Overall side effects were more prevalent after Moderna's third dose: Half of Moderna booster recipients reported muscle aches and headaches, and around 60% reported fatigue. The following table shows how booster shots affected people who got three doses of Moderna, three doses of Pfizer, or two doses of Johnson & Johnson's vaccine, according to CDC data.Īside from local reactions at the injection site, fatigue was most common among people who received a Pfizer or Moderna booster. However, the study included far more data on mRNA boosters - 12,000 people, compared to 48 who received two J&J doses. Other side effects such as fatigue, muscle aches, or headaches were less common, affecting 74% after their third dose, compared with 77% after dose two.Ī second dose of J&J's vaccine yielded the fewest side effects of all: Only 10% of J&J booster recipients said their side effects prevented them from performing normal daily activities - usually on the day after their booster shot - while the rest said they were able to go about their day as normal.īy comparison, 28% of Pfizer or Moderna booster recipients said the shots hindered their daily routine. It's one of the most comprehensive looks at how people are responding to boosters to date.īroadly, the CDC found that people who'd received three doses of either Pfizer or Moderna saw more local reactions - pain, itchiness, redness, or swelling at the injection site - after dose three compared to dose two. In September, the Centers for Disease Control and Prevention (CDC) gave the first comparison between booster shots of all three vaccines available in the US: Pfizer and Moderna (both mRNA shots), and Johnson & Johnson (an adenovirus vaccine). Second and third doses of COVID-19 vaccines generally produce similar side effects but there are some slight differences. See more stories on Insider's business page.

Side effects from COVID-19 booster shots generally resemble those after a second dose.įatigue, headaches, and muscle aches are common after both.īut two shots of J&J's vaccine yield fewer side effects than three shots of Pfizer or Moderna. Vichan Poti/Pacific Press/LightRocket via Getty Images A Thai healthcare worker receives a booster dose of Pfizer's vaccine in Bangkok on August 9, 2021.

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