Covid-19 Vaccines

Learn some quick facts about the efficacy, safety, and similarities between the three COVID-19 vaccines.

June 10, 2021

Covid-19 Vaccines

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Efficacy of Covid-19 Vaccines

All COVID-19 vaccines authorized for use in prevention of COVID-19 are efficacious. Clinical trials have shown the Pfizer BioNTech, Moderna, and Johnson and Johnson (Janssen) COVID-19 vaccines are 95%, 94.1%, and 66.3% effective against the virus, respectively. Vaccine efficacy represents the percent reduction in disease occurrence.

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Safety of Covid-19 Vaccines

All three (3) available COVID-19 vaccines have a similar common adverse effects. These adverse effects are generally mild to moderate. They include injection site reactions, fatigue, headache, muscle/joint pain, chills, fever, diarrhea, and nausea. In those vaccines that require two (2) doses, an increase in adverse effects is common after the second dose.

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Similarities & Differences

Just like any other vaccine, all COVID-19 vaccines do not give you the disease. Two (2) doses are needed for both mRNA vaccines (Pfizer-BioNTech and Moderna) and one (1) dose is needed for the DNA vaccine (Johnson and Johnson (Janssen)). The Pfizer-BioNTech COVID-19 vaccine can be given to those 12 and older, whereas the Moderna and Johnson and Johnson (Janssen) vaccine can only be given to those 18 and older.

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Special Populations

Any of the available COVID-19 vaccines can be offered to people who are pregnant or breastfeeding. Pregnant women are at increased risk for severe illness from COVID-19, and they may be at increased risk of adverse pregnancy outcomes. Currently, there are limited data on the safety of COVID-19 vaccines in pregnant women, but experts believe the vaccines are unlikely to pose a specific risk. Studies in animals receiving a COVID-19 vaccine before or during pregnancy found no safety concerns. COVID-19 vaccines have not been studied in lactating people; however, the vaccines are not thought to be a risk to lactating people or breastfeeding infants.

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Recent Events

Reports of a rare and severe type of blood clot (thrombosis with thrombocytopenia syndrome (TTS)) with the Johnson and Johnson (Janssen) COVID-19 vaccine have been observed in women < 50 years old. These cases are extremely rare, and the CDC and FDA still recommend the use of the Johnson and Johnson (Janssen) vaccine. This adverse effect has NOT been reported with the Moderna or Pfizer-BioNTech COVID-19 vaccines.

This guide has been provided for general information purposes only and is not intended to be used as medical advice. If you have any specific questions regarding your own circumstances, please contact your health provider directly.


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