People younger than 60 are potentially driving the spread of the coronavirus pandemic in Georgia, according to a new study.

The study by the National Academy of Science collected data from five counties in Georgia, including four metro Atlanta areas, between March and May. An analysis of the data showed that people under the age of 60 were almost three times as likely to spread COVID-19 as people older than 60.

Researchers also found that people younger than 60 tended to be responsible for super-spreading events. Overall, 2% of cases were directly responsible for 20% of all infections, according to the study, which was published last Thursday in Proceedings of the National Academy of Sciences, the official journal of the National Academy of Sciences.

ABC News' Sony Salzman contributed to this report.

Palestinian authorities have imposed a 48-hour lockdown on the besieged Gaza Strip after officials said a family of four tested positive for COVID-19 at a refugee camp there.

The Palestinian health ministry said another case was identified Monday at a quarantine center in Gaza, bringing the total count to five.

The cause of the cluster is unclear and authorities are working to trace it. It’s the first known instance of the novel coronavirus spreading through Gaza’s local community.

The full lockdown went into effect Monday night across the entire 140-square-mile-long coastal enclave, which shares borders with Egypt and Israel.

The Gaza Strip, a densely populated area that forms part of the so-called Occupied Palestinian Territories, is inhabited by some 2 million Palestinians, most of whom are registered refugees living in overcrowded camps. Both Egypt and Israel have imposed restrictions on movement in and out of Gaza, citing concerns over the militant group Hamas, which rules the territory and has been designated a terrorist organization by Israel and the United States.

However, a small number of Palestinians still travel to Jerusalem for routine cancer treatments, and Egypt partially lifted its blockade recently to allow Palestinians back in.

ABC News’ Nasser Atta and Guy Davies contributed to this report.

The University of Southern California is reporting an “alarming increase in the number of COVID-19 cases” among students living in off-campus housing.

In a letter sent to students Monday, the university’s student health center said it had identified 43 cases in the past seven days. All cases are related to students in off-campus living environments, and more than 100 students are now in a 14-day quarantine due to exposures.

“This increase comes despite the continued state and county health guidance that significantly restricts in-person instruction and on-campus activities for universities located in counties that are on the state’s COVID-19 monitoring list, including Los Angeles County,” the letter states. “We continue to strongly discourage students from returning to the campus area until further notice.”

The private university, located in the heart of Los Angeles, kicked off its fall semester online last week, but many students remain in apartments and off-campus residences near the campus.

The numbers of new COVID-19 cases and new deaths in the United States have both decreased by substantial amounts in week-over-week comparisons, according to an internal memo from the Federal Emergency Management Agency obtained by ABC News Monday night.

Just five U.S. states and territories are currently in an upward trajectory of new cases, while five states are at a plateau and 46 states are going down, the memo said.

There were 300,366 new cases confirmed during the period of Aug. 17-23, a 16.2% decrease from the previous seven-day period. There were also 6,873 new deaths recorded Aug. 17-23, an 8.5% decrease from the previous week, according to the memo.

Meanwhile, the national positivity rate for COVID-19 tests ticked downward slightly from 6.4% to 5.5%, the memo said.

Oregon appears to be coming down from a peak with a 7% decrease in infections, a 19.5% decrease in hospitalizations and a 20% reduction in deaths for the week ending on Aug. 16, compared to the previous week, according to the memo.

Idaho has seen an 8.5% decrease in the seven-day case rate since Aug. 18, but a 12.2% increase in the seven-day death rate, the memo said.

In Montana, the Native American community makes up 7% of the state’s population but accounts for 18% of cases statewide and 34% of deaths, according to the memo.

ABC News’ Josh Margolin contributed to this report.