It can be overwhelming deciding which COVID-19 vaccine you want to get, if you are given the choice. Below we break it down into some easy facts that will help you decide which one is the right one for you and your family.
The Vaccines
By definition, a vaccine is a substance used to start the production of antibodies and provide immunity, also known as protection, against a virus, such as COVID-19. Antibodies are blood proteins produced by your body in response to specific antigens, also known as foreign substance like viruses.
Currently available in the United States are three COVID-19 vaccines: Moderna, Pfizer and Johnson & Johnson (also known as Janssen), named after the companies that developed them. We often associate the vaccines with percentages representing how effective they are—Pfizer is 95% effective at preventing severe illness and death, for example. But what are the true differences between the vaccines, what do the numbers mean, and which statistics matter the most?
There are similarities between all of them:
- None of the vaccines will give you a COVID-19 infection.
- None of the vaccines will change your DNA.
- None of the vaccines contain eggs, latex or preservatives.
- All of the vaccines have been authorized by the Food and Drug Administration (FDA) for emergency use, and Pfizer and Moderna have since been FDA approved.
- All of the vaccines could cause some injection site pain, tiredness, headache, muscle pain, chills, fever and nausea following vaccination.
- It is not fully known how well the vaccines will prevent you from spreading COVID-19 to others, even if you do not have symptoms.
- It is not fully known how long the COVID-19 vaccines protect people from COVID-19.
- It is not fully known how effective the vaccines are against new variants of COVID-19.
Comparing the Available COVID-19 Vaccines
Moderna
- A mRNA vaccine - which teaches the cells in your body how to make a protein that triggers an immune response, providing protection
- Two doses of the shot are needed, 28 days apart
- Booster shots: 18 and older can receive booster 5 months after
- Some protection is provided after the first dose
- Full protection is provided two weeks after the second dose
- People 6 months and older can receive this vaccine
- Additional side effects include swollen lymph nodes in the arm that received the shot
Pfizer (BioNTech)
- Also a mRNA vaccine
- Two doses of the shot are needed, 21 days apart
- Booster shots: 5 months after
- Some protection is provided after the first dose
- Full protection is provided two weeks after the second dose
- People 6 months and older can receive this vaccine
- Additional side effects include swollen lymph nodes in the arm that received the shot
Johnson & Johnson (Janssen)
- A vector vaccine – which uses a modified version of a different virus to deliver important instructions to your body to start building protection
- Only one dose of the shot is needed
- Full protection is provided two weeks after vaccination
- People 18 and older can get this vaccine if they specifically request it or cannot use other available vaccines for medical reasons
The Bottom Line
“Vaccine efficacy” is the term statisticians use to measure how much a vaccine lowers the risk of getting infected with a disease. Efficacy isn’t always the same. For example, Johnson & Johnson’s vaccine had an 85% efficacy rate against severe cases of COVID-19, which is important because that means it prevents hospitalizations and deaths.
“What is important is the herd immunity – the critical level of immune individuals that will end the pandemic by natural infection and vaccination. We do not need vaccines to be 100% effective to remove the public health measures currently in place,” says Dr. Armando Paez, Division Chief, Infectious Diseases, Department of Medicine at Baystate Health.
Each vaccine is a little bit different, but they all provide the protection we need against COVID-19. We hope that this comparison will help you make an informed decision about the COVID-19 vaccines.
Learn More
For information on Massachusetts vaccine eligibility, visit mass.gov. If you are a Connecticut resident, visit ct.gov. click here.
Still unsure? Hear Baystate Health experts share why they got the COVID-19 vaccine.