Hi everyone. As you know, I had my first Astra Zeneca jab on March 23rd, appropriately enough the 1-year anniversary of lockdown #1. I will be very relieved to get my second one on 8th June – I’m counting the days! In this post I am hoping to answer some of the most common questions and debunk some common myths about the vaccine.
How does the vaccine work?
All vaccines work on the same basic principle. Something is introduced into the body that fools your immune system into thinking you have a disease, so it produces antibodies and other cells to fight that disease. If you are then infected with the actual disease, your immune system ‘remembers’ how to produce those antibodies. This means that your immune system will fight off the disease without you developing symptoms or becoming infectious.
The COVID vaccine contains a small segment of the virus’ RNA containing the instructions to make the spike protein, which is found on the surface of the virus. When you are vaccinated, your cells will take up this RNA and use it to manufacture the spike protein; this provokes your immune system into producing antibodies and white blood cells to destroy it. If you are then exposed to the actual virus, your body will be able to produce antibodies and destroy it very quickly.
What is the difference between the various vaccines?
All the vaccines contain the RNA for the spike protein, encased in a capsule. When you receive the vaccine, the capsule breaks down inside the body and releases the RNA. Different vaccines use different capsules. The Pfizer and Moderna vaccines both use a lipid (fat) capsule; Astra Zeneca (AZ) uses a deactivated virus capsule.
Is the AZ vaccine less effective than the others?
No. Apparent differences in the effectiveness of the vaccines are basically due to differences in the way the data has been processed and presented in the scientific literature; and the way the data has then been represented – or misrepresented – in the media.
All three of the currently licensed vaccines in the UK have very similar effectiveness. Data published by Public Health England at the end of March has shown that all three vaccines provide on average 60 % protection after the first dose and over 85% after the second. To put that in context, the effectiveness of the seasonal flu vaccine is between 55 and 60 %.
It’s also worth noting that the higher the uptake of a vaccine, the more effective it is – this is because if the majority of the population is vaccinated, the probability that the virus mutates and becomes vaccine resistant is much lower.
How have the vaccines been developed?
The various vaccines have been developed through collaborations between researchers who develop and test the vaccine, and pharmaceutical companies who develop and implement manufacturing processes.
The big advantage of these collaborations is that by the time each vaccine had been developed and tested by researchers, the pharmaceutical companies had the manufacturing processes ready to go. This dramatically reduced the time needed to get the vaccines into clinical use.
Is this untried technology that has been rushed into use too quickly?
Definitely not. Research and development into RNA vaccines has been going on for over 30 years. Several companies including Pfizer were already actively researching RNA vaccines for flu; however, without the pandemic, it would have been several more years before any RNA vaccines made it into clinical use. The pandemic has accelerated the process because vast amounts of funding were made available.
Is the vaccine safe?
The COVID vaccine is very safe indeed. Traditional vaccines use either a dead or weakened version of the organism that causes the disease. There is a small but significant segment of the population that cannot have these vaccines, including the elderly and people who are immunosuppressed.
Because the COVID vaccine uses RNA rather than dead or weakened virus, it can be given to the majority of the population including the very elderly and those who are immunosuppressed.
What side-effects might I get?
The most common side-effects are some soreness at the injection site, and mild flu-like symptoms. Both resolve within a couple of days. Many people, including myself, have experienced a metallic taste in the mouth for approximately 24 hours after the AZ vaccine.
When you have the vaccine, you will be given a leaflet which includes a list of side-effects. If you do get side effects, however mild, it is worth reporting them using the MHRA’s yellow card scheme: https://coronavirus-yellowcard.mhra.gov.uk/.
Will I test positive after the vaccine?
The vaccine will not cause a positive test. The vaccine causes your body to make the spike protein; both the lateral flow and PCR tests detect other parts of the virus structure. If you have had the vaccine and get a positive result afterwards, you should follow the normal procedure for self-isolating.
What about blood clots?
The media has made much of the risk of a rare form of blood of blood clot associated with the Astra Zeneca vaccine. However, the actual figures tell a different story. As of March 31st, there have been 79 instances of this rare type of blood clot (14 fatalities) following the first dose of the AZ vaccine; this is out of 20.2 million doses. Analysis has found that the risk is slightly higher among the under-30s; as a precaution, the AZ vaccine is no longer being offered to this age group.
To put these figures in context, according to Department of Transport statistics, in 2020 there were 24,470 people killed or seriously injured in road accidents – an average of 67 per day. Personally, I was quite happy to have my first dose of AZ vaccine and will be even happier when I’ve had my second.
Will the virus’ RNA remain in my body forever?
One piece of disinformation that is doing the rounds on social media is that once you are vaccinated, the virus’ RNA will remain in your body forever; and that you will effectively have become genetically modified. This is not the case. RNA is a short-lived molecule which is broken down once it has served its purpose. Once the RNA from the vaccine has been used to make the spike protein, it will be broken down and eliminated from your body. The same thing will happen to the spike protein; your immune system will destroy it and it will be eliminated from your body.
What if the virus mutates?
A big advantage of RNA vaccines is that if variants emerge that are resistant to the existing vaccines, a new vaccine can be created in a matter of a few weeks. This is because all that needs to be done is to isolate the RNA for the new spike protein, then insert it into the existing capsule. Manufacturing processes do not need to be altered, and much less safety testing is required.
Now that RNA vaccines are a reality, it possible that in the next few years they will replace traditional vaccines for other rapidly mutating viruses such as influenza.
Will I need a jab every year?
This is still being debated but it is likely that for the next few years at least, an annual COVID vaccine will be needed. There are two reasons for this. Firstly, we do not yet know how long the immunity provided by the vaccine lasts; a yearly booster is therefore a sensible precaution. Secondly, it may be necessary to vaccinate annually due to changes to the virus that make previous vaccines ineffective.
Why is the vaccine not available to under-18s?
At present, clinical trials for vaccines have only been carried out in adults. Children and adolescents are physiologically very different to adults. Because of this, dedicated clinical trials must be carried out in children before any vaccine can be licensed for the under 18s.
Now that the safety of the various vaccines in adults has been well established, small-scale clinical trials are underway in children and adolescents for both the Pfizer and Moderna vaccines. A trial of the AZ vaccine has been suspended as a precaution following the decision not to use it for those under 30.