Last updated 10/5/2021

You have questions about the COVID-19 vaccines.


That’s okay. 

It’s normal to be cautious when something new comes along.

Gradient background.jpg

We know there's a lot to consider.

As the county’s two largest healthcare providers, we’ve joined binomo 100% bonus code together to help provide you with solid, unbiased answers to your questions about the COVID-19 vaccines. And, as always, we encourage you to talk with your healthcare provider for more information. 

Press release: County’s Two Largest Private Healthcare Providers to Offer Vaccine Answers

KP_Signature_Stacked_307_rgb_0817_ WHITE

How do the vaccines protect me?

When we get a vaccine, it activates our immune response. This helps our bodies learn to fight off the virus without the danger of an actual infection. If we are exposed to the virus in the future, our immune system remembers how to fight it. All COVID-19 vaccines available in the United States provide significant protection against serious illness and hospitalization due to COVID-19.

The Moderna and Pfizer vaccines use messenger RNA, or mRNA. mRNA vaccines do not contain a live virus — they give our bodies instructions for how to make and fight the harmless spike-shaped proteins, protecting us from COVID-19 infection. Scientists have been studying this vaccine method for decades.

The Johnson & Johnson/Janssen vaccine is a viral vector vaccine and also does not contain a live virus. It uses a harmless adenovirus to create a spike protein that the immune system responds to, creating antibodies to protect against COVID-19.

None of these vaccines can give you COVID-19.

It takes time for your body to build immunity after vaccination, so you won’t have full protection until two weeks after your final dose.

Gradient background_2.jpg
Gradient background_2.jpg

How do we know the vaccines are safe?

The arrival of COVID-19 vaccines marked a big step toward getting back to the people, places, and things we’ve been missing for so long. But you might be hearing different things about the vaccines in the news, on social media, and from family and friends. Here’s fact-based information from medical experts and doctors that explains how we know the vaccines are safe and effective

COVID-19 vaccines were developed safely.

The first COVID-19 vaccines began rolling out less than a year into the pandemic. Vaccine development typically takes much longer, so it’s easy to wonder how we got these vaccines so soon. But the COVID-19 vaccines have been held to the same safety standards as any other vaccine — and rigorous clinical trials have proven that they’re safe and effective. 

Each COVID-19 vaccine went through the same process as any other vaccine — only faster.

Accelerated COVID-19 vaccine development timeline

The public health emergency fast-tracked vaccine development.

We knew early on that COVID-19 was extremely serious and spreading fast. The world needed a safe, effective vaccine as soon as possible. Here’s how we did it:

  • Unprecedented funding: The government spared no expense responding to COVID-19. The time, money, and resources dedicated to making vaccines meant multiple steps could happen at once — instead of one at a time. 

  • Established research: COVID-19 vaccines are new, but the technology behind them is not. Research to develop new vaccines designed to address serious pandemic situations like COVID-19 has been underway for decades. So when the COVID-19 pandemic hit, scientists were able to put those technologies into practice fast, tailor them to protect against the specific virus we’re trying to fight, and develop COVID-19 vaccines more efficiently.

  • Widespread collaboration: Groups of scientists and medical experts around the world recognized the need to work together to create vaccines quickly. Joining forces and sharing resources helped everyone accomplish more in less time.

  • High numbers of research volunteers: The public was well-aware of the dangers of COVID-19. Finding clinical trial volunteers is usually a challenge, but this time researchers had a robust sample size almost immediately.

  • Early results: Because COVID-19 was spreading so fast, it didn’t take long for researchers to prove that the vaccines were preventing infection. While widespread exposure is never a good thing, we had robust data about safety and effectiveness much faster than usual.

  • Front-end manufacturing: Vaccine manufacturers typically don’t start planning for production until clinical trials are complete. With the pandemic surging, they scaled up earlier so vaccines could be produced as soon as they got approved.

Gradient background_2.jpg

Will I have side effects from the vaccines?

COVID-19 vaccine side effects are usually minor, if you have any at all. Like most vaccines, the ones for COVID-19 can produce minor side effects that go away in a day or two. This is a normal sign that the body is building protection.

Side effects may include:

  • Pain at the injection site

  • Fatigue

  • Headache

  • Muscle pain

  • Chills

  • Joint pain

  • Fever


Millions of people have safely received a COVID-19 vaccine.

It’s important to remember that all vaccines carry risks for side effects. These risks must be balanced with the benefits. COVID-19 is a serious illness — and anyone can develop life-threatening complications if they get it. Fortunately, scientists and health experts have confirmed that the benefits of the COVID-19 vaccines outweigh any risks for possible side effects.

Long-term side effects are unlikely.

Serious side effects that could cause a long-term health problem are extremely unlikely following any vaccination, including COVID-19 vaccination. Vaccine monitoring has historically shown that side effects generally happen within six weeks of receiving a vaccine. All COVID-19 vaccines have been studied for at least two months (eight weeks) after the final dose. Millions of people have received COVID-19 vaccines and no long-term side effects have been detected.

Gradient background.jpg
Gradient background_3.jpg

What are the long-term effects of COVID-19?

Some people experience post-COVID conditions (also known as “long COVID” or “chronic COVID”) which may last for months after getting COVID-19.

Even people who did not have COVID-19 symptoms when they were infected can have post-COVID conditions. People most commonly report experiencing different combinations of the following symptoms:

  • Difficulty breathing or shortness of breath

  • Tiredness or fatigue

  • Symptoms that get worse after physical or mental activities

  • Difficulty thinking or concentrating (sometimes referred to as “brain fog”)

  • Cough

  • Chest or stomach pain

  • Headache

  • Fast-beating or pounding heart (also known as heart palpitations)

  • Joint or muscle pain

  • Pins-and-needles feeling

  • Diarrhea

  • Sleep problems

  • Fever

  • Dizziness on standing (lightheadedness)

  • Rash

  • Mood changes

  • Change in smell or taste

  • Changes in menstrual period cycles

Although COVID-19 is seen as a disease that primarily affects the lungs, it can damage many other organs as well. This organ damage may increase the risk of long-term health problems. Organs that may be affected by COVID-19 include:

  • Heart: Imaging tests taken months after recovery from COVID-19 have shown lasting damage to the heart muscle, even in people who experienced only mild COVID-19 symptoms. This may increase the risk of heart failure or other heart complications in the future.

  • Lungs: The type of pneumonia often associated with COVID-19 can cause long-standing damage to the tiny air sacs (alveoli) in the lungs. The resulting scar tissue can lead to long-term breathing problems.

  • Brain: Even in young people, COVID-19 can cause strokes, seizures and Guillain-Barre syndrome — a condition that causes temporary paralysis. COVID-19 may also increase the risk of developing Parkinson's disease and Alzheimer's disease.

Health experts around the world are working to learn more about short- and long-term health effects associated with COVID-19, who gets them, and why. The best way to prevent post-COVID conditions is to get a COVID-19 vaccine.

Gradient background_2.jpg

Why do some vaccinated people still get COVID-19?

A small percentage of people fully vaccinated against COVID-19 will develop COVID-19 illness (called “vaccine breakthrough cases”) – but this doesn’t mean that the vaccines don’t work.

The vaccines are extremely effective at preventing severe illness, hospitalization and death from COVID-19. Large-scale clinical studies also found that COVID-19 vaccination prevented the vast majority of people from getting COVID-19. However, no vaccine is 100% effective, and some people that get a COVID-19 vaccine may still contract COVID-19.

New, more contagious variants of the virus that cause COVID-19 illness are spreading.

Some variants cause illness in some people after they are fully vaccinated. The Delta variant, for example, is nearly twice as contagious as previous variants of the virus. A more contagious virus means more people can get infected, even if they are vaccinated.

If you get COVID-19 after vaccination, your symptoms typically are far less severe.

In those who are vaccinated and get sick, there is evidence that the vaccine makes illness less severe.

Fully vaccinated people are much less likely to be hospitalized or die than people with similar risk factors who are not vaccinated.


I take good care of my health. Can my body build natural protection without a vaccine?

Even if you are in good health, COVID-19 can have serious, life-threatening complications, and there is no way to know how COVID-19 will affect you. You could also spread COVID-19 to your family, friends, and others around you.

The good news is the vaccines are extremely effective in preventing severe illness and death. The risk of severe illness and death from COVID-19 far outweighs any benefits of natural immunity. COVID-19 vaccination will help protect you by creating an immune system response without having to experience sickness.

Gradient background_2.jpg

Did the clinical trials include people like me?

Researchers made sure that the trials included adults of diverse backgrounds, races, ethnicities, and geographic areas. They collaborated with faith leaders, community organizations, and health clinics to reach volunteers from many different walks of life across the United States.

Health experts and doctors want to make sure the vaccines work safely and effectively for as many people as possible. People may respond differently to vaccines based on factors like age, gender, and health conditions — so it is important to have a diverse group of participants in clinical trials.

Gradient background_2.jpg

Do vaccines affect fertility?

There is no evidence that any vaccines, including COVID-19 vaccines, cause fertility problems.

If you are trying to become pregnant now or want to get pregnant in the future, you can still get a COVID-19 vaccine. While fertility was not specifically studied in the clinical trials of the vaccine, no loss of fertility has been reported among trial participants or among the millions who have received any of the authorized vaccines.

Like with all vaccines, health experts are studying COVID-19 vaccines carefully for side effects and will report findings as they become available.

Gradient background_3.jpg

What if I’m pregnant or considering becoming pregnant?

We recommend that people who are pregnant or considering becoming pregnant get a COVID-19 vaccine. Clinical trials are underway to look at the safety and how well the COVID-19 vaccines work in pregnant people. To date, thousands of pregnant people have safely received the COVID-19 vaccine. Please talk with your health care provider if you have any additional concerns.

There are several benefits of vaccination for people who are pregnant or considering becoming pregnant: 

  • Being pregnant increases the risk of getting COVID-19.

  • Being pregnant may also increase the risk of severe COVID-19 infection, especially among Latinx and Black people.

  • Pregnant people with COVID-19 are at increased risk of maternal and fetal complications such as preterm labor.

  • Getting vaccinated during pregnancy can protect your baby as well as you.

Gradient background_2.jpg

Even highly effective vaccines, like the COVID-19 vaccines, can become less effective over time. A booster – additional dose –provides the body with an extra boost of protection.  

At this time, additional doses are only recommended for a portion of high-risk, fully-vaccinated people.  If you think you are eligible, contact your healthcare provider or local pharmacy for more information. Eligible populations include:

If you received the Pfizer vaccine:

Booster shots are available to the following people six months after their second dose of the Pfizer vaccine:

If you have received the Pfizer vaccine and you’re not sure if you qualify, talk to your health care provider, or ask yourself:

  • Do you have an underlying condition that puts you at serious risk of COVID-19 complications?

  • Do you work in a setting, such as health care, that puts you at greater risk for exposure to COVID-19?

  • Do you live in a congregate setting (live with many other people) that puts you at greater risk for exposure to COVID-19?

  • Do you live with someone who is at high risk for serious COVID-19 disease?


People with qualifying immunocompromised conditions may also get a third dose of the Pfizer vaccine at least 28 days after their second dose.


If you received the Moderna-vaccine:

Third doses of the Moderna vaccine are available to people with immunocompromised conditions 28 days after their second dose. The FDA is meeting in mid-October to discuss a booster shot for people who received the Moderna vaccine.

If you received the Johnson & Johnson vaccine:

Booster shots are not available yet. The FDA is meeting in mid-October to discuss a booster shot for people who received the Johnson & Johnson vaccine.

Gradient background_3.jpg

There is no cost to you to get a vaccine.

Vaccination providers may charge an administration fee - usually billed to your insurance - but you do not need to have insurance to get a vaccine.


 Ask the expert.

Have a question about COVID-19 vaccines? Send it to our team of experts for an answer (please allow three days for a response).

Please note that this is not a forum for medical advice or diagnosis. Please contact your healthcare provider if you have specific questions related to your care.


Find a vaccine near you.

COVID-19 vaccines are free and available at a variety of locations in Contra Costa County. All people ages 12 and older can get a vaccine.

Retail Locations (Costco, Safeway, Walmart, etc.)

All Californians can schedule an appointment online.


County-run sites

Anyone can get vaccinated at a county-run site. No appointment is required but can be made online or by calling 1-833-829-2626. People can choose which vaccine they get at most sites.


Kaiser Permanente

Members and non-members can schedule an appointment online or call 1-866-454-8855.


John Muir Health

Anyone can schedule an appointment via John Muir Health’s MyChart. Current patients can schedule an appointment via MyChart here. Patients new to John Muir Health can sign up for MyChart here.

State-run sites

All Californians can schedule an appointment online or call 1-833-422-4255.​