After Your Vaccine

After you get your vaccine, you will need to stay for 15-30 minutes to be monitored any symptoms or side effects you may have. 

If my first shot is Pfizer, can my second shot be Moderna?

In general, you will want to stick with the same vaccine for your second dose, however, mixing and matching vaccines is permitted. If you experienced an adverse effect following your first dose, please speak with your primary care provider for guidance for your second dose. Boosters can be the vaccine of your choosing. 

Can I skip my second shot?

No, unless you had a severe allergic reaction to your first dose, the second dose is required to reach its full effectiveness. 

Once I receive my second shot, am I immediately protected?

No, It takes roughly two weeks after your second shot to be considered fully vaccinated. This is the time it takes for your body's immune system to build up its defenses.  

Why will I need to be monitored After the injection?

You will be monitored to make sure you do not have an allergic reaction to any of the ingredients.  

Do I need a booster shot?

Boosters are currently recommended for everyone 12 and older as soon as you are eligible. If you got a Moderna or Pfizer vaccine, you are eligible 5 months after your second dose. If you got a Johnson & Johnson vaccine, you are eligible after 2 months.

Second boosters are also recommended for individuals over 50, individuals 12+ who are moderately or severely immunocompromised, and those who got the Johnson & Johnson vaccine AND who got their first booster dose at least 4 months ago. 

If you have questions about your need for a booster, please speak with your primary care provider. 

COVID_ After the vaccine
More information on common side effects can be found here.


Any vaccine can cause side effects. For the most part, these are minor (for example, a sore arm or low-grade fever) and go away within a few days.  

Adverse reactions are unintended pharmacologic effects that occur when a medication is administered correctly while a side effect is a secondary unwanted effect that occurs due to drug therapy. It is a common misconception that adverse events and side effects are the same things.


In most cases, discomfort from fever or pain is normal. Contact your doctor or healthcare provider:

  • If the redness or tenderness where you got the shot increases after 24 hours
  • If your side effects are worrying you or do not seem to be going away after a few days


1. Contact your healthcare provider.

2. Report an Adverse Event using the VAERS online form or downloadable PDF.

For help with submitting your report, you can call 1-800-822-7967 or email

Important: If you are experiencing a medical emergency, seek immediate assistance from a healthcare provider, or call 9-1-1. CDC and FDA do not provide individual medical treatment, advice, or diagnosis. If you need individual medical or health care advice, consult a qualified healthcare provider.