Answers to your questions about the COVID-19 vaccine

image of a vaccine about to be injected into someone's arm
Our experts answer common questions about the new coronavirus vaccines. (Image: Adobe Stock; Illustrations: Fawn Gracey, Boston Children's)

As the new COVID-19 vaccines roll out across the country, many people have questions about them. Are they safe? Who will get vaccinated when? And does this mean life will get back to “normal” sometime in 2021?

To help answer the most common questions about the new vaccines, we reached out to Drs. Melanie Dubois and Kristin Moffitt, infectious disease specialists at Boston Children’s Hospital.

What vaccines are approved for COVID-19?

At this time, the U.S. Food and Drug Administration (FDA) has approved two COVID-19 vaccines: one from Pfizer (approved for those ages 16 and older) and one from Moderna (approved for ages 18 and older). Both are mRNA vaccines. These vaccines use genetic material called mRNA to encode the spike protein to allow our immune system to make antibodies to the SARS-CoV-2 coronavirus that causes COVID-19. These antibodies block the virus from entering healthy cells.

There are many other vaccines in development for COVID-19, with different mechanisms to protect against the virus (such as viral vector vaccines and protein-based vaccines).

Why are only certain people getting the vaccine now?

The vaccines are being distributed in phases, based on who is at highest risk of being exposed to the virus or having severe COVID-19 disease. This is decided by a group of public health experts and medical professionals at a national and local level. 

Here in Massachusetts we’re currently in phase 1. This means we’re focusing on getting the vaccine to health care workers, first responders, and residents of long-term care facilities. Phase 2, estimated to start in February, will include essential workers like teachers and food service and grocery store workers, as well as people over age 65 and those with health conditions that put them at risk for more severe disease. Phase 3, which is slated to begin in April, will include the general public.

Is the vaccine safe for kids?

While it’s encouraging that these two vaccines are generally safe in adults, we still have limited data on their safety in children under age 16. We will know more once we get results from the clinical trials currently being performed in children ages 12 and older. Eventually, there will also be clinical trials in children younger than 12 to ensure that we have safety data in this population.

When will they start giving the COVID-19 vaccine to kids?

While the guidelines are similar nationally, the specific guidelines may vary from state to state. In Massachusetts, teens ages 16 and older will be eligible to receive the Pfizer vaccine in phase 2 if they are an essential worker (such as in a restaurant or grocery store) or have a condition that puts them at higher risk for severe illness from COVID-19, such as cancer or chronic kidney disease. All other teens ages 16 and older will be eligible to receive the vaccine in phase 3. Children under age 16 will need to wait until further data is available from clinical trials in children. While we don’t yet know when that will be, we are hopeful for fall of 2021.

After our high-risk and older family members get vaccinated, will we be able to visit them again? 

For now, it’s important that everyone continue to wear masks and practice social-distancing measures even after receiving the vaccine. While the COVID-19 vaccine prevents symptomatic COVID-19 infection, it’s unclear if it prevents spreading of the virus from person to person.  We are hopeful that the vaccine will also reduce spreading of the virus this way, particularly as more people receive the vaccine, but this is still being studied.

Also, it’s important to remember that you are not fully protected after the first dose. Both the Pfizer and Moderna vaccines require two doses to be considered fully vaccinated.

So although it’s encouraging to know that those at risk in your family will have more protection against COVID-19 after receiving the vaccine, it’s best to continue social distancing measures until we know more. 

How long does vaccine protection from COVID-19 last?

We’re not sure yet. We will need to continue to follow patients who receive the vaccine to know how long immunity lasts. But from the data we have so far, it seems that it lasts at least several months.

Does getting the vaccine hurt?

People who receive the vaccine may have mild symptoms, including a sore arm, mild fever, fatigue, and a headache, but these usually go away in a day or two. These symptoms also show that your immune system is responding to the vaccine. Some people have more serious side effects, such as allergic reactions, but these are rare.

Can the vaccine give me COVID-19?

No. The goal of the vaccine is to prevent symptomatic COVID-19 and provide you with protection against the virus. None of the authorized vaccines contain the actual virus, so while the vaccine may lead to mild symptoms that last for a couple days, it will not make you sick with COVID-19.

Should I get the vaccines if I’ve already had COVID-19?

Yes. Even if you’ve already had a test showing that you’ve had COVID-19, you should still get a vaccine if you are eligible. Although your body makes antibodies after being infected with COVID-19, experts don’t know how long these antibodies will protect you from the virus.

How many people need to get vaccinated before we can start doing normal things again?

There are two ways to get immunity to the virus: becoming infected with the SARS-CoV-2 coronavirus or receiving the COVID-19 vaccine. When a large part of the population is immune to a disease, it’s called “herd immunity.” We don’t know exactly how many people will be needed to achieve herd immunity for COVID-19, but most experts think it’s at least 70 percent of the population. One thing we do know for certain: The more people who are vaccinated, the more protected we will be against the virus and be able to return to work, school, and social gatherings in a safe way.

Learn more about Boston Children’s response to COVID-19.

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