(CNN)More than 2 million US teens say they use e-cigarettes, with a quarter of them saying they vape daily, a new national survey finds.

Even with many middle and high school students home because of the pandemic, the survey found, they found ways to get hold of e-cigarettes and other vape devices and use them.The US Food and Drug Administration and Centers for Disease Control and Prevention survey middle school and high school students every year for the National Youth Tobacco Survey. Because of the pandemic, this year's results cannot be compared to previous years."Approximately 2.06 million youths were estimated to be current e-cigarette users in 2021. Use of tobacco products by youths in any form, including e-cigarettes, is unsafe. Most e-cigarettes contain nicotine, and nicotine exposure during adolescence can harm the developing brain," the FDA and CDC said in their report, published in the CDC's weekly MMWR report.FDA blocks sale of 55,000 flavored e-cigarette products"Notably, when many students were in remote learning environments that might have affected their access to tobacco products, an estimated 11.3% (1.72 million) of high school students and an estimated 2.8% (320,000) of middle school students reported current e-cigarette use," the FDA and CDC said in a joint statement.About 85% of the students said they used flavored vapes, especially fruit, candy, mint and menthol flavors. Anti-tobacco groups have been pressing the FDA to ban all flavored vape products."Among high school students who currently used e-cigarettes, 26.1% reported their usual brand was Puff Bar, followed by Vuse (10.8%), SMOK (9.6%), JUUL (5.7%) and Suorin (2.3%)," the FDA and CDC said."These data highlight the fact that flavored e-cigarettes are still extremely popular with kids. And we are equally disturbed by the quarter of high school students who use e-cigarettes and say they vape every single day," Mitch Zeller, director of the FDA's Center for Tobacco Products, said in the statement.Vaping debate 'heating up' once again"It is noteworthy that the survey finds higher rates of e-cigarette use among high school students who took the survey in school compared to those participating at home or some other place (15% to 8.1%), raising concern that rates would be much higher if the survey had been conducted entirely in schools as in previous years," Matthew Myers, president of the Campaign for Tobacco-Free Kids, said in a statement."As kids return to school, we face the real risk of a resurgence of the youth e-cigarette epidemic unless the FDA quickly eliminates all flavored e-cigarettes. With 85% of youth e-cigarette users using flavors, our kids will remain in jeopardy as long as any flavored products remain on the market."The agencies noted that Puff Bar brand vapes are made using synthetic nicotine, perhaps in an attempt to evade FDA's mandate to regulate tobacco products.US e-cigarette sales rose by nearly 300%, says a new CDC report"FDA is aware of a number of companies, such as Puff Bar, claiming their products contain only synthetic nicotine not sourced from tobacco, which may raise separate regulatory and legal issues that the agency is considering how best to address," the agency said."The number one brand used by youth, Puff Bar, not only comes in a wide variety of flavors, but has also recently indicated that it will now be manufactured with synthetic nicotine in a brazen attempt to thwart FDA oversight," Robin Koval, CEO of the Truth Initiative, said in a statement.CNN has reached out to Puff Bar for comment.The data showing that more than 43% of students who use e-cigarettes do so nearly daily "underscores the trap of nicotine addiction and the risk that once hooked, many young people will be users of these and potentially even more dangerous tobacco products for life," added Koval, whose organization arose out of the 1998 Master Settlement Agreement between the major tobacco companies, 46 U.S. states, territories and Washington, DC."This is especially troubling given the youth mental health crisis exacerbated by the pandemic, and the fact that nicotine can worsen symptoms of anxiety and depression in addition to the physical health risks associated with its use."FDA takes more time to decide on e-cigarettesThe FDA has delayed making a decision on how to regulate many vape products. E-cigarette products have been allowed to remain on the market for years, even though none have been given the official green light by the FDA. Manufacturers were given until September 9 of last year to submit applications for the agency's authorization to remain on the market.Earlier this month, the FDA said it had rejected pre-market applications from more than 6 million electronic nicotine delivery systems or ENDS products, but made no ruling on big players such as Juul.E-cigarettes were not subject to FDA regulation until 2016. They were in regulatory limbo after that until July 2019, when a federal court gave companies until May of 2020 to apply to FDA for premarket review.The FDA is still reviewing some of those applications."This study shows yet again the urgent need for federal action to address the nation's youth e-cigarette epidemic," Lisa Lacasse, president of the American Cancer Society Cancer Action Network, said in a statement."Flavored tobacco products of all kinds, including those flavored with menthol, enable the tobacco industry to entice and hook another generation of users on their deadly products -- no less, a generation who was on track to be the first tobacco-free generation," Lacasse added.