Covid-19
Understanding the facts
Science behind the Vaccine
According to the NHS.UK the most common symptoms reported throughout your body are tiredness, headaches, muscle pain, chills, fever, nausea while at the site of injection, you might experience pain, redness and swelling. https://www.nhs.uk/conditions/coronavirus-covid-19/coronavirus-vaccination/coronavirus-vaccine/
People suffering of asthma and are actively treated with biologics (monoclonal antibodies) should discuss vaccine therapy with their clinician.[4] https://www.asthma.org.uk/advice/resources/helpline/
Similarly, people undertaking blood thinning therapy (warfarin) as a result of pulmonary embolism should be monitoring the thickness of their blood while having the vaccine.[4]
The possibility of a vaccine enhancing the risk of immune-mediated pathology rather than inducing antibodies that neutralises the virus should be taken in consideration. Such side-effects have been reported from other coronaviruses, SARS and MERS, but not in Covid-19 patients.[4] Severe adverse events have been linked to the adenovirus vaccines, AstraZeneca and Johnson&Johnson/Janssen, rare thrombocytopenia (low levels of platelets and can affect the coagulation of blood) and atypical blood clots side effects were reported. These instances may have not been detected during clinical trials but can be life-threatening if comorbidities and age-related illnesses (e.g, Diabetes Mellitus, heart diseases) are present. However, this is an unconfirmed theory and more research is underway, but it could potentially be linked to the production of autoantibodies which have been detected in some patients and, therefore, requires close monitoring.[4] Media report on these rare cases has caused vaccine hesitancy
What are the main side effects observed across vaccines?
Side
What is the vaccine and why do they work?
What is efficacy?
According to the data obtained from various literature , we can say that overall, the Pfizer vaccines, Oxford AstraZeneca and Moderna vaccines all provide the highest percentage of protection when tested amongst individuals present in their clinical trials.
What must be considered, therefore is what has been previously mentioned about why certain countries may have access vaccines compared to others. Therefore, we don’t want to dissuade anyone from taking a particular vaccine because they all provide a very good level of protection when observing the data trends objectively.
Furthermore, the type of vaccine may also dictate the number of doses received. The Moderna and Pfizer vaccines employ the mRNA-based therapy and the number of mRNA vaccines that can be produced is a curious subject. mRNA-based vaccine development is still a relatively new process and therefore the number of scientists that have expertise in this therapy form is still rather limited. Most recent literature on the topic of such vaccines stems from 2017-2018 and alongside the use of existing RNA knowledge from the past 10-15 years, a greater focus upon the RNA molecules has brought about recent breakthroughs in RNA-based therapies. The Johnson & Johnson/Jessen vaccine employs an adenovirus vector vaccine, which uses a modified, non-infectious virus as an antigen delivery vector. This style of vaccine and component introduction into the human body is a much more established therapy. A single dose is required for this particular Johnson & Johnson vaccine.
Efficacy of a vaccine is the percentage reduction of a disease of those who received the vaccine versus those who did not (placebo group) in a clinical trial which has more ideal settings and different studies are conducted using different groups of people for example they might not include children or older people
What is the difference between efficacy and effectiveness?
Effectiveness is a measure of how the vaccine reduces rates of disease in the community/real world rather than within the constraints of a lab setting in clinical trials
Effectiveness may differ from efficacy due to factors such as underlying health conditions and .. may vary between different virus mutations (which are common)
How did we make the vaccines available so fast?
This genomic and protein similarities between SARS-CoV-2 the causative viruses of previous epidemics such as SARS-CoV and MERS-CoV proved to be of importance in the creation of the “prototype” vaccine in previous epidemics, therefore driving vaccine innovation to create the first messenger RNA (mRNA) vaccine by Pfizer/BioNtech and Moderna pharmaceutical companies.[4]
The mRNA code is encased in fat droplets and hijacks our cells into synthesizing the spike protein (S), trigger T cells to mount a response to fight the infection and ultimately to make antibodies.[4] The attenuated adenovirus-vectored vaccines, such as Oxford AstraZeneca and Johnson&Johnson/Janssen, works similarly, by expressing and displaying the spike protein on the cells surface from an adenovirus vector platform.[3,4] The immune cells will recognise that is “foreign”, therefore, will trigger an immune response, fight off the infection and produce antibodies.[3,4] This pre-existing understanding about SARS, MERS and their genomic similarities, allowed scientists to shorten the usual time frames expected in conventional vaccine development.
What is herd immunity? and how does it work?
Herd Immunity is a term used to explain the way in which individuals are protected from a particular disease as a result of being part of a population that has exhibited immunity to the disease. It is therefore a term used often when referring to vaccination programmes as the greater a proportion of a population is vaccinated, the higher the ability of a population to indirectly protect individuals from infection. However, in order to herd immunity to be achieved, there has to be a particular threshold value has to be met, this refers to the number of people within the population that are immune in comparison to the number of individuals that could get the infection. When the number of those that could be infected declines to a value lower than the threshold for transmission, then herd immunity has been achieved.
A way to envisage this is as follows…
If you walk into a room and two out of 10 people have been vaccinated and are immune to a disease present in just that room, the remaining 8 are not immune and can pass on the infection after being infected themselves. These 8 are not able to reduce transmission as they have not built-up immunity themselves. Now if this room dynamic changes and 5 more people become vaccinated, now suddenly 7/10 are immune and 3/10 are not, the number of people that can break up the chain of infection is much larger than the number of people that could give you the infection. This increases the overall immunity of the population in that room and reduces the unimmunised proportion of that same population. On a much larger scale, this describes the basics of how Herd Immunity works.
In the context of the COVID-19 vaccination programme in the UK, we can see that children aren’t being vaccinated, but the rest of the population is. Children become the unimmunised proportion of the population; a much smaller proportion of the population compared those immunised. This means that children are protected through the principle of herd immunity as the rest of the population is able to contribute to the reduction in transmission of COVID-19.