More than 60% of the world’s population – 4.8 billion people – have received at least one dose of the coronavirus vaccine.
Various approved types and brands are available, all of which have undergone rigorous testing and safety assessments.
Safety trials begin in the laboratory with testing and research in cells and animals before moving on to human studies.
The principle is to start small and only move on to the next level of testing if there are no outstanding security concerns.
- When will I get a coronavirus vaccine?
If the safety data from the labs is good, scientists can check the vaccine or treatment for effectiveness.
That means testing on a large number of volunteers – around 40,000 in the case of Pfizer-BioNTech, the first to be approved in the UK.
Half will receive the vaccine and the other half will receive a placebo shot. Researchers and participants are told which group belongs to which group only after the results, to avoid bias.
All work and findings are independently checked and verified.
The Covid vaccine trials have been going at breakneck speed, but they haven’t skipped a step – they’ve been able to move faster because so many people were involved and other projects were pushed aside.
Approval is only granted when regulators are satisfied that a vaccine is safe and effective.
After approval, further checks are carried out to determine whether there are any other side effects or long-term risks.
In the UK, independent experts from the Joint Committee on Vaccination and Immunization decide how best to use a vaccine and who should receive it once it has been approved by the Medicines and Healthcare Products Regulatory Agency.
Scientists hope to tweak coronavirus vaccines to ensure they continue to provide high levels of protection as new variants of the disease emerge.
The UK Medicines Agency says new vaccines can be approved quickly if needed.
No corners are cut, with safety in the first place.
However, lengthy clinical trials involving thousands of volunteers are not required.
Instead, data from existing studies and ongoing use in practice could be used.
Pfizer-BioNTech’s (and Moderna’s) vaccine uses parts of the genetic code to trigger an immune response. These are called mRNA vaccines.
They don’t alter human cells, they just give the body instructions on how to build up immunity to Covid.
The Oxford-AstraZeneca vaccine uses a harmless virus that has been modified to look much more like the pandemic virus.
Vaccines sometimes contain other ingredients, such as aluminum, that make the vaccine more stable or more effective.
Vaccines don’t give you disease. Instead, they teach your body’s immune system to recognize and fight the infection they are designed to protect against.
Some people experience mild to moderate symptoms after vaccination. This is not the disease itself, but the body’s response to the vaccine.
Common reactions, which may affect more than 1 in 10 people and usually get better within days, are chills, tiredness and sore muscles.
It is rare for health problems that occur after vaccination to actually be caused by the vaccination itself. Events can be random and unrelated to vaccination.
The Oxford-AstraZeneca vaccine has been linked to very rare cases of blood clots. This is not proof that the vaccine is to blame. Also, having a Covid infection itself can make blood clots more likely, and they can also occur naturally.
The likelihood of this happening to an individual is still extremely slim but as a precaution alternative Covid vaccines have been offered to younger age groups in the UK.
Allergic reactions to vaccinations are rare. The ingredients are listed for each approved vaccine.
A very small number of people given the Pfizer-BioNTech vaccine have experienced serious but treatable allergic reactions.
As a precaution, the MHRA says that people with a history of significant allergic reactions to any ingredient in this vaccine should not receive this vaccine at this time.
Be aware that anti-vaccination stories are spreading online through social media. These posts are not based on scientific advice (or mixing fact with misinformation).
People will still be offered the vaccine even if they have had Covid in the past.
This is because natural immunity may not last long and vaccination could offer more protection.
The guidance says there are also no safety concerns about giving vaccinations to people with ‘long’ Covid. But people who are currently sick with Covid-19 should not receive the vaccine until they have recovered.
Some vaccines, such as the shingles vaccine and childhood nasal flu vaccine, may contain porcine gelatin.
Pfizer, Moderna and AstraZeneca’s Covid vaccines do not contain this or any other animal products.
The British Islamic Medical Association says there is negligible alcohol in it – no more than, say, bread.
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