WASHINGTON | The real number of people infected by the new coronavirus in the United States was two to 13 times higher than the official number of cases in the spring, according to data Centres for the prevention and control of diseases (CDC) released Tuesday, which confirmed that the epidemic is largely fuelled by people without symptoms.
The CDC has tested the blood of blood banks in 10 regions of the United States between march and June to find antibodies to SARS-CoV-2, signs that the person has come previously in contact with the virus, even if she is not ill.
They found that between 1 and 5.8 % of the inhabitants of these regions had been contaminated in this period, with the exception of the city of New York, where the prevalence has reached 23.2% of the population in the 6 may, is a New Yorker in four.
Compared to the official number of recorded cases to these dates, the actual number of infections was two times higher in Utah, but ten times higher in south Florida at the end of April and up to 13 times in the State’s most rural Missouri at the end of may.
Even in New York, the epicenter of the us epidemic in the spring, there were ten times more people are infected that the number of cases official.
These serological studies (from a blood test) are conducted in many countries, and allow researchers and health authorities can know the progress of the virus in the population, regardless of the availability of screening tests (in the nose or throat) that say to people if they are infected at the time of the test.
In the spring of the United States, there was a lack of testing, which has contributed to under-estimate the movement of the virus and the mortality rate, and experts say that the country does not test still not enough.
The conclusion is twofold: on the one hand, hundreds of thousands of Americans have the coronavirus without the knowledge and contribute to the spread; on the other hand, with in general of the order of 5 % of the population infected, the country was at the end of the spring still far beyond the threshold of herd immunity.
The next wave of analyses of the CDC should probably see a jump in infections in Florida and other regions of the country experiencing since June an outbreak.