Employees of more than 400 hospitals were vaccinated against COVID-19 this Tuesday

"I am happy that in a month and a half I will not be afraid to walk into a room. I will not have to fear doing chest compressions or being present when a patient is intubated."

Maritza Beniquez, a New Jersey nurse who has been working on the front lines of COVID-19 for months, is more hopeful this Tuesday, as thousands of healthcare workers like her in the United States continued to receive the newly approved Pfizer vaccine.

Beniquez, 56, 

was the first healthcare worker to receive the injection in New Jersey.

The vaccination of health personnel, a priority group, began this Monday and has meant a drop of hope within a gray context of more than 16.3 billion infected and more than 300,000 deaths from coronavirus.

"

I don't want to be afraid anymore

, and I don't want to risk taking it (the virus) home with me and infecting my own family and friends," said the nurse, who has spent the last few months treating minority groups in the ward. Newark University Hospital emergencies.

Nurse Maritza Beniquez receives the COVID-19 vaccine from Pfizer-BioNTech in Newark, NJ.AP

Like her, all recipients of the Pfizer vaccine will receive a second dose a few weeks later, as part of treatment.

[Follow our coverage on the coronavirus pandemic]

The first doses of vaccines are being strictly administered to first-line healthcare workers and nursing home patients, the two priority groups designated by healthcare experts.

Benriquez was the first person to receive the vaccine in New Jersey.

The United States expects to distribute nearly 

3 million vaccines

 from Pfizer's first dose.

The first part of the shipment left Sunday from the pharmaceutical factory in Michigan, in boxes with dry ice to keep them deep-frozen.

The doses were transported by trucks and planes to hospitals and pharmacies in New York, Iowa, Washington DC, Kentucky, Arizona, Massachusetts and other 

states across the country

. 

On video: Boston hospital staff celebrate the arrival of the COVID-19 vaccine by dancing

Dec. 15, 202000: 29

Shipping companies UPS and FedEx delivered about 189 boxes first to 145 hospitals

. 

This Tuesday, they delivered to another 450 sites and, on Wednesday, they will do so to 66 more. 

The federal government is planning to make hundreds more shipments over the weekend.

"We are beginning our pace of continuous delivery of the vaccine as it becomes available," said Gustave Perna, Operation

Warp Speed

chief of operations 

.

"We pack and deliver. It is a constant stream of available vaccines," he reiterated.

Dr. Marina Del Rios, from the University of Illinois, receives the first vaccine against COVID-19 in Chicago.

Vaccinations for residents of about 1,100 nursing homes will not begin in most states until next week. 

Perna and other officials reiterated their projection that

20 million Americans will be able to receive their first vaccinations by the end of December, and 30 million more in January.

Projection that involves the rapid authorization of Moderna's vaccine, which also requires two doses for total protection.

The United States government purchased 100 million doses of the Pfizer-BioNTech vaccine and orders 200 million doses of Moderna.

Assuming there are no manufacturing or distribution delays, that would be enough to vaccinate 150 million Americans by mid-2021.

When will the coronavirus vaccine reach the entire population of the United States?

Dec. 15, 202002: 14

One day after the launch of the Pfizer-BioNTech coronavirus vaccine, the US Food and Drug Administration (FDA) concluded that Moderna's vaccine is "safe and effective."

This second immunization option is expected to be approved for emergency use as soon as Friday. 

The weapon against the wave of outbreaks due to COVID-19 comes at a time when record numbers of cases are registered.

This Monday there were more than 300,000 deaths from the virus in the United States.

The number of infections is expected to worsen in the coming weeks, taking into account vacation trips and family gatherings.  

Epidemiologist Hilda Aleman receives the vaccine from Pfizer-BioNTech in San Juan, Puerto Rico.

In other parts of the world, the Pfizer-BioNTech vaccine is being administered in the UK and Canada.

And European Union regulators brought the meeting to evaluate the vaccine forward a week.

This under pressure from Germany and other countries on the continent.

In examining the first results of a study of 30,000 people, the FDA found that Moderna's vaccine worked almost the same as Pfizer-BioNTech's.

Elliot Hospital Intensive Care Unit nurse receives COVID-19.AP vaccine

The Moderna vaccine was more than 94% effective in preventing COVID-19 and 86% effective in people over 65 years of age.

The FDA did not discover any major problems.

As well as no serious allergic reaction.

Side effects can include fever, fatigue, and aches, as the vaccine revolutionizes the immune system. 

Both Moderna and Pfizer-BioNTech vaccines are not made with the virus itself, which means that there is no possibility that someone could get it from the injections.

Instead, the vaccine contains a piece of genetic code that trains the immune system to recognize the protein on the surface of the virus.

With information from the Associated Press.