COVID Vaccine

COVID-19 Vaccine Safety & Development

Updated August 13, 2021

Vaccine Information
Vaccine Safety

VACCINE INFORMATION

Why should I get the Covid-19 vaccine?

The only safe way to end the pandemic is for the majority of people to get vaccinated.

The Covid-19 pandemic will continue to spread until the majority of the population is immune to the virus, also known as herd immunity. When herd immunity is achieved, those who are immune to a virus are effectively protecting people around them who are not able to achieve immunity.

CDC website: Benefits of Getting a COVID-19 Vaccine

What were the results of the vaccine trials?

Pfizer vaccine trial:

Demonstrated to be 95% effective in protecting against Covid-19 infection
- This is significantly higher than the vaccines developed to treat many other illnesses.
Majority of participants experienced mild to no side effects
- Side effects were typical and lasted a short time (sore arm, fever, headache, body ache, fatigue)

Moderna’s vaccine trial showed similar results.

For more information about each of the vaccines, please visit:

Information About the Pfizer-BioNTech COVID-19 Vaccine

Information About the Moderna COVID-19 Vaccine

Information about the Johnson & Johnson (Janssen) COVID-19 Vaccine

I hear that the efficacy of the Johnson & Johnson vaccine is lower than the efficacy of the Pfizer and Moderna vaccines. Is that true? Should I only get Pfizer or Moderna vaccine?

In clinical trials, the Johnson & Johnson vaccine proved to be effective against COVID-19. We encourage people to get whichever vaccine is offered. It’s most important that you get vaccinated. Vaccine efficacy looks at how well the vaccine prevents any type of illness. However, we ultimately measure the effectiveness of the vaccines by how well they do at preventing severe illness, hospitalizations and death. All three of the approved vaccines have proven to be very effective by that measure.

Was the Johnson & Johnson vaccine developed in the same way as the Pfizer and Moderna vaccines?

The Johnson & Johnson vaccine uses a different mechanism than the Pfizer and Moderna vaccines and requires one dose rather than two. It comes out of decades of research on adenovirus-based vaccines. This type of vaccine uses a modified adenovirus that can enter cells but can’t replicate inside them or cause illness. It proved to be effective in clinical trials and was approved by a panel of physicians, public-health officials and infectious-disease specialists. The same rigorous approval process was used for the Johnson & Johnson, Pfizer and Moderna vaccines.

After a temporary pause (April 13 – 25, 2021), the U.S Centers for Disease control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA) recommended that use of Johnson & Johnson’s (Janssen) COVID-19 vaccine resume in the United States. Bay Area Health Officers, representing the counties of Alameda, Contra Costa, Marin, Napa, San Francisco, Santa Clara, Santa Cruz, and Solano and the City of Berkeley, also support resuming the use of the Johnson & Johnson (Janssen) vaccine.

Reports of adverse events following the use of J&J/Janssen vaccine suggest an increased risk of a rare adverse event called thrombosis with thrombocytopenia syndrome (TTS). Nearly all reports of this serious condition, which involves blood clots with low platelets, have been in adult women younger than 50 years old.
A review of all available data at this time shows that the J&J/Janssen COVID-19 Vaccine’s known and potential benefits outweigh its known and potential risks.
However, women younger than 50 years old should be aware of the rare but increased risk of this adverse event and that there are other COVID-19 vaccine options available for which this risk has not been seen.
CDC and FDA will continue to monitor the safety of all COVID-19 vaccines.
Seek medical care right away if you develop any of these symptoms after receiving the J&J/Janssen COVID-19 Vaccine.
If you have any questions or concerns, call your doctor, nurse, or clinic.

For more information about the CDC & FDA’s recommendation, please see the CDC website.

I heard that the Johnson & Johnson vaccine can cause blood clots. Is John Muir Health using the Johnson & Johnson vaccine?

Reports of adverse events following the use of J&J/Janssen vaccine suggest an increased risk of a rare adverse event called thrombosis with thrombocytopenia syndrome (TTS). Nearly all reports of this serious condition, which involves blood clots with low platelets, have been in adult women younger than 50 years old.
A review of all available data at this time shows that the J&J/Janssen COVID-19 Vaccine’s known and potential benefits outweigh its known and potential risks.
However, women younger than 50 years old should be aware of the rare but increased risk of this adverse event and that there are other COVID-19 vaccine options available for which this risk has not been seen.
CDC and FDA will continue to monitor the safety of all COVID-19 vaccines.
Seek medical care right away if you develop any of these symptoms after receiving the J&J/Janssen COVID-19 Vaccine.
If you have any questions or concerns, call your doctor, nurse, or clinic.

Based on the CDC and FDA recommendation, John Muir Health has resumed using the Johnson & Johnson vaccine in limited situations as we had been doing prior to the pause. The Pfizer vaccine continues to be the primary COVID-19 vaccine used at John Muir Health.

For more information about the CDC & FDA’s recommendation, please see the CDC website.

How will the vaccine be given?

Vaccines will initially be given to people 16 and older. Trials are currently underway for pregnant people and children ages 12-17. Eventually there will be trials for children under 12 and specific immunosuppressed groups.

Pfizer or Moderna vaccine includes two doses, spaced 3-4 weeks apart depending on which vaccine you receive.
Johnson & Johnson vaccine includes one dose.
Vaccine is given by injection into the upper arm, similar to a flu shot.

I already had Covid-19, do I still need to get vaccinated?

Yes. It’s important to get vaccinated even if you have previously had Covid-19.

It’s unknown whether having Covid-19 infection gives you immunity.
People have become re-infected with Covid-19 three months after having it.

All three vaccines available in the U.S. have been proven to be effective in protecting against Covid-19 infection.

CDC Website: Frequently Asked Questions about COVID-19 vaccination

VACCINE SAFETY

Is the Covid-19 vaccine safe?

Yes, the vaccine is safe based on the clinical trial and expert review.

No steps were eliminated or skipped in vaccine development and testing and all usual safety protocols for new vaccines were followed.

CDC Website: Key Things to Know About COVID-19 Vaccines

Should I wait to get the vaccine until other ones are developed?

We encourage you to get vaccinated when it is your turn and you are offered any of the approved vaccines. All three of the approved vaccines have proven to be very effective at preventing severe illness, hospitalizations and death. It’s important to weigh the benefits of getting the vaccine versus the risks of getting COVID-19.

CDC Website: Key Things to Know About COVID-19 Vaccines

If I’m young and healthy, why should I get the vaccine when it’s offered?

We won't be able to stop the pandemic and return to normal life until all of us get vaccinated, including young healthy people. We all have to do our part to stop the chain of infection from one person to another. And while it’s possible you won’t get very sick, you never know how your body might react to the disease. You could also pass it along to your family members and friends who could be more at risk of serious infection. We encourage everyone eligible to get vaccinated.

Is it safe to get the vaccine if I'm actively trying to get pregnant?

The American College of Obstetricians and Gynecologists (ACOG) recommends that all eligible persons, including pregnant and lactating individuals, receive a COVID-19 vaccine or vaccine series. If you find out that you're pregnant after the first dose, it's recommended that you still get the second dose. Read the ACOG's full advisory here and talk to your doctor about what may be best for your situation.

CDC Website: Myths and Facts About COVID-19 Vaccines

Is it safe to get the vaccine if I'm currently pregnant or lactating?

The American College of Obstetricians and Gynecologists (ACOG) recommends that all eligible persons, including pregnant and lactating individuals, receive a COVID-19 vaccine or vaccine series. Read the ACOG's full advisory here and talk to your doctor about what may be best for your situation.

CDC Website: Myths and Facts About COVID-19 Vaccines

Will the vaccine affect my future fertility?

Given the safety profile of the mRNA and adenovirus Covid-19 vaccines, it's not thought or expected that the vaccine would decrease your fertility in any way. Read the ACOG's full advisory here and talk to your doctor about what may be best for your situation.

I have specific medical conditions, should I get vaccinated?

The Centers for Disease Control and Prevention (CDC) advise that mRNA COVID-19 vaccines may be administered to people with underlying medical conditions provided they have not had a severe or immediate allergic reaction to any of the ingredients in the vaccine.

For more information, please see the CDC website.

Is the COVID-19 vaccine suitable for vegans or vegetarians?

None of the currently approved COVID-19 vaccines contain animal products. For a full list of ingredients, see:

Pfizer's COVID-19 Fact Sheet for Recipients and Caregivers

Moderna's COVID-19 Fact Sheet for Recipients and Caregivers

Johnson & Johnson’s COVID-19 Fact Sheet for Recipients and Caregivers