COVID-19 Frequently Asked Questions for Health Professionals

Read the FAQs for Healthcare workers in relation to people who are immunocompromised and require an extended COVID-19 vaccination course 5 October 2021

Read the FAQs for Healthcare workers in relation to COVID-19 vaccines booster dose 5 October 2021

Read the FAQs for Healthcare workers in relation to heterologous COVID-19 vaccination schedules for those who have had a first dose of Vaxzevria® 27 August 2021

Read the Frequently Asked Questions for parents and guardians considering COVID-19 vaccine for their 12-15 year olds 11 August 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.

Those who have had laboratory confirmed COVID-19 infection within 9 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 nine 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 nine months after natural infection.

Those who have had laboratory confirmed COVID‐19 infection within 9 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?

The day that the first dose of vaccine is given is day 0.

Comirnaty® (Pfizer BioNTech) 

  • If the second dose is given at an interval of less than 17 days, this this is not considered a valid dose. A third dose should be given 28 days after the second (invalid) vaccine.
  • If a dose is given between 17 and 27 days, this is considered a valid dose.

SpikeVax® (COVID‐19 Vaccine Moderna)

  • If a dose is given at an interval of less than 24 days, it is not considered a valid dose. A third dose should be given 28 days after the second (invalid) vaccine.
  • If a dose is given between 24 and 27 days, this is considered a valid dose.

Vaxzevria® (COVID‐19 Vaccine AstraZeneca)

  • If a dose is given at an interval of less than 24 days, it is not considered a valid dose. A third dose should be given 28 days after the second (invalid) vaccine.
  • If a dose is given between 24 and 27 days, this is considered a valid dose.

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® (Pfizer BioNTech) 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.

In CVC where doses may be prepared in advance, if eight doses have been obtained from a vial, each of the syringes must be examined by another person to identify the syringe with less than 0.3ml. If all syringes contain 0.3ml then more than 1.8ml must have been added and the vial has been over‐diluted.

What if a person under 12 years is given Comirnaty® (Pfizer BioNTech) or Spikevax® (Moderna) vaccine inadvertently

The vaccine is currently licensed by the EMA from age 12 years and above only. The young person and their parent/guardians should be informed. A HSE incident form should be completed and the incident reported to the HPRA. The young person and their parents/guardians should be advised regarding the common adverse events expected after vaccination. They should also be informed of the very rare adverse event of myocarditis and pericarditis, the symptoms to be aware of, and to seek medical attention if they develop.

What if a person under 18 years is given Vaxzevria®(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. They should be advised of Thrombosis with Thrombocytopenia syndrome (TTS) reported very rarely after vaccination, and of the symptoms to be aware of, and to seek urgent medical attention should these appear. They should also be advised of the very rare reported adverse event of capillary leak syndrome and of the symptoms to be aware of. If they received COVID‐19 vaccine Janssen®, they should also be advised of the very rare adverse event of Guillain‐Barré syndrome and of the symptoms to be aware of.

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

The woman should have had an individual benefit/risk discussion with their obstetric care prior to vaccination.

Women who are receiving a second dose of an mRNA vaccine may receive the vaccine at any stage of pregnancy.

If the woman received a 1st dose of Vaxzevria®, she may receive a second dose between 14 and 36. If the woman choses to receive an mRNA vaccine as a second dose, the vaccine can be given at any stage of pregnancy.

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, the second dose can be given at any stage of pregnancy, following an individual benefit/risk discussion with their obstetric care giver.

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 6 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 a vaccine but it is not a contraindication to vaccination, it is not currently recommended to give a vaccine from a different platform (i.e., mRNA or viral vector) as a second dose. However, a person who has received a 1st dose of Vaxzevria® but has chosen not to receive a second dose may receive an mRNA vaccine at least 28 days after the 1st Vaxzevria® dose.

Please refer to Section 6 for more details and to the Immunisation Guidelines for Ireland Chapter 5a.

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 SpikeVax® (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 for both vaccines are a genetically modified organism (GMO) with a new combination of genetic material. These changes to the adenovirus in each of the vaccines allow the vaccine to deliver the spike protein genetic code to the cells without causing COVID‐19.

Does Vaxzevria® (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 Vaxzevria® (AstraZeneca) 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

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

They should receive their second dose of Vaxzevria® (AstraZeneca) as scheduled. There is no evidence of an increased risk of TTS after the second dose of Vaxzevria® (current evidence suggests the risk may be much lower after the second dose 1.6/million). If a person has received a 1st dose of Vaxzevria and has decided not to receive a 2nd dose, they can receive an mRNA vaccine as a second dose at least 28 days after the 1st dose of Vaxzevria.

Should a person who has already received a first dose of Vaxzevria® (AstraZeneca) be offered a different vaccine for their second dose?

The National Immunisation Advisory Committee have recently revised their recommendations regarding heterologous (different vaccine) COVID‐19 vaccination schedules. NIAC have advised that homologous (the same vaccine) vaccination schedules are recommended for all age groups and preferred especially for those aged under 50 years. This is recommended because of the proven effectiveness and safety of two Vaxzevria® doses against COVID‐19. Therefore, Vaxzevria® should be used for both doses unless contraindicated.

However, in the event where a person who has received a first dose of Vaxzevria® does not wish to get a second dose they can choose to get an mRNA vaccine as their second dose. Those who choose to receive an mRNA vaccine as their second dose must be informed that:

  • This option is not approved or licensed by the EMA and is “off‐label”
  • While there is evidence of increased immunogenicity for this schedule compared to two doses of Vaxzevria®, there is no evidence that this results in increased protection against COVID‐19.
  • There is no evidence that this schedule has efficacy against COVID‐19.
  • There is limited evidence about the safety of mixing two different COVID‐19 vaccines although there have not been safety concerns identified so far
  • The rate of side effects following the administration of a heterologous vaccination schedule may be higher

Would you recommend taking paracetamol before being vaccinated?

It is not recommended that over the counter medicines such as paracetamol or ibuprofen are taken before being vaccinated with a COVID‐19 vaccine for the purposes of preventing potential vaccine related side effects. However, if you are taking any of these medications regularly as prescribed  by a doctor do continue to take them as usual.. 

Can other vaccines be co‐administered with COVID‐19 vaccines?

Yes, recent NIAC recommendations have been updated to enable co‐administered of other vaccines with COVID‐19 vaccines. Other vaccines may be administered with COVID‐19 vaccines at the same time or at any interval. If other vaccines are being given at the same time as COVID‐19 vaccines it is preferable to give them in different limbs.

Do COVID‐19 vaccines affect the results of COVID‐19 tests?

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

Comirnaty® (Pfizer BioNTech) and Spikevax® (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.

What is the advice if someone has received a COVID-19 vaccine outside Ireland?

Those who have documentary evidence of a complete COVID‐19 vaccination course with a COVID‐19 vaccine authorised by the FDA, MHRA or recommended by WHO should be considered fully vaccinated.

Those who have partially completed a COVID‐19 vaccine course with a vaccine authorised by the FDA, MHRA or recommended by WHO should be offered an EMA authorised COVID‐19 vaccine to complete the series, and then should be considered fully vaccinated. The minimum interval between the last vaccine dose and an EMA authorised COVID‐19 vaccine is 28 days.

Those who have received a partial or complete course of COVID‐19 vaccine not authorised by the FDA, MHRA or recommended by WHO should be offered a complete course of an EMA authorised COVID‐19 vaccine. The minimum interval between the last dose and an EMA authorised COVID‐19 vaccine is 28 days.

Are booster doses of COVID‐19 vaccines be needed?

The only groups recommended to receive a booster dose of a COVID-19 vaccine are people aged 65 years and older living in long-term care facilities, and people aged 80 years and older living in the community. The need and timing for booster doses for any other groups has not been established and is not recommended.

See Section 8 of the COVID-19 Clinical Guidelines for more information 

What is the advice for timing of a booster dose in someone who has had a breakthrough infection since completing their primary vaccination course?

If a person has had laboratory confirmed (PCR) breakthrough COVID-19 infection since completion of their primary course, the booster dose should be deferred for at least 6 months after diagnosis. If it is not possible to establish if a person had breakthrough COVID-19 infection in this timeframe, they may be vaccinated.

What is the advice for timing of an additional dose of vaccine for an immunocompromised person who has had a breakthrough infection since completing their primary vaccination course?

If a person has had laboratory confirmed (PCR) breakthrough COVID-19 infection since completion of their primary course, the booster dose should be deferred for at least 6 months after diagnosis. If it is not possible to establish if a person had breakthrough COVID-19 infection in this timeframe, they may be vaccinated.

 

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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.

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 8 October 2021