People injected with Moderna COVID -19 vaccine reports more side effects

People who receive the Moderna COVID-19 vaccine say they have more side effects than people who get the Pfizer/ BioNTech shots.

The study analyzed reports collected through the Center for Disease Control and Prevention program called v-safe. It’s a text message-based program designed to track side effects in vaccine dose, people who enrol are prompted to fill out a daily survey about any symptoms, like fatigue or arm pain.


Over 3,600,000 people who got their first dose of a COVID-19 vaccine before February 21st enrolled in v-safe and checked in at least once. Around 70 per cent of those people said they had some kind of injection site reaction, like pain or swelling, and half had a more generalized reaction like fatigue or chills. For both, people who got a Moderna shot were more likely to have a side effect — 73 per cent had an injection site reaction, compared with 65 per cent of people who had a Pfizer / BioNTech dose. Around 51 per cent of Moderna recipients had full-body symptoms, compared with 48 per cent of people who got Pfizer / BioNTech.

The gap widened after the second dose. About 1.4 million people completed those check-ins. Almost 82 per cent of people getting their second Moderna shot had injection site pain versus just under 69 per cent of people with Pfizer / BioNTech. Overall, 74 per cent of people said they had general reactions after their Moderna shot, compared with 64 per cent of people getting Pfizer / BioNTech. The biggest difference was for chills, which were experienced by 40 per cent of people taking Moderna and only 22 per cent of people taking the Pfizer / BioNTech shot.

People over 65 were also less likely to have side effects than people under 65, regardless of which vaccine they received.


Overall, the side effects and frequency of side effects were similar to the ones seen in clinical trials testing these vaccines. The clinical trials gave researchers and doctors an accurate look at the types of side effects people can expect after they get their shots.