All you need to know about the COVID-19 vaccines

FULL ARTICLE

By Julia Riopelle, SciTech Editor

Currently, 17,247,442 people have received the first dose of a COVID-19 vaccine in UK. You or a family member may be invited to get one soon! Here is all you need to know about the three approved COVID-19 vaccines before getting vaccinated.

Doctor holding up the COVID-19 vaccine developed by Pfizer | Flickr / Marco Verch

Pfizer Vaccine

Who developed the Pfizer Vaccine?
The Pfizer COVID-19 vaccine was developed by husband-wife-team Dr Ugur Sahin and Dr Ozlem Tureci. They work for the company BioNTech, based in Mainz, Germany. It was the first COVID-19 vaccine to be approved by the FDA, on the 11 of December 2020.

How does the Pfizer vaccine work?
In the past, vaccines have for the majority contained weakened versions of the target virus, in order for the body to create the necessary antibodies against it. However, the Pfizer vaccine is an mRNA vaccine, which essentially teaches our cells how to make the antibodies needed to fight COVID-19.

All viruses or pathogens have proteins located on their cell surface, which function as ‘identification tags’. These identifying proteins are what allows our immune systems to recognize the pathogen as a ‘foreign’ object, and if considered dangerous, will trigger an immune response to fight the invader. The surface proteins located on the COVID-19 virus are called ‘spike proteins’; alone they are not dangerous and do not cause any form of infection.

Messenger RNA (mRNA) is essentially the same as the instructions provided by our DNA, but in a format, which can be transported around the cell and turned into proteins. The Pfizer vaccine uses the specific mRNA that creates the spike proteins of COVID-19 and injects them into the muscle cells of the arm. Our cells then use the instructions to produce these spike proteins and presents them on its cell surface. Our immune system recognizes the spike proteins as foreign and triggers the same immune response that would occur if one was actually infected with COVID-19, but without the actual virus present.

The Pfizer vaccine requires two doses, given three weeks apart. The second dose is a booster, to remind your immune system of what the COVID-19 virus looks like, in order to make them more effective should you encounter the real virus. The Pfizer vaccine is said to have 94 percent effectiveness.

Who was tested during the Pfizer vaccine trials?
According to the Centers of Disease Control and Prevention (CDC), in phases two and three of the Pfizer trials, 81.9 percent participants were Caucasian, 26.2 percent Hispanic/Latino, 9.8 percent African American and 4.4 percent Asian. Less than three percent were of other ethnic minorities. Currently, the vaccine is only available to people aged 16 and older. However, now 2259 children aged 12 to 15 years are enrolled for the COVID-19 vaccine trials.

Who shouldn’t get the Pfizer COVID-19 vaccine?
There have been reports of people having allergic reactions (anaphylaxis) within four hours of being vaccinated. This includes experiencing hives, abnormal swelling or respiratory distress. Despite these cases being little in number, one should always approach with caution. If you have had any severe allergic reactions to past mRNA or viral vaccines, read the ingredients of this COVID-19 vaccine.

The Pfizer researchers specifically warn people who have had allergic reactions to polysorbate or polyethylene glycol (PEG). Polysorbate is used an emulsifier to help dissolve the vaccine ingredients. PEG is being increasingly implemented in pharmaceuticals for PEGylation, where linking PEG to the drug will mask it from the host’s immune system, preventing it from attacking the vaccine before it has time to work.

Although polysorbate is not in the COVID-19 vaccine, PEG is, and the two molecules are closely related. There have been a few reported cases of anaphylaxis in patients and healthcare workers minutes after receiving the vaccine, but they recovered quickly with an epi-pen.

What are common side effects can you expect after getting the Pfizer vaccine?
A common reaction people get when getting any vaccine is some pain, redness and swelling on the arm which received the shot. This is no different in the Pfizer vaccine. Some have also reported feeling more tired, experiencing chills and headaches a few hours to days after receiving the shot. Just know, that as long as these symptoms are mild, they are fairly ‘normal’ and there is no need to worry.

Visit the CDC for more information on the Pfizer Vaccine.

COVID-19 vaccinations | Flickr / Phil Murphy

Moderna Vaccine

Who developed the Moderna Vaccine?
The vaccine was developed by the small ModernaTX, Inc. biotech company in Cambridge, Massachusetts. The team was led by 35-year-old female Senior Director and epidemiology researcher, Dr Hamilton Bennett. The Moderna vaccine was approved on the 18 of December 2020.

How does the Moderna vaccine work?
The Moderna vaccine is also an mRNA vaccine and works the same as the one developed by Pfizer. It requires two doses, four weeks apart and is said to have around 92 percent effectiveness against COVID-19.

Who was tested during the Moderna vaccine trials?
According to the Centers of Disease Control and Prevention (CDC), in phases two and three of the Moderna trials, 79.4 percent participants were Caucasian, 20 percent Hispanic/Latino, 9.7 percent African American and 4.7 percent Asian. Less than three percent were of other ethnic minorities. Currently, the vaccine is only available to people aged 16 and older, however they are currently testing on 3000 children aged 12 to 17 years and hope to get have results by summer this coming summer.

Who shouldn’t get the Moderna COVID-19 vaccine?
As in the Pfizer vaccine, the Moderna researchers also warn individuals who have had allergic reactions to any mRNA vaccines, polysorbate or polyethylene glycol (PEG) not get the COVID-19 vaccine.

What are common side effects can you expect after getting the Moderna vaccine?
Expected normal side effects of the Moderna vaccine are similar to the ones of the Pfizer vaccine. Although, you may experience flu-like symptoms on the second day after being vaccinated. In the trial phase, it was found that the side effects were more prominent after participants received the second dose. Any symptoms should go away in a matter of a few days.

Visit the CDC for more information on the Moderna Vaccine.

UK Prime Minister Boris Johnson holding a vial containing the Oxford/AstraZeneca COVID-19 Vaccine | Flickr / Number 10

The Oxford/AstraZeneca Vaccine

Who developed the Oxford/AstraZeneca Vaccine?
The initial research on COVID-19, which contributed the Oxford/AstraZeneca, was conducted across many UK institutions, including the University of Bristol.

The direct team which developed the COVID-19 vaccine at the Oxford Vaccine Group was led by Professor Sarah Gilbert, Professor Andrew Pollard, Professor Teresa Lambe, Dr Sandy Douglas, Professor Catherine Green and Professor Adrian Hill. It is the third COVID-19 vaccine to be approved on the 30 of December 2020.

How does the Oxford/AstraZeneca vaccine work?
The Oxford/AstraZeneca vaccine is not an mRNA vaccine. It uses a weakened version of an adenovirus, which is a ‘common cold equivalent’ of chimpanzees. This adenovirus has been genetically altered to look like COVID-19 and not cause any disease in humans. This technology has already been successfully used by the Oxford vaccine group to engineer vaccines against the Zika Virus and Middle East Respiratory Syndrome (MERS), another coronavirus.

Basically, the researchers took the weakened version of the well-studied adenovirus and used it has a ‘host’ to insert the genetic sequence of the ‘spike proteins’ into its DNA. This genetically modified adenovirus now displays COVID-19 spike proteins, or identification tags, on its surface, making it look like a COVID-19 virus. Once injected into the patient, the adenovirus will trigger an immune response, which will create all the necessary antibodies against COVID-19. This virus will not replicate in the human body!

As in the other two vaccines, Oxford/AstraZeneca also requires two doses, where the first ‘half-dose’ is followed by a booster dose four weeks later. The vaccine is said to have 82 percent effectiveness against COVID-19.

Who was tested during the Oxford/AstraZeneca vaccine trials?
It is reported that over 90 percent of volunteers who participated in the Oxford/AstraZenaca vaccine trials in phases two and three were Caucasian. The later trial phases of the vaccine took place in the UK and Brazil. In Brazil 11.1 percent of participants were Black, 2.6 percent Asian and 19.1 percent Mixed. Currently, the vaccine is only available to people aged 16 and older, however Oxford University is extending the vaccine trials to children. The trials will enrol 300 children aged 6 to 17 years.

Who shouldn’t get the Oxford/AstraZeneca COVID-19 vaccine?
As in the Pfizer vaccine, the Oxford researchers also warn individuals who have had allergic reactions to any mRNA vaccines, polysorbate or polyethylene glycol (PEG) not get the COVID-19 vaccine.

These are also ingredients in the vaccine, alongside the active mRNA component: L-Histidine, L-Histidine hydrochloride monohydrate, Magnesium chloride hexahydrate, Polysorbate 80, Ethanol, Sucrose, Sodium chloride and Disodium edetate dihydrate.

So, if you know you are allergic against any of these, then probably don’t get the vaccine.

What are common side effects can you expect after getting the Oxford/AstraZeneca vaccine?
Expected normal side effects of the Oxford/AstraZeneca vaccine are similar to the ones of the Pfizer vaccine. Although, less common side effects may occur, such as dizziness, abdominal pain, decreased appetite, enlarged lymph nodes or a slight rash. Any symptoms should go away in a matter of a few days. Oxford University is currently recruiting volunteers to take part in a ‘side effect’ trial of the vaccine.

Exclusive interviews with COVID-19 vaccine trial participants
Oxford COVID-19 vaccine effectiveness validated by Bristol researchers

Be aware of any allergic reactions you have before getting vaccinated and monitor any side effects you may experience. If you have any severe side effects, call your doctor and if you experience an allergic reaction go to the hospital immediately!

To conclude, it is encouraged for you to get vaccinated in order for us to gain control over the COVID-19 pandemic. Most people who have received their first dose of the vaccine are doing perfectly fine!

Featured Image: Flickr / Tim Dennell


Have you or a family member already been vaccinated?

AUTHOR

Julia Riopelle

SciTech Editor