COVID-19 Frequently Asked Questions for Health Professionals

Download the Vaxzevria® (COVID-19 Vaccine AstraZeneca) - Questions and Answers 30 April 2021

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The following questions and answers have been developed by the National Immunisation Office and are included in the Clinical Guidance for COVID-19 Vaccination.

Should people who have had COVID‐19 infection be offered COVID‐19 vaccine?

Yes. People who have had COVID‐19 infection should be offered COVID‐19 vaccines.

Vaccination should be deferred until clinical recovery from COVID‐19 and at least four weeks after diagnosis or onset of symptoms, or four weeks from the first PCR positive specimen in those who are asymptomatic.

For those who have had a previous laboratory confirmed COVID‐19 infection within 6 months:

  • aged 50 years and older should receive a full COVID‐19 vaccine schedule
  • aged under 50 years and immunocompromised should receive a full COVID‐19 vaccine schedule
  • aged under 50 years and immunocompetent: a single dose of COVID‐19 vaccine is sufficient and they should then be considered fully vaccinated

Those who have had laboratory confirmed COVID‐19 infection within 6 months after a first dose of COVID‐19 vaccine should complete the course.

What if somebody is diagnosed with COVID‐19 infection after a first dose of vaccine?

Vaccination should be deferred until clinical recovery from COVID‐19 and at least four weeks after diagnosis or onset of symptoms, or four weeks from the first PCR positive specimen in those who are asymptomatic.

  • For those who are aged under 65 years and are not immunocompromised who have had confirmed SARS‐CoV‐2 infection (symptomatic or asymptomatic),vaccination may be deferred, if the person vaccinated chooses to do so, for up to six months after diagnosis, symptom onset, or from the first PCR or antigen positive specimen for those with asymptomatic infection. This is because there is evidence of natural immunity for up to 6 months after natural infection.

For those who have had a previous laboratory confirmed COVID‐19 infection within 6 months: 

  • aged 50 years and older should receive a full COVID‐19 vaccine schedule 
  • aged under 50 years and immunocompromised should receive a full COVID‐19 vaccine schedule 
  • aged under 50 years and immunocompetent: a single dose of COVID‐19 vaccine is sufficient and they should then be considered fully vaccinated

Those who have had laboratory confirmed COVID‐19 infection within 6 months after a first dose of COVID‐19 vaccine should complete the course

What if the second dose of COVID‐19 vaccine is administered at less than the recommended interval?

Comirnaty® (Pfizer BioNTech) COVID-19 mRNA Vaccine

The advice of the National Immunisation Advisory Committee is that evidence of efficacy of doses given before 17 days is lacking. However there is also no safety and efficacy date in relation to repeating vaccination in this situation (giving a total of 3 doses). Therefore a further dose is not required. This should be reported to HPRA and an incident report form completed.

If a dose is given between 17 and 21 days, this is considered a valid dose.

COVID‐19 Vaccine Moderna®

The advice of the National Immunisation Advisory Committee is that evidence of efficacy of doses given before 24 days is lacking. However there is also no safety and efficacy date in relation to repeating vaccination in this situation (giving a total of 3 doses). Therefore a further dose is not required. This should be reported to HPRA and an incident report form completed. 

If a dose is given between 24 and 27 days, this is considered a valid dose.

Vaxzevria® (COVID‐19 Vaccine AstraZeneca)

The advice of the National Immunisation Advisory Committee is that evidence of efficacy of doses given before 24 days is lacking. However there is also no safety and efficacy date in relation to repeating vaccination in this situation (giving a total of 3 doses). Therefore a further dose is not required. This should be reported to HPRA and an incident report form completed.

If a dose is given between 24 and 27 days, this is considered a valid dose.

(Please note that for those aged <50 who do not have a high risk or very high risk medical condition, the interval between doses should be extended to 16 weeks).

What if the second dose of COVID‐19 vaccine is administered at longer than the recommended interval?

If the interval between doses is longer than the recommended interval, the second dose should still be given. The course does not need to be restarted.

What if the vaccine leaks during administration?

If some of the vaccine leaks out of the syringe during administration this is not a valid dose. A further dose of the vaccine should be administered at a separate site at the same visit.

What if a vaccine is given after the expiry date of after the use before or discard time?

If a vaccine is given after the expiry date or after the use before or discard date and time it is considered an invalid dose, and the dose should be repeated that day or as soon as possible.

This should be explained to the person and a correctly diluted dose of the vaccine should be given as soon as possible. 

This should be reported to HPRA and an incident report form completed.

What if the whole multi‐dose vial of vaccine is administered instead of the recommended dose?

Trial data showed that higher doses of a similar vaccine were not harmful but the person is more likely to have more local reactions with very painful arms being reported.

The person should be reassured that this is not harmful but that they are more likely to experience pain in their injected arm. They should be given their second dose of vaccine according to the recommended schedule.

This should be reported to HPRA and an incident report form completed.

What if only the diluent of Comirnaty® is administered?

The diluent for Comirnaty® is sodium chloride, which is salt and purified water so no adverse reactions would be expected.

This should be explained to the person and a correctly diluted dose of the vaccine should be given as soon as possible.

This should be reported to HPRA and an incident report form completed.

What if an over‐diluted Comirnaty® vaccine is administered?

In this case, the person will not have received a sufficient dose of vaccine for protection.

This should be explained to the person and a correctly diluted dose of the vaccine should be given as soon as possible.

This should be reported to HPRA and an incident report form completed.

What if a person under 16 years is given Comirnaty® vaccine inadvertently?

If a person under the age of 16 years receives the vaccine inadvertently, this should be reported to the HPRA and an incident form completed. The person and their parents/guardians should be advised regarding the common adverse events expected after vaccination.

What if a person under 18 years is given COVID‐19 Vaccine Moderna® or Vaxzevria® (COVID‐19 Vaccine AstraZeneca®) or COVID‐19 Vaccine Janssen® inadvertently?

If a person under the age of 18 years receives the vaccine inadvertently, this should be reported to the HPRA and an incident form completed. The person (and their parents/guardians if less than 16 years old) should be advised regarding the common adverse events expected after vaccination. If Vaxzevria® is given inadvertently, they should be advised of the clotting events reported very rarely after vaccination, and of the symptoms and signs to be aware of, and to seek urgent medical attention should these appear.

Will a booster dose of COVID‐19 vaccines be needed?

The need for and timing of booster doses has not been established. No additional doses beyond the two‐dose primary series (or one dose for COVID‐19 Vaccine Janssen®) are recommended at this time.

What if a woman becomes pregnant between the first and second dose of vaccine?

If a woman reports that they are pregnant between the first and second dose, this should be reported to the Health Products Regulatory Authority (www.hpra.ie).

Animal studies do not indicate direct or indirect harmful effects with respect to pregnancy, embryo/foetal development, parturition or post‐natal development. The available safety data do not indicate any safety concern or harm to pregnancy, although there is insufficient evidence to recommend routine use of COVID‐19 vaccines during pregnancy.

If a woman has recived a first dose of a COVID‐19 vaccine, they should be advised to speak to their Obstetrician (or GP) regarding the risks and benefits of receiving the second dose of COVID‐19 vaccine, once they areat or over 14 weeks gestation. The second COVID‐19 vaccine dose should not be given while less than 14 weeks gestation.

Does a woman who wishes to conceive need to leave any interval after getting COVID‐19 vaccines before getting pregnant?

It is not necessary to leave any interval after having the vaccine and becoming pregnant. If a woman becomes pregnant following the first dose, they should wait until 14 weeks or after to get the second dose, and should discuss the risks and benefits with their Obstetrician or GP.

What if someone has a history of anaphylaxis or severe allergic reaction to a type of food ‐ can they receive a COVID‐19 vaccine?

A history of anaphylaxis or severe allergic reaction to a type of food (e.g. egg allergy) is not a contraindication to vaccination (see Immunisation Guidelines for Ireland from the National immunisation Advisory Committee)

Persons with such a history can receive a COVID‐19 vaccine. They should be monitored for a period of 30 minutes after vaccination.

See also Frequently Asked Questions about COVID‐19 vaccines for people with pre‐existing allergic conditions.

What is someone has had a reaction to a first dose of vaccine, should they get the second dose of the vaccine?

The contraindications and precautions to vaccination are detailed in section 4 of the clinical guidelines, these are as per the recommendations of the National immunisation Advisory Committee.

If someone has had a reaction to the first dose of vaccine but it is not listed as a contraindication then they can receive the second dose of the vaccine.

Where can COVID‐19 vaccine be given in the event that a person cannot receive the vaccine in the deltoid muscle?

In the event that a person cannot receive the vaccine in the deltoid muscle, the vaccine can be given into the vastus lateralis muscle.

What size needle should be used to vaccinate people with an elevated BMI?

If it is available, it is recommended to use a 23‐25 gauge 40mm needle when vaccinating females >90kg and males >120kg. If a 38‐40 mm needle is not available, a 23‐25 gauge 25mm needle should be used.

(As an example, the quadrivalent inactivated influenza flu vaccine that is licensed and used in Ireland and in Europe comes in a prefilled syringe with a fixed needle attached, and the needle is not the longer 40mm in length).

Can mRNA vaccines like Comirnaty® and COVID‐19 Vaccine Moderna® interact with a person’s DNA?

No they cannot. The mRNA contained in these vaccines does not enter the nucleus of human cells, which is where DNA is contained. mRNA does not interact with a person’s DNA. The cell breaks down and gets rid of the mRNA soon after it is finished using the instructions.

Can viral vector vaccines like Vaxzevria® (COVID‐19 Vaccine AstraZeneca®) and COVID‐19 Vaccine Janssen® interact with a person’s DNA?

No they cannot. The viral vector enters the body's cells and delivers the genetic code for the spike protein. The human cells then produce the spike protein but there are no changes to the human DNA.

Can COVID‐19 vaccines affect fertility?

There is no biologically plausible reason why the vaccines would affect fertility. The European Medicines Agency licensed documentation states that animal studies do not indicate direct or indirect harmful effects on fertility.

Do Vaxzevria® (COVID‐19 Vaccine AstraZeneca) and COVID‐19 Vaccine Janssen® contain genetically modified organisms?

Yes. Vaxzevria® (COVID‐19 Vaccine AstraZeneca) and COVID‐19 Vaccine Janssen® contain a genetically modified adenoviruses. Two genetic alterations have been made in order to make the vaccine:

  • Genes essential for adenovirus replication have been deleted.
  • The coronavirus (SARS‐CoV‐2) spike protein gene has been added.

The result is a genetically modified organism (GMO) with a new combination of genetic material. These changes to the adenovirus allow the vaccine to deliver the spike protein genetic code to the cells without causing COVID‐19.

Does Vaxzevria® (COVID‐19 Vaccine AstraZeneca) contain cells of human embryonic origin?

No. The foetal cells were used only to begin the cell strains that were used in the preparation of the vaccine virus. Since that time (the early 1970s) the cell lines have grown independently The descendant cells are not the cells of the terminated foetus. There has been no further use of foetus cells to develop the vaccine.

The cell‐lines used in COVID‐19 Vaccine Astra Zeneca are HEK (human embryonic kidney) 293 cell lines, which were started in the 1970s using small quantities of kidney cells taken from a foetus following a termination. The termination was legal and agreed to by the mother, and it was not performed for the purpose of vaccine development.

The original foetal cells have long since disappeared. None of these cells remain at the time the vaccine is administered.

Other vaccines are developed using cell lines that were originally of foetal origin e.g. MMR vaccine.

The Irish Catholic Bishops Conference has released a statement that it is morally permissible for Catholics to accept a vaccine which involves the use of foetal cell‐lines, especially if the potential risk to life or health is significant, as in the case of a pandemic. Read the full statement on the Catholic Bishops Website

Does COVID‐19 Vaccine Janssen® contain cells of human embryonic origin?

No. The foetal cell lines were used only to begin the cell strains that are used in the preparation of the adenovirus vector. Since that time (the late 1980s) the cell lines have grown independently. The descendant cells are not the cells of the terminated foetus.

The cell line in the COVID‐19 Vaccine Janssen are PER.C6 line. The PER.C6 cell line is derived from human embryonic retinal cells, originally from the retinal tissue of an 18 week old foetus from a termination in 1985. 

The original foetal cells have long since disappeared. None of these cells remain at the time the vaccine is administered.

Other vaccines are developed using cell lines that were originally of foetal origin e.g. MMR vaccine. 

The Irish Catholic Bishops Conference has released a statement that it is morally permissible for Catholics to accept a vaccine which involves the use of foetal cell‐lines, especially if the potential risk to life or health is significant, as in the case of a pandemic. Read the full statement on the Catholic Bishops Website

Can people who have recently had a blood clot or are taking blood thinning treatments receive Vaxzevria® (COVID‐19 Vaccine AstraZeneca) or COVID‐19 Vaccine Janssen®?

Yes, they can still have the Vaxzevria® (COVID‐19 Vaccine AstraZeneca) or COVID‐19 Vaccine Janssen® if they have recently had a blood clot or are on blood thinning treatments. There is no reason to delay vaccination.

Like anyone who has received COVID‐19 vaccine AstraZeneca or COVID‐19 Vaccine Janssen®, they should be aware of the symptoms to look out for and to seek urgent medical attention in the few weeks after receiving the vaccine if they experience any of the following:

  • breathlessness,
  • pain in the chest or stomach,
  • swelling or coldness in an arm or leg,
  • severe or worsening headache (particularly 3 days or more after vaccination)
  • blurred vision,
  • persistent bleeding,
  • multiple small bruises, reddish or purplish spots, or blood blisters under the skin

Can people who have a condition or are on a treatment that may make them more likely to get a blood clot receive Vaxzevria® (COVID‐19 Vaccine AstraZeneca) or COVID‐19 Vaccine Janssen®?

Yes, they can still have Vaxzevria® COVID‐19 Vaccine AstraZeneca or COVID‐19 Vaccine Janssen. There is no reason to delay vaccination. Like anyone who has received Vaxzevria® COVID‐19 vaccine AstraZeneca, they should be aware of the symptoms to look out for as listed above and seek urgent medical attention if they experience any of these. 

There is no evidence that those with clotting or platelet disorders are at an increased risk e.g. idiopathic or heparin induced thrombocytopenia, autoimmune conditions, history of cerebral venous sinus thrombosis unrelated to vaccination, acquired or hereditary thrombophilia, or antiphospholipid syndrome.

Can people with a family history of thromboembolic disease receive Vaxzevria® (COVID‐ 19 vaccine AstraZeneca) or COVID‐19 Vaccine Janssen?

Yes, they can still have Vaxzevria® (COVID‐19 Vaccine AstraZeneca®) or COVID‐19 Vaccine Janssen®. There is no reason to delay vaccination. Like anyone who has received Vaxzevria® (COVID‐19 vaccine AstraZeneca) they should be aware of the symptoms to look out for as listed above and seek urgent medical attention if they experience any of these.

What advice can we give people under 50 who have already recived a first dose of Vaxzevria® (COVID‐19 Vaccine AstraZeneca)?

People who are aged <50 and are at high risk of very high risk of severe are advised to have their second dose 12 weeks after their 1st dose.

All other aged <50 should have the scheduled interval between doses extended to 16 weeks to allow further assessment of the benefits and risks of the vaccine as more evidence becomes available. Clinical trial data has shown that the Vaxzevria® is efficacious, with no waning of immunity, up to at least 12 weeks after the first dose. Data supports evidence of protective immunity for at least 16 weeks following a first dose of the vaccine.

Do COVID-19 vaccines affect COVID-19 tests?

Receiving a COVID‐19 vaccine will not result in a false positive PCR or antigen COVID‐19 test.

Comirnaty® and COVID‐19 Vaccine Moderna® are mRNA vaccines. They encode the spike protein of the virus that, when expressed on the cell surface, provokes generation of neutralising antibodies and activation of T‐cells. The mRNA vaccines are rapidly degraded.

Vaxzevria® (AstraZeneca ) and COVID‐19 Vaccine Janssen® contain a modified adenovirus that binds to the surface of human cells and delivers the genetic code for the coronavirus spike protein, where it is processed to form the spike protein itself.  

The spike protein, is not a molecular target of either PCR or antigen COVID‐19 tests. The antibodies produced following vaccination may affect the result of a COVID‐19 antibody test, but only if the test looks for antibodies against the spike protein of the coronavirus.   

 

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The following questions and answers for healthcare workers have been provided by the HSE Workplace Health and Wellbeing Unit.

Can someone who has been vaccinated still be considered a close contact of a positive case?

No. Close contacts with a history of confirmed COVID-19 infection within the previous 6 months, and HCWs who have completed vaccination and the specified period following vaccination to achieve immunity, do not require restricted movement, testing or active follow-up unless specific circumstances apply:

  • The case is a Person Under Investigation (PUI), probable or confirmed variant of concern (VOC). In this situation the close contact should be managed as a close contact of a VOC.
  • If the person’s immune system response to vaccination could be compromised due to either a known medical condition or being on immunosuppressive treatment. See Guidance on Fitness for Work of Healthcare Workers in the Higher Risk Categories, including Pregnant Healthcare Workers
  • It is otherwise recommended by the local Outbreak Team/Consultant Microbiologist , in the case of a Hospital Acquired infection or outbreak

Please visit the HSE website for advice.

Do vaccinated people need to restrict movements when returning from abroad?

There is no change in advice for the management of those travelling from abroad. Please visit the Government website for up to date information about travel.

HSE healthcare workers should not attend the workplace for 14 days post travel, even if they can exit restricted movement following day 5 testing, based on Government advice.

What should a healthcare worker do if they develop a fever after getting the COVID-19 vaccine?

Vaccinated individuals should be advised that COVID-19 vaccines may cause a mild fever which usually resolves within 48 hours. This is a common, expected reaction. Please visit the HSE Website for more information.

However due to the transmission rates of COVID-19 at the moment, healthcare workers should self‐isolate and seek a clinical assessment through their Occupational Health Department or GP (as appropriate) if they develop possible COVID-19 symptoms including fever following vaccination.  As has always been recommended, if individuals are concerned about their health at any time, they should seek medical advice.

Should someone who is pregnant or breastfeeding get the COVID-19 vaccine?

Recommendation from NIAC advise that Pregnant women should be offered mRNA COVID-19 vaccination between 14-36 weeks gestation following an individual benefit/risk discussion with their obstetric care giver

The Institute of Obstetricians and Gynaecologists, Royal College of Physicians of Ireland and National Immunisation Advisory Committee have provided information and COVID-19 Vaccine Decision Aids for pregnant or breastfeeding women and their doctors.

Please visit their website to view the information.

Can a healthcare worker who has been cocooning because of an underlying condition get the vaccine and return to work?

Yes, they can get the vaccine.

.The decision regarding a return to work is based on a assessment with Occupational Health where your medical condition and vaccination will be taken into account. Other factors such as the community prevalence of infection and the workplace risk must also be considered – see Guidance on Fitness for Work of Healthcare Workers in the Higher Risk Categories, including Pregnant Healthcare Workers

Can a healthcare worker with an underlying condition get the vaccine?

Yes. The only circumstances that preclude people from getting the vaccine are if they have had an anaphylactic (severe allergic) reaction to the vaccine or any of its ingredients.

Specific advice on when people shouldn’t get the vaccine can be found here and it would be important for people to discuss any concerns regarding their medical suitability for the vaccine with their GP. 

This page was updated on 7 May 2021