Alexandra Edmonson, Family Nurse Practitioner Resident at Community Health Center, answers this week’s questions:
What side effects should we expect after receiving a COVID-19 vaccination?
Side effects are possible whenever receiving a vaccine. They can be local, meaning the side effect is limited to the area where the vaccine was injected (e.g. arm soreness, swelling or redness), or they can be systemic, meaning they can affect the whole body (e.g. fever, chills, fatigue, or muscle aches). Most of us have experienced a sore arm after getting a tetanus shot (a local side effect) which then goes away after a day or two. Many of us who receive the flu shot have also felt a little run down afterwards (a systemic side effect), and may have mistakenly assumed that the flu shot gave us the flu. In reality, these side effects are a sign that your immune system is working hard to produce antibodies to keep you safe. It is hard work fighting viruses and bacteria, and the extra energy needed to do so can make you feel a little unwell in the meantime.
In data published by the CDC regarding the first month of COVID-19 vaccinations (12/14/20 – 1/13/21), nine side effects were reported by people who received at least one dose of the Pfizer or Moderna vaccine. Local side effects on day 1 after receiving the 1st dose included: 1) Injection Site Pain (73% of Pfizer vaccine recipients, 78% of Moderna vaccine recipients), and 2) Injection Site Swelling (4% of Pfizer vaccine recipients, 6% of Moderna vaccine recipients).
Systemic side effects on day 1 after receiving the 1st dose included: 1) Fatigue (22% for Pfizer, 25% for Moderna), 2) Headache (18% for Pfizer, 20% for Moderna), 3) Muscle Aches (15% for Pfizer, 18% for Moderna), 4) Chills (6% for Pfizer, 8% for Moderna), 5) Fever (6% for Pfizer, 8% for Moderna), 6) Joint Pain (5% for Pfizer, 7% for Moderna), and 7) Nausea (4% for Pfizer, 6% for Moderna).
Local side effects after receiving the 2nd dose of the Pfizer vaccine from the data mentioned above include: 1) Injection Site Pain (79%) & 2) Injection Site Swelling (9%). Systemic side effects after receiving the 2nd dose of the Pfizer vaccine include: 1) Fatigue (54%), 2) Headache (43%), 3) Muscle Aches (47%), 4) Chills (31%), 5) Fever (29%), 6) Joint Pain (24%), and 7) Nausea (14%). All nine of the reported side effects increased with the second dose of the Pfizer vaccine, some by as much as five times (e.g. fever). Unfortunately, no data was published on those who received their 2nd Moderna dose. However, anecdotal evidence regarding Moderna is consistent with the Pfizer vaccine results.
How likely is a severe reaction?
Anaphylaxis, a severe potentially life-threatening reaction that can happen within seconds of exposure to an allergen, has occurred following COVID-19 vaccination, though it is very uncommon. Signs of anaphylaxis include difficulty breathing, swelling of the mouth, hives, a fast heart rate, and nausea or vomiting. According to data on the first month of COVID vaccination (12/14/20 – 1/18/2021), reported anaphylaxis cases were as follows: 1) Pfizer: 4.7 cases per million doses of vaccine administered, and 2) Moderna: 2.5 cases per million doses of vaccines administered.
For people with a diagnosed allergy to any component in the COVID vaccine, COVID vaccination is contraindicated. It is also contraindicated to receive a 2nd dose of the Pfizer or Moderna vaccine if a severe allergic reaction (e.g. anaphylaxis) occurred after the first dose. Those who experience a severe allergic reaction to the first dose of Pfizer or Moderna may consider the Johnson & Johnson vaccine (Janssen).
To ensure patient safety, all vaccine recipients are required to remain under observation for at least 15 minutes following each vaccine dose. Those with a history of anaphylaxis to anything other than a COVID vaccine or component in a COVID vaccine, are required to remain for 30 minutes of observation. Those with a history of an immediate allergic reaction to other vaccines or injectable therapies may consider COVID vaccination and are also required to remain under observation for 30 min.
Millions of people in the US have safely been vaccinated against COVID-19. If you have any questions regarding vaccination, please contact your primary care provider.