Understanding COVID-19 vaccine side effects, why second dose could feel worse – Mayo Clinic News Network

All vaccines could trigger some diploma of response, and the identical is accurate for COVID-19 vaccines. Post-vaccine signs and symptoms are generally mild and take care of immediately without having the require to use any medication.

Prevalent COVID-19 vaccine aspect effects involve:

  • Redness or soreness at injection web-site.
  • Muscle aches.
  • Fatigue.
  • Headache.
  • Fever or chills.

For some folks, the second dose in a COVID-19 vaccine sequence is producing a more powerful response and extra facet consequences than the preliminary dose. The exact was accurate for the duration of scientific trials.

Observe: Dr. Melanie Swift describes attainable COVID-19 vaccine facet results.


Journalists: Broadcast-excellent seem bites with Dr. Swift are readily available in the downloads at the conclusion of the article. Remember to courtesy: “Melanie Swift, M.D./COVID-19 Vaccine Allocation and Distribution/Mayo Clinic.”

In this Q&A, Dr. Melanie Swift, co-chair of the COVID-19 Vaccine Allocation and Distribution Operate Group at Mayo Clinic, describes why vaccine side outcomes happen and what is recognized about indicators pursuing COVID-19 vaccination:

Why do people expertise side outcomes from COVID-19 vaccines?

When we get vaccinated for COVID-19, we typically expertise some side effects. The motive that we get aspect results is that our immune procedure is revving up and reacting. When you get ill, the similar point happens. Basically, a good deal of the signs or symptoms from health problems that we get, like influenza and COVID-19, are actually not triggered by the direct motion of the virus, but alternatively by our immune program. Our bodies react, and that gives us these normal signs or symptoms like fever, achiness and headache.

Why are some individuals extra probable to expertise aspect results immediately after the second dose of a COVID-19 vaccine?

When you consider two doses of a COVID-19 vaccine, the 1st dose is the initially time for your physique to see the spike protein that the COVID-19 vaccines produce, and your entire body starts to develop an immune response. But that occurs bit by bit. Then when you come again with a second dose, your system is prepared to attack it. Your human body is primed by that initially dose of vaccine. The second vaccine dose goes into your entire body, begins to make that spike protein, and your antibodies jump on it and rev up your immune procedure response. It can be kind of like they have examined for the take a look at. And it can be acing the examination.

How lengthy could symptoms or facet results of COVID-19 vaccination past?

The vaccine aspect results that we’ve witnessed in these substantial phase three trials solve inside of about 72 hours of getting a COVID-19 vaccine. At most, these facet effects can very last up to a week. We really have not observed very long-expression facet consequences from COVID-19 vaccines further than that, and that will make sense when you glance at other vaccines. And we have a whole lot of working experience with distinctive vaccines. Extensive-expression aspect consequences are just basically unheard of in the vaccine entire world.

So with two months of stick to-up data in folks undergoing those people scientific trials, and now even extended stick to-up from the trials and our expertise providing vaccines to the public, we really are not looking at any trend toward any lengthy-term facet consequences.

Read COVID-19 vaccines: Get the points to discover a lot more about the various COVID-19 vaccines and the rewards of becoming vaccinated for COVID-19.


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Details in this publish was correct at the time of its posting. Due to the fluid character of the COVID-19 pandemic, scientific comprehension, along with recommendations and recommendations, could have altered given that the primary publication day

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