FAQs about COVID-19 vaccines

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Vaccination offers you the best protection from getting seriously ill or even dying from COVID-19, and enables society to function without strict lockdowns


When eligible to receive the COVID-19 vaccine, including booster doses, it is recommended that you take it, even if you have already had COVID-19. There is increasing evidence to show that natural infection with COVID-19 does not lead to long-lasting immunity. COVID-19 vaccination offers the best defence against the virus.


Children and young people have a very low risk of becoming seriously ill from COVID-19 disease compared to adults. However, there is evidence of significant transmission of the virus in children and young people, which can lead to children missing school or the virus being passed on to older family members who are more at risk. In the UK, all children aged five and over, on and before 31 August 2022, can get a 1st and 2nd dose. People over the age of 16 and some 12 to 15 year olds can also get a booster. Parents and young people will be contacted by the NHS to invite them for vaccination. This will take place in a vaccination centre, GP surgery or in school. 


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.


At this point we cannot say whether further booster doses may be needed in the future, but this is something that scientists and the government are closely monitoring. Current studies show that booster doses increase immune responses against COVID-19, including new variants, and provide the best defence against the virus. 


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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 have completed a full review of the safety information reported from the trials, including from several months after trial participants received the vaccines.

The MHRA reviewed all the side effects and medical conditions that people in the trials experienced. The number of illnesses reported in the vaccinated group was compared 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 COVID-19 pandemic led to an international effort in vaccine development. The urgent need to control the pandemic, and save lives, meant that development processes were significantly accelerated. For example, many of the obstacles which usually slow down vaccine development were removed, with the help of funding, previous scientific advances, 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. All of the approved vaccines to date have intentionally included people from diverse communities in many different countries such as 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 contains a live adenovirus vector, but it has been modified so that it cannot replicate and is also considered 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 after being vaccinated. Side effects that would be expected are mostly “flu-like” symptoms 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 Pfizer-BioNTech, Moderna, and Oxford-AstraZeneca vaccines 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 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 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.


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.



Page last updated Tuesday, January 17, 2023