Coronavirus vaccine safety: what to know

How do we know that the coronavirus vaccine is safe? Find out how the coronavirus vaccines work and how it has been tested to ensure it is safe before it is made available to the public.

The development of a COVID-19 (coronavirus) vaccine is essential in the fight to bring the current pandemic to an end. With the speed at which development is progressing, there are some questions over how safe any vaccines will be once they are produced. In this article we’ll go over the main concerns related to the safety of the new coronavirus vaccine candidates.

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How do the coronavirus vaccines work?

Vaccines work by harmlessly introducing elements of a disease to the body to teach it how to fight specific infections.

Before a vaccine can be made, researchers have to understand how coronavirus attacks the body.

When creating a prospective vaccine, scientists first have to understand how the coronavirus attacks the body. The vaccine developers can then take genetic material from the coronavirus and use it to create a vaccine that appears to the body in the same way the virus would.

This is injected into the patient, stimulating an adaptive immune response where the body creates antibodies that can fight coronavirus. Antibodies are a type of blood protein used by the body to fight infection, so if the patient comes into contact with coronavirus, their body will already know how to fight it.

When a viable vaccine candidate has been created, it should create immunity from coronavirus in the patient.

There are currently two coronavirus vaccines approved for use in the UK, the Oxford/Astrazeneca vaccine and the Pfizer/BioNTech vaccine.

The University of Oxford coronavirus vaccine works by taking a lesser virus (similar to a common cold) and manipulating it so it is no longer harmful. The manipulated virus acquires the surface features which mimic coronavirus, appearing to the body in the same way and triggering the creation of coronavirus antibodies. The Chinese coronavirus vaccine candidate created by CanSino Biologics is based upon a similar principle.

Other vaccines use synthetic DNA to teach the body how to create the proteins which can fight coronavirus and create immunity, such as the vaccine being developed by American biotechnology company Moderna. The vaccine being produced by the collaboration between American pharmaceutical giant, Pfizer, and the German biotechnology company, BioNTech, also uses synthetic DNA technology.

Patients who recieve the vaccine will then have the antibodies that can fight coronavirus.

Vaccines can be created in many different ways, but ultimately all vaccines allow your immune system to learn how to fight infection and gain immunity. It is far safer to gain immunity through vaccination than it is by catching a potentially life-threatening disease.

How can a vaccine be made in months when it usually takes years?

There are over 70 coronavirus vaccines currently being tested in clinical trials all over the world, and many of the frontrunners in the race to make the coronavirus vaccine have created vaccines using established platforms. This means that the vaccine developers have a specific method of creating vaccines which can be applied to similar viruses.

Some of the vaccine candidates (such as the one being developed by the University of Oxford) have already been tried and tested with previous coronaviruses, such as SARS and MERS. Previous research and vaccine development with similar coronaviruses has made the process of creating a COVID-19 vaccine much faster.

If similar technology used with previous coronaviruses has been successful, it is also a good indication that it will be successful with COVID-19 too.

Another factor in the speed of the coronavirus vaccine development is the increase in funding and resources. Owing to the severity of the pandemic and its repercussions, a lot more funding that usual has been dedicated to vaccine development. As a result, progress has been made a lot faster than it would under other circumstances.

How can they make a vaccine for coronavirus when there aren’t yet vaccines for viruses like HIV?

Creating vaccines for different viruses can be very different. Although HIV affects many people all over the world, the complexity with which the virus affects the body makes it difficult to develop a vaccine that can guarantee immunity.

By contrast, the COVID-19 coronavirus attacks the body in a different way. After early progress was made in understanding the structure of the virus and sequencing its genetic information, efforts to create the vaccine could already begin.

There has also been an unprecedented cross collaboration between biotechnology firms, pharmaceutical companies, public organisations and government agencies around the world in the work to create a functioning coronavirus vaccine.

How are the coronavirus vaccines tested to ensure they are safe?

All candidates for the coronavirus vaccine will pass through a rigorous testing process to ensure that they work properly and are safe.

Once a vaccine candidate is ready, it must pass through three phases of clinical trials. In the first phase, a small group of volunteers is given the vaccine to ensure the vaccine is safe and has no adverse side effects.

Once the vaccine is established to be safe, testing can move on to the second phase, in which a larger group is given the vaccine. This second group of volunteers should be of different ages and backgrounds to mimic how the vaccine might work for different people. The phase of testing will establish whether the vaccine is efficient in creating immunity against the coronavirus.

The third phase involves testing on an even larger group of volunteers to ensure the efficiency and safety of the vaccine on wider society.

Only then can a vaccine be approved for distribution to the general public.

How many people have taken the coronavirus vaccine in clinical trials?

Over 44,000 volunteers have participated in clinical trials for the Pfizer/ BioNTech vaccine, more than 40,000 in the clinical trial for the University of Oxford vaccine, and 30,000 in the clinical trial for another mRNA vaccine developed by Moderna.

In any given clinical trial, around half of the volunteers will receive the COVID-19 vaccine, and the rest are given a placebo (a vaccine for a different disease). Of the people who were given the Pfizer/BioNTech COVID-19 vaccine, none experienced significant or severe lasting side effects that can be attributed to the vaccine, which is why it has been judged as safe for wider distribution.

Were there any deaths during the clinical trials of the coronavirus vaccine?

There have been deaths in the clinical trials for different coronavirus vaccines, but none that were out of the ordinary for such a large number of people.

For example, in the Pfizer/BioNTech clinical trial 6 people died out of 44,000 people. Of these 6 people, 2 received the Pfizer vaccine and 4 received a placebo. The two people who received the vaccine were over 55, one of which died from cardiac arrest more than 3 months after receiving the vaccine, and the other a few days after receiving the vaccine from arteriosclerosis, a condition which causes blood vessels to thicken and harden with age.

According to a report by the US Food and Drug Administration “all deaths represent events that occur in the general population of the age groups where they occurred, at a similar rate”. This means that within a group of 44,000, it could also be expected that the same number of deaths might occur, regardless as to whether they had been vaccinated or not.

Does the coronavirus vaccine have side effects?

In some people the coronavirus vaccine will have mild side effects, similar to that of other vaccines.

Find out more about the side effects of the different coronavirus vaccines.

Will the vaccine be mandatory?

Health Secretary Matt Hancock has said that the COVID-19 vaccine will not be made mandatory, however, it is possible that it will be for front line health professionals who are at high risk and working with vulnerable patients.

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Before the coronavirus vaccine is ready it must go through a number of stages in development. Take a look at our coronavirus vaccine tracker for the latest news and results on vaccines in each stage.

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