Edmonds Medical Clinic Articles

COVID-19 Vaccine Side Effects & Tips

Possible Side Effects from COVID-19 Vaccines & Tips

Common Side Effects

1. On the arm where you got the shot: Pain, redness, swelling
2. Throughout the rest of your body: Tiredness, headache, muscle pain, fever, chills, nausea, joint pain, armpit pain or swelling.

Helpful Tips:

1. For any pain or discomfort you may experience after getting vaccinated:

  • You can take over-the-counter medicine, such as ibuprofen (Advil), acetaminophen (Tylenol), or antihistamines (Benadryl).
  • You can take these medications to relive post-vaccination side effects if you have no other medical reasons that prevent you from taking these mediations normally.
    (Some studies suggest that ibuprofen may interfere a little with antibody formation, so I think it is better to take acetaminophen. However, current CDC guidelines suggest that you can take ibuprofen as well.)
  • It is not recommended you take these medications before vaccination for the purpose of trying to prevent side effects.

2. For reducing pain and discomfort where you got the shot:

  • Apply ice pack topically over the area.
  • Use of exercise your arm.

3. For reducing discomfort from fever:

  • Drink plenty of fluids, and dress lightly.

* If you received a 2nd shot:

Side effects after your 2nd shot may be more intense than the ones you experienced after your 1st shot. These side effects are normal signs that your body is building protection and should go away within a few days.

* When to call the doctor:

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

* When to seek immediate medical care by calling 911:

  • If you think you might be having a severe allergic reaction after leaving the vaccination site, call 911.
  • The severe allergic symptoms include difficulty breathing, swelling of the face or throat, rapid heartbeat, severe systemic rash or itching, severe dizziness, severe weakness, or severe blood pressure decrease.

* Can a COVID-19 vaccine cause a false positive on mammogram?

Yes, when the body is building an immune response to the vaccine, in a small percentage of people, it can cause the lymph nodes to swell temporarily. If the lymph nodes under the arm are swollen, it could be a false positive on a mammogram. Because of this, it is recommended you schedule a routine mammogram either before receiving a COVID-19 vaccine, or 4 weeks after receiving a 2nd dose.

How long to stay at vaccination site prior to leaving, after vaccination:

After getting the vaccine, stay at the vaccination site for 15 to 30 minutes as follows to see if any dangerous allergic reactions occur.

15 minutes: general people
30 minutes: Those who have had a sudden allergic reaction after receiving injections or other vaccines in the past, or those who have had anaphylactic shock for any reason.

Vaccine type:

Age Requirements
Pfizer: 16+
Moderna: 18+
Johnson & Johnson: 18+

Doses Required
Pfizer: 2
Moderna: 2
Johnson & Johnson: 1

Recommended Time Between Doses
Pfizer: 21 days
Moderna: 28 days
Johnson & Johnson: N/A

Do I get to choose which vaccine brand I want to receive?

In general, given scarce supply, only one vaccine may be available through your provider. If you are 16 or 17 years old, you may only receive the Pfizer vaccine.

Can I choose the vaccine that says it is the most effective?

All three vaccines are safe and highly effective against illness and death from COVID-19. Getting the vaccine as soon as soon as possible, regardless of the brand, will protect you from severe illness, hospitalization, and the risk of death from COVID-19. The bottom line is the best shot you can get is the one that is available.

How effective are the COVID-19 Vaccines?

The vaccines are emergency approval from the FDA appear to provide significant protection against COVID-19, but they do not offer 100% protection. Preliminary data suggests the Pfizer and Moderna vaccines offer about 95% protection. Johnson & Johnson vaccine offers about 72% protection.

If you do get COVID-19 after vaccination, the chance of severe or critical illness and death due is significantly reduced.

How long does it take for full protection?

It takes 2 weeks after your last dose of vaccine to achieve full protection.


Steven Koh, MD
Family Medicine
Edmonds Medical Clinic