Washington (AFP)

The actual number of people infected with the novel coronavirus in the United States was two to 13 times the official number of cases in the spring, according to data from the Centers for Disease Prevention and Control (CDC) released on Tuesday, which confirms that the pandemic is largely fed by people without symptoms.

The CDC tested blood from blood banks in 10 regions of the United States between March and June for antibodies to SARS-CoV-2, signs that the person had previously come into contact with the virus, even though they did not. did not get sick.

They found that between 1 and 5.8% of the inhabitants of these regions had been infected in this period, with the exception of New York City, where the prevalence reached 23.2% of the population as of May 6. , or one in four New Yorkers.

Compared to the official number of cases on those dates, the actual number of infections was twice as high in Utah, but ten times as high in South Florida at the end of April and up to 13 times in the state. more rural Missouri in late May.

Even in New York City, the epicenter of the US epidemic in the spring, there were ten times more people infected than the official number of cases.

These serological studies (from a blood test) are carried out in many countries and allow researchers and health authorities to know the progress of the virus in the population, regardless of the availability of screening tests (in the nose or throat) that tell people if they are infected at the time of the test.

In the spring in the United States, there was a shortage of testing, which has contributed to underestimating virus circulation and mortality, and experts say the country is still not testing enough.

The conclusion is twofold: on the one hand, hundreds of thousands of Americans have the coronavirus without knowing it and are helping to spread it; on the other hand, with in general around 5% of the infected population, the country was still far from the collective immunity threshold at the end of spring.

The next wave of CDC scans is likely to see a surge in infections for Florida and other parts of the country that have been experiencing an outbreak since June.

© 2020 AFP