COVID-19 Vaccine: What You Need to Know About the Second Dose

COVID-19 Vaccine stickers
(This story was updated on Jan. 19, 2022)

The mRNA vaccines are a two-dose series, and it is important to understand why and, if you get one of these vaccinations, to ensure you get both shots.

What we know about the second dose

The first two vaccines to become available for use — those developed by Pfizer and its German partner, BioNTech, and Moderna — use messenger RNA (mRNA) to instruct the body to build the coronavirus’ signature spike protein. The body then produces antibodies to combat the Coronavirus when it enters the body.

The first dose helps your body create an immune response, while the second dose strengthens your immunity to the virus. The Pfizer-BioNTech vaccine requires two doses given 21 days apart. The Moderna vaccine requires two doses given 28 days apart. 

How does the two-dose series work in practice?

At your first appointment, you’ll receive a vaccination card noting the manufacturer of the vaccine you receive, the dose and date. Keep the card — you’ll need to present it to get the second shot and might need it in the future to prove you’ve been vaccinated. Tip: Take a photo of the card as a backup in case you lose it.

Your second dose should be the same manufacturer as your first shot, and in most cases you will receive it from the same vaccinator and likely in the same location. The process for scheduling your second-dose appointment differs depending on which vaccinator provides your shots.

If you miss your second dose

There are many reasons you might miss your second dose. If you test positive for COVID-19 after your first dose but before your second, it is recommended that you wait until you are done with the isolation period before you get your second dose.

If you miss your second dose for any reason, get it as soon as possible. The CDC recommends the second dose of Pfizer-BioNTech and Moderna COVID-19 vaccines should be administered up to six weeks after the first dose. Reach out to the site where you received your first dose to reschedule. You do not need to restart the two-dose series again.

Common, temporary side effects

The second shot produces a stronger immune system response, so reactions are more common. These temporary symptoms are expected, normal reactions when receiving a vaccine. Each person reacts differently to a vaccine, so it’s possible you won’t experience any symptoms.

Below are the reported reactions to the mRNA vaccines:

  • Injection site discomfort, such as pain, swelling, redness, or bruising
  • Muscle pain
  • Joint pain
  • Headache
  • Fatigue
  • Chills
  • Fever
  • Lymph node swelling

Relieve your symptoms

Side effects should resolve within 24-72 hours. Consider having a flexible schedule when making your vaccine appointments in case you experience any reactions. Below are some ways to decrease any discomfort you might feel after the vaccine, especially the second dose:

  • Rest
  • Drink plenty of fluids
  • Apply cool compresses to the injection site
  • Talk with your doctor about taking over-the-counter pain relievers/fever reducers

Can I stop wearing a mask after I’ve had two doses?

Fully vaccinated people should wear a mask in public indoor settings in areas of substantial or high transmission. But you can take off the mask when meeting with other fully vaccinated people or those who are not vaccinated but at low risk of serious COVID-19 infection.


Find COVID-19 Vaccines

Read more stories like this