COVID cases plunge from post-holiday peak in the US. But what is causing the drop?

The number of new coronavirus cases in the U.S. has dropped in recent weeks — but what is causing the dip? .

Of course, the threat of COVID-19 is far from over — more than 478,000 Americans had died from COVID-19 complications as of Feb. 16. But in the week leading up to Friday, the U.S. Centers for Disease Control and Prevention reported a seven-day average of 104,217 cases.

That’s down from 134,524 the week before.

The count has fallen after a nationwide peak of 314,093 new cases was reported on Jan. 8, data show. Since then, officials said the “the daily number of cases has declined by 69%.”

Despite the falling case count, experts still urge people to wear face masks and take other precautions to help protect against the contagious disease.

So why do you still have to be careful? And what could be behind the falling caseload?

Here are some ideas from experts.

Explaining the trend

More people are wearing masks and practicing social distancing following a relatively busy holiday season, and those factors could contribute to the drop in cases, officials told multiple news outlets.

“If I were ranking explanations for the decline in COVID-19, behavior would be No. 1,” Ali Mokdad, a University of Washington professor, told The Atlantic. “If you look at mobility data the week after Thanksgiving and Christmas, activity went down.”

Though health officials warned of the potential dangers of gathering for year-end celebrations, millions of people traveled during the end of 2020 — including 9 million Americans the weekend before and after Thanksgiving. New records for coronavirus cases, deaths and hospitalizations in the U.S. were set weeks later in early January.

And while experts say the nation is likely coming down from a post-holiday surge in coronavirus cases, there could be other factors at work.

“I think in a lot of communities, we’ve had so much infection that you have some level of population immunity,” said Dr. Ashish Jha, dean of the School of Public Health at Brown University, according to CNN. “Not herd immunity, but enough population immunity that it is causing the virus to slow down.”

A model from the Institute of Health Metrics and Evaluation shows the positive trend can continue if there are widespread vaccination efforts and “declining seasonality,” which “will contribute to declining transmission potential from now until August,” according to the IHME.

Some news outlets reported the growing number of vaccinated Americans likely doesn’t play a notable role in the case count going down. Only about 15 million of the nation’s more than 300 million residents have received the recommended two vaccine doses, according to the CDC.

With the focus shifting to the COVID-19 vaccination effort, Eleanor Murray, a Boston University School of Public Health expert, pointed out some cases may simply be going unnoticed. Murray said she worried it could be getting more difficult to be tested as focus shifts to vaccination efforts.

This week, testing sites in some states closed as a deadly blast of snow and ice swept across the country. The seven-day average of new tests was trending downward in recent days, data from The COVID Tracking Project show.

Precautions still encouraged

Even with lowering case counts, health officials urge people to continue to take steps to help protect against the spread of the coronavirus.

“Don’t let your guard (or mask) down,” the CDC said on its website. “COVID-19 cases, hospitalizations, and deaths continue to trend downward. But even with that progress, the daily numbers of new cases and deaths remain much higher than the first two peaks of the pandemic in the spring and summer of 2020.”

The CDC shared that information Friday, the same day The COVID Tracking Project reported a seven-day average of 97,131 new cases. As a comparison, the seven-day averages were lower when cases spiked in June and July.

“It’s clear we are currently on the downward slope of the current curve, but there are no guarantees that the momentum won’t shift back again in the other direction,” said Jennifer Dowd, associate professor of demography and population health at the University of Oxford, according to Newsweek.

To help slow the spread of COVID-19, health officials urge everyone to wear face masks in public, wash their hands and avoid going to crowded places. If out in public, you are encouraged to stay at least six feet away from others.