Common questions about COVID-19 vaccination answered

Quick answers to some key questions you may be asked about the COVID-19 vaccination, based on information from the Green Book.
Common questions about COVID-19 vaccination answered

This article provides quick answers to common questions patients may ask about the COVID-19 vaccination. 

This summary is based on the information in COVID-19: the green book, chapter 14a and focuses on the Pfizer BioNTech COVID-19 vaccine, approved on 02 December, and the Oxford–AstraZeneca COVID-19 vaccine, which is undergoing phase 3 trials.

Update: the Oxford University/AstraZeneca vaccine is now authorised in the UK
as of 30/12/2020.

For a comparison of the key characteristics of each vaccine, you can also access our practical reference table, which you can download:

Common questions about COVID-19 vaccination

  1. Doctor I have a bleeding disorder, should I be concerned?
  2. What should be done if a patient’s vaccination course is interrupted?
  3. Is a booster dose required after the two doses?
  4. Can I have the COVID-19 vaccine with other vaccines?
  5. Is the vaccine safe in pregnancy or when breastfeeding?
  6. Is the vaccine safe in children?
  7. Is the vaccine safe in those with immunosuppression or HIV?
  8. What are the contraindications to use of the vaccine?
  9. What happens if the patient has a minor illness?
  10. What adverse events should patients be warned about?
  11. Is there any reported anaphylaxis or other allergic reactions?
  12. Can vaccination be used if a patient was exposed to COVID-19?

Q1. Doctor I have a bleeding disorder, should I be concerned?

A: Individuals with bleeding disorders may be vaccinated intramuscularly if, in the opinion of a doctor familiar with the individual’s bleeding risk, vaccines or similar small volume intramuscular injections can be administered with reasonable safety by this route. If the individual receives medication/ treatment to reduce bleeding, for example treatment for haemophilia, intramuscular vaccination can be scheduled shortly after such medication/ treatment is administered. Individuals on stable anticoagulation therapy, including individuals on warfarin who are up-to-date with their scheduled INR testing and whose latest INR is below the upper level of the therapeutic range, can receive intramuscular vaccination. A fine needle (23 or 25 gauge) should be used for the vaccination, followed by firm pressure applied to the site without rubbing for at least 2 minutes (ACIP 2019). The individual/parent/ carer should be informed about the risk of haematoma from the injection.

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Q2. What should be done if a patient’s vaccination course is interrupted?

A: Previous incomplete vaccination If the course is interrupted or delayed, it should be resumed using the same vaccine but the first dose should not be repeated. There is no evidence on the interchangeability of the COVID-19 vaccines although studies are underway (JCVI, 2020). Therefore, every effort should be made to determine which vaccine the individual received and to complete with the same vaccine. For individuals who started the schedule and who attend for vaccination at a site where the same vaccine is not available, or if the first product received is unknown, it is reasonable to offer a single dose of the locally available product. This option is preferred if the individual is likely to be at immediate high risk or is considered unlikely to attend again. In these circumstances, as both the vaccines are based on the spike protein, it is likely the second dose will help to boost the response to the first dose. For this reason, until additional information becomes available, further doses are not required.

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Q3. Is a booster dose required after the two doses?

A: Booster doses of COVID-19 vaccine are not yet recommended because the need for, and timing of, boosters has not yet been determined.

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Q4. Can I have the COVID-19 vaccine with other vaccines?

A: Because of the absence of data on co-administration with COVID-19 vaccines, it should not be routine to offer appointments to give this vaccine at the same time as other vaccines. Based on current information about the first COVID-19 vaccines being deployed, scheduling should ideally be separated by an interval of at least 7 days to avoid incorrect attribution of potential adverse events.

As both of the early COVID-19 vaccines are considered inactivated (including the nonreplicating adenovirus vaccine), where individuals in an eligible cohort present having received another inactivated or live vaccine, COVID-19 vaccination should still be considered. The same applies for other live and inactivated vaccines where COVID-19 vaccination has been received first. In many cases, vaccination should proceed to avoid any further delay in protection and to avoid the risk of the patient not returning for a later appointment. In such circumstances, patients should be informed about the likely timing of potential adverse events relating to each vaccine.

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Q5. Is the vaccine safe in pregnancy or when breastfeeding?

A: Although the available data do not indicate any safety concern or harm to pregnancy, there is insufficient evidence to recommend routine use of COVID-19 vaccines during pregnancy. In addition to not vaccinating in pregnancy, MHRA advise that pregnancy should be avoided until 2 months after the second dose of vaccine. They also have advised vaccination should not be given whilst breastfeeding. MHRA have not advised performing a pregnancy test prior to offering vaccination.

JCVI have advised that routine questioning about last menstrual period and/or pregnancy testing is not required before offering the vaccine. JCVI have agreed that those being invited for vaccination should be able to access this additional advice (for example as a leaflet or by signposting to online information) but their understanding checked as part of the consent process. This will also help to avoid health and care staff having to disclose the fact that they are pregnant or planning pregnancy during mass vaccination sessions in the workplace.

If a woman finds out she is pregnant after she has started a course of vaccine, she should complete her pregnancy before finishing the recommended schedule. Women at high risk (including health care workers), should be offered vaccine as soon as possible after pregnancy.

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Q6. Is the vaccine safe in children?

A: SARS-CoV-2 vaccine trials have only just begun in children and there are, therefore, very limited data on safety and immunogenicity in this group. Children and young people have a very low risk of COVID-19, severe disease or death due to SARS-CoV-2 compared to adults and so COVID-19 vaccines are not routinely recommended for children and young people under 16 years of age.

Given the increased risk of exposure to infection and outbreaks in institutional settings, vaccination may be considered for children with serious neuro-disabilities (including cerebral palsy, severe autism and Down’s syndrome) who spend regular time in specialised residential care settings for children with complex needs. As older children have higher risk of acquiring and becoming sick from infection and there are some safety data on the Pfizer BioNTech COVID-19 vaccine in children aged 12 years and older, vaccination of older children in these settings should be considered. As this would be outside the terms of the MHRA approval, this would be considered unlicensed use.

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Q7. Is the vaccine safe in those with immunosuppression or HIV?

A: Individuals who have immunosuppression and HIV infection (regardless of CD4 count) should be given COVID-19 vaccine in accordance with the recommendations and contraindications above. Although AstraZeneca COVID-19 vaccine contains a live adenovirus vector, this virus is not replicating and is considered safe in immunosuppressed people. Other adenovirus vector vaccines have been trialled in populations with high prevalence of HIV and shown no serious adverse events. Although individuals with stable treated HIV infection were not excluded from the phase 3 trial of the Pfizer BioNTech COVID-19 vaccine, data on safety and effectiveness in this group have not been presented. These individuals may not make a full antibody response and should therefore continue to follow advice to avoid exposure unless they are advised otherwise by their doctor.

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Q8. What are the contraindications to use of the vaccine?

A: There are very few individuals who cannot receive the Pfizer-BioNTech or AstraZeneca COVID-19 vaccines. Where there is doubt, rather than withholding vaccination, appropriate advice should be sought from the relevant specialist, or from the local immunisation or health protection team.

The vaccine should not be given to those who have had:

  • a confirmed anaphylactic reaction to a previous dose of a COVID-19 vaccine,
  • a confirmed anaphylactic reaction to any components of the COVID-19 vaccine

The MHRA has issued update advice on the Pfizer/BioNTech vaccine on Wednesday 09 December following two reports of anaphylaxis and one report of a possible allergic reaction following immunisation:

  • Any person with a history of immediate-onset anaphylaxis to a vaccine, medicine or food should not receive the Pfizer/BioNTech vaccine.
  • A second dose of the Pfizer/BioNTech vaccine should not be given to those who have experienced anaphylaxis to the first dose of Pfizer/BioNTech vaccination.

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Q9. What happens if the patient has a minor illness?

A: Minor illnesses without fever or systemic upset are not valid reasons to postpone immunisation. If an individual is acutely unwell, immunisation may be postponed until they have fully recovered. This is to avoid confusing the differential diagnosis of any acute illness (including COVID-19) by wrongly attributing any signs or symptoms to the adverse effects of the vaccine.

There is no evidence of any safety concerns from vaccinating individuals with a past history of COVID-19 infection, or with detectable COVID-19 antibody.

Vaccination of individuals who may be infected or asymptomatic or incubating COVID-19 infection is unlikely to have a detrimental effect on the illness. Vaccination should be deferred in those with confirmed infection to avoid confusing the differential diagnosis. As clinical deterioration can occur up to two weeks after infection, ideally vaccination should be deferred until clinical recovery and at least four weeks after onset of symptoms or four weeks from the first PCR positive specimen in those who are asymptomatic.

Having prolonged COVID-19 symptoms is not a contraindication to receiving COVID-19 vaccine but if the patient is seriously debilitated, still under active investigation, or has evidence of recent deterioration, deferral of vaccination may be considered to avoid incorrect attribution of any change in the person’s underlying condition to the vaccine.

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Q10. What adverse events should patients be warned about?

A: Local reactions at the injection site are fairly common after Pfizer BioNTech COVID-19 vaccine, primarily pain at the injection site, usually without redness and swelling. Systemic events reported were generally mild and short lived. In the final safety analysis of over 21,000 participants 16 years and older, the most common events were injection site pain (>80%), fatigue (>60%), and headache (>50%). Myalgia, arthralgia and chills were also common with fever in 10-20%. Most were classified as mild or moderate. Lymphadenopathy was reported in less than 1%.

In an earlier analysis of around 8,000 recipient, severe side effects, defined as those that interfere with daily activity, included fatigue in around 4% and headache in 2%. Older adults tend to report fewer adverse events following vaccination. This earlier analysis also showed no signal for enhanced disease in vaccine recipients with only 1 case of severe COVID in the 8 vaccine failures at that time.

From early phase trials, mild pain and tenderness at the injection site was common with AstraZeneca COVID- 19 vaccine occurring in 88% of 18-55 year olds, 73% of 56-69 year olds and 61% of people aged 70 years or over; similar levels were reported after each dose. Short lived systemic symptoms including fatigue and headache were also common but decreased with age, being reported in 86%, 77%, and 65% of those aged 18-55, 56-69 and 70 years or over respectively; most of these were classified as mild or moderate. These reactions were unusual after the second dose. Mild fever (>38˚C) was recorded in the first 48 hours for around a quarter of younger participants and but was not reported in those over 55 years of age or in any age group after the second dose. Fever can be modified by the prophylactic use of paracetamol, which does not affect the immune response to this vaccine.

Vaccinated individuals should be advised that the COVID-19 vaccine may cause a mild fever which usually resolves within 48 hours. This is a common, expected reaction and isolation is not required unless COVID-19 is suspected.

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Q11. Is there any reported anaphylaxis or other allergic reactions?

 A: Anaphylaxis is a very rare, recognised side effect of most vaccines and suspected cases should be reported via the Coronavirus Yellow Card Scheme.

Two reactions in atopic individuals were reported as well as one possible allergic reaction following immunisation with the Pfizer/BioNTech vaccine during the early rollout of the vaccination programme

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Q12. Can vaccination be used if a patient was exposed to COVID-19?

A: There is currently limited evidence to support the use of COVID-19 vaccines as postexposure prophylaxis or to interrupt transmission during outbreaks.

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