An app used by 15 percent of the population together with a well-staffed contact-tracing workforce can lead to a 15 percent drop in infection rates and an 11 percent drop in COVID-19 deaths, according to statistical modeling by the Alphabet Inc unit and Oxford's Nuffield Department of Medicine.

With a 15 percent uptake of contact tracing apps alone, the researchers calculated an 8 percent reduction in infections and 6 percent reduction in deaths.

The findings were based on data from a digital tracing system similar to one jointly developed by Google and Apple Inc.

The app made by the two tech giants tracks interactions through Bluetooth signals and anonymously notifies a person if someone they met contracts COVID-19.

Read also: Google, Apple roll out built-in COVID-19 exposure notifications to phones

Six US states and about two dozen countries have launched exposure notification apps based on the Apple-Google technology in recent weeks without major hitches.

The researchers simulated the spread of COVID-19 based on interactions at homes, offices, schools and social gatherings in Washington State's King, Pierce and Snohomish counties.

"We see that all levels of exposure notification uptake levels in the UK and the U.S. have the potential to meaningfully reduce the number of coronavirus cases, hospitalizations and deaths across the population," Christophe Fraser, the study's co-lead author and group leader in Pathogen Dynamics at Oxford University's Nuffield Department of Medicine, said in a statement.

The researchers noted that a contact tracing app is not a stand-alone intervention. They also said their model still represents a "dramatic simplification of the real world", and does not take into account cross-county movement of people contributing to disease spread.

The research has not been peer-reviewed.