Public Health

COVID-19 Vaccine Update: When will a COVID-19 vaccine be available?

Mira Research Team
Mira Research Team20 Jan 2021

COVID-19 Vaccine Update: When will a COVID-19 vaccine be available? 


Quick Digest and COVID Vaccine Updates - December 1, 2020: 

  • Globally, there are over 155 coronavirus vaccines being tested across national institutes, and 54 are currently in human trials.
  • Although vaccines typically take between 10-15 years to create and perfect, scientists and researchers are pushing to get a vaccine out by 2021.
  • Both Moderna and Pfizer have preliminary phase 3 results that show that their vaccines are over 90% effective.
  • The distribution of a vaccine may begin in early 2021, but we will likely need to wait until the spring until people can easily get vaccinated.
  • The cost of a vaccine will likely be under $30 per dose.
  • Moderna and Pfizer are both seeking FDA approval for their vaccines.


Petri, William A. - Research Faculty Directory
Dr. William Petri, MD, PhD

Dr. William Petri, MD, Ph.D. was interviewed for information on the development of a COVID-19 vaccine. Dr. Petri is the Vice-Chair for Research of the Department of Medicine and The Chief of Division of Infectious Diseases and International Health at The University of Virginia. He is currently working on the development of a COVID-19 vaccine.


How long until the COVID-19 vaccine becomes available?

The development of a vaccine is usually a process that takes anywhere from 10 to 15 years. The development of the coronavirus vaccine is highly expedited and the first vaccine should be approved by early-mid 2021. 

Dr. Fauci predicts that we could have an approved vaccine as early as April 2021. However, having an approved vaccine does not mean that we will all be able to immediately get it. Moderna CEO, Stephane Bancel, believes that everyone in the U.S. will be able to get a vaccine by June 2021. 


How is the COVID-19 vaccine being created so quickly?

The preclinical phase, which includes laboratory and animal studies, typically takes between 3 and 6 years. However, the COVID vaccine timeline is highly expedited. This process is made possible by the increase in government funding, shortened testing timelines, advances in technology, and previous knowledge of other coronaviruses. Additionally, rather than following the aforementioned testing phases in sequential order, researchers have been granted permission to run multiple phases simultaneously.

For example, phase I clinical trials last a full year. However, pharmaceutical companies will be allowed to begin phase II and III before phase I ends. Even once a vaccine is on the market, it will likely be subject to changes and improvements over the next several years in order to increase its efficacy.

Timeline of Typical of Vaccine Development. Source:


What are the most promising COVID-19 vaccines in-development?

The federal government identified 5 vaccine candidates for Operation Warp Speed, an initiative that aims to help get a vaccine to the market as soon as possible. These candidates seemed the most promising in terms of producing a safe and effective vaccine by 2021. In addition to these 5 promising vaccines, several other companies have high hopes of producing effective vaccines within the next year. 

The 5 companies are Moderna, a collaboration between Oxford University and AstraZeneca, Johnson & Johnson, Pfitzer, and Merck. The goal is to have the vaccine ready by early next year. And if one of these companies are able to do so, it would be setting a record as no vaccine has ever been developed so quickly. The current record for vaccine development is currently only 4 years. 

Pfizer and BioNTech

Pfizer is collaborating with BioNTech and Fosun Pharma to work on a messenger RNA (mRNA) based vaccine. This vaccine is currently in Phase III of clinical trials. The vaccine showed to be 95% effective in preventing COVID-19 in a sample of 43,538 participants. Individuals who received this vaccine only experienced mild side effects, such as fatigue in 3.7% of recipients. 

The Pfizer vaccination includes two shots which must be given 3 weeks apart. One drawback of this vaccine is that it must be stored at very cold temperatures, which may make distribution difficult. They expect to produce 50 million doses by the end of 2020 and 1.3 billion doses in 2021. Pfizer may request Emergency Use Authorization from the FDA in the coming months. 


Moderna is currently in phase III of clinical trials, where the vaccine has been tested on 30,000 people. This vaccine is also using messenger RNA (mRNA). The vaccine showed to be almost 95% effective so far. Participants only experienced mild side effects, such as fatigue and headache after injection. 

The Moderna vaccination includes two shots which must be given 4 weeks apart. Moderna's vaccine can be stored at slightly warmer temperatures than Pfizer's vaccine. In a press release, Moderna noted that they expect to have 20 million doses by the end of 2020

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Oxford, AstraZeneca 

The vaccine developed by scientists at Oxford is currently in phase III of clinical trials. The vaccine is based on a common cold virus in chimpanzees (ChAdOx1). This virus has been modified to express a spike protein from the COVID-19 virus. 

Oxford temporarily stopped trials to investigate a volunteer who got sick. The Food and Drug Administration (FDA) reviewed that case and deemed it safe to resume. Oxford's current trial includes 50,000 people globally. They expect some results by December 2020. 

Johnson & Johnson

The vaccine being developed by Johnson & Johnson is currently in phase III clinical trials.  Johnson & Johnson is using an adenovirus (Ad26), which is used in the vaccine to prevent Ebola. Johnson & Johnson paused their clinical trials to investigate a volunteer who got sick but found no evidence that the vaccine caused the illness and resumed their trials. 

Johnson & Johnson is currently examining the efficacy of giving two doses rather than one. 


Merck is currently working on two coronavirus vaccines. They are working with Themis Bioscience to create a vaccine that uses a weakened measles virus. This vaccine candidate is in phase I trials. 

In addition, Merck is working with IAVI to work on a vaccine that is based on vesicular stomatitis viruses (VSV). This is the same method that was used to produce a vaccine for Ebola. The dose of this vaccine would be taken as a pill rather than an injection. It is currently in phase I trials. 

How do vaccines work?

Vaccines generally function by introducing a weakened virus or bacteria into the body to kickstart an immune response. The immune system responds to this virus, or pathogen, by making two types of cells:

  • Plasma cells produce antibodies, which are able to neutralize the specific virus that caused the infection.
  • Memory B cells are also produced, which remain dormant in the body. If infected with the virus again, the memory B cells recognize the virus and stimulate an immune response to fight infection.


How long does a vaccine protect me from a disease?

The duration of protection varies by vaccine. Some vaccines, such as the Measles vaccine, leads to lifelong protection in over 99% of cases, while the Pertussis vaccine is effective for about 4-6 years.

Other vaccines, such as the Influenza vaccine, may only be effective for a few months. Some people may experience mild side effects from vaccines, such as fevers or rashes. However, these side effects are typically less dangerous than contracting the virus that the vaccine prevents.


What are the types of vaccines?

According to the CDC, there are currently 4 main types of vaccines that are given to young children in the United States. However, the development of the coronavirus vaccine may stray outside of these commonly used approaches.

1. Live virus vaccines use a weakened version of the living bacteria or virus. In a healthy individual, this weakened version of the virus does not typically cause serious illness. However, it is advised that individuals who are immunocompromised consult a health care provider before receiving this type of vaccine. 

Live virus vaccines typically result in an immune response that lasts many years. Examples include MMR, smallpox, varicella, and yellow fever.  

2. Inactivated virus vaccines use a killed virus or bacteria; however, these vaccines are typically not as long-lasting as the live virus vaccines. Several doses or boosters of inactivated virus vaccines are typically needed to build up immunity. Examples include polio, flu shot, and hepatitis A. 

3. Toxoid vaccines target bacteria that produce toxins in the body. These vaccines work by injecting weakened toxins (toxoids) into the body. An example is the DTaP vaccine, which protects against diphtheria and tetanus. 

4. Subunit vaccines include only the specific parts of the virus that are needed to confer immunity. Therefore, there are fewer side effects and it is safer for immunocompromised individuals to receive these vaccines. Boosters may be needed over time. Examples include hepatitis B, HPV, and shingles. 

Phases of Vaccine Testing and Approval

There are several phases a vaccine must go through before being given to the public:

Pre-clinical testingThe vaccine is given to animals (mice, monkeys) to see if they have any immune response.
Phase I (safety trials)The vaccine is tested by giving it to a small group of people to test the safety and dosage as well as the immune response. 38 vaccines for COVID-19 are in phase 1 testing. 
Phase II (expanded trialsThe vaccine is tested on several hundred people, including specific groups such as young children or older adults. 17 vaccines for COVID-19 are in phase 2 testing. 
Phase III (efficacy trials)The vaccine is given to thousands of people. The rate of infection in this population is compared to a placebo group who does not receive the vaccine. For COVID-19 vaccines, phase III trials will include administering the vaccine to 30,000 people. 12 vaccines for COVID-19 are in phase 3 trials. 
ApprovalEach country has regulators to review the results from the trials and determine whether or not the vaccine is deemed effective and safe. However, during a pandemic, a vaccine may receive emergency approval.
Phase IVIt is impossible to know all side effects of a vaccine before it reaches the population. Therefore, most vaccines undergo studies once they are already on the market. The Vaccine Adverse Event Reporting System studies the vaccines to troubleshoot for problems once the vaccine is already approved. 


Herd immunity: What is it and what does it mean in terms of the end of coronavirus COVID-19?

Herd immunity is when a large percentage of the population is immune to a disease, making its spread within that population highly unlikely. The entire population does not necessarily need to be immune in order to achieve herd immunity. The percentage of the population that needs to be immune is called the threshold proportion and it depends on the specific virus.

For example, according to the Mayo Clinic, the threshold potential is about 60% for the flu and 94% for measles. It is estimated that the threshold potential for COVID-19 is around 70%. 

In order to reach the threshold potential of COVID-19, enough people need to be vaccinated or become naturally infected with the virus. The problem with achieving herd immunity through natural infection is that the antibodies created by means of natural infection may only last several months, potentially leaving people susceptible to reinfection.

Additionally, over 200 million individuals in the U.S. would need to be infected and recover in order to have herd immunity via natural infection. The infection of over 200 million people will likely result in many deaths, an economic burden, and overwhelmed hospitals. Therefore, a vaccine is the most promising way to achieve herd immunity.

Herd Immunity. Source:


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Questions and concerns about COVID-19 vaccines 

Will there be one vaccine or multiple vaccines on the market?

According to Dr. Petri, there will likely be a few vaccines available in the United States in 2021. Over the next few years, however, these vaccines will likely be modified and improved. Modifications will hopefully include increasing the efficacy of the vaccine and increasing the amount of time that the vaccine protects people against the virus.

How long will the vaccine be effective?

The amount of time the vaccine will be effective for and the frequency of booster vaccines needed to confer immunity is currently unknown. Some methods in developing a vaccine may create immunity for several months, similar to the influenza vaccine. 

This type of vaccine would require booster vaccines every few months. Other teams are looking for a way to create long term immunity. Dr. Petri's team is using a similar model to the Yellow Fever vaccine to create a long-lived antibody response.

Will there be side effects of the vaccine?

According to current clinical studies, there have already been some very mild side effects noted by researchers. These side effects include body aches, soreness at the point of injection, fever, and sleep disruptions. 

Dr. Petri explained that rare side effects, however, may not be able to be understood until the vaccine is already on the market. Since some side effects will only affect 1/1,000,000 people, they will likely not be prominent in phase II and III trials, which only include up to 30,000 individuals. The COVID-19 vaccine will likely be under surveillance in phase IV.

Who will get the vaccine first?

Decisions regarding vaccine distribution will be made by The CDC's Advisory Committee on Immunization and The World Health Organization Strategic Advisory Group of Experts on Immunizations. In previous cases, individuals such as health care providers, military, older adults, and first responders are usually given priority. 

Ethicists are currently evaluating which groups of people will benefit most from an early vaccine. Dr. Petri explained that COVID-19 is largely linked to clusters of people, so groups of people in nursing homes, prisons, and healthcare personnel may be a priority.

Will people want to get the vaccine?

Recent research indicates that as few as 50% of people in the United States reported that they would be committed to receiving a coronavirus vaccine once available. People are likely worried due to the fast-paced nature of COVID-19 vaccine production. However, once vaccines reach phase III and are tested on 30,000 individuals, the public trust in the vaccines may increase. 

In addition, the results from Moderna and Pfizer's trials are reassuring for those who may be worried about potential side effects. Dr. Petri also noted that it is possible that schools and universities mandate the vaccine once it becomes widely available. This would be following a similar trend as the Meningitis vaccine, which is now required by the College Student Health Association. 

Why do we have over 140 groups working on a vaccine?

Over 140 teams are developing a COVID-19 vaccine and have registered with The World Health Organization. Dr. Petri explained that each group working on the COVID-19 vaccine development has unique aspects to offer. The competition of all these teams is actually a good thing, as it will likely result in the most effective vaccine down the line. 

For example, Dr. Petri's laboratory is working on making its vaccine heat-stable, long-lasting, and resistant to mutations. Additionally, Dr. Petri explains that there unfortunately will be another pandemic down the line. This investment in science, technology, and understanding a vaccine is bound to pay off when we need to come up with new treatments and vaccines for another virus.


What to do until the approval of a vaccine

Since we will likely need to wait until Spring 2021 to get vaccinated, we must continue to take precautions to mitigate the spring of COVID-19 this winter. This is a collective effort - so be sure to:

  • Wear a mask
  • Wash your hands thoroughly
  • Practice social distancing
  • Monitor your symptoms
  • Stay home if you are feeling sick or had a recent exposure


Here are some additional resources you might find helpful:




Mira Research Team

The Mira Research team conducts original data and medical research on the most applicable topics of today and translates them into easy-to-understand articles to educate the public. Each of our articles is carefully reviewed and curated with interviews and opinions from medical experts, public health officials, and experienced administrators. The team has educational backgrounds from New York University, the University of Virginia, more.