COVID-19 Vaccine Q&A Part 2 - Harry S. Truman Memorial Veterans’ Hospital
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Harry S. Truman Memorial Veterans’ Hospital

 

COVID-19 Vaccine Q&A Part 2

Portrait of senior man with protective face mask getting vaccine. Mature man against brown background after receiving corona virus vaccination.

Don't be confused about the COVID-19 vaccine. We have the answers for you.

Monday, August 30, 2021

COVID-19 Vaccine Q&A

How do vaccines work?

  • Part of a germ is weakened or killed to the point that it cannot make you sick. This germ is then put into a vaccine. After a vaccine is given, the body’s immune system creates antibodies, which are protective proteins that help remove the disease from the body. This response creates immunity to the disease without having to be exposed to the disease.
  • mRNA Vaccines
    • mRNA vaccines have material from the virus that have instructions to make a protein found on the COVID-19 virus that cannot make you sick (called a spike protein). Once the cells receive the instructions, they make copies of the protein, then destroy the genetic material from the vaccine. mRNA from the vaccines do not enter the part of the cell where our DNA is made and kept and, therefore, cannot interact with our DNA. The immune system responds with immune cells to fight the virus. If a person is infected in the future, the immune system will respond with these cells that remember how to fight the virus.
  • Viral Vector Vaccines
    • Viral vector vaccines are a modified, harmless virus that is different than the virus that causes COVID-19. In this modified virus, there is material from the COVID-19 virus that cannot make you sick. This piece of the COVID-19 virus is called a viral vector. Once the viral vector is inside the body, it provides instructions to make a harmless protein found on the COVID-19 virus (called a spike protein). Cells in the body make copies of this protein and the immune system responds with immune cells to fight the virus. If a person is infected in the future, the immune system will respond with these cells that remember how to fight the virus.

What COVID vaccines are available?

  • Currently three different vaccines available:
    • Pfizer-BioNTech
      • mRNA vaccine
      • Two doses given 21 days apart (3 weeks)
      • Fully vaccinated two weeks after second dose
      • For people 12 years and older
    • Moderna
      • mRNA vaccine
      • Two doses given 28 days apart (four weeks)
      • Fully vaccinated two weeks after second dose
      • For people 18 years and older
    • Johnson & Johnson/Janssen
      • Viral vector vaccine
      • One dose
      • Fully vaccinated two weeks after dose
      • For people 18 years and older
    • Although both are mRNA vaccines, the Moderna and Pfizer vaccines are not interchangeable. Your second dose should match the product used for your first dose.

Are they safe?

  • People may experience side effects from the vaccines. The most common side effects are pain, redness and swelling in the arm, general tiredness, headache, muscle pain, chills, fever, and nausea. The side effects are a result of your immune system building protection and may be more common after the second dose of a two-dose vaccine. The side effects should go away in a few days.
  • Two rare but serious side effects have been noticed in relation to the COVID vaccines. These risks are clots and myocarditis (inflammation of the heart) or pericarditis (inflammation of the outer lining of the heart).
    • There may be a risk of clots after receiving the Johnson & Johnson vaccine. This risk is very low and occurs at a rate of about seven per one million vaccinated women between the ages of 18 and 49. Women who are older than 50 and men of all ages have an even lower risk.
    • The immune system can cause inflammation that results in myocarditis and pericarditis. More than 177 million people in the U.S. have received at least one dose of a COVID-19 vaccine. Since April, there have been just over one thousand reports of myocarditis or pericarditis. Given the hundreds of millions of vaccines received, these reports are rare. Myocarditis or pericarditis are usually seen in male adolescents and young adults between the ages of 16 and 30 and occur within several days after getting the vaccine. Myocarditis and pericarditis can be treated with medications and mild cases may go away without treatment.

Are they effective?

  • Although no vaccine can prevent disease 100 percent of the time, the current vaccines provide effective prevention of COVID-19.
    • Pfizer-BioNTech vaccine was shown to be 95 percent effective in clinical trials. Current evidence shows similar effectiveness in real-world conditions.
    • Moderna vaccine was shown to be 94.1 percent effective, Johnson & Johnson/Janssen was shown to be 66.3 percent effective
    • While vaccines prevent most people from getting sick, some people who have been vaccinated will still get sick. These are called vaccine breakthrough cases. Evidence is showing that vaccinated people who have breakthrough cases may have less severe illness and are less likely to be hospitalized or die than those who are not vaccinated.

Are the available vaccines effective against variants?

  • A variant is a virus that has changed, creating a small difference in that particular virus. The differences in a variant may affect how it spreads or how sick people will get. Currently, there are four variants: alpha, beta, gamma, and delta. So far, studies show that the vaccines are effective against the current variants.

Do I need to get a vaccine if I’ve already had COVID-19?

  • Even if you have recovered from COVID-19, you should still receive a vaccine. Experts do not know how long immunity lasts after recovering from COVID-19 and receiving a vaccine can provide a strong boost in protection.

Which vaccine should I get?

  • The CDC does not recommend one vaccine over the other.

For more information please visit:

Different COVID-19 Vaccines | CDC

Frequently Asked Questions about COVID-19 Vaccination | CDC

Heart Inflammation | NHLBI, NIH

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