WASHINGTON D.C.: In the past three weeks, the latest campaign to offer a second Covid booster shot has seen 4.4 million vaccinations delivered in the United States.

However, the number of vaccinations received remains below the government's targets.

The U.S. government has said that it has shipped 25 million vaccinations that provide wide protection against contracting the Covid Omicron variant.

The first group of vaccinations were primarily manufactured by Pfizer. A similar vaccination is being produced by Moderna, which has been slower to arrive due to quality control issues, reports the U.S. Food and Drug Administration.

Meanwhile, Dr. Amesh Adalja of Johns Hopkins University Center for Health Security told Reuters that he expects demand for the updated shots to remain low, "as has been the case with boosters from the very beginning."

"I think that stems from kind of the poor messaging in the way this booster campaign and prior booster campaigns have been managed, as political issues rather than focusing on where boosters are going to be beneficial," he said.