RELATED: If You’re Vaccinated, This Is How Likely You Are to Get COVID, New Data Shows. While appearing on CBS’s Face the Nation on Oct. 3, host Margaret Brennan asked Fauci about how the Delta variant’s increased transmissibility could affect gatherings as winter approaches and the holiday season begins. “When you are in a situation where you have a dynamic of virus in the community, where there’s clearly a lot of spread, even if you are vaccinated and you are in an indoor setting, a congregate setting, it just makes sense to wear a mask and to avoid high-risk situations,” he said when addressing whether or not it was safe for unvaccinated children to attend indoor parties. He then added: “What we should be doing is look at ventilation in indoor places.” “We know now that this is clearly spread by aerosol, and when you have something spread by aerosol, you absolutely want more ventilation, which is the reason why outdoors is always much safer than indoors,” he explained. “And if you are indoors, ventilation is going to be key.” Fauci’s recommendation comes on the heels of updated guidance from the Centers for Disease Control and Prevention (CDC) that outlines how to stay safe as cooler weather is likely to bring gatherings indoors over the fall and winter. The agency still advises that celebrating remotely, limiting parties to only those you live with, or hosting an outdoor party where guests can stay six feet apart are all still the best ways to avoid spreading COVID-19. Otherwise, increasing ventilation can be vital in reducing the risk of breakthrough infections. “If celebrating indoors, bring in fresh air by opening windows and doors, if possible,” the CDC website says. “You can use a window fan in one of the open windows to blow air out of the window. This will pull fresh air in through the other open windows.” RELATED: The 5 Most Common Signs You Caught Delta If You’re Vaccinated, Study Says. When Fauci was asked whether or not new surges would make it too risky to travel and celebrate the holidays this year, he refused to offer a prediction. “It’s just too soon to tell. We’ve just got to concentrate on continuing to get those numbers down and not try to jump ahead by weeks or months and say what we’re going to do at a particular time,” he said. RELATED: For more up-to-date information, sign up for our daily newsletter. He explained that focusing on stopping the spread of the virus would rely primarily on getting shots in the arms of people who need them the most. “Let’s focus like a laser on continuing to get those cases down. And we can do it by people getting vaccinated and also in the situation where boosters are appropriate to get people boosted because we know that they can help greatly in diminishing infection and diminishing advanced disease, the kinds of data that are now accumulating in real-time,” Fauci said.ae0fcc31ae342fd3a1346ebb1f342fcb RELATED: A Virus Expert Says She Still Wouldn’t Go Here—Even With a Booster.