COVID-19 Vaccines – Your Questions Answered

By June Shannon Coronavirus News   |   2nd Mar 2021

We answer some of the questions you may have about the COVID-19 vaccines

After clean water, vaccination is the most important public health intervention. According to the World Health Organisation, vaccines prevented  at least 10 million deaths between 2010 and 2015 alone and many millions more were protected from illness. Vaccines are safe and effective and in the ongoing fight against COVID-19 have provided some much needed hope that we will soon be able to return to some kind of normality.

Q. What COVID-19 vaccines are available in Ireland?

There are currently three COVID-19 vaccines approved for use in Ireland these are the Pfizer-BioNTech vaccine, named Comirnaty, the Moderna vaccine, and the Astra Zeneca vaccine.

All these vaccines have been proven to be safe and efficacious, i.e., they protect the vaccinated individual against disease, in robust clinical trials.

Q. How do the vaccines work?

Both the Pfizer-BioNTech and Moderna vaccines are mRNA vaccines. Messenger RNA (mRNA) is a string, or sequence, of nucleic acids that, once inside a cell,  instructs protein-making machinery in the cell to produce the spike protein found in the SARS-CoV-2 virus that causes COVID-19. Once our bodies produce the spike protein, our immune system recognises it as a threat and starts to build up an immune response by developing antibodies and T cells against it. However, as the vaccine delivers the instructions of only one of the 29 SARS-CoV-2 proteins that are required to cause infection, it is impossible for the vaccine to make us sick with COVID-19; it simply tells the body how to fight COVID-19. The COVID-19 mRNA vaccines therefore protect the person who has been vaccinated and reduces their risk of contracting the virus.

The Astra Zeneca vaccine uses a type of adenovirus. The adenovirus used in the vaccine  has been modified to contain the gene for making a protein from SARS-CoV-2 and it has also been modified so that it is incapable of replicating in the body. The adenovirus in the vaccine cannot reproduce and does not cause disease. Similar to the mRNA vaccines, once the replication-incompetent adenovirus gets into a cell, the protein-making machinery of the cell reads the instructions for the spike protein and produces it.  The person’s immune system will then recognise this protein as foreign and produce antibodies and activate T cells (white blood cells) to attack it.

If, later on, the person comes into contact with SARS-CoV-2 virus, their immune system will recognise it and be ready to defend the body against it.

Q. How do I know I’m getting the right/best vaccine for me?

We are in a very lucky position right now to have three safe and effective vaccines available for use in Ireland. All three vaccines currently licensed for use in Ireland are safe and effective and all protect against serious illness and hospitalisation from COVID-19. More vaccines will likely be licensed in the coming months. Therefore, whichever vaccine you are offered is the best one for you.

After clean water, vaccination is the most important public health intervention


Q. Are these vaccines safe?

Yes, these vaccines would not have been authorised for use by the European Medicines Agency (EMA) and the Health Products Regulatory Authority in Ireland (HPRA) – the body in Ireland responsible for regulating all medicines including vaccines- if they weren’t safe and effective. They have all undergone rigorous safety and efficacy checks and their safety continues to be monitored as the vaccines are rolled out across the world.

Q. Will the mRNA from the vaccine go into my DNA and change my genetics?

No this will not happen. The mRNA is not the same as DNA and it is impossible for it to combine with our DNA to change our genetic code. The mRNA in the mRNA vaccines never enters the part of cell where our DNA is kept. mRNA also breaks down and degrades very easily and quickly. The cell in your body breaks down the mRNA and gets rid of it after it has finished using its instructions. 

Q. Are these vaccines safe for people with a heart condition/ heart disease/ stroke?

Vaccination is recommended for the protection from COVID-19. This is particularly important for people living with underlying conditions such as heart disease, stroke, diabetes and obesity as these groups are at high risk of becoming severely ill if they contract COVID-19. The COVID-19 vaccines approved for use in Ireland are safe and effective for people with heart conditions/stroke/heart disease.

Q. If I have a condition such as LQTS where there are certain drugs I can’t take, will the COVID vaccine affect this?

To the best of our knowledge all COVID-19 vaccines are safe and effective for people with Long QT Syndrome. However, it is important that you tell the person who is vaccinating you that you suffer with Long QT Syndrome. This is because in that unlikely event that you suffer a severe allergic reaction, it is important that QT prolonging drugs are avoided to treat this. For example, some antihistamines need to be avoided. It is also very important to let the vaccinating team know if you have had any problem with other vaccines in the past. It is also important to monitor for a fever after you have had your vaccination and treat it appropriately.

Q. How long after a surgical procedure do I have to wait until I can get my vaccination?

Once you feel well and have fully recovered from surgery with no temperature or other symptoms you should be eligible for the vaccine. If you have any concerns please discuss these with your surgeon.

People who are most at risk from COVID-19 will be vaccinated first.


 Q. When will I get my vaccine ?

People who are most at risk from COVID-19 will be vaccinated first.

Frontline healthcare workers and people aged 65 and over who live in long term residential settings are currently being vaccinated. After these groups those aged 85 and over living in the community will be vaccinated and vaccination programme for this group has already commenced.

If you are 85 of over there is no need to register for your vaccine your GP will contact you when your vaccine is available.

After this group has been vaccinated people in the next priority groups will be invited to have their vaccine.

You can read more about the priority groups here.

Where do people living with heart disease stroke come on the priority list?

After those aged 85 and older are vaccinated, the next group to receive their vaccine will be those aged 80-84, 75 to 79, and 70 to 74.

After those aged 70 and over (group 4) people aged 16 to 69 with a medical condition that puts them at very high risk of severe disease and death if they contract COVID-19 are next in line to receive their vaccine.(group 5)

This group includes  people who are severely immunocompromised due to disease or treatment including people waiting for a heart transplant or those who have received one. This group also includes people with Down Syndrome and those living with obesity (BMI >40 Kg/m2). It also includes all cancer patients actively receiving (and/or within 6 weeks of receiving) systemic therapy with cytotoxic chemotherapy, targeted therapy, monoclonal antibodies or immunotherapies and radical surgery or radiotherapy for lung or head and neck cancer as well as all patients with advanced/metastatic cancers.

The next cohort to be vaccinated are those aged 65 to 69 with an underlying condition that puts them  at high risk of severe disease and death if they get COVID-19. (group 6)

These underlying conditions include: chronic heart disease, for example: heart failure, hypertensive cardiac disease, and all other diabetes (Type 1 and 2) and people living with obesity BMI >35 Kg/m2.

People aged 16 to 64 with underlying condition are in group 7 of the schedule to receive the COVID-19 vaccine.

These underlying conditions include: chronic heart disease, for example: heart failure, hypertensive cardiac disease, and all other diabetes (Type 1 and 2) and people living with obesity BMI >35 Kg/m2

More details on the vaccine allocation list are available here.

Its important to note that medical conditions and the size of the risk they pose will continue to be monitored and periodically reviewed.

Q. Who will give me my vaccine and do I have to contact my GP to organize an appointment?

Initially vaccines were administered in hospitals and nursing homes.

Those aged 85 and over will get their vaccines at Mass Vaccination Clinics currently being established around the country.  Later, when vaccines are more generally available, GPs and pharmacies may also give vaccinations.

You do not need to apply to get the vaccine. The HSE will let you know when you can get the vaccine through communication with your healthcare team news or public advertising.

If you don’t have a GP you can contact The HSELive COVID-19 Helpline for advice. It is open 8am to 8pm Monday to Friday and 9am to 5pm Saturday and Sunday.Lo-call: 1850 24 1850

The COVID vaccine is free so you don’t have to pay to get it


Q. How much does the vaccine cost?

The COVID vaccine is free so you don’t have to pay to get it

Q. Do I have to get vaccinated?

Getting vaccinated against COVID-19 is not mandatory. The HSE, Department of Health and the World Health Organization recommends that you get your COVID-19 vaccine when it is offered to you.

Q. What happens when I get my vaccine?

You will get your COVID-19 vaccine as an injection in your upper arm. It will only take a few minutes.

You will need 2 doses.

Your second dose will be at least:

84 days (12 full weeks) after your first dose if you get the AstraZeneca vaccine

28 days (4 full weeks) after your first dose if you get the Moderna vaccine

21 to 28 days (3 to 4 weeks) after your first dose if you get the Pfizer/BioNTech vaccine

Do not get your COVID-19 vaccine if you:

If you have had an immediate allergic reaction to any other vaccine or injectable therapy, you should talk to your doctor before getting your COVID-19 vaccine.

Q. What are the side effects of the COVID-19 vaccines?

Like all medicines, vaccines can cause side effects. Most of these are mild to moderate and short-term. The can include: pain at the injection site, tiredness, headache, fever, muscle pain and nausea.

The HPRA has been actively encouraging the public and healthcare professionals to report any suspected side effects experienced following vaccination.

Of the reports notified to the HPRA, the most commonly reported suspected side effects include dizziness, headache, tiredness, as well as itching and/or rash at the site of injection.

These were mild to moderate in nature and resolved, or were resolving, at the time of reporting.

According to the HPRA, “For mRNA vaccines, we have seen a trend for increased frequency or intensity of side effects reported after the second dose, particularly in younger age groups. This is fully consistent with the known safety profile for these vaccines demonstrated during clinical trials.”

There has been a small number of reports of people experiencing suspected anaphylaxis following vaccination with the Pfizer/BioNTech vaccine. All have now fully recovered. Anaphylaxis is a very rare side effect associated with most vaccines and all vaccinators, as standard, are fully trained to deal with such an occurrence. Widespread use of the mRNA vaccines internationally now suggests an incidence rate in the region of 1 in 100,000.

The HPRA stated that is has also received reports describing facial paralysis, including cases of suspected Bell’s palsy, or conditions associated with temporary weakness in the muscles on one side of the face. “As always, we will continue to monitor these cases to establish that these symptoms have resolved. The number of reports of facial paralysis received so far is in line with the expected rate at which these conditions occur naturally and does not currently suggest an increased risk following vaccination,” it added.

Serious side effects after COVID-19 vaccines

Serious side effects, like a severe allergic reaction, are extremely rare.

Be assured that your vaccinator is trained to treat any serious allergic reactions.

*Advice about the Astrazeneca  COVID-19 vaccine has been updated and as a result it has been restricted to be used only in people aged over 60. You can read more about this update here. 

Q. Do the vaccines have any side effects on the heart?

COVID infection itself can affect the heart and cause damage however the vaccines have been shown to be safe and there are no recorded cardiac issues other than the rare case of severe allergy /anaphylaxis.

For more information on side effects please see here

There is no evidence that any of the COVID-19 vaccines affect fertility.


Q.I am pregnant, should I get the COVID-19 vaccine?

If you are pregnant you should get your COVID-19 vaccine when it is offered to you as it will reduce your risk of getting very unwell if you contract COVID-19. For more information on pregnancy and breastfeeding and the COVID-19 vaccines please see here.

Q. Can COVID-19 vaccines affect your fertility?

There is no evidence that any of the COVID-19 vaccines affect fertility. COVID-19 vaccines cannot become part of your or your baby’s DNA.

Q. I have already had COVID-19 do I still need to be vaccinated?

Yes, just because you have had COVID-19 doesn’t mean that you cannot get it again. There’s a small chance you might still get COVID-19 even if you have been vaccinated. But vaccination will protect you from the serious illness the virus can sometimes cause

Q. Can I pass on COVID-19 once I am vaccinated?

For now, we are not 100 per cent certain whether or not the COVID-19 vaccines will have an impact on the transmission of the virus. Therefore, until more data is available we must continue to follow the public health guidelines on social distancing, wearing face coverings and good hand hygiene and cough etiquette.

Q. At what point after vaccination am I likely to have immunity?

We do not know yet how long immunity will last. Clinical trials are ongoing to find this out.

Q. How long it takes COVID-19 vaccines to work


It takes 3 weeks after getting the first dose for the AstraZeneca COVID-19 vaccine to start to work. You should get your second dose 12 weeks after your first dose. It takes 15 days after getting the second dose to have the best protection.


It takes 14 days after getting the second dose for the Moderna COVID-19 vaccine to work. You should get your second dose 4 weeks after your first dose.


It takes 7 days after the second dose for the Pfizer/BioNTech COVID-19 vaccine to work. You should get your second dose 3 to 4 weeks after your first dose.

Q. Once I am fully vaccinated am I protected from COVID-19?

After having both doses of a COVID-19 vaccine, most people will be protected against the virus. There is a small chance you might still get COVID-19 after vaccination. Even if you do get COVID-19, being vaccinated can reduce how serious your symptoms will be.

Even after you are vaccinated, continue to follow public health advice on how to stop the spread of COVID-19. For example, social distancing, wearing a face covering and washing your hands properly and often.

Please note the information on this page is for general guidance and comes from national and international guidance. It is not intended to replace the individual support of a medical professional.

As this is an evolving situation please note that this information is correct at time of publication but may change. For regular updated information on COVID-19 and vaccinations please see here.

For more information on COVID-19 vaccines please see the HSE website.

( * updated on Thursday 15th of April 2021 to include update on Astrazeneca vaccine)



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