FAQs Booster Dose

Booster COVID-19 vaccination for recommended groups who have already completed their primary course with any COVID-19 vaccine type

Frequently asked questions for vaccinators and health professionals 

 

First Booster Information

Who is recommended to get a COVID-19 vaccine booster dose?

The National Immunisation Advisory Committee has advised one booster dose of an mRNA vaccine is recommended for people aged 12 years and older who have already completed their primary course with any COVID-19 vaccine type.

People who are immunocompromised and have received an additional dose, should also receive a booster dose.

Why is a booster dose recommended?

All authorised COVID-19 vaccines have high levels of vaccine effectiveness against hospitalisation, severe disease and death against both the Alpha and the Delta variants. While there is some decline in protection against infection with time from primary vaccination, high protection against severe disease is retained for at least six months.

Declines in vaccine effectiveness with an increase in breakthrough infections in those aged 65 and older, increasing with age, have been reported from Israel and the US. This decline may be due to waning immunity in older persons coupled with relaxation of non-pharmaceutical interventions and the emergence of the Delta variant.

Is there scientific evidence for a booster dose?

The additional dose elicits significantly higher neutralising antibody (NA) titres against the initial SARS-CoV-2 virus (wild type), and the Beta and Delta variants, compared to the levels observed after the two-dose primary series.

A population based booster programme of Comirnaty® vaccine to approximately one million people, shared by the Israeli Health Ministry reported that no safety concerns were identified. A similar profile of adverse events were reported, but lower rates of systemic and local reactions were reported after a 3rd dose than following the first or second doses.

Which COVID-19 vaccine is recommended?

  • People who are 30 years or older are recommended a single dose of the Comirnaty®/Pfizer BioNTech or Spikevax®/Moderna vaccine.
  • People aged 12-29 years inclusive are recommended Comirnaty®/Pfizer BioNTech vaccine, and not Spikevax®/Moderna vaccine.

This is as a precaution, because of reports of more frequent cases of myocarditis and pericarditis associated with a second dose of Spikevax®/Moderna compared to Comirnaty®/Pfizer BioNTech.

This is the recommendation regardless of the type of vaccine previously administered.

What is the vaccine dosage for a booster dose of vaccine?

  • For Comirnaty®, the recommended vaccine dose is the same as the that for the primary course i.e 0.3mls
  • For Spikevax®, for those aged 30 years and older only, the recommended vaccine dose is 0.25mls (half the dose used for the primary course)

When is the booster dose recommended for those aged 16 years or older?

The booster dose should be given after an interval of at least 3 months following the last dose of an authorised COVID-19 vaccine.

When is the booster dose recommended for those aged 12 to 15 years (inclusive)?

The booster dose should be given after an interval of at least 6 months following the last dose of an authorised COVID-19 vaccine.

In exceptional circumstances a minimum interval of 5 months after the last dose of covid vaccine may be used.

When is the booster dose recommended for those aged 12 to 15 years (inclusive) with immunocompromise?

Anyone aged 12-15 years inclusive with an immunocompromise at the time of primary vaccination, the booster dose should be administered at least 3 months after the last dose of a COVID-19 vaccine (the additional dose). In exceptional circumstances, a minimum interval of two months can be used here.

Has the EMA recommended booster doses of COVID-19 vaccines?

Yes, the European Medicines Agency (EMA) has authorised booster doses of the same mRNA vaccine as that given for the primary course. The National Immunisation Advisory Committee has recommended a booster dose of an mRNA vaccine or these groups, regardless of the vaccine received as the primary course.

Is it recommended to check serology before administering a booster dose?

No. This is not recommended. There is no agreed or recommended correlate of protection (there is no agreed or recommended antibody level above which you would not vaccinate, or below which you would vaccinate).

What is the recommended timing of the booster dose in people who have had laboratory-confirmed breakthrough infection since they completed their COVID-19 vaccination course?

The National Immunisation Advisory Committee continue to advise the booster dose should be delayed for at least 3 months after the laboratory-confirmed COVID-19 infection was diagnosed. This is because a laboratory-confirmed COVID-19 infection is known to be highly immunogenic.

Serological testing prior to giving a booster dose is not recommended as mentioned above. If it cannot be established if an individual had COVID-19 infection in the time frame they may be vaccinated.

Can the booster dose be given with flu vaccine or other vaccines?

Yes. The booster dose can be given at the same time as or at any interval before or after seasonal influenza vaccine (or any other vaccine including PPV23 vaccine). This will allow the uptake of both COVID and seasonal influenza vaccines to be optimised in these groups. The vaccines should be given in separate arms if possible.

What vaccine is recommended as a booster dose if someone has a contraindication to an mRNA vaccine?

A booster adenoviral vector vaccine (COVID-19 Vaccine Janssen®) can be considered for those with a contraindication or precaution to an mRNA vaccine. This includes pregnant women.

New NIAC recommendation in relation to the waiting time after booster COVID-19 vaccination

The National Immunisation Advisory Committee (NIAC) has suspended the 15-minute wait time after vaccination for those who are receiving a booster covid vaccine only.  This is because the risk of anaphylaxis is extremely rare (1-10 per million) after an mRNA vaccine.

However those attending for Primary Covid vaccination should continue to wait for 15 minutes.

Those with a history of anaphylaxis from any cause will still need to wait 30 minutes after vaccination.

What if the booster dose is given before then minimum 2 months interval?

If a booster dose was given in error before the minimum interval, this is not considered a valid vaccine. However there is no evidence of the safety and efficacy of any additional doses. Revaccination is not recommended.

Second Booster Information

Who is recommended to get a 2nd COVID-19 vaccine booster dose?

a) All those aged 65 years and older (a 4th Covid vaccine dose)

b) All those aged 12 or older with immunocompromise associated with suboptimal response to vaccines (a 5th Covid vaccine dose).

Why is a 2nd COVID-19 vaccine booster dose recommended for these cohorts?

To maintain high levels of immunity in those most at risk of severe disease and prevent severe breakthrough infection, hospitalisation, and death from Covid the National Immunisation Advisory Committee (NIAC) is now recommending a second booster dose of an mRNA vaccine.

Which COVID-19 vaccine is recommended?

An mRNA vaccine is now recommended

People who are 30 years or older are recommended a single dose of the Comirnaty®/Pfizer BioNTech or Spikevax®/Moderna vaccine. For Spikevax (Moderna) vaccine the booster dose is 0.25ml.

People aged 12-29 years inclusive are recommended Comirnaty®/Pfizer BioNTech vaccine, and not Spikevax®/Moderna vaccine.

At what time interval is the 2nd COVID-19 vaccine booster dose recommended?

NIAC advises a second booster vaccine is recommended at least six months after the first booster. NIAC also advises a minimum interval of four months may be used for operational reasons.  Following NAIC Guidance the HSE is operationalising the 2nd COVID-19 vaccine booster dose from at least 4 months after the 1st COVID-19 vaccine booster dose.

What is the recommended timing of the booster dose in people who have had laboratory-confirmed breakthrough infection since they received their 1st COVID-19 vaccine booster?

It is recommended to defer the second booster vaccine for six months following breakthrough infection onset.  A minimum interval of four months may be used for operational reasons. Following NIAC Guidance the HSE is operationalising the 2nd COVID-19 vaccine booster dose from at least 4 months after a breakthrough Covid infection.  This is when the breakthrough infection occurred after the 1st COVID-19 vaccine booster dose.

Is 2nd COVID-19 vaccine booster vaccine given before the minimum 4 months interval valid?

If a 2nd COVID-19 vaccine booster vaccine dose was given in error before the minimum interval, this is not considered a valid vaccine. However there is no evidence of the safety and efficacy of any additional doses. Revaccination is not recommended.

Is there evidence for effectiveness a 2nd COVID-19 vaccine booster?

Two Israeli studies support the effectiveness of a second booster in older populations. In a study of those aged 60 years a second booster of Comirnaty®/Pfizer BioNTech provided considerable additional protection against both infection and severe disease compared to one booster dose. Although additional vaccine effectiveness against infection waned rapidly, declining from a peak of 64% to 29% after 10 weeks, the additional protection against severe disease was sustained at greater than 73% over 6-9 weeks follow-up.

Is a 2nd COVID-19 vaccine booster safe?

First and second booster doses of mRNA vaccines have not shown any unexpected short term safety concerns. Myocarditis and pericarditis are very rare risks of mRNA vaccination, predominantly in males aged under 30 years after the second dose of the primary vaccination course and the risk appears to be comparatively lower following a first booster dose.

Data on second booster doses is more limited but preliminary experience from Israel in studies mentioned above has not revealed any new safety concerns.

Has the EMA recommended a 2nd COVID-19 vaccine booster?

Both the European Centre for Disease Prevention and Control (ECDC) and EMA’s COVID-19 task force (ETF)agencies agree that a fourth dose (or second COVID-19  vaccine booster) can be given to adults 80 years of age and above after reviewing data on the higher risk of severe COVID-19 in this age group and the protection provided by a fourth dose.

The EMA concluded however that it is too early to consider using a fourth dose (or second COVID-19 vaccine booster) of mRNA COVID-19 vaccines in the general population.

Can the a 2nd COVID-19 vaccine booster be given with other vaccines?

Yes. The 2nd COVID-19 vaccine booster dose can be given at the same time as or at any interval before or after seasonal influenza vaccine (or any other vaccine including PPV23 vaccine). This will allow the uptake of both COVID and seasonal influenza vaccines to be optimised in these groups. The vaccines should be given in separate arms if possible.

If a 2nd COVID-19 vaccine booster is contraindicated can another vaccine be given?

A non m RNA vaccine can be considered for a 2nd COVID-19 vaccine booster dose for those with a contraindication or precaution to an mRNA vaccine. This includes pregnant women.

How long do people need to be observed after a 2nd COVID-19 vaccine booster?

NIAC recommends that the 15 minute observation period following administration of a homologous or heterologous booster COVID-19 mRNA vaccine can be temporarily waived. The reasons for this recommendation are:

  • The risk of a serious allergic reaction after mRNA vaccination is very rare (1-10 per million).
  • Removing the 15 minute post observation requirement will enable more people to be vaccinated.

However Vaccine recipients should be advised to seek urgent medical attention if they have symptoms suggestive of an allergic reaction such as difficulty breathing, feeling faint, rapid heartbeat or a skin rash.

 

 

Additional resources 

This page was updated on 19 March 2022