Coronavirus updates: 84% of California population to go on lockdown Sunday night

The Transportation Security Administration (TSA) said it screened 1,176,091 people at its checkpoints in airports across the United States on the Sunday after Thanksgiving, making it the busiest day for air travel since the start of the coronavirus pandemic.

The previous pandemic record was set on Wednesday, the day before the holiday, when TSA screened 1,070,967 individuals at airport security checkpoints.

By comparison, 2,882,915 travelers were screened on the Sunday after Thanksgiving last year, which remains the highest volume in TSA history.

Earlier this month, the U.S. Centers for Disease Control and Prevention said it is recommending that Americans do not travel for Thanksgiving.

"It's not a requirement, it's a recommendation for the American public to consider," Dr. Henry Walke, the CDC's COVID-19 incident manager, told reporters during a call on Nov. 19. "Right now, as we're seeing exponential growth in cases and the opportunity to translocate disease or infection from one part of the country to another leads to our recommendation to avoid travel at this time."

ABC News' Sam Sweeney contributed to this report.

New research suggests England has seen roughly a 30% drop in COVID-19 infections three weeks into its second nationwide lockdown.

The Real-time Assessment of Community Transmission (REACT) program, run by Imperial College London and research firm Ipsos MORI, is tracking current cases of COVID-19 in England by testing more than 150,000 randomly-selected people each month over a two-week period. An interim report released Monday from the latest round of testing, which includes results from more than 105,000 at-home tests between Nov. 13 and Nov. 24, shows that an estimated 0.96% of England's population -- or around one in 100 people -- is infected with COVID-19.

The study, which is commissioned by England's Department of Health and Social Care, also found that the overall reproduction (R) number has fallen to below 1 -- estimated at 0.88 -- meaning the country's outbreak is currently shrinking rather than growing.

"In this interim report from the seventh round of data collection, we found a reduction in national prevalence of infection by around 30% from the high levels in the latter half of round 6 (26 October to 2 November 2020)," the study's co-authors wrote in the report. "The national prevalence has now dropped to ~1%, a level last seen 6 weeks earlier. This fall in prevalence covers a period of nearly three of the four weeks of the second national lockdown, and is consistent with an observed reduction in the number of daily swab-positive cases recorded in routine surveillance data."

Paul Elliott, professor of epidemiology and public health medicine at Imperial College London and director of the REACT program, called the data "encouraging" for England, which was under a regional tiered system of COVID-19 restrictions before entering lockdown again on Nov. 5. A tougher three-tier system will come into force when the lockdown ends just after midnight on Wednesday.

"We're seeing a fall in infections at the national level and in particular across regions that were previously worst affected. These trends suggest that the tiered approach helped to curb infections in these areas and that lockdown has added to this effect," Elliott said in a statement Monday. "As we approach a challenging time of year, it’s even more vital that through our actions and behaviors we all play our part in helping to keep the virus at bay."

Moderna announced it plans to submit a request on Monday to the U.S. Food and Drug Administration for emergency use authorization of its COVID-19 vaccine, becoming the second company after Pfizer to do so.

Moderna said in a press release that the FDA's meeting to review the safety and efficacy data for its National Institutes of Health-funded vaccine candidate, called mRNA-1273, will likely be scheduled for Dec. 17. The FDA hearing for the vaccine candidate developed by New York-based pharmaceutical company Pfizer and its German partner BioNTech is slated for Dec. 10.

Moderna also announced that the final analysis of its Phase 3 clinical trial of mRNA-1273 indicates a vaccine efficacy of 94.1%. Pending FDA authorization, Moderna said it expects to have approximately 20 million doses of mRNA-1273 available in the United States by the end of the year. The Massachusetts-based biotechnology company remains on track to manufacture 500 million to 1 billion doses globally in 2021.

"This positive primary analysis confirms the ability of our vaccine to prevent COVID-19 disease with 94.1% efficacy and importantly, the ability to prevent severe COVID-19 disease," Moderna CEO Stephane Bancel said in a statement Monday. "We believe that our vaccine will provide a new and powerful tool that may change the course of this pandemic and help prevent severe disease, hospitalizations and death."

ABC News' Sony Salzman contributed to this report.

There were 138,903 new cases of COVID-19 confirmed in the United States on Sunday, according to a real-time count kept by Johns Hopkins University.

It's the 27th straight day that the country has reported over 100,000 newly diagnosed infections. Sunday's count is down from a peak of 205,557 new cases on Friday.

An additional 826 fatalities from COVID-19 were also registered nationwide on Sunday, less than the all-time high of 2,609 new deaths on April 15.

COVID-19 data may be skewed in the coming days and weeks due to possible lags in reporting over Thanksgiving followed by a potentially very large backlog from the holiday.

A total of 13,384,651 people in the United States have been diagnosed with COVID-19 since the pandemic began, and at least 266,875 of them have died, according to Johns Hopkins. The cases include people from all 50 U.S. states, Washington, D.C. and other U.S. territories as well as repatriated citizens.

Much of the country was under lockdown by the end of March as the first wave of pandemic hit. By May 20, all U.S. states had begun lifting stay-at-home orders and other restrictions put in place to curb the spread of the novel coronavirus. The day-to-day increase in the country's cases then hovered around 20,000 for a couple of weeks before shooting back up over the summer.

The numbers lingered around 40,000 to 50,000 from mid-August through early October before surging again to record levels, crossing 100,000 for the first time on Nov. 4 and reaching 200,000 for the first time on Nov. 27.