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covid19 vaccine what to expect - doctor injecting needle into woman's arm
covid19 vaccine what to expect - doctor injecting needle into woman's arm
covid19 vaccine what to expect - doctor injecting needle into woman's arm

Getting the COVID-19 Vaccine: What to Expect

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As the COVID-19 vaccines are authorized and become more widely available, many are wondering what to expect when they get vaccinated. Lisa Maragakis, M.D., M.P.H., senior director of infection prevention, and Gabor Kelen, M.D., director of Johns Hopkins Office of Critical Event Preparedness and Response, talk about what’s involved in getting vaccinated for COVID-19 and answer some of your most common questions.

When can I get the coronavirus vaccine?

Now that the Food and Drug Administration has issued emergency use authorizations for COVID-19 vaccines, initial quantities of the vaccine are being distributed across the United States.

Because it will take a while to make and distribute enough of the vaccine for everyone who wishes to be vaccinated against COVID-19, the U.S. Centers for Disease Control and Prevention (CDC) is recommending groups of people who should get priority. The CDC has been working closely with state health departments and partners to develop these recommendations.

If you are a Johns Hopkins Medicine patient, visit our COVID-19 Vaccine Information and Updates page for current information on getting vaccinated. Your state’s health department website can also provide updates on vaccine distribution in your area.

How many shots are in the COVID-19 vaccine?

The first two coronavirus vaccines (Pfizer’s and Moderna’s) require two doses given several weeks apart (Pfizer’s second shot is given three weeks after the first, and Moderna’s is four weeks after the first).

When will I be protected from catching COVID-19?

The vaccine doesn’t work right away. You are not considered appropriately protected after the first shot. It takes up to two weeks after the second shot for your immune system to fully respond to a vaccine and provide protection against an infectious disease.

Do I still have to wear a mask if I get the COVID-19 vaccine?

For now, yes. Even with a vaccine that is 95% effective, about 1 in 20 people who get the vaccine will not become immune. It is not yet clear if you can carry the SARS-CoV-2 coronavirus and pass it along to others after getting the vaccine.

Until enough people become immune (either from being vaccinated or by getting and recovering from COVID-19), everyone should follow precautions such as physical distancing, hand-washing and mask-wearing. Vaccinating as many people as possible is a very big job, and it will take months before we can consider cutting back on these basic safety practices.

What are the coronavirus vaccine side effects?

You may have pain in the arm where you got the shot, and you might run a fever and experience body aches, headaches and tiredness for a day or two. The chance of having noticeable side effects is higher after the second shot.

Experiencing side effects does not mean that you have COVID-19, but signals that your immune system is responding to the vaccine. These side effects are considerably less severe or lasting than COVID-19, but if they persist, call your doctor and ask about taking over-the-counter pain and fever reducers to help you feel better.

covid19 vaccine coronavirus - doctor preparing to inject syringe into female patient

Is the COVID-19 Vaccine Safe?

Now that there is an authorized COVID-19 vaccine, our experts answer some frequently asked questions about vaccine safety.

Is it OK to get the COVID-19 vaccine if I have allergies?

While there have been reports of severe allergic-type reactions in a very small number of patients, the CDC says that people with allergies to certain foods, drugs, insects, latex and other common allergens can still get the COVID-19 vaccine.

If you have had a severe allergic reaction (anaphylaxis) to injectables or other vaccines, be sure to discuss the COVID-19 vaccination with your doctor, who can evaluate you and assess your risk. The vaccine provider should observe you for 30 minutes rather than the routine 15 minutes after vaccination, and if you have an allergic reaction to the first shot, you may not receive the second.

The CDC says that at this time, anyone who has a severe allergy (such as anaphylaxis) to any of the Pfizer/BioNTech vaccine ingredients should not get this vaccine.

How long am I immune after getting the coronavirus vaccine?

This is a question researchers are eager to answer. People who are infected with the coronavirus show a decline in antibodies within a few months, but their immunity may last significantly longer than that. (A few people appear to have caught COVID-19 twice, but this is unusual). Data from the vaccine trials indicate strong immunity at least months after vaccination, indicating possible long-term immunity.

The good news is that the SARS-CoV-2 coronavirus does not appear to change (mutate) very much, especially compared with other coronaviruses and other viruses that affect the respiratory system, such as influenza. (The flu virus changes frequently, which is why you need a flu shot every year.) Still, the SARS-CoV-2 coronavirus could change in the future, and a substantial mutation might have an impact on the effectiveness of the vaccines.

Demographics of the COVID-19 Vaccine Trials

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

People who have gotten sick with COVID-19 may still benefit from getting vaccinated. Due to the severe health risks associated with COVID-19 and the fact that re-infection with COVID-19 is possible, people may be advised to get a COVID-19 vaccine even if they have been sick with COVID-19 before.

There is not enough information currently available to say if or for how long people are protected from getting COVID-19 after they have had it (natural immunity). Early evidence suggests natural immunity from COVID-19 may not last very long, but more studies are needed to better understand this.

scientist with pipette

Coronavirus (COVID-19)

What you need to know from Johns Hopkins Medicine.

Updated: January 8, 2021