More Side Effects With Moderna COVID-19 Vaccine: CDC Study

People who received the Moderna COVID-19 vaccine reported more side effects than those who got the Pfizer/BioNTech shot, according to a recent study by the Centers for Disease Control and Prevention (CDC).

The study—published online in the Journal of the American Medical Association (JAMA) on April 5—looked at data collected from over 3 million participants vaccinated from Dec. 14, 2020, through Feb. 28, 2021, in the CDC’s v-safe active surveillance system. However, only 1,920,872 participants reported getting the second vaccine dose.

More than 46 million Americans had gotten at least one dose of the vaccine by Feb. 21.

The participants were asked about their “postvaccination experience,” including occurrences of adverse events within seven days after being vaccinated. The report included only local or systemic reactions and did not include severe side effects like anaphylactic shock, which will be addressed in a later study.

Of those who received one dose of the messenger RNA vaccine, 74 percent of Moderna recipients reported injection site reactions of pain, swelling, redness, and itching, as opposed to 65.4 percent of the Pfizer/BioNTech recipients.

Furthermore, 52 percent of those who received the Moderna vaccine said they had a generalized reaction like fatigue, headache, and body pain, compared to 48 percent of recipients who had the Pfizer/BioNTech vaccine.

Both local and systemic reactions occurred more frequently after the second dose for both vaccines: Moderna recipients reported 82 percent and 74 percent, while Pfizer/BioNTech recipients reported 69 percent and 64.2 percent, respectively.