COVID-19 has so far killed more than 308,000 Americans, as officials roll out nearly 3 million doses of Pfizer’s vaccine, which was approved last week, across all states.

The virus has infected more than 16 million Americans. On Saturday, health officials reported over 2,300 deaths, as the number of new cases continues to surge across the country.

As the nation grapples with the highest number of death tolls and hospitalizations, a historic effort to achieve herd immunity is underway.

On December 11, the US Food and Drug Administration (FDA) granted Emergency Use Authorization (EUA) for the vaccine developed by Pfizer in association with BioNTech, with the companies claiming that their vaccine is 95% effective.

On Saturday, CDC Director Dr. Robert Redfield signed off on the vaccine, allowing officials to distribute and deliver vaccines to people aged 16 and above.

The first doses of Pfizer’s vaccine will be given to frontline health workers and long-term residents and employees of care facilities.

Soon, the FDA will release a data assessment for Moderna’s COVID-19 vaccine, reviewing the company’s request for EUA. If approved, the officials will start administering Moderna’s vaccine as early as December 21.

Nearly 75 to 80% of Americans must get vaccinated to achieve herd immunity, according to top US health officials.

Chief Medical Advisor to Operation Warp Speed Dr. Moncef Slaoui said Sunday that he hopes to “achieve herd immunity between May and June,” according to CNBC.

However, some experts have expressed concerns over people’s speculation about the safety and efficacy of the speedy vaccine rollout. A recent poll has shown that only 50% of Americans say they want a shot, while 25% of people are not sure about getting it and the remaining say they will not get one.

Even after the distribution of the vaccine, some researchers believe that the death toll could reach a total of 539,000 by April 1. They have urged people to wear facemasks and practice social distancing in order to curb the spread of the virus.

A report published by the Institute for Health Metrics and Evaluation at the University of Washington’s School of Medicine said vaccine distribution will only reduce the US death toll by 9,000 by April 1, while a rapid vaccine rollout targeting high-risk individuals could save a further 14,000 lives.

Last week, Dr. Eric Dickson, CEO of UMass Memorial Health Care, told CNBC that there has seen a major influx of COVID-19 patients in hospitals after the Thanksgiving holiday, making it difficult for hospitals to maintain staffing as some residents and employees were tested positive and forced to quarantine.

“The worst is unfortunately yet to come,” Dr. Dickson said. “There is nothing to suggest that the rate of hospitalizations is going to slow down. So at this point, we’re absolutely confident that this will be worse than the first surge.”

Dr. Dickson urged people to do everything they can to stop the spread of this infection for the next two months, explaining that this could help prevent additional strain on the health care system.

He said, “If you can give us those two months, we’ll bring the hospitalizations down, we’ll have enough room, we’ll have the workforce to deliver the vaccine and we’ll be out of this thing in early summer.” “But if we don’t get the public’s help during those two months, it’s going to be a horrible, horrible long winter because there will be a lot of people dying that didn’t have to die,” Dr. Dickson added.