Pfizer/ BioNtech Covid-19 FAQs

 In COVID-19, News

Vaccines save lives. Yet there is a lot of disinformation online deterring people from getting the vaccine. Below I have shared a frequently asked questions briefing I received from the British Society for Immunology . It provides a host of questions and answers about the Pfizer/ BioNTech Covid-19 vaccine.

Please note that the answers to the following questions apply only in relation to the Pfizer/BioNTech COVID-19 vaccine, and many will be different for other COVID-19 vaccines as they become available.

Please note that the answers to the following questions apply only in relation to the Pfizer/BioNTech COVID-19 vaccine, and many will be different for other COVID-19 vaccines as they become available.


Who is eligible to receive the vaccine?
The Joint Committee on Vaccination and Immunisation (JCVI) has prioritised people for vaccination based on their risk of serious COVID-19 disease after SARS-CoV-2 infection. The priority order, confirmed on 2nd December and subject to logistical challenges in rollout, is as follows:

1.       Residents in a care home for older adults and their carers

2.       All those 80 years of age and over; frontline health and social care workers

3.       All those 75 years of age and over

4.       All those 70 years of age and over; clinically extremely vulnerable individuals

5.       All those 65 years of age and over

6.       All individuals aged 16 years to 64 years with underlying health conditions which put them at higher risk of serious disease and mortality

7.       All those 60 years of age and over

8.       All those 55 years of age and over

9.       All those 50 years of age and over

As more vaccine becomes available, it will be rolled out to those in each descending group.

Why are older people being prioritised over younger people who are out of the house working?
The priorities are based on reducing risk of harm. The immune system of older people differs from that of younger people and whilst the younger, working population are just as likely to become infected they are much, much less likely to become severely ill. An older person becoming infected with SARS-CoV-2 is more likely to result in severe COVID-19 disease. The biggest risk of mortality from COVID-19 comes with age, even more so than underlying conditions such as cardiovascular disease or diabetes, for example, or being male or being in BAME groups. Each older generation has approximately 10 times the risk of dying from COVID-19 than the generation below it. When a vaccine has been shown to be effective in preventing disease in older people, then they should be the first to receive it as they are most at risk.

Do I need to get the vaccine if I have contracted COVID-19 and recovered?
Yes. There is a lot of uncertainty about how much immunity a person gains after natural infection. The levels of immunity that we can measure so far show a lot of individual variation – some people have very few antibodies after infection but these antibodies can be boosted by vaccination. We can’t assume that everyone who has had COVID-19 would have enough immunity to protect them. It is likely that, in a significant proportion of the population, the vaccine will induce more effective and longer lasting immunity than that induced by infection. Hence it is recommended that everyone take the vaccine so that, if your immunity after disease is absent or low, it can be boosted.

Why should a young person take the vaccine when the risk of COVID-19 mortality is so low?
There is a huge variability in the symptoms and severity of COVID-19 disease between different people; from an infection with SARS-CoV-2 that doesn’t have any symptoms (asymptomatic infection) to severe COVID-19 disease resulting in hospitalisation and in some cases death. While younger people are usually at the less severe end of the spectrum this does not mean that the illness is not harmful to their health. In fact, there are many instances of long COVID that have blighted the lives of young people.

In addition, although we don’t yet have a lot of evidence to support this, having the vaccine might stop you being able to be part of the chain of infection that spreads the virus. So, an added benefit might be to help reduce spread of the virus for everybody.

There is COVID-19 at my child’s school. Why aren’t my children being given the vaccine?
Initial vaccine testing was not done on children. Children are at extremely low risk of becoming severely ill with COVID-19 – they are at higher risk of being involved in a serious traffic accident than they are of ending up in hospital with Covid-19. So the benefits of vaccinating children are not yet clear. If the vaccine stops people from passing the infection to others, then vaccinating children in order to stop the spread of the virus will make a lot of sense.



Does the vaccine being developed so quickly mean that it is less safe than other vaccines?
No, it doesn’t. The reasons that this was developed so quickly do not include cutting corners on safety. There are a few reasons that enabled the speed in 2020:

1.       Technology. These mRNA vaccines (in common with many of the approaches used for the other vaccine candidates) could be rapidly deployed for development and testing once the SARS-CoV-2 sequence became known, but this was actually done on the back of 10 years prior research using this platform.

2.       Scientists. A LOT of scientists contributed to this, working extra long hours to make it work and to assess the results.

3.       Money. Normally raising money to develop a vaccine takes a long time. At each stage you have to stop and apply for more funding to carry out the next stage. Funding applications take a year or more. In 2020 for SARS-CoV-2, rapid investment of a lot of taxpayers’ money in many countries meant there weren’t the normal financial obstacles.

4.       Environment. Sometimes you can develop a vaccine but can’t test it until there is an epidemic in progress. There was no problem in this regard.

5.       Luck. Sometimes the target that is picked for vaccine studies, which is usually something seen on the outside of the virus, is not a good candidate for raising an immune response. The S protein target on SARS-CoV-2 that most vaccine companies picked to work with turns out to be an excellent target for activating the immune response.

6.       Volunteer test subjects. Last but definitely not least. Tens of thousands of volunteers took part in the safety trials and the randomised control trials so recruiting volunteers was not an issue as it may be under normal circumstances.

Are there any side effects from the vaccine?
Yes, but these are generally mild. As with all vaccines, because you are stimulating the immune system you may experience some mild flu-like symptoms, but these are temporary. The most common reactions are fatigue, headache and pain at the injection site. Some people might also get chills, joint pain or fever. Younger people are more likely to get these reactions than older people.

Should people with allergies take the vaccine?
There are varying degrees of allergy. Some allergies, such as hay fever, are mild and do not pose a risk. Others are more dangerous and can lead to immediate anaphylactic shock. The vaccine should not be given to people who have a history of immediate-onset anaphylaxis to a vaccine, medicine or food. If you carry an EpiPen in case of allergic reaction, you have a history of immediate-onset anaphylaxis and so should discuss this with your doctor before getting the vaccine. All people who are vaccinated are asked not to leave immediately so that the health care professionals can check there is no anaphylaxis.

Who should not get the vaccine? (I’m immunocompromised/pregnant etc.)
The Pfizer/BioNTech COVID-19 vaccine has not yet been tested on pregnant women or children so these groups should not be vaccinated, unless a child is at high risk of severe disease for some other reason.

Immunocompromised people are at high risk so should get the vaccine. However, because their immune systems may not be able to make a response to vaccine they should still take other precautions against the disease.

Who was the Pfizer/BioNTech COVID-19 vaccine tested on?
There were 43,448 people in the phase 3 clinical trial, 21,720 of whom had the COVID-19 vaccine and the rest were given a placebo injection.

Of the COVID-19 vaccine recipients, 58% were aged between 16 and 55, 42% were aged over 55 (the oldest being 89). 35% were classified as obese, 17% were BAME, 51% were male. Volunteers were from Argentina (15%), Brazil (6%), South Africa (2%) and USA (77%). People characterised as high risk due to underlying conditions (e.g. autoimmunity, hypertension; diabetes; asthma; pulmonary, liver, or kidney disease) or due to high risk occupations were included.

Are there risks that might have been missed in the trials, but will become apparent in the longer term?
All known risks have been checked, but there may be unknown risks. Reactions to vaccines usually happen very soon after vaccination – if you have the vaccine, you are asked to wait for a few minutes as a precaution. All the initial phase 1 safety trial volunteers have been followed up for at least 4 months and no major concerns have been raised. Safety monitoring, known as pharmacovigilance, is to be continued for 2 years after the vaccine is released – in the UK, this is carried out by the MHRA.

How are long term side effects tested/monitored?
Safety monitoring is to be continued for 2 years after the vaccine is released. There is a system in place to monitor and report adverse events immediately in a process known as pharmacovigilance. In the UK, this is carried out by the MHRA.

Has the vaccine been tested on people of different ethnicities?
Yes, of the 21,720 volunteers who had the COVID-19 vaccine, 17% were BAME.


Does immunity from the vaccine last longer than immunity after getting COVID-19?
We do not know the answer to this question yet because people have only been followed up for a maximum of 6 months after vaccination so far. We suspect that in some cases (e.g. mild or asymptomatic infection), the immunity elicited by the vaccine would be better than that elicited by the natural infection but we do not know for sure. But, from the concentrations of antibodies induced by the vaccine, and the rate at which these antibodies decline over time, it is looking very promising that immunity induced by the vaccine will last at least as long as the immunity induced by infection and in all likelihood it will last much longer.

Do I still need to wear a mask or observe social distancing after receiving the vaccine?
Yes. We know the vaccine can protect people from getting sick from the disease COVID-19 that is caused by the viral infection. However, we do not yet know if it will stop you getting the viral infection so you could be an asymptomatic carrier who could pass the infection onto others who may be vulnerable.

Also, you will not be fully protected against the disease until the second dose of vaccine.


How do mRNA vaccines, such as the Pfizer/BioNTech vaccine, work?
The vaccine contains a segment of the SARS-CoV-2 virus genetic material that codes for a specific protein from the virus. In the case of the Pfizer/BioNTech vaccine, the specific code is for the spike protein from the surface of the SARS-CoV-2 virus. The genetic material in the vaccine is mRNA, which is used as instructions for the cell to make proteins. When the vaccine is given, our cells at the site of injection take up the mRNA and make the SARS-CoV-2 spike protein. The mRNA is subsequently destroyed by the body. The spike protein is then recognised by the immune system and triggers a response. This response builds immune memory so your body can fight off SARS-CoV-2 immediately if you come across it in future. Please also see this infographic.

Will the Pfizer/BioNTech vaccine still provide protection against the new strain of Coronavirus in the UK?
We think it will, but we don’t yet know this for a fact. Scientists are currently carrying out tests in the lab to check this out. We expect to find out more about this in the coming weeks.

  • Steve Reed
    Steve Reed Member of Parliment for Croydon North

Steven Reed is Labour MP for Croydon North and Shadow Minister for Children and Families. In 2018 his private member’s bill on reducing violent mental health restraint became law. In June 2019 he launched Labour’s civil society strategy outlining radical plans to empower citizens and communities.

Steve chairs the Cooperative Councils Innovation Network, co-chairs the All-Party Parliamentary Group for London, was Leader of Lambeth Council 2006-12 where he led the council’s children’s services to become best-rated in the country and pioneered the public-health approach to tackling violent youth crime. He worked in publishing for 16 years and was an elected trade union branch secretary.