We would like to share more insight into how the COVID vaccine will work, but before that; it is important to start this blog post by saying vaccines, in general, save more lives than any other medicine and come only second to clean water when it comes to preventing disease. Vaccines have been given to billions of people and have shown to be safe. They have become so successful that we have lost sight of many fatal diseases like measles, mumps and rubella. Instead, we’re left with no disease, and all everyone sees is a side effect from the vaccine, so they often get a bad press.
How do they work?
Most vaccines work by stimulating the immune system so it thinks it has met the disease before and fought it off. A lot of the vaccines we are used to are ‘attenuated pathogens’. This means taking a virus or bacteria and making it so it doesn’t cause that infection anymore but induces an immune response. They are called ‘replicating vaccines’, and some precautions sometimes need to be exercised in the immunosuppressed.
With Influenza, for instance, we take the virus, grow it, render it non-infectious by vaccinating with parts of the virus which triggers an immune response. This means if you were to come into contact with it, your body would be able to respond by releasing the immune cells needed as it had been tricked into thinking you’ve had it before.
There are several myths around, such as ‘the flu vaccine gives you flu’. But there is no possibility of this as the ingredients are inactive. We know it’s safe and it works.
Side effects are common, such as a short-lasting fever and a sore arm. Sometimes, the vaccine doesn’t work as well as we would like but that’s about matching the seasonal strain. We believe it to be a good match for the 2020 year.
What safety checks does the COVID vaccine have to pass before it can be used?
As the different variants of the COVID vaccine are being rolled out, they will be in rigorous trials. Once the trials have passed through the relevant stages, the regulator gives approval for the vaccine.
In the UK, the regulator is the MHRA. The Pfizer vaccine was approved by the MHRA a few weeks ago and has just received emergency approval from the FDA (American regulator).
Even after the vaccine receives approvals, safety checks are still carried out and any effects are reported and reviewed.
Who decides who receives the vaccine?
The joint committee on vaccination and immunisation has independent experts who decide how the vaccine programme is rolled out.
mRNA Vaccines (Pfizer/Moderna)
Both the Pfizer and Moderna jabs use technology known as mRNA, which introduces into the body a messenger sequence that contains the genetic instructions for the vaccinated person’s own cells to produce the antigens and generate an immune response.
It does not alter human cells but merely presents the body with instructions to build immunity to Coronavirus. These are new, but not completely new, as they have been used in oncology and other clinical settings.
Concerned by the speed of the COVID-19 vaccine development?
With most vaccine development, it takes a long time to study and get the evidence as the infection pool is so small. With COVID-19, there was a huge infection pool, so we have been able to study the numbers needed in a small period of time.
The mRNA vaccines have been tested on up to 40,000 individuals, so they have been tested on the same number of individuals as any other previous vaccine in circulation. We know these vaccines are not causing severe adverse effects at this scale. Acute side effects are common, like being feverish next day or having a sore arm, but this is a strong signal that they are giving the immune system a kick and reassures you that your body is mounting a good immune response.
We know the first two vaccines prevent people from becoming unwell with COVID-19 and prevent serious illness. However, we don’t data have to see if they block transmission at present. As private doctors, we know that the risk of having serious consequences from getting COVID-19 – even if you’re not in a vulnerable category – is significantly higher than the risk of suffering mild side effects from the mRNA vaccines.
There have been some concerns raised that the mRNA vaccines may influence your chromosomes, but this is a myth; they are particularly safe as don’t penetrate the nucleus of cells. Plus, they are cleared from the system within 72 hours. There is therefore no link to mRNA vaccines and genetic modification.
The Pfizer vaccine has passed rigorous safety checks and, very recently, we received the welcomed news it has also passed emergency FDA approval so it will be rolled out in the United States.
The MHRA are continuing to monitor for side-effects, but only 2 people out of the thousands who received the vaccination in the first week developed allergic reactions.
Therefore, the advice has changed so that people with previous severe allergic reactions are unable to receive the Pfizer vaccine and the situation is being monitored.
AstraZeneca/Oxford Vaccination
The Oxford vaccine works like a traditional vaccination, more like the attenuated vaccines already discussed. It uses a harmless virus altered to look a lot more like the pandemic virus. An attenuated ‘spike protein’ of the virus is injected which the immune system builds up a response to as if the real virus has entered the body. Therefore, if you then come into contact with COVID-19, the body’s immune system will recognise this ‘spike protein’ and raise the immune response.
Two full doses of the Oxford vaccine gave 62% protection, a half dose followed by a full dose was 90% and overall, the trial showed 70% protection.
Should I have the vaccine if I have had COVID?
Yes, is the short answer. The current recommendation would be to have the vaccine if offered, even if you have had a proven COVID-19 infection.
