FAQs about COVID-19 vaccines

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At the start of the pandemic, vaccination offered you the best protection from getting seriously ill or dying from COVID-19, and enabled society to function without strict lockdowns.

When the vaccine was well-matched to the circulating virus, as it was early in the vaccine roll out, getting vaccinated helped to protect yourself, as well as others who could not get vaccinated, because it reduced your risk of spreading the virus.

The emergence of new variants means that the current vaccines are not as well-matched. But they  are still good at preventing severe disease and death from COVID-19. They are less protective against mild infection.

Now that most people have either been vaccinated, or have had COVID-19, the risk of severe illness has receded for most of us. Vaccination is now best targeted to people in the population who have frailty, such as the very elderly, or those with other health conditions.

This is because COVID-19 is now more like seasonal influenza, which acts as a co-factor in hospital admission or death and is largely restricted to those in vulnerable groups. Seasonal influenza is far less likely to cause severe illness on its own in healthy individuals.

Because none of the approved COVID 19 vaccines contain live virus, they are suitable for the large majority of people. A few people with known, specific vaccine-related allergies may not be able to get vaccinated.


If you are eligible for vaccination, including any booster doses, you are recommended to have them, even if you have already had COVID-19, as vaccination offers the best defence against serious infection with the virus.


Children and young people have a very low risk of becoming seriously ill from COVID-19 disease compared with adults. 

When vaccine programmes were rolled out, children were offered vaccination to prevent rare episodes of severe disease and death. Today with many children vaccinated, and most having already developed some immunity from infection, the additional benefits of further vaccine doses are more limited.

In the UK, all children aged five and over, on and before 31 August 2022, were offered a 1st and 2nd dose of the vaccine. People over the age of 16, and some 12 to 15 year olds, were also offered a booster. These programmes have now ended.

Currently, children aged five and over are eligible for a 1st and 2nd dose of the vaccine if they are at high risk due to a health condition or if they have a weakened immune system, or if they are living with someone with a weakened immune system. 

Children in this category are also eligible for a booster dose as part of the UK's Autumn 2023 booster programme. This also includes children who are 16 and classified as carers, or working in a care home.

From June 2023 very young children in the UK, aged six months to four years of age who are in a clinically vulnerable group, have been offered two doses of the Pfizer-BioNTech vaccine.

This vaccine was first authorised for use in this very young age group by the Medicines and Healthcare products Regulatory Agency in December 2022.

Following a review of the available evidence, the government’s advisory group, the Joint Committee on Vaccination and Immunisation, recommended its use for clinically vulnerable children only in April 2023.

Very young children, up to four years of age, will also be eligible for a booster as part of the Autumn 2023 booster programme.

If your child is in a clinically vulnerable group, and eligible for these vaccinations, you will be contacted directly by the NHS.



The overall aim of vaccination programmes, including COVID-19 vaccination, is to protect the most vulnerable populations. The COVID-19 vaccines are found to be effective in preventing severe disease and hospitalisation, including those aged over 65 and those with other medical conditions.

In the UK vaccination priority list, the elderly populations are the first groups recommended for vaccination. See the priority list here

An early monitoring report from Public Health England shows that between December 2020 - February 2021 when vaccinations for the elderly age group were initiated, weekly hospitalisations fell by at least 60% in those aged over 65.

Similar trends are seen in the weekly rate of deaths for this age group in the same period. See the latest report here.


Most experts think some individuals will need booster doses in future, particularly those who are elderly or with certain underlying health conditions. This is something that scientists and governments are closely monitoring. So far the seasonality of the virus is unpredictable, so it is unclear when or how often to boost. This will become clearer the longer the virus is around.

Current studies show that booster doses increase immune responses against COVID-19, including new variants, and provide the best defence against the virus. 

While there is potential benefit for everyone in receiving booster doses because they will reduce the risk of infection, for most previously-vaccinated people the virus causes only a mild illness, and so governments have to balance the benefits with the cost of the vaccine.

Most governments are expected to limit boosters to vulnerable individuals who will become more seriously unwell if they develop infection and are likely to be hospitalised or die.



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The COVID-19 vaccines currently approved in the UK have been thoroughly reviewed by the Medicines and Healthcare products Regulatory Agency (the MHRA). 

The regulatory team completed a full review of the safety information reported from the vaccines’ trials, including from several months after trial participants received the vaccines, and continue to review any safety-related data that emerges.

The MHRA carried out their review of side effects and medical conditions that people in the trials experienced by comparing the number of illnesses reported in the vaccinated group with the control group to see whether the vaccine could be associated with an increase in any medical conditions.

The rates of illness are also compared with the rate of those illnesses in the general population. For any severe illnesses reported, a specialist doctor involved in treating the person, and an independent safety committee, consider whether the illness could be associated with the vaccine. All the information about adverse events (unexpected illnesses) reported during the trials would have been provided to the regulators.

The vaccines are also being continuously monitored in a number of ways. In the UK, the MRHA has a dedicated scheme - Yellow Card – to which people can report any side-effects. In addition, the health of participants from the original clinical trials is ‘followed up’ for a number of years.

Work to develop coronavirus vaccines actually began some 20 years ago because this family of viruses was already a threat to our health. For example, coronaviruses are cause of the original SARS (Severe Acute Respiratory Syndrome), as well as the common cold.  

The COVID-19 pandemic led to an international effort to carry out the final stages of vaccine development. Many of the obstacles which usually slow down vaccine development were removed.

In addition, there was the help of significant funding, collaboration, efficient large-scale manufacturing and thousands of volunteers. This does not mean that steps were skipped, or that safety was compromised. 

More information about the speed of vaccine development is available here: 

Vaccines 101: How new vaccines are developed


There is no scientific evidence to suggest that the COVID-19 vaccines work differently in people of different ethnic groups. The vaccines approved for use in the UK have been tested in a diverse range of ethnic groups.

For example, the Oxford-AstraZeneca vaccine intentionally included people from ethnically diverse communities within different countries including South Africa, Brazil and the UK, as part of their clinical trials to investigate both efficacy and safety of the vaccines.


COVID-19 vaccination is recommended for people who are pregnant, breastfeeding, or trying to become pregnant. COVID-19 disease can cause severe illness in pregnant individuals, especially if they become infected during the third trimester or have underlying health conditions.

There is no evidence that the COVID-19 vaccines cause additional side effects in pregnant people or any harm to the unborn baby. There is no evidence of COVID-19 vaccines affecting fertility.


The currently approved COVID-19 vaccines are not live vaccines and are therefore considered safe in immunocompromised people.

The Oxford-AstraZeneca vaccine, which is the most widely used globally, contains part of a weakened adenovirus as a vector to deliver the genetic sequence for the SARS-CoV-2 spike protein into cells. The vector has been modified so that it cannot replicate and is safe.

For people that are yet to begin immunosuppression treatments, general best practice is that they should be considered for vaccination at least two weeks before starting therapy and when possible, it is preferable to complete the two doses prior to starting immunosuppression.

Studies have shown that some individuals with compromised immune systems have lower or weaker responses to the COVID-19 vaccines. Additional doses may help to raise immunity provided by vaccines, so those who are immunocompromised are encouraged to take up boosters if they are offered them. 


Some people experience side effects in the days following vaccination. Side effects that would be expected are mostly “flu-like”, such as a headache, aching, fever, as well as pain and tenderness at the injection site. More information about expected side effects and allergic reactions is available here.


None of the currently approved vaccines are using a live SARS-CoV-2 virus in them, so you cannot get COVID-19 from them. It is common to get symptoms that feel the same as an infection for a few days after you have a vaccine (e.g. feeling “fluey”).  This is a sign that your immune system is responding to the vaccine, not that you have got a real infection. 


There has been inaccurate information circulating online about the new technologies used for the Pfizer-BioNTech, Moderna, and Oxford-AstraZeneca vaccines. Whilst these technologies use genetic codes to produce a harmless version of the spike protein inside the body, this code cannot be incorporated into the body’s DNA. This is because:

  • mRNA vaccines like the Pfizer-BioNTech and Moderna vaccines cannot reach the part of the cell that holds the DNA, called the nucleus.
  • mRNA cannot be translated back into DNA.
  • Both mRNA and adenovirus vaccines do not contain the “specialised tools” needed to “copy” or “edit” DNA.

These vaccines cannot replicate inside the body and only stay in the body for a few days. After helping the cells to produce an immune response against the spike protein, the vaccine is removed by the body.

For more information about the genetic technologies used in the COVID-19 vaccines, please see COVID-19 vaccines.


There is no evidence that the immune response to coronaviruses has any impact on fertility in animals or humans, and there is no biological mechanism that has been shown to result in an impact on fertility.

Regulators have looked at the data carefully from the clinical trials and have not recommended any precautions for individuals planning to become pregnant. 


Studies have shown that mixing vaccine schedules is safe and effective against COVID-19. You may be offered different vaccines for any booster doses to ensure you are protected against different types of the virus that have emerged since the start of the pandemic.


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The vaccines approved for use in the UK do not contain any human or animal derived ingredients.


No pork or other animal derived ingredients are contained in the Pfizer-BioNTech, Moderna, or Oxford-AstraZeneca vaccines. The Oxford-AstraZeneca vaccine has ethanol (alcohol) listed as an ingredient, but this is in amounts lower than found in natural foods.

Most scholars have deemed these vaccines permissible. For further information about this, visit the British Islamic Medical Association.


For further information about who is eligible to receive the vaccine in the UK, see COVID-19 vaccines. You will be contacted by the NHS if you are eligible to receive a booster dose of the vaccine.

Information about who is eligible to receive the vaccine in the USA is available from the Centers for Disease Control and Prevention.

COVID-19 vaccination strategies for the EU/EEA is available from the European Centre for Disease Control and Prevention.


Yes, the approved vaccines in the UK are given as injections in the upper arm.

Although there is ongoing work to develop a vaccination delivered by nasal spray, this is still a long way off.


ChAdOx1 nCoV-19 is made from a virus (ChAdOx1), which is a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees. The adenovirus has been genetically changed so that it is impossible for it to cause infection in humans.   

Genetic material has been added to the ChAdOx1 virus, that is used to make a protein from the COVID-19 coronavirus (SARS-CoV-2) called Spike glycoprotein (S). This protein is found on the surface of SARS-CoV-2 and plays an essential role in how the SARS-CoV-2 virus infects our cells.

Vaccinating with ChAdOx1 nCoV-19 trains the body to recognise and develop an immune response to the spike protein that helps to prevent infection from the SARS-CoV-2 virus if it later enters the body.

For more information, see our page on COVID-19 vaccines.



There are six vaccines approved for use in the UK, although only three are currently in use. There are:

  • Moderna (Spikevax)
  • Pfizer/BioNTech (Comirnaty)
  • Novavax (Nuvavaxoid)
  • AstraZeneca (Oxford – not in use in the UK)
  • Janssen (Johnson & Johnson – not in use in the UK)
  • Valneva (Valneva – not in use in the UK)


In all, the World Health Organization has approved 9 different COVID-19 vaccines for use in a public health emergency. This includes the six approved in the UK, along with three more produced by companies in China and India. These have met WHO regulatory standards before being added to their emergency list.


Page last updated Monday, August 14, 2023