Get the latest on the coronavirus vaccines
Since the start of the worldwide pandemic in early 2020, researchers have been working hard to develop COVID-19 vaccines. Currently, more than 81 vaccines are in clinical development by researchers across the globe. The hope is that multiple ones will work in fighting the coronavirus. Developing a vaccine requires multiple steps, during which researchers test to confirm that the vaccine is safe and that it works. These steps are:
- Preclinical: Vaccines are not yet ready to be tested on humans (there are currently 182 vaccines in this stage)
- Phase I: A safety trial where the vaccine is tested on a few people
- Phase II: Expanded trials including a variety of people
- Phase III: Efficacy trials including thousands of people, with comparisons to a placebo group
- Approval: Regulators review the results of phases I through III and approve or deny the use of the vaccine
As COVID-19 vaccines are authorized and then recommended for use in the United States, it is important to understand the information available about each vaccine. The Centers for Disease Control and Prevention (CDC) provides guidance and recommendations about who should receive the vaccines, what to expect after vaccination, as well as information about ingredients, safety and effectiveness.
To keep up to date on the current recommendations, bookmark the CDC website and check it regularly.
Currently, the following vaccines are approved by the U.S. Food and Drug Administration (FDA) for use in preventing COVID-19:
- Pfizer-BioNTech’s COVID-19 vaccine
- Moderna’s COVID-19 vaccine
- Johnson & Johnson’s COVID-19 vaccine
Both the Pfizer-BioNTech and Moderna vaccines require 2 doses, given 21 to 28 days apart. Both are mRNA vaccines. The Johnson & Johnson shot is a viral vector vaccine. It requires only 1 dose. Learn more about the different types of vaccines below.
Types of coronavirus vaccines
When talking about vaccines, it helps to know how our bodies fight infections. When foreign cells — like a virus — enter your body, your immune system responds by making proteins called antibodies to destroy the foreign invaders before they replicate. Once your immune system recognizes a type of foreign cell, it can kill it faster in the future, which is how we acquire immunity. Traditional vaccines, such as those for the measles or the flu, help us develop immunity by introducing a weakened or killed virus into our bodies in a way that allows the immune system to learn how to fight it without making us sick. The new coronavirus vaccines work a little differently.
- mRNA vaccines contain messenger RNA, which is a type of genetic material that instructs our cells to make certain proteins. In this case, the mRNA tells them to make a harmless version of coronavirus’s “spike” protein. The immune system recognizes these spikes as foreign and begins to build up antibodies. If you are exposed to the real coronavirus later, your body will know how to fight it. The mRNA vaccines do not contain the actual coronavirus, and they cannot make you sick with COVID-19. Once the instructions are delivered, your body disposes of the mRNA.
- Viral vector vaccines use a harmless version of a virus — not the coronavirus — to deliver instructions. For the COVID-19 vaccine, the modified virus (aka the vector) enters cells and tells them to start making the spike protein that’s unique to the coronavirus. The immune system recognizes the proteins as foreign, attacks them, and builds antibodies. The viral vector vaccine cannot make you sick with COVID-19, nor can you become ill from the virus used as the vector.
COVID-19 vaccine rollout timeline
Who will get the COVID-19 vaccine first?