LONDON, March 28 (Xinhua) -- Existing delays with vaccination and a lack of federal funding could slow the next booster rollout across the United States, The Guardian has reported.

The rollout of the first round of boosters, authorized in the United States last fall, "just fell off the cliff," with many Americans still not realizing they are eligible or that the booster is recommended, said the British newspaper on Sunday.

With a potential second booster on the horizon for vulnerable groups, the U.S. government is still struggling to drum up American public interest in additional shots and funding from Congress to pay for COVID-19 initiatives, said the report.

The United States is likely to see another wave of COVID-19 infections and vaccines can take weeks to become fully effective, making vaccination campaigns urgent now, experts said. ■