COVID Vaccine Related FAQs

Vaccine safety and the speed of vaccine development

The goal of vaccination is to stop you from getting sick. The COVID-19 vaccines train your immune system to recognize COVID-19. They have been designed to help you fight off COVID-19 before it makes you sick, and to reduce the severity of your symptoms if you do get sick.

Vaccine ingredients vary depending on what the vaccine is for. Generally, vaccines may contain some of the following ingredients:

 a protein component of a virus

 a piece of genetic code (DNA or mRNA)

 a very small dose of a weakened virus

 a substance to boost the immune response (an adjuvant)

 a small amount of preservative

 sterile salt water (saline) for injections

The approved COVID-19 vaccines do not contain any animal products or egg.

The vaccines do not contain the full live SARS-CoV-2 virus and therefore cannot cause COVID-19. The only part of the virus they contain or make is spike protein. As such, there is NO risk of becoming infected with COVID because of the vaccine. The first vaccines that will be available will either contain mRNA (non-infectious genetic material), viral vectors, (modified versions of live viruses), or protein subunits (parts of viral proteins) which cannot cause infection.

Different types of vaccines work in different ways to offer protection. But every type of vaccine works by teaching our bodies how to make cells that trigger an immune response. That immune response, which produces antibodies, is what protects us from getting infected if the real virus enters our bodies.

Currently, there are three main types of COVID-19 vaccines:

  • mRNA vaccines
  • Protein subunit vaccines
  • Vector vaccines

Viral vector-based vaccines use the body’s own cells to produce antigens. They do this by using a modified virus (the vector) to deliver the genetic code for the antigen, which then triggers an immune response. The vaccine mimics what happens during natural infection with certain pathogens — especially viruses. This has the advantage of triggering a strong cellular immune response by T cells as well as the production of antibodies by B cells.

Vaccine safety is always a top priority, and this is no different for COVID-19 vaccines. COVID-19 vaccines were tested in large clinical trials to make sure they meet safety standards. The Food and Drug Administration (FDA) carefully reviews all safety data from clinical trials and an authorizes emergency vaccine use only when the expected benefits outweigh potential risks.

No. Vaccines build immunity without the damaging effects that COVID-19 can have, including long-term effects and death. Allowing the disease to spread until herd immunity is reached could cause millions of deaths and even more people living with the long-term effects of the virus.

Yes, you should be vaccinated regardless of whether you already had COVID-19 infection, due to the severe health risks and as reinfection with COVID-19 is possible. Experts do not yet know how long someone is protected from getting sick again after recovering from COVID-19. As long as you are feeling well, and no longer have confirmed infection it is recommended to still receive COVID-19 vaccines.

However, if you are currently infected, you must wait for your symptoms to resolve, your isolation period to end and if you were prescribed steroids, these must also have ended. This applies to either of the doses of the COVID-19 vaccine.

People who currently have COVID-19 should not be vaccinated while being sick.

If the vaccine you received recommends two doses and you miss the second dose, it is best that you take it within seven (7) days of the missed date.

Different COVID-19 vaccines may be more suitable for certain people. Your age and/or underlying conditions may also affect when you are eligible to get the vaccine. Talk to a healthcare provider to get information specific to you and the COVID-19 vaccine.

Most of the vaccines developed so far work in similar ways, by making responses against a spike protein. This means vaccinating with different versions is not necessary, but studies are needed to see if boosters with different vaccines might work well. There is every reason to believe that this would work but does need to be formally tested.

To date, research has continued to determine the duration of immunity provided by the COVID-19 vaccines that are available. We will have the answer to this and other questions as we have more studies in the vaccinated populations that will determine whether annual vaccinations or vaccinations at different periods will be necessary.

It is not currently recommended to take painkillers such as ibuprofen, aspirin or paracetamol before your COVID-19 vaccine to prevent side effects. However, if you do experience side effects such as fever, pain, or headaches after receiving the vaccine, you can take medicines containing paracetamol. For those that take similar medications routinely, you should continue your medications as prescribed.

NO. The vaccine cannot give you the virus. This is true of traditional vaccines made from dead viruses, and almost always true of live, attenuated vaccines, which in rare cases, can cause mild illness in some vulnerable populations.


Yes. COVID-19 vaccines protect you from getting severely sick by instruction your body how to fight off the virus.

You may experience minor reactions or side effects following COVID -19 vaccination like other vaccination. Most reactions or side effects last no more than a couple of days and do not require special treatment. Serious reactions like allergic reactions are extremely rare.

Common reactions to the COVID-19 vaccines include:

 tenderness, pain and swelling at the injection site

 tiredness

 headache

 muscle and joint pain

 chills

 fever.

Some people may also experience redness at the injection site, nausea, itching at the injection site, pain in the limb, enlarged lymph nodes, difficulty sleeping or generally feel unwell.

These symptoms usually go away on their own within a week. These side effects are a sign that your immune system is doing exactly what it is supposed to do. It is working and building up protection to disease.

Within 15 minutes of vaccination, there is a doctor to provide care at the vaccination center. Beyond 15 minutes (and after leaving the vaccination center) please obtain care at the Accident and Emergency department.

Yes. Some of the vaccines that some countries have approved for emergency use require that people get a second shot within a certain number of days. Getting this second shot when recommended strengthens your body’s immune response to the virus.  Failing to get the second dose as recommended means you will not be optimally protected from the disease.

Yes, according to WHO recommendations the second dose should be from the same manufacturer.

No, there is no need to use the vaccine from the same batch for vaccines that have a two-dose schedule.

No, you do not have to start all over. Missing the suggested interval delays full protection. But you can still get the second dose later if you have difficulty getting it within the recommended time. Just don’t get it earlier than recommended.

The COVID-19 vaccines currently in use target the spike (S) protein of the coronavirus to produce an immune response. Antibody tests used to check for a previous COVID-19 infection have been designed to assess the presence of antibodies against one or other of two different proteins from the coronavirus: the spike (S) protein and the nucleocapsid (N) protein. After vaccination, presence of antibodies against the S protein is expected, producing a positive result. However, the presence of antibodies against the N protein would not be expected, so for this type of antibody test, a negative result would be seen following vaccination. Vaccinated individuals who have had an N protein antibody test that is negative do not need additional vaccine doses above those recommended, as the results of this test are not affected by vaccination. Both tests would be expected to show a positive result after a recent COVID-19 infection.

Yes. We will need to continue to wear masks, practice physical distancing, and wash our hands frequently, even after COVID-19 vaccines are in use in the general public. It will take a long time to produce enough doses of the vaccines and distribute them widely enough to stop the spread of the virus.

Practice the same safety habits you’ve been doing to prevent the spread of COVID-19. Take the following precautions to limit exposure for yourself and others:

  • Wear a mask in public and when around people.
  • Practice social distancing and avoid close contact with others:
    • Outside your home:Stay at least 6 feet away from others and avoid crowded places.
    • Inside your home:Avoid close contact with household members who are sick. Avoid sharing personal items and use a separate room and bathroom for sick household members, if possible.
  • Wash your hands often with soap and water for at least 20 seconds, especially after going to the bathroom; before eating; and after blowing your nose, coughing, or sneezing. If soap and water are not readily available, you can use an alcohol-based hand sanitizer that contains at least 60% alcohol.
  • Clean and disinfect frequently-touched objects and surfaces using a household disinfectant.
  • Avoid touching your eyes, nose, and mouth with unwashed hands.
  • Cover your cough or sneeze with a tissue, then throw the tissue in the trash and wash your hands.
  • Stay home when you are sick.

Early research indicates that the vaccines may be able to reduce how infectious we are if we do catch COVID-19. Research is ongoing to understand whether the vaccines can stop a person passing the virus onto another person. This is why it’s important that even if you have been vaccinated, you should continue practicing good hygiene, using the COVID Safe Check-In, physical distancing, and getting tested and staying home if you are unwell.

Getting the vaccine does not require quarantine, but it typically takes a few weeks for the body to build an immune response after getting the vaccine. This means it is possible you could be infected with COVID-19 just before or after vaccination. If you believe you have been exposed or are having symptoms you should quarantine until you talk to your doctor and get tested.

Clinical trials have shown that the COVID-19 vaccines protect against COVID-19 symptoms and severe disease after a person receives two doses. At this stage, there is not enough information to understand the long term protection against COVID-19 after vaccination.

It is anticipated that the COVID-19 vaccines will be effective against the newer strains of COVID-19. This is because the vaccines work by inducing what is known as a “polyclonal” response – a collection of immunological responses to many different parts of the COVID-19 “spike” protein. In the new variants, only a limited part of the spike protein is changed, and much is unchanged, so the vaccines should still work against the main, unchanged parts to the COVID-19 spike protein.


No, mRNA vaccines cannot give someone COVID-19. mRNA vaccines do not use the live viruses that causes COVID-19.

mRNA vaccines do not affect or interact with our DNA in any way. mRNA never enters the nucleus of the cell where our DNA is kept. The cell breaks down and gets rid of the mRNA soon after it is finished using the instructions.


Both COVID-19 and the vaccines are new. We do not know how long protection lasts for those who get infected or for those who are vaccinated. What we do know is that COVID-19 has caused very serious illness and death for a lot of people. If you get COVID-19, you also risk giving it to loved ones who may get very sick. Getting a COVID-19 vaccine is a safer choice. Keep in mind that the vaccines are not a perfect fix. We will still need to practice other precautions like wearing a mask, social distancing, and hand washing.

Yes, even if you have already had COVID-19 you should be vaccinated. Experts do not yet know how long you are protected from getting sick again after recovering from COVID-19. Even if you have already recovered from COVID-19, it is possible, although rare, that you could be infected with the virus that causes COVID-19 again.

If you were treated for COVID-19 with monoclonal antibodies or convalescent plasma, you should wait 90 days before getting a COVID-19 vaccine. Talk to your doctor if you are unsure what treatments you received or if you have more questions about getting a COVID-19 vaccine.

Yes, it is possible. However, experts believe that getting a COVID-19 vaccine may help keep you from getting seriously ill even if you do get COVID-19, and it also may protect people around you, particularly people who are at increased risk for severe illness from COVID-19.

People with COVID-19 should wait to be vaccinated until they have recovered from their illness and have met the criteria for discontinuing isolation.


All FDA authorized COVID-19 vaccines have been shown to prevent severe COVID-19 illness, hospitalizations and death. The different vaccines were studied at different times, in different countries, and under different conditions and thus comparing them is difficult. When it is your turn to get vaccinated, you should take the first vaccine available to you.

Polyethylene glycol (PEG) is a common ingredient in a wide variety of vaccines and FDA-approved medications. It is found in the colonoscopy preparation, Golytely, in the constipation treatment, MiraLax, as well as in IV medications such as PEGylated medications. It is also in a steroid injection, Depo Medrol (methylprednisolone acetate). Polysorbate is not an ingredient in either of the mRNA COVID-19 vaccines, but it is closely related to PEG.

Any currently authorized COVID-19 vaccine can be administered to persons with underlying medical conditions who have no contraindications to vaccination, including immunocompromised persons, people with autoimmune conditions, people with a history of Guillain-Barré syndrome, Bell’s palsy, dermal filler use.

Yes. Persons with one or more of these comorbid conditions are considered high risk category. They need to get COVID -19 vaccination after advice from health provider.

YES. People with a history of severe allergic reactions not related to vaccines or injectable medications; such as food, pet, venom, environmental or latex allergies—get vaccinated. But if you have had an immediate allergic reaction, even if it was not severe, to a vaccine or injectable therapy for another disease, ask your doctor if you should get a COVID-19 vaccine.

If you had a severe allergic reaction after getting the first dose of an mRNA COVID-19 vaccine, CDC recommends that you not get the second dose. If you have had an immediate allergic reaction (hives, swelling, wheezing), even if it was not severe, to any ingredient in an mRNA COVID-19 vaccine, CDC recommends that you not get either of the currently available mRNA COVID-19 vaccines. If you had an immediate allergic reaction after getting the first dose of an mRNA COVID-19 vaccine, you should not get the second dose.

The CDC has recommended that pregnant women and women planning to become pregnant may choose to receive a COVID-19 vaccine. A conversation between patient and provider may assist with decisions to receive COVID-19 vaccine, however, it is not required before vaccination.

Currently no specific data on the safety of the available vaccines in breastfeeding women and their effects on the baby are available.

There is no evidence that the immune response to coronaviruses has any impact on fertility, and there is no biological mechanism that has been shown to result in an impact on fertility.

At this time, the CDC does not recommend routine testing for pregnancy prior to receiving a COVID-19 vaccine.

The currently approved COVID-19 vaccines are also considered safe in immunocompromised people. For people that are yet to begin immunosuppression treatments, general best practice is that they should be considered for vaccination at least 2 weeks before starting therapy and when possible, it is preferable to complete the two doses prior to starting immunosuppression.

At first, COVID-19 vaccines may not be recommended for children but as more studies are completed, COVID-19 vaccine may be available for children.

COVID-19 vaccines should not be given at the same time as other vaccines. There should be a period of 14 days on either side of your COVID-19 vaccination where you do not receive other immunizations. However, if a COVID-19 vaccine is given at the same time or within 14 days of another vaccine, neither dose should be repeated. Attempts should be made to schedule other vaccines where possible 14 days before or after each dose of COVID-19 vaccination.

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