Vaccines typically take years to go from early development to approval and distribution.

However, a large influx of funding and collaboration among scientists in 2020 has enabled research teams to produce safe and effective COVID-19 vaccines in record time.

More than 50 vaccines for the novel coronavirus are being tested in clinical trials around the world with at least 80 others in earlier stages of development.

The leading vaccines have already been approved fully or for emergency use in one or more countries. More approvals are expected over the coming months.

Given the enormous impact of COVID-19, more than one vaccine will be likely needed to end the pandemic.

In the United States, a limited number of doses will be available in the beginning, so people with the highest risk of developing COVID-19 will be prioritized to receive the vaccine first.

The Centers for Disease Control and Prevention (CDC) is recommendingTrusted Source that these two groups be in the initial phase of vaccination:

  • healthcare personnel
  • residents of long-term care facilities

However, the Trump administration has reportedly told Walgreens and CVS to wait until at least Dec. 21 to start vaccinating people at long-term residential facilities.

As more doses of the vaccine become available, other high-risk groups will be eligible for vaccination. States have the final say over which groups are vaccinated first.

Hospitals and long-term care facilities will likely be among the first to distribute the vaccines, especially vaccines that require ultralow freezer storage, such as the Pfizer-BioNTech vaccine.

States may later widen this to include pharmacies, doctor offices, clinics, health departments, schools, community centers, and mobile vaccination sites.

You can learn more about vaccine distribution plans in your area by visiting your state’s health department website, or check out this document from Duke University and the National Governors Association (see page 25).

Here’s a rundown of the leading COVID-19 vaccines with details about their efficacy, approval status, and availability.


Vaccine name: BNT162b2, or Tozinameran (INN)

Efficacy: 95 percent

Dosage: 2 doses, 3 weeks apart

Administration: Muscle injection

Storage: Ultralow temperatures, freezer only, at -80ºC to -60ºC (-112ºF to -76ºF). Room temperature for up to 6 hours.

Type: mRNA vaccine

Status: Approved in Canada and Saudi Arabia. Emergency use in United States, United Kingdom, and other countries. Approved in the United States for 16 years and older.

U.S. availability: The United States has a deal with Pfizer for the company to supply 100 million doses by next March, enough to vaccinate 50 million people.

Earlier in the summer, the Trump administration passed on a chance to secure additional doses of Pfizer’s vaccine, according to the New York Times.

Pfizer may not be able to supply the United States with more than the initial 100 million doses until June due to its existing contracts with other countries.

The company expects to be able to deliver 25 million doses to the country by the end of this month with the rest of the 100 million doses by March.

Immediately after emergency approval, more than 6 million doses were available, with nearly 3 million doses being shipped initially to states. The rest will held in reserve for those recipients’ second dose.

Moderna-National Institutes of Health

Vaccine name: mRNA-1273

Efficacy: 94 percent (preliminary results)

Dosage: 2 doses, 28 days apart

Administration: Muscle injection

Storage: 6 months in standard freezer at -20°C (-4°F); 30 days in refrigerator; 12 hours at room temperature

Type: mRNA

Status: Vaccine has been approvedTrusted Source by the FDA under emergency use authorization for people 18 years and older.

U.S. availability: The United States has purchased 200 million doses from Moderna, which was part of the federal government’s Operation Warp Speed program. This is enough to vaccinate 100 million people.

The government has an option to acquire an additional 300 million doses.

About 20 million doses are expected to be delivered by the end of December with the rest during the first quarter of 2021.

University of Oxford-AstraZeneca

Vaccine name: AZD1222

Efficacy: 62 percent (2 standard doses); 90 percent (low dose followed by standard dose)

Dosage: 2 doses, 28 days apart

Administration: Muscle injection

Storage: 6 months in standard refrigerator

Type: Chimpanzee adenovirus

Status: Still in phase 3 clinical trial

U.S. availability: The United States has agreed to buy 500 million doses if the vaccine receives emergency or regular approval from the FDA.