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A recent survey of U.S. adults revealed that most of the people who are hesitant to get a Covid-19 vaccine have concerns about the science of vaccines. These concerns include the vaccines' side effects, pace of development, and effectiveness. Similarly, a recent U.S. study found that a lack of certainty and an accurate understanding of how vaccines work are in part why some parents have low levels of confidence in childhood vaccination. Thus, it is crucial to provide correct, easy-to-understand information about vaccines. This outreach is particularly important among populations with higher vaccination hesitancy. These include people under 30 and Black Americans, who are more likely to hold "wait and see" attitudes; white evangelical Americans; some Latinx and Native Americans; and people who live in rural areas or places with lower levels of income and education. 


Harness trusted messengers.

Think about whom your employees trust. They may trust a public health institution like the CDC or community leaders or senior peers. Trusted sources change depending on attitudes toward the government and authorities. Medical professionals may be especially trusted when it comes to health information. If possible, recruit these trusted sources to help deliver your message.

Highlight diversity in vaccine testing.

The U.S.-approved vaccines were found to be safe and effective across race, ethnicity, national origin, and disabilities. In the clinical trials for vaccines approved in the U.S. (Pfizer-BioNTech, Moderna, and Johnson & Johnson / Janssen), only three hospitalizations from Covid-19 were reported among those vaccinated. Importantly, these vaccine clinical trials enrolled some of the largest proportions of people of color to date. People who are Black, Latinx/Hispanic, Asian, Pacific Islander, Native American, and other/mixed race accounted for between 14% and 38% of participants in the U.S. clinical trials, including those for children aged 5 years or older. People with at least one high-risk condition (e.g., severe obesity, diabetes, HIV infection) were also represented at significant levels (between 22% and 46% of participants). Highlighting the diversity of people involved in clinical testing could help calm fears that “people like me” might react badly to the vaccine. 

Answering Scientific Questions About the Vaccines

Understand the unique concerns of your employees and their need for a comfortable conversation on the safety of the vaccines.


Tools and Materials


A list of relevant toolkits, guides and media we found on the web. 

How do the Covid-19 vaccines work?

The vaccines provide instructions for your body to make copies of a harmless component of the virus. These harmless copies mimic a natural infection without the danger of an actual infection. Thus, your immune system is given the opportunity to have a practice drill protecting you against the virus. If you get exposed to the real virus later, your immune system will remember how to fight it!  

Can I get Covid-19 from a Covid-19 vaccine?

No. To get Covid-19, you need to be infected with the live virus. None of the currently approved Covid-19 vaccines in the U.S. (Pfizer-BioNTech, Moderna, or Johnson & Johnson / Janssen) contain the live virus.

Learn more about how the Covid-19 vaccines work


Will a Covid-19 vaccine make me sick?

You will not get infected with Covid-19 from a Covid-19 vaccine. You may experience side effects, which are normal and typically only last a few days. Common side effects include pain and swelling at the site of vaccination, mild fever and muscle soreness. These side effects are a result of your body’s natural defense response and actually mean that the vaccine is working. Your body is training itself to protect you against the virus! 

Will a Covid-19 vaccine alter my DNA?

No. The materials provided by the vaccines do not interact with your DNA at all. Vaccines contain instructions that build up protection without involving your DNA. This is true for the Johnson & Johnson / Janssen vaccine (which uses a disabled, harmless non-covid virus messenger) and the Pfizer-BioNTech and Moderna vaccines (which use mRNA). When the instructions are in the form of mRNA , the mRNA is immediately broken down after use.

Acknowledge their concerns.

Vaccination can be an uncomfortable topic. People may be afraid of the side effects, scared of needles, or worried that they might “catch” Covid-19 from the vaccine itself (which is not possible). People may also be reluctant to share their concerns because they anticipate being judged or embarrassed. Start by listening. Refrain from overloading them with all the scientific facts you have. You might share a few pieces of information that made a difference in your own decision to get vaccinated, but try to stay focused on information, not opinion.


Emphasize harmlessness.

Explain that the vaccines do not contain the live virus. They work by providing instructions to make copies of a harmless part of the virus.


You may hear questions about the viral vector used in the Johnson & Johnson / Janssen vaccine. Explain that the viral vector is a harmless version of a completely different virus from the virus that causes Covid-19. And viral vectors are not new! Scientists have studied them since the 1970s for many applications including cancer treatment. Viral vectors were also used in some vaccines during the recent Ebola outbreaks.

Manage your reactions.

We all have different levels of science and health knowledge and also have access to different sources of information. You may get questions that catch you by surprise or seem confusing. Be mentally prepared for such surprises. In the moment, try to maintain a neutral reaction and stay focused on understanding rather than questioning.

Consider unique cultural and linguistic needs.

Consider the cultural and linguistic backgrounds of your employees. Consult or partner with community-specific leaders and organizations to better understand why employees may be hesitant to get vaccinated. Remember, hesitancy may come from barriers to access and day-to-day mistreatment in the healthcare system. In presenting information, consider whether another language may be more accessible for some people. If so, engage a partner who speaks that language or provide resources with clear visuals and/or texts in that language (e.g., multilingual infographics from the CDC).


How long will the protection from a Covid-19 vaccine last? Do I need a booster?

Recent studies show that all vaccines remain highly effective against hospitalization at 25 weeks post-vaccination. There is more decline over time in vaccine effectiveness against infection and milder symptoms, likely due to decreasing protection over time combined with increased infectiousness of the Delta variant. Thus, CDC recommends certain groups to get booster shots, which have been shown to increase the immune response. The booster can be any of the three authorized vaccines. Check the CDC webpage on COVID-19 Vaccine Booster Shots to see if you should get a booster now.

The vaccines were developed so quickly. Are we sure they are safe?

Scientists were able to develop Covid-19 vaccines quickly because of a huge body of previous research. Scientists have studied related viruses for years and mRNA and viral vector vaccine technology for decades. The development was also sped up by faster ways to manufacture vaccines, enormous funding that allowed firms to run many clinical trials in parallel, and regulators prioritizing vaccines. Ongoing safety monitoring efforts have also been expanded.


All Covid-19 vaccines authorized in the U.S. (Pfizer-BioNTech, Moderna, and Johnson & Johnson / Janssen) met the FDA standard of being at least 50% more effective than not getting a vaccine in preventing symptomatic Covid-19. 

Which Covid-19 vaccine is the best?

Without clinical trials that directly compare these vaccines, we do not have the evidence to claim that one vaccine is more effective than another. We do know that all of the currently approved Covid-19 vaccines in the U.S. (Pfizer-BioNTech, Moderna, and Johnson & Johnson / Janssen) are safe with similar side effects. They also meet the FDA standard of being at least 50% more effective than not getting a vaccine (placebo) in preventing symptomatic Covid-19. Moreover, all vaccines were highly effective in preventing hospitalization from Covid-19. Please consult your local medical clinics to determine which vaccine is available. Ask your doctor if you have any questions regarding vaccination and your medical history. 

Should I be concerned about the Johnson & Johnson / Janssen Covid-19 vaccine?

The CDC has recommended use of the Johnson & Johnson / Janssen Covid-19 vaccine to resume after a temporary pause. According to research on the effectiveness of the vaccine, for every 1 million doses given to women younger than 50 years old, 650 hospitalizations and 12 deaths due to Covid-19 can be prevented. Of these 1 million doses, only seven cases of blood clots with low platelets (thrombosis with thrombocytopenia syndrome, or TTS) may develop. Thus, blood clots with low platelets are a rare risk. Nonetheless, it is important to be aware of this risk, particularly if you are a woman younger than 50 years old (the demographic making up the majority of reported cases). Consult your doctor or clinic if you have any questions about vaccination. 

If you have gotten the J&J / Janssen vaccine already, continue to monitor symptoms up to three weeks after vaccination and seek medical care immediately if you experience any of the following: severe or persistent headaches, blurred vision, shortness of breath, chest pain, leg swelling, persistent abdominal pain, and easy bruising or tiny blood spots under the skin beyond the injection site. For the most up-to-date information, visit this CDC webpage.

Avoid repeating misinformation.

Try not to repeat misinformation - even if you explain why it’s not true right after, this can still make it stick in people’s heads. This is especially true for highly emotional ideas. Try saying things like ‘you may hear concerns about safety’ rather than ‘some people claim the vaccine will give you coronavirus’.


Keep Learning

What is the Delta variant? Will it infect vaccinated people?

A variant of the virus has one or more unique genetic mutations from other variants. The Delta variant is more than twice as contagious as previous variants and has become the most common variant in the U.S. It also has the potential to make people more severely ill. Vaccines are still highly effective against the Delta variant in terms of preventing infection and severe illness even if a breakthrough infection occurs. 

Do people who have gotten Covid-19 need vaccination?

Available data suggest that full vaccination offers better protection than natural immunity from having had Covid-19. In general, vaccines induce strong immunity in everyone whereas the level of natural immunity varies between people. One study showed that unvaccinated people who had Covid-19 were more than twice as likely to get Covid-19 again compared to fully vaccinated people. 

Will it be safe to vaccinate my children?

The Pfizer-BioNTech Covid-19 vaccine has been authorized by the FDA and recommended by the CDC for children over the age of 5. The vaccine dose and needle size are appropriately reduced for children aged 5-11 years. The vaccine was shown to be over 90% effective in preventing Covid-19 in clinical trials in people 16 years and older, in teens 12-15 years old, and in children 5-11 years old. Side effects tend to be mild like those seen in adults, with a sore arm being the most common side effect.

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