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How quickly can I get the COVID-19 vaccine?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Dec 14, 2020.

Official Answer


Is the vaccine for COVID-19 now available in the US?

On Dec. 14, 2020 Pfizer / BioNTech received emergency use authorization (EUA) from the FDA for their COVID-19 vaccine candidate, BNT162b2 to be used in people ages 16 and over. Approval of the EUA now allows the vaccines to be given to the public without being enrolled in a clinical study. The first of Pfizer's vaccine was given to the public on Dec. 14, 2020 in the U.S.

Over the winter and spring of 2021, vaccines will be rolled out to the U.S. public based on priority ultimately decided upon by the states, with recommendations from the CDC. Check with your individual states public health authorities to determine the timeline based on your age, health risk factors and classification as an essential worker. Initially, limited vaccines are expected to be available.

A vaccine to prevent SARS-CoV-2 infection is an urgent public health emergency, as no humans -- other than those who have now recovered from the virus -- have immunity to the new virus. At mid-December 2020, over 47 million people around the world have recovered from COVID-19, yet over 1.6 million people have died.

Both Pfizer / BioNTech and Moderna have reported on the effectiveness of their vaccine candidates, with both showing close to 95% effectiveness compared to placebo groups. Other vaccine trials are not far behind. Published study data for the Pfizer vaccine is now available.

  • The Pfizer study has over 40,000 participants. Out of 170 COVID-19 cases in the Pfizer and BioNTech trial, 8 had received the vaccine and 162 received a placebo (an inactive treatment). Ten cases of severe COVID-19 were reported, with nine of those in the placebo group.
  • At the time of analysis, 30,000 participants in the Moderna study had been evaluated. Out of a total of 100 COVID-19 cases, 5 had received the vaccine and 95 were in the placebo group. Eleven cases, all in the placebo group, had a report of severe disease. Moderna states submittal of an EUA is "the coming weeks."

What drugs are approved to treat COVID-19?

The coronavirus (SARS-CoV-2) has few approved drug treatments.

  • Veklury (remdesivir) is approved as a single drug agent. Veklury is also approved via emergency use authorization to be used in combination with baricitinib (Olumiant), an anti-inflammatory drug used in rheumatoid arthritis.
  • On Nov. 20th, WHO recommended that remdesivir not be used to treat COVID-19 due to lack of positive outcomes.
  • Anti-inflammatory corticosteroid use, such as with dexamethasone, has been shown to be effective in reducing death from COVID-19.

Promising investigational agents include the direct-acting antiviral agents that can be given orally for 5 to 6 days to suppress viral replication.

What side effects can occur with the COVID-19 vaccine?

Side effects will become more apparent as larger groups of the public receive the vaccine in 2021.

According to Pfizer, no serious safety concerns have been reported out of over 43,000 participants. Side effects such as fatigue (3.7%) and headache (2%) were reported. Over 19,000 participants have been followed for at least 2 months since their second dose of the Pfizer vaccine. Anecdotal reports from trial participants also include chills, fever, and muscle aches, which tend to resolve quickly.

In the press release from Moderna, severe events such as injection site pain (2.7%), redness at the injection site (2%), muscle aches (8.9%), fatigue (9.7%), joint pain (5.2%), and headache (4.5%) were reported in 2% or more of participants, but were short-lived. These data may change based on ongoing analysis of study data.

Side effects such as fever, muscle aches fatigue and chills are expected side effects from vaccine administration and indicate that an immune-response is being initiated for COVID-19 protection.

Recipients of the vaccine should still practice social distancing, wear a face mask, and frequently wash their hands, along with other public health measures. Researchers are not sure if the vaccine will prevent the spread of COVID yet (and many people are asymptomatic, not knowing they are spreading). In addition, herd immunity may not occur until 60% to 70% of the population is fully vaccinated.

How will the COVID-19 vaccine be distributed?

The vaccines will be rolled out in stages based on level of risk and availability. There are over 300,000 million U.S. citizens. High risk groups for COVID-19 will most likely include health care workers, first responders, and the elderly, including those in nursing homes. Those with certain chronic conditions like diabetes, obesity, heart and lung disease will most likely be high on the list, as well.

  • In the US, the vaccine distribution will be coordinated at the federal, state and local level.
  • Pfizer's vaccine is now being distributed to the first high-risk and essential groups (healthcare providers). Nursing homes are also first in line.
  • By the end of 2020, Dr. Anthony Fauci, Director for NIAID, stated up to 20 million people could get COVID-19 vaccinations, if the Moderna vaccine is also available.
  • Alex Azar, MD, Secretary for HHS, also stated that by early spring 2021, general availability of the vaccine for all groups may be possible in the US.

Cold storage of the vaccine is a hurdle for the Pfizer vaccine, which needs to be stored at subzero temperatures, -70 degrees C (-94 degrees F). However, Pfizer has developed special cold storage packs for shipment and storage. The Moderna storage temperature is more like a regular freezer, at -20 degrees C (-4 degrees F).

Another hurdle: both vaccines require two doses separated by a few weeks, so it will be important that there is adequate education and follow-up with the public to complete the series.

What is an mRNA vaccine?

Both the Pfizer and Moderna vaccines are novel messenger RNA (mRNA) vaccines, which is a new science and technology never used before in a marketed vaccine. mRNA, which comes from DNA, is a short-term set of instructions that tells a cell how to make one certain coronavirus protein.

Take for example Moderna’s vaccine, currently known as mRNA-1273.

  • The vaccine includes a short length of mRNA that is made in a lab, but does not contain any part of the actual coronavirus and cannot cause infection. Since it's only one protein, it cannot cause the coronavirus infection, it only illicits an immune response.
  • The investigational vaccine directs the body’s cells to express a virus protein that is designed to elicit the immune response.
  • Quick action on the development of mRNA-1273 stems from Moderna’s prior work on a vaccine for Middle East Respiratory Syndrome Coronavirus (MERS-CoV).

For the Moderna vaccine, a Phase 1 clinical trial began in mid-March 2020 at Kaiser Permanente Washington Health Research Institute in Seattle. The open-label trial enrolled 45 healthy adult volunteers ages 18 to 55 years over approximately 6 weeks.

Researchers looked for dose safety and the ability of the vaccine to elicit an immune response in the first phase. Researchers then continued with larger Phase 2 and 3 studies for safety and effectiveness.

This study, in conjunction with the National Institute of Allergy and Infectious Diseases (NIAID) was launched in record time, according to Anthony Fauci, MD, Director for NIAID. In fact, all the studies have been launched in record time. Public, private, and governmental groups have come together to speed the process.

How long will the vaccine protect me from COVID-19?

Answers to this question are not yet known. Unlike the flu vaccine which requires a yearly injection, the coronavirus vaccine might be effective over the longer-term due to more stability of SARS-CoV-2 to mutations and greater immunity. The vaccine might be good for years, but the research on this question is not yet complete.

Scientists, looking at data from people previously infected with the actual virus have suggested antibody levels of COVID-19 might wane in a few months. However, immunity with B and T cells, "memory" cells that can recognize a foreign intruder like a virus over a longer period and launch an attack, appear to last longer. It's important to note data from this immunity study is in preprint, not peer reviewed, and research is still ongoing.

Bottom Line

  • The FDA allowed an Emergency Use Authorization of the Pfizer / BioNTech COVID-19 vaccine known as BNT162b2 was Dec. 11, 2020.
  • In the US, as of Dec. 14, the first rounds of vaccines are now rolling out to the highest-risk groups, such as essential healthcare workers and the elderly in nursing homes.
  • The Pfizer vaccine requires two doses, and length of immunity is still an unanswered question.
  • Public health authorities are optimistic that availability of COVID-19 vaccines to the average-risk person in the US may occur by spring of 2021.
  1. Moderna’s COVID-19 Vaccine Candidate Meets its Primary Efficacy Endpoint in the First Interim Analysis of the Phase 3 COVE Study.
  2. Immunity to the Coronavirus May Last Years, New Data Hint
  3. Dan J, Mateus J, Kato Yu, et al. Immunological memory to SARS-CoV-2 assessed for greater than six months after infection (preprint). bioRxiv.
  4. U.S. has a plan to start Pfizer vaccine shots in December: Health Secretary Azar
  5. Fauci says 20 million Americans could get COVID vaccinations around the end of the year
  6. Moderna’s Covid-19 vaccine is strongly effective, early look at data show.
  7. Pfizer and BioNTech to submit Covid-19 vaccine data to FDA as full results show 95% efficacy StatNews.
  8. The WHO Rapid Evidence Appraisal for COVID-19 Therapies (REACT) Working Group. Association Between Administration of Systemic Corticosteroids and Mortality Among Critically Ill Patients With COVID-19: A Meta-analysis. JAMA. 2020;324(13):1330–1341. doi:10.1001/jama.2020.17023
  9. Why Does Pfizer's COVID-19 Vaccine Need To Be Kept Colder Than Antarctica? NPR.
  10. NIH clinical trial of investigational vaccine for COVID-19 begins. National Institute of Health (NIH). Accessed March 31, 2020 at
  11. Genetic Engineering and Biotechnology News. Accessed March 30, 2020 at

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