From the Guidelines
COVID-19 vaccines can cause several adverse reactions, though most are mild and temporary, with common side effects including pain, redness, or swelling at the injection site, fatigue, headache, muscle pain, chills, fever, and nausea, typically lasting 1-3 days, as reported in the most recent study 1.
Adverse Reactions to COVID-19 Vaccines
The adverse reactions from COVID-19 vaccines can be categorized into common and rare reactions. Common side effects include:
- Pain, redness, or swelling at the injection site
- Fatigue
- Headache
- Muscle pain
- Chills
- Fever
- Nausea These reactions are typically mild and temporary, lasting 1-3 days.
Rare but Serious Adverse Reactions
More serious but rare adverse reactions include:
- Anaphylaxis (severe allergic reaction occurring within minutes to hours after vaccination)
- Myocarditis and pericarditis (inflammation of the heart muscle or lining, primarily in young males after mRNA vaccines) 1
- Guillain-Barré syndrome (rare neurological disorder more commonly associated with Johnson & Johnson vaccine)
- Thrombosis with thrombocytopenia syndrome (blood clots with low platelets, primarily with adenovirus vector vaccines like Johnson & Johnson) These serious reactions typically occur within days to weeks after vaccination.
Reporting Adverse Events
Adverse events after vaccination should be reported to the Vaccine Adverse Event Reporting System (VAERS) 1. Vaccination providers are required to report certain adverse events to VAERS, and additional information is available at https://vaers.hhs.gov or by telephone at 1-800-822-7967.
Recommendation
The risk of serious adverse reactions from COVID-19 vaccines is significantly lower than the risks associated with COVID-19 infection itself, which is why vaccination is still recommended for most people, as stated in the most recent guideline 1. If you experience severe symptoms like difficulty breathing, chest pain, severe headache, blurred vision, or persistent abdominal pain after vaccination, seek immediate medical attention.
From the Research
Adverse Reactions to Covid Vaccines
The Covid vaccines have been associated with various adverse reactions, ranging from mild to severe. According to the studies, the most common adverse reactions include:
- Headache 2, 3
- Fever 2, 3
- Pain, redness or swelling at the site of vaccine shot 3
- Fatigue 3
- Muscle pain 3
- Nausea 3
- Vomiting 3
- Itching 3
- Chills 3
- Joint pain 3
Serious Adverse Reactions
While rare, some serious adverse reactions have been reported, including:
- Anaphylaxis 2, 4, 5
- Vaccine-induced thrombotic thrombocytopenia 5
- Myopericarditis 5
- Guillain-Barré syndrome 5
- Death 2, 4
Comparison of Adverse Reactions between Vaccines
The studies suggest that the frequency and severity of adverse reactions may vary between different Covid vaccines. For example:
- The Pfizer-BioNTech vaccine has been associated with a lower frequency of adverse reactions compared to the Moderna vaccine 3
- The Johnson & Johnson's Janssen vaccine has been associated with a higher frequency of adverse reactions compared to the Pfizer-BioNTech and Moderna vaccines 2
Population-Specific Adverse Reactions
Some studies suggest that certain populations may be more susceptible to adverse reactions, including:
- Individuals aged 65 and older, who may be at a higher risk of serious adverse reactions 4
- Individuals with a history of allergic reactions, who may be at a higher risk of anaphylaxis 3
Overall Safety Profile
Despite the potential for adverse reactions, the overall safety profile of the Covid vaccines is considered to be favorable, with the benefits of vaccination outweighing the risks 2, 4, 5, 6