Oct 12 (Reuters) - The number of new COVID-19 cases rose 11% in the United States last week compared to the previous seven days, with infections spreading rapidly in the Midwest, which reported some of the highest positive test rates, according to a Reuters analysis.

Deaths fell 3% to about 4,800 people for the week ended Oct. 11, according to the analysis of state and county reports. Since the pandemic started, nearly 215,000 people have died in the United States and over 7.7 million have become infected with the novel coronavirus.

Twenty-nine out of 50 states have seen cases rise for at least two weeks in a row, up from 21 states in the prior week. They include the entire Midwest except Illinois and Missouri, as well as new hot spots in the Northeast, South and West. (Open https://tmsnrt.rs/2WTOZDR in an external browser for state-by-state details)

In Idaho, 23.5% of more than 17,000 tests came back positive for COVID-19 last week, the highest positive test rate in the country, according to data from The COVID Tracking Project, a volunteer-run effort to track the outbreak. South Dakota, Iowa and Wisconsin also reported positive test rates above 20% last week.

For a third week in a row, testing set a record high in the country, with on average 976,000 tests conducted each day last week. The percentage of tests that came back positive for the virus rose to 5.0% from 4.6% the prior week.

The World Health Organization considers rates above 5% concerning because it suggests there are more cases in the community that have not yet been uncovered.