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Key Questions and Answers About the UK's First Approved COVID-19 Vaccine

Key Questions and Answers About the UK's First Approved COVID-19 Vaccine  content piece image
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The UK government has announced that the COVID-19 vaccine BNT162b2 – developed by Pfizer and BioNTech – has been authorized for use. The approval comes just three weeks after the companies shared the Phase III clinical trial interim analysis data that suggests the vaccine has a 90% efficacy rate.

Here, we address some of the key questions you may have about this announcement.

Who has approved the BNT162b2 vaccine, and what does this mean?

The vaccine has been approved by the Medicines and Healthcare Products Regulatory Agency (MHRA), which is responsible for regulating medicines and medical devices in the UK, ensuring that they meet standards for safety, quality and efficacy.

The MHRA has conducted a scientific review of the safety, quality and effectiveness data of Pfizer and BioNTech's COVID-19 vaccine and has decided to grant a licence for its use in the UK.

How does the vaccine work?

The vaccine is an mRNA-based vaccine. In our body, DNA codes for proteins – the workhorses of our cells that are involved in many different molecular processes that underpin life. To make proteins from our DNA code, a middleman is required, and this is mRNA. DNA is transferred to mRNA in a process known as

Whilst most traditional vaccines are made from inactivated doses of a pathogen which causes a disease, mRNA vaccines contain – as the name suggests – mRNA, which codes for a specific antigen of the disease-causing pathogen. In the example of BNT162b2, the mRNA encodes the Spike protein of SARS-CoV-2, the virus that has caused COVID-19.

This mRNA is stored in lipid nanoparticles, and once delivered into the cell via injection, it provides a set of instructions for the cells to start producing antigens. The antigens are then presented to the immune system, and an immune response is triggered.

Introducing mRNA into human cells this way does not change the DNA of these cells. If the cells replicate, the mRNA is not incorporated into the new cell's genetic composition.

Over recent years, increasing research has been exploring the potential utility, safety and efficacy of mRNA-based vaccines for different diseases, leading to "a new era in vaccinology", as Pardi and colleagues described in 2018.1

BNT162b2 is the first mRNA-based vaccine to be approved for human use. It is important to remember that under normal conditions, vaccine development and approval is a process that can take many years. Therefore, it is possible that mRNA-based vaccines would have reached human approval at some time point, it has just been accelerated by the COVID-19 global pandemic.

“This is excellent news and a huge landmark in the global efforts to address this pandemic. The regulators have clearly been satisfied with the data presented to them," – Dr Michael Head.

Has the vaccine only been approved in the UK?

For now, yes. However, the European Medicines Agency (EMA), responsible for scientific evaluation, supervision and safety monitoring of medicines in the European Union, announced yesterday that it has received an application for conditional marketing authorization for BNT162b2. This will proceed under an accelerated timeline: "Such a short timeframe is only possible because EMA has already reviewed some data on the vaccine during a rolling review. During this phase, EMA assessed data on the vaccine’s quality (such as information about its ingredients and the way it is produced) as well as results from laboratory studies. EMA also looked at results on the vaccine’s effectiveness and initial safety data emerging from a large-scale clinical trial as they became available," the EMA has said.

How has the vaccine been approved so quickly? Does this affect its safety?

BNT162b2's approval in the UK marks a historical moment – it is the shortest time period ever in which a vaccine has progressed from concept to authorization. This process can typically take over a decade.

This short time frame, which is mirrored in other COVID-19 vaccines also in Phase III trials, has led some to question whether safety could be compromised.

Due to the urgent need created by the COVID-19 pandemic, rather than being conducted sequentially, different stages of clinical trials have been conducted at the same time for the same vaccine candidate, allowing faster data collection. Despite being completed under a short timeframe, the safety measures and assessments of these trials have remained the exact same as they would in normal circumstances.

The Civil Contingencies Committee have shared a graphic which clearly delineates these accelerated programs.

Furthermore, regulatory authorities such as the MHRA have been conducting rolling reviews, whereby they have been provided with direct access to information generated by clinical studies as soon as it becomes available, rather than upon completion of the trial.   

Why is a COVID-19 vaccine necessary?

Center for Disease Control and Prevention acknowledges that some individuals may be concerned about receiving a COVID-19 vaccine, but emphasizes that vaccination will be an important tool to help stop the global pandemic. 

Vaccine hesitancy is defined by the World Health Organization as "the reluctance or refusal to vaccinate despite the availability of vaccines". It was listed on the WHO's top ten threats to global health in 2019. In the COVID-19 era, there are fears that vaccine hesitancy could have catastrophic effects on the efforts to immunize and create herd immunity to block SARS-CoV-2 transmission.

Taking novel vaccines successfully through phase 1 to phase 3 trials within a year has been an outstanding achievement, but equally challenging over the coming year will be persuading governments and populations to use COVID-19 vaccines effectively to create herd immunity to protect all," write Anderson and colleagues in The Lancet.2

Jeff Wolf, CEO of Heat Biologics, told Technology Networks, "COVID-19 does not affect all people uniformly: seniors and people with comorbidities like diabetes and obesity face much higher mortality rates than other groups do. It is then especially incumbent upon people who face less risk to make sure they get vaccinated, to avoid spreading the infection to the most vulnerable people around them."

Vaccines have proven to be one of the most effective public health approaches for tackling and eradicating diseases such as smallpox and rinderpest.

What will happen if people do not get vaccinated? Anderson said: "If countries do not reach high vaccine coverage of levels, SARS-CoV-2 will become endemic but at a low level, the precise level depending on the degree of vaccine uptake, with peaks in winter and troughs in summer in the northern hemisphere."

Are there any challenges associated with BNT162b2?

mRNA-based vaccines must be kept at a very low temperature (-70 OC) to maintain their effectiveness, which creates logistical problems surrounding storage and deployment of the Pfizer vaccine.

Whilst today's announcement is good news, scientists welcome further developments from the other vaccine developers; particularly Moderna and the University of Oxford who have also embarked on achieving regulatory approval. Dr Michael Head, senior research fellow in global health at the University of Southampton, said, "The Pfizer vaccine does require storage at around -70 OC, which will pose significant logistical challenges for all countries that choose to use it."

He continued by adding that these are not insurmountable issues but are certainly challenging: "Other vaccines, such as the Oxford AstraZeneca candidate, require storage at much lesser temperatures and will be simpler to transport. Given we will certainly need more than one licensed vaccine to maximise global coverage, everyone will still be eagerly waiting for further developments from Oxford and Moderna."

“For the foreseeable future – and maybe forever – we are very unlikely to reach the situation we are in with smallpox (gone), polio (almost gone), or measles (controlled in populations with high enough vaccine coverage). Instead, we are going to need to find ways to fairly happily live alongside this virus," – Professor Liam Smeeth.

When will distribution begin, and who will get the vaccine?

The BNT162b2 vaccine is manufactured at different Pfizer plants across the UK and Europe. Stocks for the UK will be supplied by the company's plant in Belgium.

Exactly who will be provided with the option to get the vaccine first, and when, remains to be clarified, but a UK government spokesperson said, “The Joint Committee on Vaccinations and Immunisations (JCVI) will shortly publish its final advice for the priority groups to receive the vaccine, including care home residents, health and care staff, the elderly and the clinically extremely vulnerable."

Matt Hancock, the Secretary of State for Health and Social Care, added "We will have it ready early next week," said Matt Hancock, the Secretary of State for Health and Social Care Matt Hancock said.

A spokesperson for the UK government added that, "The NHS has decades of experience in delivering large scale vaccination programmes and will begin putting their extensive preparations into action to provide care and support to all those eligible for vaccination," said a Department of Health and Social Care spokesperson. 

What's next?

Over time, more data will be collected regarding vaccine safety, the long-term duration of protection they provide and how a vaccine effects virus transmission across different populations. In the meantime, the UK Government states, "To aid the success of the vaccination programme it is vital everyone continues to play their part and abide by the necessary restrictions in their area so we can further suppress the virus and allow the NHS to do its work without being overwhelmed."


1.     Pardi N, Hogan MJ, Porter FW, Weissman D. mRNA vaccines — a new era in vaccinology. Nature Reviews Drug Discovery. 2018;17(4):261-279. doi:10.1038/nrd.2017.243.

2.     Anderson RM, Vegvari C, Truscott J, Collyer BS. Challenges in creating herd immunity to SARS-CoV-2 infection by mass vaccination. The Lancet. 2020;396(10263):1614-1616. doi:10.1016/S0140-6736(20)32318-7.