals."

This article has been updated with information from Bergamo's public health department.

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A health worker wears a protective mask and suit as she extracts blood from a patient to perform an antibody test for COVID-19 at the Dworska Hospital on April 9, 2020 in Krakow, Poland. Getty