The novel coronavirus has wreaked havoc on the world, and a vaccine seems to be our best bet against containing it. At present, two COVID-19 vaccines (both mRNA-based) are in emergency use in the United States—the Moderna vaccine and the Pfizer-BioNTech vaccine.

Certain reactions (such as swelling, redness or pain around the injection site, fever, fatigue, and headache) typically occur three days after getting vaccinated. These are signs that the vaccine is working and your body is forming antibodies. These reactions have also been reported by people who received the Moderna or Pfizer-BioNTech vaccines.

The Pfizer-BioNTech vaccine

The BNT162b2 vaccine by US company Pfizer and German company BioNTech didn’t cause any serious side effects during the approval phase. Typical vaccine reactions such as headache and fatigue weren’t as frequent and prominent in older patients.

However, a few patients were reported to have had a severe allergic reaction after receiving this vaccine. Two Britons and one American went into anaphylactic shock, wherein they suffered from shortness of breath and reddening of the skin. These individuals had no previous illnesses or history of allergies to certain ingredients in the vaccine. 

The Moderna vaccine

The mRNA-1273 vaccine by US company Moderna is similar to the Pfizer-BioNTech vaccine. The participants responded well to the vaccine during the clinical trials. Typical vaccine reactions were mild or moderate and short-lived. As per an interim report by an independent surveillance panel, 10% of the individuals who received the vaccine experienced fatigue.

The US Centers for Disease Control and Prevention (CDC), based on the 4,041,396 doses of the vaccine administered between December 21, 2020, and January 10, 2021, said that severe allergic reactions to the Moderna vaccine are rare. A total of 108 allergic reactions were recorded, out of which only 10 recipients went into anaphylactic shock. A few people who received the vaccine experienced facial nerve paralysis. However, it’s still unclear whether it was because of any core ingredient of the vaccine.

Please note that the long-term risks and benefits associated with these vaccines will only be known for sure after enough time has passed.