COVID-19 Vaccine Side Effects; Why Second Dose Could Feel Worse

Rochester, Minnesota — Some people are reporting the second dose in a COVID-19 vaccine series is causing a stronger reaction and more side effects than the initial dose.

Mayo Clinic experts tell us the same was true during clinical trials.

Dr. Melanie Swift, co-chair of the COVID-19 Vaccine Allocation and Distribution Work Group at Mayo Clinic, explains why vaccine side effects happen and what is known about symptoms following COVID-19 vaccination.

(as said) “When we get vaccinated for COVID-19, we often experience some side effects. The reason that we get side effects is that our immune system is revving up and reacting. When you get sick, the same thing happens. Actually, a lot of the symptoms from illnesses that we get, like influenza and COVID-19, are actually not caused by the direct action of the virus, but rather by our immune system. Our bodies react, and that gives us these general symptoms like fever, achiness and headache.”

She tells us why some are people more likely to experience side effects after the second dose of a COVID-19 vaccine.

(as said) “When you take two doses of a COVID-19 vaccine, the first dose is the first time for your body to see the spike protein that the COVID-19 vaccines produce, and your body begins to develop an immune response. But that happens slowly. Then when you come back with a second dose, your body is ready to attack it. Your body is primed by that first dose of vaccine. The second vaccine dose goes into your body, starts to make that spike protein, and your antibodies jump on it and rev up your immune system response. It’s kind of like they’ve studied for the test. And it’s acing the test.”

Swift says the symptoms or side effects shouldn’t last too long.

(as said) “The vaccine side effects that we’ve seen in these large phase three trials resolve within about 72 hours of taking a COVID-19 vaccine. At most, those side effects can last up to a week. We really have not seen long-term side effects from COVID-19 vaccines beyond that, and that makes sense when you look at other vaccines. And we have a lot of experience with different vaccines. Long-term side effects are just basically unheard of in the vaccine world.”

So with two months of follow-up data in people undergoing those clinical trials, and now even longer follow-up from the trials and their experience giving vaccines to the public, she says they really are not seeing any trend toward any long-term side effects.

Information from the top clinics in the world like the Mayo Clinic can be heard on the Med Clinic Radio Program, Sunday evenings from 5 to 6 p.m. on KIWA 1550 AM and 100.7 FM.

Video, audio, and story courtesy Melanie Swift, M.D./COVID-19 Vaccine Allocation and Distribution/Mayo Clinic.

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