Five facts about COVID-19 vaccines

Pharmaceutical Manager at Bupa UK
16 February 2021

This article was written in line with the best available evidence and guidelines at the time of publishing. Keep up-to-date with the latest guidelines on coronavirus at

Across the UK, millions of people have now had their first dose of a COVID-19 vaccine through the NHS vaccination programme. This is a huge step forward – vaccines are our best hope for ending the pandemic.

Unfortunately, misinformation about vaccines is making some people feel less confident about having one. One in three of us have come across ‘fake news’ about COVID-19 vaccines. To help spread correct information instead, here are my five key facts to dispel some of the false claims you might be seeing or hearing.

Fact: Vaccination cannot give you COVID-19

An infographic explaining vaccination cannot give you Covid-19

COVID-19 vaccines cannot cause COVID-19 infection. The myth that vaccination can give you COVID-19 seems to stem from a misunderstanding about what vaccines are and how they work.

Many traditional types of vaccine contain a weak or inactive form of the infection they protect against. Your body then develops antibodies. These fight off infection, without you experiencing the full symptoms of the disease. If you have contact with the disease again, your immune system remembers and protects you again. This means you have developed immunity to the disease. Because these vaccines do not contain any ‘live’ virus or bacteria, they cannot cause the infection they are designed to protect against.

The COVID-19 vaccines approved in the UK work in a slightly different way, but again do not contain any live COVID-19 infection and therefore cannot give you COVID-19.

  • The Pfizer-BioNTech and Moderna vaccines are ‘RNA vaccines’. They temporarily tell your body to create a particular part of the COVID-19 virus (called a ‘spike protein’).
  • The AstraZeneca-Oxford vaccine is a ‘viral vector’ vaccine. It uses a safe virus to introduce the ‘spike protein’.

In both cases, your body develops antibodies to the proteins. This usually leads to immunity from COVID-19.

It is possible, however, to have caught COVID-19, but not realise that you have done so until after your vaccination. There’s also the possibility of catching COVID-19 before the protective effects of a vaccine start working, which may be two to three weeks after your first dose.

Fact: The approved vaccines do not contain any animal products

An infographic showing approved vaccines do not contain animal products

The three COVID-19 vaccines approved in the UK do not contain any animal products. You can read lists of the ingredients found in each of the vaccines on the Coronavirus Yellowcard website. The website can also be used to report any side effects that you might experience after your vaccination.

You may be concerned about animal products. If this is because of your religious beliefs, it’s worth noting that many religious leaders and faith organisations have encouraged followers to have a COVID-19 vaccine when one is offered. These include the British Islamic Medical Council, Hindu Council UK and the Board of Deputies of British Jews.

Fact: The side effects of COVID-19 vaccines are usually mild

An infographic explaining mild side effects of Covid-19 vaccine

COVID-19 vaccines do not, for most people, cause more than mild side effects. These generally last for one or two days and may include:

  • arm pain
  • muscle or joint aches
  • fatigue
  • flu-like symptoms

Having symptoms like these is common after many types of vaccination. This is because vaccines trigger your immune system into action, and the response can be similar to having a mild form of the real infection.

People with certain allergies may be at risk of a more severe reaction. It’s important to speak to your doctor if you’ve had a severe allergic reaction in the past, to check that the vaccine will be suitable.

Side effects are looked at carefully as part of the rigorous clinical trials that new vaccines must go through. When the Medicines and Healthcare Products Regulatory Authority (MHRA) checks all the data from trials, the side effects that people in the trial have experienced are a big part of their considerations before they give approval.

Fact: The vaccine cannot affect your DNA

An infographic explaining the Covid-19 vaccine cannot affect your DNA

Rumours suggesting that COVID-19 vaccines can affect your DNA are not true.

The Pfizer-BioNTech and Moderna vaccines contain messenger RNA (mRNA) which give instructions to your cells. The mRNA instructs your body to make proteins found on the surface of the virus that causes COVID-19, which your body creates antibodies against. This usually leads to immunity. The mRNA usually stays in your body for a few days, before being broken down and removed by the body. It cannot influence or affect your DNA at all.

Fact: After vaccination, you still need to follow COVID-19 safety guidelines

An infographic explaining Covid-19 guidelines

Being vaccinated does not mean that you, or those around you, should be any less vigilant about following government COVID-19 guidance.

Firstly, it may take two to three weeks after your first vaccine dose to build up any protection. After your second vaccine dose this protection will increase. But even after this point, no vaccine approved against COVID-19 is completely effective in every case. We know that the COVID-19 vaccines can prevent people from being seriously ill from the infection. But to minimise the risk as much as possible, it’s important that all of us keep practising social distancing, wearing face masks and washing our hands regularly in line with the latest government guidance.

Justin Hayde-West
Pharmaceutical Manager at Bupa UK

    • Kings College London. Coronavirus: vaccine misinformation and the role of social media., published December 2020
    • Understanding how COVID-19 vaccines work. Centers for Disease Control and Prevention (CDC)., last updated January 13 2021
    • Types of vaccine. Vaccine Knowledge Project. Oxford Vaccine Group., last updated January 12 2021
    • The different types of COVID-19 vaccines. World Health Organization., published January 12 2021
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    • Coronavirus (COVID-19) vaccine. NHS., last reviewed 4 February 2021
    • There isn’t pork in Covid-19 vaccines. Full Fact., published 22 January 2021
    • COVID-19 vaccines. Vaccine Knowledge Project. Oxford Vaccine Group., last updated 22 January 2021
    • Understanding mRNA COVID-19 Vaccines. Centers for Disease Control and Prevention (CDC)., last updated 18 December 2020
    • mRNA vaccines do not change DNA. The European Society of Human Genetics., published 28 December 2020
    • Voysey M, Clemens SAC, Madhi SA et al. Single dose administration, and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine. Preprint with The Lancet. February 2021

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