The Covid-19 virus made its first appearance in China in December of last year. Since then, over 70 million people have been infected with the virus, and over 1.6 million have died. In an effort to contain Covid-19 and an end to the pandemic, several companies have put all their resources and effort into finding a vaccine. And after almost a year of work, several of these vaccines have moved into phase three of testing, and one, the Pfizer vaccine, has been approved for distribution in America. But how do vaccines get approved? And how will they be distributed?

Only one vaccine has been approved for use in the United States, the Pfizer-BioNTech vaccine. But there are several other vaccines waiting for approval, or finishing their clinical trials. The AstraZeneca, Janssen, and Moderna vaccines are all in phase 3 of their clinical trials. New treatments begin in phase 1, and simply seek to see if the treatment is safe or not. Participants will be given an extremely low dose of the treatment and monitored closely. If there are minor side effects, the next round of participants gets a higher dose, and so on. This process continues until doctors find the most effective dose with minimal side effects. Phase two seeks to find if the treatment works. A slightly larger group of participants are given the previously found dosage, and doctors continue to monitor side effects and effectiveness. Finally, in phase three studies, a large number of participants are given either the treatment or a placebo. Studies including a placebo are generally referred to as double-blind studies, as both the doctor and the participant do not know who is getting the treatment, and who is getting the placebo.

After these trials have been conducted and data has been presented, the Food and Drug Administration (FDA) will assess the safety of the vaccine. Due to the nature of the Covid-19 pandemic, the Pfizer vaccine was authorized for emergency use, meaning that the vaccine will continue to be studied in real-world situations in order to determine its real-world effectiveness. There are several methods to study vaccine effectiveness in real-world situations. For example, the screening method will look at vaccination coverage among a group of cases and compare it to the vaccination coverage among a general population (of a state, county, etc.). This will allow researchers to understand whether or not the vaccine is working as expected. The FDA, along with the U.S. Centers for Disease Control and Prevention (CDC), Centers for Medicare and Medicaid Services (CMS), Department of Defense (DoD), Indian Health Service (IHS), and the Veteran’s Health Administration (VHA) will work together to affirm the vaccine is safe for public use.

The next step is distribution. But who gets vaccinated first? Because of the limited supply in the United States, the CDC recommends the first doses be given to healthcare personnel and long-term care facility residents since they are most at risk of contracting the virus or experiencing complications. The CDC made this recommendation with the goal to decrease the number of those dying of Covid-19 by as much as possible, preserve the functioning of society, and reduce the general burden of Covid-19 and its effects on the general public. However, as vaccine availability increases, vaccination recommendations will expand to more groups. The CDC asserts, “The goal is for everyone to be able to easily get a COVID-19 vaccination as soon as large quantities of vaccine are available. As vaccine supply increases but remains limited, ACIP [Advisory Committee on Immunization Practices] will expand the groups recommended for vaccination.”

With information from the CDC and other health organizations, we can estimate a brief timeline of the distribution of the vaccine. In the remainder of December, we can expect the Pfizer vaccine to continue to be rolled out to millions of healthcare workers and long term care facility residents. This will likely be the case for the Moderna vaccine as well, once it is authorized for use by the FDA. In the new year, we will likely see more essential healthcare workers vaccinated, as well as other essential emergency workers, like firefighters and police. Dr. Larry Corey of the University of Washington, a leader in the American clinical trials, if both Pfizer and Modern get vaccines authorized, a total of 150 million doses would be available (enough to vaccinate 75 million people, as the vaccine is effective after two doses about three weeks apart). If enough dosages are available, vaccines may be made available to the second phase of individuals. This group has not been decided yet, but it is likely to include school teachers and childcare, retail, and transportation workers. If distribution is running smoothly, phase 3, which includes healthy adults, teenagers, and children) will be permitted to receive the vaccine in May at the absolute earliest.

Once the vaccine is made available to the general public, it will be up to each individual to decide if they wish to receive the vaccine, or which vaccine works best for them. According to the CDC, each patient will be given a vaccination card, which states what vaccine they received, the date they received it, and where they received it. The CDC also advises that many will experience side effects after receiving the vaccine. These include pain or swelling at the site of the shot, fever, chills, fatigue, and headache. Additionally, most Covid-19 vaccines require two doses to be effective, so each individual will return to receive a second dose. And as it takes time for our bodies to build an immune response, the vaccine may not fully protect us for one to two weeks after the second dose.

The FDA continues to update and revise the vaccine distribution plan, even after the Pfizer vaccine’s approval for emergency use. If all goes well, we will likely see a vaccine made available to the general public in the late spring and early summer of 2021. The beginning of the end of the pandemic is on its way.

*All information in this article is as of December 17th, 2020